Geometrical and Mechanical Properties of the Fractures and ... · brittle deformation zones,...

POSIVA OY

FI-27160 OLKILUOTO, FINLAND

Tel +358-2-8372 31

Fax +358-2-8372 3709

Hanna Mönkkönen

Tuomas Rantanen

Harri Kuula

May 2012

Working Report 2012-23

Geometrical and Mechanical Properties of theFractures and Brittle Deformation Zones Based

on the ONKALO Tunnel Mapping,2400 – 4390 m Tunnel Chainage

May 2012

Working Reports contain information on work in progress

or pending completion.

Hanna Mönkkönen

Tuomas Rantanen

Harri Kuula

WSP Finland Oy

Working Report 2012-23

Geometrical and Mechanical Properties of theFractures and Brittle Deformation Zones Based

on the ONKALO Tunnel Mapping,2400 – 4390 m Tunnel Chainage

GEOMETRICAL AND MECHANICAL PROPERTIES OF THE FRACTURES AND BRITTLE DEFORMATION ZONES, 2400 – 4390 M TUNNEL CHAINAGE

ABSTRACT

In this report, the rock mechanics parameters of fractures and brittle deformation zones have been estimated in the vicinity of the ONKALO area at the Olkiluoto site, western Finland. This report is an extension of the previously published report: Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0–2400 m tunnel chainage (Kuula 2010). In this updated report, mapping data are from 2400–4390 m tunnel chainage.

Defined rock mechanics parameters of the fractures are associated with the rock engineering classification quality index, Q , which incorporates the RQD, Jn, Jr and Ja values. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers. There are no new data from laboratory joint shear and normal tests.

The fracture wall compressive strength (JCS) data are available from the chainage range 1280–2400 m.

Estimation of the mechanics properties of the 24 brittle deformation zones (BDZ) is based on the mapped Q value, which is transformed to the GSI value in order to estimate strength and deformability properties. A component of the mapped Q values is from the ONKALO and another component is from the drill cores. In this study, 24 BDZs have been parameterized. The location and size of the brittle deformation are based on the latest interpretation (Aaltonen et al. 2010). New data for intact rock strength of the brittle deformation zones are not available.

Keywords: Nuclear waste disposal, Olkiluoto, ONKALO, rock mechanics, fracture, brittle deformation zones, mechanical properties, Q-mapping.

ONKALON AJOTUNNELIN PAALUVÄLILTÄ 2400–4390 m MÄÄRITETYT RAKOJEN JA RAKOVYÖHYKKEIDEN KALLIOMEKAANISET OMINAISUUDET

TIIVISTELMÄ

Tässä raportissa on esitetty kallion rakojen ja hauraiden deformaatiovyöhykkeiden kalliomekaanisten parametrien määritys Olkiluodon alueella ONKALOn läheisyydessä

Raportti on laajennus aiemmin julkaistusta raportista Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0-2400 m tunnel chainage (Kuula 2010). Tässä päivitetyssä raportissa on lähtöaineistona käytetty ONKALOn ajotunnelin paaluvälin 2400 - 4390 m kalliolaatu-kartoitusta.

Raportissa esitettyjen kalliorakojen parametrien määritys (RQD, Jn, Jr ja Ja) perustuu pääosin Q-luokituksella määritettyyn kalliolaatuun. Rakopintojen kitkakulma on määritetty luokituksen Jr ja Ja lukujen avulla. Rakopintojen puristuslujuus (JCS) on määritetty paaluväliltä 1280 – 2400 m. Uutta aineistoa rakojen laboratoriotestauksista ei ollut käytettävissä.

Kahdenkymmenenneljän (24) hauraan deformaatiovyöhykkeiden (BDZ) mekaaniset ominaisuudet on määritetty myös Q-luokituksen avulla. Q -luvun avulla on laskettu GSI-luku, josta on määritetty rakovyöhykkeen lujuus- ja muodonmuutosominaisuudet. Lähtöaineistona on käytetty sekä tunnelikartoituksessa että kairasydänkartoituksessa määritettyjä Q -arvoja. Deformaatiovyöhykkeiden geometria perustuu viimeisimpään tulkintaan (Aaltonen et al. 2010). Uutta aineistoa kiven lujuudesta hauraiden defor-maationvyöhykkeiden kohdalla ei ollut käytettävissä.

Avainsanat: Ydinjätteen loppusijoitus, Olkiluoto, ONKALO, kalliomekaniikka, hauras deformaatiovyöhyke, rakovyöhyke, rakoilu, mekaaniset ominaisuudet, Q-luokitus.

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TABLE OF CONTENTS

ABSTRACT TIIVISTELMÄ 1 INTRODUCTION .................................................................................................... 3 2 GEOMETRICAL PROPERTIES OF FRACTURES ................................................. 5

2.1 Major fracture sets from tunnel mapping data ................................................ 5 2.1.1 Major fracture sets in chainage 0-2400 m ............................................... 6 2.1.2 Major fracture sets in chainage 2400–4390 m ........................................ 8

2.2 Number of fracture sets, Jn value ................................................................. 12 2.3 Fracture intensity, RQD value ....................................................................... 15 2.4 Fracture length and end type ........................................................................ 19

3 MECHANICAL PROPERTIES OF FRACTURES ................................................. 23

3.1 Fracture surface parameters, Jr and Ja values............................................. 23 3.2 Fracture friction angle ................................................................................... 26 3.3 Fracture undulation ....................................................................................... 27 3.4 Summary of fracture mechanical properties ................................................. 28

4 BRITTLE DEFORMATION ZONES ...................................................................... 31

4.1 Location of brittle deformation zone intersections ......................................... 31 4.2 Estimation of strength and deformability properties ...................................... 33 4.3 Strength of the intact rock ............................................................................. 38 4.4 Strength and deformability properties of brittle deformation zones ............... 38

5 CONCLUSIONS AND RECOMMENDATIONS ..................................................... 43 REFERENCES ............................................................................................................. 47 APPENDICES ............................................................................................................... 49

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1 INTRODUCTION

To characterize the Olkiluoto rock mass for the purpose of hosting a radioactive waste repository in western Finland, it is necessary to have a rock mechanics model in order to be able to predict the consequences of various repository design options, including the repository depth and deposition tunnel orientations. If the rock stresses are too high, due to the repository being located at too great a depth, damage or even spalling could occur in the deposition tunnels and emplacement boreholes. If the tunnels intersect the fracture zones or are situated close to such zones, heavier rock support is required for the tunnels. If there are fractures forming rock blocks, there could be block fallout from the tunnel roof or wall. The extent to which these problems might occur is a function of the stress state, the intact rock properties and fracture/fracture zone properties, and the location and orientation of the excavations.

In this report, the rock mechanics parameters of fractures and brittle deformation zones in the vicinity of the ONKALO area have been estimated. This report is an extension of the previously published report: Geometrical and Mechanical properties if the fractures and brittle deformation zones based on ONKALO tunnel mapping, 0–2400 m tunnel chainage (Kuula 2010). In this updated report, new mapping data are from 2400–4390 m tunnel chainage.

The term ‘fracture’ refers to a discontinuity in the rock mass which can have been caused by tensile or shear stress. The brittle deformation zones are the major zones of fracturing characterized by a large geometrical extent and much greater width than in individual fractures. The results are used in various rock mechanics analyses: such as key block analyses for rock support design, to estimate the excavation response in the discontinuous rock mass, repository scale thermo-mechanical analyses, and in large scale stress-geology interaction analyses (see e.g. Valli et al. 2011).

According to Hudson et al. (2008), there are six different methods to estimate the mechanical properties of brittle deformation zones. The one used in this report, is based on rock mass classification. Other methods involve direct and indirect measurements, analytical formulae based on knowing the properties of individual fracture components, numerical modelling and back analysis.

In this report, the rock mechanics parameters of the fractures are mainly associated with the Rock Tunnelling Quality index, Q (Barton et al. 1974) including RQD value, Jn, Jr and Ja number. The friction angle of the fracture surfaces is estimated from the Jr and Ja numbers.

Estimation of the mechanical properties of the brittle deformation zones is based on the mapped Q value which is transformed to the GSI value in order to estimate strength and deformability properties.

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2 GEOMETRICAL PROPERTIES OF FRACTURES

The mapping in the ONKALO access tunnel is achieved in two stages: first round mapping; and then systematic mapping. The mapping procedure is described in detail in Engström & Kemppainen (2008).

The data from the both mapping stages (round mapping and systematic mapping) are used in this report to study the geometrical properties of fractures.

For this report, the mapping data from the ONKALO access tunnel are available from chainage 0–4390 m, corresponding to an approximate depth range from +3 m to -420 m.

Fracture mapping data from the ONKALO area drillholes and tunnel pilot holes are also available, but these data do not include fracture length and waviness values. Core logging data have also more uncertainties compared to tunnel mapping and for these reasons are not used to evaluate geometrical properties of the fractures.

2.1 Major fracture sets from tunnel mapping data

The tunnel chainage with available data is divided into four sections in order to track possible variation of fracture properties and orientations as a function of depth. The locations of these sections, as well as their approximate depth coverage, are presented in analysed tunnel sections (Figure 2-1). The section division is made in a way that preserves comparability with the previous report by Kuula (2010).

The major fracture sets for the first 2400 m tunnel chainage were interpreted and the related data analysed by Kuula (2010), covering the Sections 1 and 2 (Figure 2-1). The results concerning major fracture sets from that report are briefly summarized in Chapter 2.1.1.

The chainage range 2400–4390 m is analysed in this report (sections 3 and 4, Figure 2-1). The major fracture sets used for this chainage range are from Nordbäck (2010). The distribution of interpreted major fracture sets is presented in similar manner as in Kuula (2010). Note that the length of the section 4 is only 790 m due to data availability at the time of writing this report.

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Figure 2-1. Analysed tunnel sections.

2.1.1 Major fracture sets in chainage 0-2400 m

Four major fracture sets have been interpreted for the first 2400 m chainage from the systematic mapping data (Engström & Kemppainen 2008) and are presented in Table 2-1 and in Figure 2-2.

Table 2-1. Major fracture sets for chainage 0-2400 m.

Major fracture set Mean dip Mean dip direction Set 1 08° 065° Set 2 89° 081° Set 3 85° 359° Set 4 32° 135°

The dominant fracture set (Set 1) is almost horizontal, dipping to the NE. The second fracture set is nearly vertical, striking in a N-S orientation. The third fracture set is also sub-vertical and perpendicular to the second set. The fourth set is parallel with the foliation, dipping around 32º to the SE (Figure 2-2).

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Figure 2-2. Fracture pole concentration contours for all mapped tunnel fractures and interpreted set windows (lower hemisphere plot) (Engström & Kemppainen 2008).

In the round mapping stage, analysis of the major fracture sets is normally carried out for each 5 m long tunnel section. If the number of accepted fractures is too low to allow an interpretation of the major fracture sets, then the neighbouring five meter sections are incorporated. Note that this method is used only to determine fracture sets; other fracture parameters are not affected.

The fracture sets presented in Figure 2-2 are compared against the distribution of the fracture sets defined in the round mapping stage. The previously interpreted fracture sets have been enlarged to obtain a better adjustment (see Figure 2-3).

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Figure 2-3. Fracture pole concentration contours for all fracture sets interpreted in round logging phase and the interpreted set windows (lower hemisphere plot) (Kuula H. 2010).

2.1.2 Major fracture sets in chainage 2400–4390 m

The major fracture sets used in this report for the 2400–4390 m chainage are from Nordbäck (2010). These sets were originally interpreted from data from chainage range 1980–3116 meters. These sets however correspond also quite well with the chainage range 2400–4390 meters. This is demonstrated in Figure 2-4.

The fracture sets for 2400–4390 m chainage are named A, B and C, to clearly distinguish them from the numbered fracture sets interpreted for 0–2400 m chainage (sets 1, 2, 3 and 4). The motivation to have different fracture sets is quite obvious when comparing fracture distributions from these chainage ranges (Figure 2-3, Figure 2-4). The fracture distribution clearly has some variation with depth, and for this reason it is not sensible to use same fracture sets for the whole 0–4390 m chainage.

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Figure 2-4. The interpreted major fracture sets from Nordbäck (2010) and contours of all the fractures from chainage 2400–4390 m.

Figure 2-5. The interpreted fracture sets from the round mapping and the set windows from Nordbäck (2010). Data from the chainage 2400–4390 m.

Table 2-2. Major fracture sets for chainage 2400–4390 m.

Major fracture set Mean dip Mean dip direction Set A 90° 084° Set B 05° 043° Set C 89° 338°

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The distribution of the major fracture sets in the length of the tunnel is studied by comparing the fracture sets defined in the round logging phase with the major fracture set windows (Figure 2-5). Every 5 m section of the access tunnel is analysed and, if a logged fracture set in a tunnel section lies within one of the three set windows (Set A, B or C), a 5 m long section is considered as containing that set. If a logged fracture set does not belong to any of the three sets, it is classified as belonging to the group “others”. If a tunnel section does not contain any of the previously mentioned groups, it means that the section does not contain mapped fracture sets. To summarise, a 5 m long tunnel section can therefore contain from none to up to four different group assignments.

From chainage 2400 m to 3240 m the mean poles of the fracture sets from the round mapping phase fall quite well into defined prominent fracture sets. After about 3200 m, there seems to be an increase in the number of fracture sets not belonging to any of the three sets, A, B or C. This might be due to fact that the prominent fracture sets from Nordbäck (2010) were interpreted from the data from chainage range 1980-3116 m and the data after 3116 m have not had an effect on the interpreted set windows. The vertical set A is most frequently observed in chainage ranges 2480–2760 m and 3780–4050 m. It is also noted that this fracture set becomes more common with increasing chainage values.

The sub-horizontal fracture set B is not commonly observed before chainage 3000 m, but is regularly observed from there on. One notable area of occurrence is between chainages 3120 m and 3320 m, where gently-dipping brittle fracture zones OL-BFZ20a and OL-BFZ20b intersect the tunnel. This is clearly seen in Figure 5 38 and Figure 5 39 and this fracturing is also noted in the DFN model as omitted fracture set DZ-SH (see Section 4.10). From this it can be expected that the brittle fracture zones might also have an influence on the dip and dip direction of fracturing in other parts of the tunnel. This influence can, however, be very difficult to notice and is also in most cases insignificant.

The third fracture set, set C, is not common. It is mostly observed in chainage range 2460–2700 m, and after that only occasionally.

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Figure 2-6. Main fracture directions for the ONKALO chainage 2400–3300 m.


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2.2 Number of fracture sets, Jn value

The Jn value in the Q system is based on the number of fracture sets, where a set is defined as sub-parallel fractures occurring systematically with a characteristic spacing (mean value); ‘random’ fractures are fractures that do not occur in this systematic manner. As is evident from Figure 2-6 to Figure 2-8, the number of fracture sets (as illustrated via the Jn value) varies with tunnel chainage. In terms of block fallout, the minimum number of faces that a block can have is four (a tetrahedral block); the tunnel periphery can form one face, so that a minimum of three fracture sets is then required for a rock block to be formed, indicated by the red lines in Figure 2-9 to Figure 2-12.

Over the first 300 m, the Jn median value is 6 (representing two joint sets plus a random set), which means that systematic or occasional rock blocks can be formed. From chainage 300 m to about 1200 m, the Jn median value is 3 and, after chainage 1200 m, the Jn median drops to 1, although there are isolated instances of Jn=6 beyond 1060 m at 2475 m and around 3300 m. In either case, rock blocks cannot be formed, although it is potentially possible for adversely orientated and weakly bonded foliation to act as one or two additional block faces.

Table 2-3 shows statistical parameters of Jn value for the different tunnel sections. Note that the analysis has been carried out using all the data, i.e. brittle fracturing zone intersections have not been filtered out.

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Table 2-3. Basic statistics of Jn value in different tunnel sections.

Section

Parameter 1

(0-1200m) 2

(1200-2400m) 3

(2400-3600m) 4

(3600-4390m) All n 236 244 252 150 882

mean 4.47 1.35 1.92 2.23 2.50 median 4 1 2 2 2

max 9 4 6 4 9 min 1 0.5 0.5 0.5 0.5

25-% 3 0.5 0.5 1 1 75-% 6 2 3 3 3

0

1

2

3

4

5

6

7

8

9

10

11

12

0 75 147 220 290 348.2 425 505 585 659 735 820 900 976 1060 1145

Onkalo Chainage

Jn v

alue

Jn = 9, three joint sets Jn = 6, two joint sets + random Jn = 4, two joint sets Jn = 2, one joint set Jn = 0.5-1, massive no or few joints

Figure 2-9. Histogram of logged Jn values in the ONKALO tunnel chainage 0–1200 m. Block fall-out due to fractures can only occur when three or more fracture sets are present, i.e. above the red line in the histogram.

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0

1

2

3

4

5

6

7

8

9

10

11

12

1200 1280 1355 1435 1510 1585 1660 1735 1810 1885 1965 2040 2115 2189 2255 2324 2380

Onkalo Chainage

Jn v

alue

Jn = 9, three joint sets Jn = 6, two joint sets + random Jn = 4, two joint sets Jn = 2, one joint set Jn = 0.5-1, massive no or few joints


0

1

2

3

4

5

6

7

8

9

10

11

12

2400 2475 2530 2605 2670.6 2735 2800 2895 2965 3040 3115.5 3180 3260 3330 3390 3465 3540

Onkalo Chainage

Jn v

alue

Jn = 9, three joint sets Jn = 6, two joint sets + random Jn = 4, two joint sets Jn = 2, one joint set Jn = 0.5-1, massive; no or few joints


15

0

1

2

3

4

5

6

7

8

9

10

11

12

3600 3675 3760 3835 3915 3995 4070 4150 4225 4305

Onkalo Chainage

Jn v

alue

Jn = 9, three joint sets Jn = 6, two joint sets + random Jn = 4, two joint sets Jn = 2, one joint set Jn = 0.5-1, massive; no or few joints


2.3 Fracture intensity, RQD value

The Rock Quality Designation index (RQD) was developed by Deere (Deere et al. 1967) to provide a quantitative estimate of rock mass quality from drill core logs. RQD is defined as the percentage of intact core pieces longer than 100 mm in the length of core being considered. When no core is available but discontinuity traces are visible in surface exposures or exploration adits, the RQD may be estimated from the number of discontinuities per unit volume (Palmström1982). The suggested relationship for clay-free rock masses is:

RQD = 115 - 3.3 Jv (1)

where Jv is the sum of the number of joints per unit length for all joint (discontinuity) sets known as the volumetric joint count.

The first quotient (RQD/Jn) of the rock tunnelling quality index (Q = RQD/Jn · Jr/Ja · Jw/SRF) represents the structure of the rock mass. It is a crude measure of the block or particle size, with the two extreme values (100/0.5 and 10/20) differing by a factor of 400. If the quotient is interpreted in units of centimetres, the extreme 'particle sizes' of 200 to 0.5 cm are seen to be crude but fairly realistic approximations. Probably the largest blocks will be several times this size and the smallest fragments less than half the size (Hoek 2007).

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The ONKALO tunnel RQD values have been estimated by 1 m long scanlines for each 5 m long tunnel section. For this report, RQD data is available up to chainage 4390 m. The mean RQD value in the ONKALO tunnel from chainage 0 to 4390 m is 97 %. From chainage 1200 m, the fracture intensity starts to decrease and the mean RQD value in the chainage range 1200–4390 m is 98.4 % compared to the mean value in the chainage range 0–1200 m of 94 % (Figure 2-13).

The minimum RQD value is 10 % at chainage 2327 m. The width of this zone is 0.2 m. This zone intersection (Zone ID ONK-BFI-232700-232810) is compiled of core with TCF (Tunnel Crossing Fracture) fracture and small damage zone on both sides of the core. A horizontal fracture set crosscut through the zone intersection. The intersection is crosscutting another zone intersection (ONK-BFI-232400-232550) in the roof.

At chainage 2481 m, the RQD value is 30% and the width of the zone is 0.3 m. This is the place where brittle deformation zone OL-BFZ100 intersects the ONKALO tunnel. The same zone intersects the tunnel also in the chainage 900-910 m, where the RQD value is about 70 %.

A significant width of high fracture intensity area can be found from chainage 285 m to 295 m where the RQD value is 50%. Chainage 292–295 m contains a BFI (Brittle Fault zone Intersection), which comprises several moderately dipping filled fractures.

Another low value section, 55 % < RQD < 65 %, exists from chainage 260 m to 274 m, where the Brittle Fault zone Intersection (ONK-BFI-24250-28700) is composed of a single sub-horizontal fracture. This fracture has a trace length of approximately 50 m and it was visible on both walls. The clay-filled fracture is surrounded by a 40 cm wide zone of soft and weathered rock in the latter part (chainage 280–285 m) of the intersection.

The Brittle Fault zone Intersection ONK-BFI-48830-48900 in the chainage 495–510 m is composed of a single slickenside fracture with a visible trace length of ca. 70 m, reaching the tunnel roof at chainage 513 m. In places this fracture branches to several fractures with the same directions as the main.

The significant drop in RQD value around chainage 3300 m is caused by the intersection of OL-BFZ020a and OL-BFZ020b.

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0

10

20

30

40

50

60

70

80

90

100

0 250 500 750 1000 1250 1500 1750 2000 2250 2500 2750 3000 3250 3500 3750 4000 4250

RQ

D v

alue

Tunnel chainage (m)

RQD value

RQD value (30 period moving average)

Figure 2-13. Logged RQD values for the ONKALO chainage range 0-4000 m.

The drillhole RQD data were recorded for 1 m long sections. The median values for the depth ranges 0…-120 m and -120…-250 were calculated for the deep drillholes (drillholes which extend at least to the level z = -250). The average RQD values of these median values are 96.6 % between 0…-120 m and 99 % between -120…250 m (Figure 2-14).

75

80

85

90

95

100

105

OL-

KR

2

OL-

KR

5

OL-

KR

12

OL-

KR

13

OL-

KR

19

OL-

KR

22

OL-

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24

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OL-

KR

48

OL-

KR

40

OL-

KR

1

OL-

KR

3

OL-

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OL-

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OL-

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OL-

KR

23

OL-

KR

27

OL-

KR

28

OL-

KR

29

OL-

KR

33

OL-

KR

37

OL-

KR

38

OL-

KR

39

RQ

D [%

]

z1 = 0…-120 m

z2 = -120 m….-250 m

Domain A Domain B

Figure 2-14. Median values of the RQD (% values) recorded over one meter sections for different drillholes.

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Drillholes in Figure 2-14 are arranged into two spatial domains containing the drillholes with median RQD-values under 97 %. These domains are presented in Figure 2-15. A single outlier, OL-KR40, is plotted immediately adjacent to drillholes assigned to domains A and B.

Figure 2-15. Locations of drillholes included in the RQD-value study. The drillholes with median RQD-value lower than 97 % are marked with red colour.

The need to calculate the RQD median value separately for two depth ranges is clearly illustrated in Figure 2-16, which is an example of the variation of RQD value in a drillhole. It can be seen how the rock quality changes with increasing depth, making it necessary to separate the more fractured surface region from the rest of the drillhole data in order to obtain a more realistic estimation of the RQD value.

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-450

-400

-350

-300

-250

-200

-150

-100

-50

0

0 10 20 30 40 50 60 70 80 90 100 110RQD-%

Depth

RQD

Median 0-120m

Median 120-250m

OL-BFZ106

High density fracturing

OL-BFZ019c

OL-BFZ100OL-BFZ122OL-BFZ129

OL-BFZ020aOL-BFZ020b

OL-BFZ019a

Figure 2-16. Variation of RQD-value with depth in the drillhole OL-KR22.

2.4 Fracture length and end type

The fracture length data distributions are both truncated and censored: truncation occurs when fractures below a certain length are ignored; censoring occurs when fracture trace lengths above a certain length cannot be observed in their entirety because of the limited dimensions of the excavation. For all fractures, both their length and end-type are mapped — a fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C).

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The distribution of fracture end data is quite similar for all the sections. Most of the short fractures end in the rock and the long fractures continue beyond the tunnel (Figure 2-17). The distribution seems to become more uniform with increasing depth. Note that the end-type has no correlation with the fracture set.

RR RJ RC CC JJ JC< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

20 m, n=47

Percentile

Fracture end type (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%


< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

20 m, n=30


Fracture length


< 1 m, n=2207

< 2 m, n=2269

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%


< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=289

20 m, n=25


Fracture length

Figure 2-17. Trace length and end-type for all mapped fractures in the ONKALO tunnel. For the x-axis, the fracture can end in intact rock (R), at another fracture (J), or continue beyond the tunnel (C), with the two letters, e.g. RR indicating both ends of the fracture.

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In the first 2400 m chainage, the mean fracture length varies from 0.5 m to 1.5 m, depending on the major fracture set. The length of the moderately dipping fractures (Set 4) seems to be greater than the length of the vertical or random fractures, but this is partly caused by the orientation of the tunnel, which biases the data (Figure 2-18).

0 %

10 %

20 %

30 %

40 %

50 %

60 %

70 %

80 %

90 %

100 %

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0Fracture length (m)

Set 1, 08°/065°Set 2, 89°/081°Set 3, 85°/359°Set 4, 32°/135°Others

Figure 2-18. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the ONKALO tunnel, 0-2400 m chainage.

For the second half of the tunnel, 2400–4390 m chainage, the mean fracture length varies from 0.8 m to 1.2 m, depending on the major fracture set. In these deeper sections of the tunnel, the fracture length distribution of the moderately dipping set B is more similar compared to other sets (Figure 2-19).

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0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0

Fracture length (m)

Set A, 90°/084°

Set B, 05°/043°

Set C, 89°/338°

Others

Figure 2-19. Cumulative distribution of trace lengths for different fracture sets for all mapped fractures in the ONKALO tunnel, 2400-4390 m chainage.

23

3 MECHANICAL PROPERTIES OF FRACTURES

The second quotient (Jr/Ja) of the rock tunnelling quality index (Q = RQD/Jn · Jr/Ja · Jw/SRF) represents the roughness and frictional characteristics of the joint walls or filling materials. This quotient is weighted in favour of rough, unaltered joints in direct contact. It is to be expected that such surfaces may be close to the peak strength, will dilate strongly when sheared, and are therefore especially favourable for tunnel stability.

When rock joints have even thin clay mineral coatings and fillings, the strength is reduced significantly. However, rock wall contact after small shear displacements may be an important factor for preserving the excavation from ultimate failure. Where no rock wall contact exists, the conditions are extremely unfavourable to tunnel stability.

The 'friction angles' are a little below the residual strength values for most clays, and are possibly down-graded by the fact that these clay bands or fillings may tend to consolidate during shear, at least if normal consolidation or if softening and swelling has occurred (Hoek 2007).

3.1 Fracture surface parameters, Jr and Ja values

The fracture roughness number, Jr, can have values between 0.5 and 4: the lowest values are for planar slickensided fractures and the highest for discontinuous or rough and undulating fractures.

With increasing depth, the fractures become smoother and more planar, the mean Jr value drops from 3 to 1.5. This is probably due to more uniform stress direction and is discussed in detail in Mattila (2009). Only the amount of long slickensided fractures is decreasing with the depth. The mean amount of slickensided fractures is less than 10%, Figure 3-1.

The vertical N-S trending fracture set, Set 2, has more smooth and planar and fewer rough and undulating fractures than the other sets. The fracture end-type does not appear to correlate with roughness.

The Jr-value is also calculated from the drillhole data, which are edited to 1 m long composites. The median values from the depth ranges 0…-120 m and -120…-250 m were calculated for deep drillholes (drillholes which extend at least to level z = -250 m). The median value of Jr is commonly 3 and no correlation with depth can be observed.

24

0.5 1 1.5 2 3 4< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

20 m, n=47

Percentile

Jr value (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0.5 1 1.5 2 3 4< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

20 m, n=30


Fracture length

0.5 1 1.5 2 3 4< 0.5 m, n=2051

< 1 m, n=2207

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0.5 1 1.5 2 3 4< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

20 m, n=27


Fracture length

Figure 3-1. Distribution of joint fracture roughness number Jr over different fracture lengths for all mapped fractures in the ONKALO tunnel chainage 0–4390 m.

The fracture alteration number, Ja, can have values between 0.5 and 20. The lowest values are for tightly-healed and unaltered fractures, where the rock walls are in contact, and the highest for thick mineral-filled fractures.

The Ja value correlates with fracture length: the shortest fractures are more often unaltered or slightly altered (Ja is 1 or 2); whereas, the medium length and long fractures more often have softening or low friction clay mineral coatings (Ja = 4) or thin or thick mineral filling and can shear without rock wall contact (Ja 5).

25

For chainages 0–1200 m, the mean Ja value is about 4. For very short fractures (length 1 m or less), the mean Ja value is 1. In the deeper sections of the tunnel (chainages 1200–4390 m), fractures are less altered. The mean Ja value for fractures with lengths varying between 0–5 m is 1. For longer fractures (20 m), the Ja value varies mainly between 2 to 3 (Figure 3-2).

Compared to other fracture sets in the 0–2400 m chainage, set 4 has more altered fracture surfaces. The Ja value is also studied from drillhole data which were edited to 1 meter long composites and the median values for the depth ranges 0…-120 m and -120…-250 m were calculated for the deep drillholes (extended at least to z = -250 m). The median value of Ja is commonly 3 and no correlation with depth can be observed.

< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

20 m, n=47

0,75 1 2 3 4 5

Fracture length

Percentile

Ja value (chainage 0-1200)

90 %-100 %80 %-90 %70 %-80 %60 %-70 %50 %-60 %40 %-50 %30 %-40 %20 %-30 %10 %-20 %0 %-10 %

< 0,5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

20 m, n=30

0,75 1 2 3 4 5

Fracture length


< 0.5 m, n=2051

< 1 m, n=2208

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

20 m, n=36

0,75 1 2 3 4 5

Fracture length

Percentile


90 %-100 %80 %-90 %70 %-80 %60 %-70 %50 %-60 %40 %-50 %30 %-40 %20 %-30 %10 %-20 %0 %-10 %

< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

20 m, n=27

0,75 1 2 3 4 5

Fracture length


Figure 3-2. Distribution of joint alternation number Ja values over different fracture lengths for all mapped fractures in the ONKALO tunnel, chainage 0 –4390 m.

26

3.2 Fracture friction angle

Friction angles of the fracture surfaces can be estimated from the Jr and Ja numbers, being atan(Jr/Ja) (Figure 3-4). In the first section, chainage range from 0 to 1200 m, the friction angle is mainly between 30°– 40°, but distribution is quite uniform. In the second section of the tunnel (chainage 1200 to 2400 m), the friction angle increases for almost all fracture lengths, being mainly between 40°– 60°. As depth increases from 2400 to 4390 meters, the friction angle value sets to 50°– 60° for short fractures (<5 meters) and 20°– 30° for longer fractures.

In the Q logging, the fracture friction angle is determined using equation +i = atan (Jr/Ja). The i in this equation consists of a geometrical component and an asperity failure component. The value thus determined is the effective friction angle and is not directly comparable with the fracture friction angle determined in the laboratory. Some typical values for different joint types are presented in Figure 3-3 (Barton 2002).

Figure 3-3. Friction angles of different fracture types (Barton 2002)

27

0 - 10° 10 - 20° 20 - 30° 30 - 40° 40 - 50° 50 - 60° 60°< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

20 m, n=47

Percentile

Friction angle (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0 - 10° 10 - 20° 20 - 30° 30 - 40° 40 - 50° 50 - 60° 60°< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

20 m, n=30


Fracture length

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° >60°< 0.5 m, n=2051

< 1 m, n=2208

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=405

20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0-10° 10-20° 20-30° 30-40° 40-50° 50-60° >60°< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

20 m, n=27


Fracture length

Figure 3-4. Friction angle and fracture length for all mapped fractures in the ONKALO tunnel, chainage 0–4390 m.

3.3 Fracture undulation

Fracture undulation is defined via the amplitude of a 1 m long straight inspection line. For chainage 0–1200 m, the undulation is mainly 20–50 mm, with the value not changing in deeper parts of the tunnel (Figure 3-5). The shortest fractures are the most planar. The main change from section 1 to section 2 concerns the fractures with lengths in excess of 20 m, where the mean undulation increases from 0 mm to 20–50 mm. In the last two sections the undulation varies almost linearly from 0 mm (fractures < 1 m) to 20–25 mm (fractures > 20 m)

28

0 cm 0-2 cm 2-5 cm 5-10 cm 10 cm< 0.5 m, n=4285

< 1 m, n=4395

< 2 m, n=4000

< 3 m, n=1319

< 4 m, n=733

< 5 m, n=337

< 20 m, n=755

20 m, n=47

Percentile

Undulation (chainage 0-1200)

Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0 cm 0-2 cm 2-5 cm 5-10 cm 10 cm< 0.5 m, n=4558

< 1 m, n=2884

< 2 m, n=1827

< 3 m, n=611

< 4 m, n=258

< 5 m, n=116

< 20 m, n=276

20 m, n=30


Fracture length

0 cm 0-2 cm 2-5 cm 5-10 cm >10 cm< 0.5 m, n=2051

< 1 m, n=2208

< 2 m, n=2272

< 3 m, n=804

< 4 m, n=327

< 5 m, n=178

< 20 m, n=406

20 m, n=36

Percentile


Fracture length

90%-100%80%-90%70%-80%60%-70%50%-60%40%-50%30%-40%20%-30%10%-20%0%-10%

0 cm 0-2 cm 2-5 cm 5-10 cm >10 cm< 0.5 m, n=471

< 1 m, n=1721

< 2 m, n=1686

< 3 m, n=555

< 4 m, n=237

< 5 m, n=134

< 20 m, n=290

20 m, n=27


Fracture length

Figure 3-5. Fracture undulation and fracture length for all mapped fractures in the ONKALO tunnel, chainage 0–4390 m.

3.4 Summary of fracture mechanical properties

Since Site description report 2008 (Posiva 2009) no new fracture laboratory shear strength tests have been carried out.

The fracture wall compressive strength has been systematically mapped for the chainage range 1280-2935 m using the Schmidt hammer. Results from the study by Kuula (2010), shows that the measured values are close to the intact rock strength for coated fracture surfaces and about 65 % of the intact rock strength for filled fracture surfaces.

29

The friction angle and cohesion is calculated with Barton-Bandis failure criterion (Barton & Bandis 1990) and it is presented in (Kuula 2010). Because no new data are available, the Barton-Bandis fracture parameters have not been updated.

A summary of the mechanical fracture properties is presented in Table 3-1. The results are based on the Q-loggings and some laboratory tests.

Table 3-1 Summary of mechanical properties of fractures for chainage 2400 to 4390. Note that the data for chainage 0 to 2400 are included in SR2008 (Kuula 2010).

Joint properties from lab. testing All sets

Basic friction angle [º] (1 26.7 JCS0 (laboratory scale) [MPa] (2 115 JRC0 (laboratory scale) 5 L0 (laboratory scale) [m] (3 0.092 Ln (natural block size) [m] (4 1 Intact rock strength [MPa] (5 115 Estimated joint properties Set A Set B Set C

Mean Dip/Dip direction [°] 90/084 05/043 89/338 JRCn (natural block size) [-] (6 2.3-8 2.3-9 2.3-9 JCSn (natural block size) [MPa] 80 80 80 Normal stress n = 0- 2 MPa (7 Friction angle [º](8 28-32 28-32 28-32 Cohesion [MPa] 0.1-0.6 0.1-0.7 0.1-0.7 Normal stiffness [GPa/m] 200-300 200-300 200-300 Shear stiffness [GPa/m] 0.1-0.3 0.1-0.3 0.1-0.3 Design dilatation angle [º] 1.5-5.3 1.5-6.0 1.5-6.0 Normal stress n = 0- 10.6 MPa (9 Friction angle [º](8 28-32 28-32 28-32 Cohesion [MPa] 0.1-0.6 0.1-0.7 0.1-0.7 Normal stiffness [GPa/m] 2500-3000 2500-3000 2500-3000 Shear stiffness [GPa/m] 0-2 0-2 0-2 Design dilatation angle [º] 1.0-3.3 1.0-3.7 1.0-3.7 1) Average residual friction angle value from laboratory tests on smooth fractures. 2) 100% of intact rock strength. 3) Specimen size at laboratory 92 mm. 4) Natural block size was selected to be equal to the block size of JRC100 value. 5) Mean strength of intact rock specimen. 6) Median values from Q-logging between chainages 2400-4390 m. Fracture length < 5 m. In the calculations, these values were used as fixed input values. 7) Near tunnel perimeter low normal stresses are possible. 8) Effective friction angles at different chainages are discussed in Section “Fracture friction angle” 9) Mean vertical stress at 400 m depth is about 10.6 MPa.

31

4 BRITTLE DEFORMATION ZONES

4.1 Location of brittle deformation zone intersections

Estimation of the mechanical properties of the brittle deformation zones (BDZ, BFZ) is based on Olkiluoto area drillholes and the ONKALO tunnel mapping (Engström & Kemppainen 2008). In this report, 24 fracture zones have been analysed. The location and size of these zones are described in Aaltonen et al. (2010). Parameterisation of brittle fault zones has previously been made in 2009 and thus this study provides an update to the earlier interpretation (Kuula 2010).

Analysed brittle deformation zones have been selected based on their size and location and available data: a direct geological observation of deformation zone must exist i.e. the deformation zone must intersect a drillhole or the ONKALO access tunnel so that a parameter can be estimated. Analysed brittle deformation zones included all zones which are classified as site-scale brittle deformation zone and which fulfil the criterion of direct geological observation. Also, repository scaled zones which are included in stress modelling (Valli et al. 2011) are analysed. These are mainly shallow dipping zones which are located central or close to ONKALO and the repository. One of the main BDZ zones is OL-BFZ100 which intersects the tunnel in several places (Figure 4-1). All analysed zones are listed in Table 4-1.

Figure 4-1. Brittle deformation zone OL-BFZ100. Deformation zone is coloured based on interpreted rock quality, see the legend in the Figure.

32

As described in Aaltonen et al. (2010), in the modelling procedure for the deformation zones, each zone is checked and described via those drillholes that penetrate the zone being considered. The intersection points of zones are connected to each other using geophysical and hydrogeological information. From those points, a 3D plane (to the upper and lower boundary of the brittle deformation zone) is created using the Gemcom Surpac® software.

The typical ‘architecture’ is shown schematically in Figure 4-2. According to Aaltonen et al. (2010) the brittle deformation zone can be a joint zone or a joint cluster (BJI) when no clear sign of lateral movement is shown. When clear signs of lateral movement are shown, the zone is designated as a fault zone (BFI).

Figure 4-2. A conceptual model of a single fault zone, consisting of a complex branching fault core zone (indicated in black) and an equally complex zone of influence (whose outer margins are indicated by dashed lines), from Mattila et al. (2007).

33

Table 4-1. Summary of analysed brittle deformation zones.

Name of Brittle deformation zones

Intersects ONKALO tunnel at chainage 0 – 4325

Pre-core, core and post-core

mapped

Intersections in drillholes (number) Confidence Scale

OL-BFZ011 2 Low Repository OL-BFZ016 1 Low Repository OL-BFZ019a ONK-BFI-93190-96300 13 + 1 (OL-PH4) High Repository OL-BFZ-019c ONK-BFI-104500-110850 x 16 + 1 (OL-PH5) High Site scaleOL-BFZ020a ONK-BFI-3159 x 33 High Site scaleOL-BFZ020b 16 High Site scaleOL-BFZ021 13 High Site scaleOL-BFZ039 2 Low Repository

ONK-BFI-136480-136600ONK-BFI-223290-223450ONK-BFI-3350ONK-BFI-4377

OL-BFZ084 ONK-BFI-3540 x 4 +1 (OL-PH10) High Repository OL-BFZ099 17 High Site scale

ONK-BFI-12850-12930ONK-BFI-52150-52300ONK-BFI-90020-90640ONK-BFI-159290-159500 xONK-BFI-181900-183100 xONK-BFI-248150-248200 xONK-BFI-293150-293750 x

OL-BFZ101 ONK-BFI-6560-6575 1 (OL-PH1) High Repository OL-BFZ106 3 Medium Repository OL-BFZ118 ONK-BFI-71310-71805 1 (OL-PH3) High Repository OL-BFZ146 7 High Site scaleOL-BFZ152 2 Medium Site scaleOL-BFZ159 1 Medium Site scaleOL-BFZ160 1 Medium Site scaleOL-BFZ161 1 Medium Site scaleOL-BFZ175 5 High Site scaleOL-BFZ214 1 Medium Site scaleOL-BFZ219 1 Low Repository

OL-BFZ100 8 + 2 (OL-PH4) High Site scale

Repository

OL-BFZ045b x Low Repository

OL-BFZ043 x 1 High

4.2 Estimation of strength and deformability properties

Determinations of the strength and deformability properties were based on the rock mass classification technique. This technique has been described by Hudson et al. (2008). The strength and deformation properties of the brittle deformation zones were calculated based on the equations of the Hoek-Brown failure criterion (Hoek et al. 2002).

The rock mass quality for brittle deformation zones is determined using the GSI value. The GSI value is calculated from the Q´ value. Q is derived from the Tunnelling Quality Index Q (Barton et al. 1974):

SRFJw

JaJr

JnRQDQ (4-1)

, when parameters Jw and SRF are set to 1 Q = Q where

34

JaJr

JnRQDQ' (4-2)

The value of Q can be used to estimate the value of GSI:

44'ln9 QGSI (4-3)

With high Q values, the GSI values calculated from equation (4-3) give values over 100. In these cases, the GSI is reduced to the value 100.

Nine of the analysed brittle fault zones intersect the ONKALO tunnel in the 0–4325 m tunnel chainage range. From six of those zones, the pre core zones, core zones and post core zones (i.e. chainages less than the core zone, within the core zone and greater that the core zone, respectively) have been mapped (Figure 4-3). The procedure for geotechnical mapping in the ONKALO access tunnel is described in Engström & Kemppainen (2008). From three of the zones, which intersect ONKALO access tunnel, only the logged Q -median value of 5 meter long chainage is available. In these cases, the drillhole data is used to classify the zones rock mass quality. Also brittle deformation zones which are not intersected by the tunnel are classified based on drillhole logging.

35

ZONE INTERSECTIONDATA IMPORT

Site Tunnel IDONKALO VT1

24-2 transition 1:-10 120 17.9.2010 PJUH

From To Dip Dip dir.4377.3 4384.6 86 92

4384.60 4389.0 89 804383,00 4387,00 86 844383,00 4387.0 86 84

Within the core zone

Within the damage zone

Dripping No Yes 4380_14380_6,4380_37,4380_38,4380_8,43

80_7,4385_47

Zone1 FootwallWidth (m)

1,5

Ri-ClassRiIII

RQD Jn Jr Ja Jw SRF Q Q-quality90 3 1 2 1 5 3,000 Poor

Zone2 SINWidth (m)

0,45

Ri-Class

RiIV-Rk4

RQD Jn Jr Ja Jw SRF Q Q-quality25 3 0,5 6 1 5 0,139 Very Poor

Zone3 Hanging wallWidth (m)

1

Ri-Class

RiIII

RQD Jn Jr Ja Jw SRF Q Q-quality90 2 1 2 1 5 4,500 Fair

Tunnel dip

Chainage (m) Orientation (degrees)

ZONE start (tunnel PLfrom)Intersection type

Geologist

Zone position

4377BFI

Tunnel profileZone Intersection ID

ONK-VT1-BFI-4377

Increased fault-parallel fracturing with some wall-rock alteration (chloritization, illitization, saussuritization, pinitization). Same width on both sides.

Q-CLASSIFICATION

DescriptionIncreased fault-parallel fracturing with some wall-rock alteration (chloritization, illitization, saussuritization, pinitization). The pre-core zone is ~2 m wide on the left wall and 1.7 m wide on the right.

Q-CLASSIFICATION

Description

Description

The core of the zone consists of a layered, cohesive breccia cemented by quartz, chlorite and sulphides (sphalerite, pyrite, chalcopyrite). In places the hydrothermal fillings form a network of undeformed hydrothermal veins. Some sections around the veins and the fault also appear to be illitized. The breccia overprints an older, also layered fine-grained mylonite with stretched quartz grains. The youngest overprinting structures observed in the core are incohesive fractures (chloritic slickensides and calcite-filled fracturing mainly). In places a very thin (some centimeters or millimeters wide) fault gouge or clay is present. The apparent slip direction is sinistral with a striation in direction 07/169. Chalcopyrite disease can be seen in the sphalerite grains filling the voids between the euhedral quartz grains in the hydrothermally cemented core. The core is ~0.45 m wide on the right wall and on the left wall the core is ~.20 m. wide and branched. Resembles OL-BFZ100 by appearance and orientation.

Q-CLASSIFICATION

Characteristics of the "Post core zone, damage zone"

Water leakage

Characteristics of the "Pre core zone, damage zone"

Sketch SampleConnection to previously known

intersections / deformation zones

Fracture Code(s)

ONK-BFI-3350,OL-BFZ045B

Characteristics of the "Core zone"

Tunnel direction Mapping date

right wallroof

middle +1 m

left wallTunnel part

Figure 4-3. Example of geotechnical mapping on of deformation zone intersection in ONKALO access tunnel.

36

Depending on the available data, the GSI value for the brittle deformation zone has been interpreted via one of the following methods. In cases where the core has been determined from the ONKALO access tunnel, the GSI value for the brittle fracture zone is the value of the zone core. If the deformation zone intersects the tunnel in several locations, the lower quartile value of mapped core value is used.

The drillhole intersection locations of the zones were based on geological indications (Table 4-2). Problems associated with the influence of the drillhole location and orientation on the observed structure has been highlighted by Hudson et al. (2008). The problem is clearly presented in Figure 4-4. From drillhole intersections depth ranges, the smallest GSI values that were found in each intersection were selected, although in the case of many drillhole intervals, it is typical that several possible fault cores may exist. The interpreted GSI value for the deformation zone is the lower quartile value of all selected GSI values (Figure 4-5). The width of the range was not taken into account.

Figure 4-4. (a) Influence of drillhole (shown in red) location and (b) drillhole orientation on the brittle deformation zone expression in a drillhole. Depending on both the location and orientation of the drillhole, the intersected expression of the zone will be different (Hudson et al. 2008).

37

Figure 4-5. Schematic figure of logged GSI value in one brittle deformation zone. Selected GSI value in each intersection coloured with red. Interpreted GSI for zone value would be 49.

Both approaches are conservative because the widths of the modelled zone are much wider than the actual intersections. A method where weighted average (weighted by length) of intersections was also considered when interpreting GSI values. However because sections of poor rock quality are quite narrow, or as in some cases, the cores consist of only one or two grain filled fractures, these poor rock quality sections “disappeared” among better rock qualities within the zone intersection. As a conclusion at this stage for rock mechanics modelling purposes, it was decided to characterize the brittle fault zones by the value of the weakest plane region existing in the zone.

In Table 4-2 and Figure 4-6 are presented geological intersections and interpreted GSI values for OL-BFZ100.

Table 4-2. Geological indications for the OL-BFZ100 intersections. Core m_from and core m_to are the depths of the selected GSI value of intersection in question.

Hole_id

Geological intersection

m_from


m_to

Core GSI

Core m_from

Core m_to

OL-PH1 151.64 154.32 26 152.38 152.62

ONK-PH4 27.10 30.57 70 28.76 29.6 OL-KR22 337.65 340.45 67 338.20 339.60 OL-KR23 372.5 373.02 67 372.50 373.02 OL-KR25 216.5 222.05 43 217.65 218.31 Ol-KR26 95.80 98.25 70 96.82 97.9 OL-KR28 170.21 178.30 62 172.60 173.20 OL-KR34 48.38 53.77 43 48.38 49.46 OL-KR37 56.23 57.5 47 56.19 56.71 OL-KR42 183.03 198.83 --- No data ONKALO 128.50 129.30 RiIV ONK_BFI_12850-12930 ONKALO 521.50 523.00 RiIV ONK_BFI_52150-52300 ONKALO 900.20 906.40 RiIV ONK_BFI_90020-90640 ONKALO 1592.90 1595.00 40 ONK_BFI_159290_159500 ONKALO 1819.00 1831.00 43 ONK_BFI_181900_183100 ONKALO 2481.50 2482.00 56 ONK-BFI-248150-248200 ONKALO 2931.50 2937.50 46 ONK-BFI-293150-293750

38

20

40

60

80O

NK_

BFI_

1592

90_1

5950

0

ON

K_BF

I_18

1900

_183

100

ON

K-BF

I-293

150-

2937

50

ON

K-BF

I-248

150-

2482

00

ON

K_BF

I_12

850_

1293

0

ON

K_BF

I_52

150_

5230

0

ON

K_BF

I_90

020_

9064

0

OL-

PH1

OL-

KR25

OL-

KR34

OL-

KR37

OL-

KR28

ON

K-PH

4

OL-

KR22

OL-

KR23

OL-

KR26

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width

Figure 4-6. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ100. The blue dashed line presents the interpreted GSI-value of the core (GSI =43).

4.3 Strength of the intact rock

The strength of the intact rock within brittle deformation zones has not been updated after data provided in 2009. Earlier data is described in the previous parameterisation report (Kuula H. 2010). Based on previous measurements, a rough estimate of the intact rock strength in the brittle deformation zone core is 20% x 114 MPa = 22 MPa which is based on Schmidt hammer measurements conducted in the ONKALO access tunnel.

4.4 Strength and deformability properties of brittle deformation zones

The strength and deformability properties of the brittle deformation zones were estimated via RocLab-software based on the equations of the Hoek-Brown failure criterion and the results are presented in Table 4-3.

The Hoek-Brown strength criterion can be expressed as (Hoek et al. 2002):

a

cibci sm ''' 3

31 (4-4)

where '1 and '3 are the major and minor effective principal stresses at failure, ci is the uniaxial compressive strength of the intact rock material.

mb is a reduced value of the material constant mi and is given by

39

DGSImm ib 1428

100exp (4-5)

s and a are constants for the rock mass given by the following relationships:

DGSIs

39100exp (4-6)

3/2015/

61

21 eea GSI (4-7)

GSI is a geological strength index. It is calculated from the Q value by using equation (4-3). D is a factor which depends upon the degree of disturbance to which the rock mass has been subjected to by blast damage and stress relaxation. It varies from 0 for undisturbed in situ rock masses to 1 for very disturbed rock masses.

The Mohr-Coulomb fit previously determined for parameterisation of brittle fault zones was made according to a normal stress of 28 MPa leading to lower angles of friction and higher joint cohesions (Kuula, 2010). 28 MPa was at that time close to the average maximum horizontal stress at depth. This approach is acceptable as it is plausible to assume generally low friction angles and high normal stresses for large-scale geological features such as brittle fault zones which extend to significant depths. The current Mohr-Coulomb fit to the Hoek-Brown failure criterion was determined according to an approximate depth of -300 m leading to a normal stress of ca. 4 MPa. This defined lower joint cohesions and higher friction angles.

The Young’s modulus of brittle deformation zones (zone core) were estimated from seismic P-wave velocities measured from drillholes. Young’s modulus was calculated from each drillhole intersection, were data was available, with equation 4-8 (Barton, 2002). The distance between transmitter and receiver when measuring seismic velocities, were 0.6 m or 1.0 m depending on available data. Data measured with 1.0 m transmitter-receiver distance were used if data measured with 0.6 transmitter-receiver distance data were not available. Data measured with 0.6 m transmitter-receiver distance were available from drillholes OL-KR29 – OL-KR40B, OL-KR42 – OL-KR50 and ONK-PH4. From drillholes OL-KR1 –OL-KR28 data measured with 1.0 m transmitter-receiver distance were used.

)3/)5.3((1010 PVE (4-8)

The determined Young’s modulus for each brittle deformation zone is the lower quartile of calculated Young’s modulus values of all drillhole intersections (core from – core to) of brittle deformation zone in question. The average value of determined Young’s modulus for brittle deformation zones is 27 GPa. This value is applied for those brittle deformation zones from which no seismic data is available (OL-BFZ045b, OO-BFZ101, OL-BFZ118 and OL-BFZ214). The results are presented in Table 4-3. The drillhole intersections and calculated lower quartile, median value and upper quartile for each brittle deformation zones are presented in Appendix 2.

40

Table 4-3. Strength and deformability properties of brittle deformation zones.

OL-BFZ011 OL-BFZ016 OL-BFZ019a OL-BFZ-019c OL-BFZ020a OL-BFZ020bBFZ characteristics

Width 0.2 0.1Rock mass quality (GSI) 54 49 58 64 54 55

1st quartile ofdrillhole

intersectionsdrillhole

intersection


intersections

mapped corevalue from

tunnelintersection


tunnelintersection


intersectionsStrength of intact parts

sigci (MPa) 22 22 22 22 22 22mi 10 10 10 10 10 10D 0 0 0 0 0 0

Strength of BFZHoek Brown Criterionmb 1.93 1.62 2.23 2.76 1.93 2.00s 0.0060 0.0035 0.0094 0.0183 0.0060 0.0067a 0.50 0.51 0.50 0.50 0.50 0.50

Mohr Coulomb Fitcohesion (MPa) 0.9 0.8 1.0 1.1 0.9 0.9friction angle (°) 35 34 36 38 35 36tensile strength (MPa) 0.07 0.05 0.09 0.15 0.07 0.07compressive strength (MPa) 1.7 1.2 2.1 3.0 1.7 1.8

Deformability of BFZYoung's Modulus (GPa) 24.5 29.4 14.6 32.0 21.4 20.5G = E / 2 (1+n), n = 0.25 (GPa) 9.8 11.8 5.8 12.8 8.6 8.2

Equivalent Stiffness of BFZ*Kn = E / width (GPa/m) 159.9 214.2Ks = G / width (GPa/m) 63.9 85.7

* Due to the variation of the width of the zone core in drillcore intersections,stiffness parameters have been determined only for zones which intersect the tunnel (minimum width used)** No seismic data available, average value of all brittle deformation zones.

OL-BFZ021 OL-BFZ039 OL-BFZ043 OL-BFZ045b OL-BFZ084 OL-BFZ099BFZ characteristics

Width 0.15 1.6 0.5 0.3Rock mass quality (GSI) 41 60 65 48 50 40



intersection


tunnelintersections


tunnelintersections


tunnelintersection



sigci (MPa) 22 22 22 22 22 22mi 10 10 10 10 10 10D 0 0 0 0 0 0



Deformability of BFZYoung's Modulus (GPa) 17.4 35.9 56.9 27.0** 27.4 24.0G = E / 2 (1+n), n = 0.25 (GPa) 7.0 14.4 22.8 10.8 10.9 9.6

Equivalent Stiffness of BFZ*Kn = E / width (GPa/m) 379.2 54.1 91.2Ks = G / width (GPa/m) 151.7 21.6 36.5


41

OL-BFZ100 OL-BFZ101 OL-BFZ106 OL-BFZ118 OL-BFZ146 OL-BFZ152

BFZ characteristicsWidth 0.25 1Rock mass quality (GSI) 43 45 37 60 58 62


tunnelintersections

drillholeintersection



intersection


intersections



sigci (MPa) 22 22 22 22 22 22mi 10 10 10 10 10 10D 0 0 0 0 0 0



Deformability of BFZYoung's Modulus (GPa) 32.0 27.0** 23.1 27.0** 12.8 8.2G = E / 2 (1+n), n = 0.25 (GPa) 12.8 10.8 9.3 10.8 5.1 3.3

Equivalent Stiffness of BFZ*Kn = E / width (GPa/m) 127.9Ks = G / width (GPa/m) 51.2


OL-BFZ159 OL-BFZ160 OL-BFZ161 OL-BFZ175 OL-BFZ214 OL-BFZ219BFZ characteristics

WidthRock mass quality (GSI) 73 46 65 51 40 51






intersectiondrillhole

intersectionStrength of intact parts

sigci (MPa) 22 22 22 22 22 22mi 10 10 10 10 10 10D 0 0 0 0 0 0



Deformability of BFZYoung's Modulus (GPa) 22.5 37.4 39.8 32.9 27.0** 28.1G = E / 2 (1+n), n = 0.25 (GPa) 9.0 14.9 15.9 13.2 10.8 11.2

Equivalent Stiffness of BFZ*Kn = E / width (GPa/m)Ks = G / width (GPa/m)


43

5 CONCLUSIONS AND RECOMMENDATIONS

In this report, the geometrical and mechanical parameters of fractures and brittle deformation zones in the vicinity of the ONKALO volume have been estimated for the tunnel chainage range 2400–4390 m. The main target of the work was to obtain preliminary parameters for rock mechanics simulations and rock mechanics design.

From the ONKALO tunnel mapping data 2400–4390 m tunnel chainage, three major fracture sets can be found.

The vertical set (set A, 90°/084°) is most frequently observed in chainage ranges 2480–2760 m and 3780–4050 m. This fracture set becomes more common as the tunnel advances to greater depths.

The sub-horizontal fracture set (set B, 05°/043°), is not commonly observed until chainage 3000 m, but it is regularly observed from there on. One notable area of occurrence of set B is between chainages 3120 m and 3320 m, where gently dipping brittle fracture zones OL-BFZ20a and OL-BFZ20b intersects the tunnel. It can be expected that the brittle fracture zones might also have an influence on the dip and dip direction of fracturing in other parts of the tunnel. However, this influence can be very difficult to notice and in most cases, is also insignificantly small.

The third fracture set (set C, 89°/338°) is not very common. It is mostly observed in chainage range 2460–2700 m, and after that only occasionally.

The number of fracture sets varies with the tunnel chainage. Over the first 300 m chainage, the Jn median is 6. From chainage 300 m to about 1200 m, the Jn median is 3 and, after chainage 1200 m, the Jn median drops to 1. The mean RQD value in the ONKALO tunnel from chainage 0 to 4390 m is 97 %. From chainage 1200 m, the fracture intensity starts to decrease and the mean RQD value in the chainage range 1200–4390 m is 98.4 % compared to the mean value in the chainage range 0–1200 m of 94%.

In tunnel mapping data it is seen that with increasing depth, the fractures become smoother and more planar, the mean Jr value drops from 3 to 1.5. Only the amount of long slickensided fractures is decreasing with the depth. The mean amount of slickensided fractures is less than 10 %. The vertical N-S trending fracture set, Set 2, has more smooth and planar and fewer rough and undulating fractures than the other sets. The fracture end-type does not appear to correlate with roughness.

For chainages 0–1200 m, the mean Ja value is approximately 4. For very short fractures (length 1 m or less), the mean Ja value is 1. In the deeper sections of the tunnel (chainages 1200–4390 m), fractures are less altered. The mean Ja value for fractures with lengths varying between 0–5 m is 1. For longer fractures (20 m), the Ja value varies mainly between 2 to 3.

Compared to other fracture sets in the 0–2400 m chainage, set 4 has more altered fracture surfaces. The Ja value is also studied from drillhole data which were edited to 1 meter long composites and the median values for the depth ranges 0…-120 m and -

44

120…-250 m were calculated for the deep drillholes (extended at least to z = -250 m). The median value of Ja is commonly 3 and no correlation with depth can be observed.

In the first section, chainage range from 0 to 1200 m, the friction angle is mainly between 30° - 40°, but distribution is quite uniform. In the second section of the tunnel (chainage 1200 to 2400 m), the friction angle increases for almost all fracture lengths, being mainly between 40°– 60°. As depth increases from 2400 to 4390 meters, the friction angle value sets to 50°– 60° for short fractures (<5 meters) and 20°– 30° for longer fractures.

Estimation of the mechanical properties of the brittle deformation zones is based on Olkiluoto area drillholes and the ONKALO tunnel mapping. In this report, 24 fractured zones have been analysed.

Analysed brittle deformation zones have been selected based on their size and location and available data: a direct geological observation of deformation zone must exist, i.e. deformation zone must intersect drillhole or ONKALO access tunnel so that any parameter can be estimated. All brittle deformation zones which are classified as site scaled zone and which fulfil the criterion of direct geological observation were analysed. Also repository scaled zones which are included in stress modelling (Valli et al. 2011) are analysed. These are mainly shallow dip zones which are located central or close to ONKALO and the repository. One of the main BDZ zones is OL-BFZ100 which intersects the tunnel in several places.

The cohesion of the brittle deformation zones varies between 0.7–1.4 MPa and friction angle between 30°– 40°. The Mohr-Coulomb fit previously determined for parameterisation of brittle fault zones was done according to a normal stress of 28 MPa leading to lower angles of friction and higher joint cohesions (Kuula 2010). 28 MPa was at that time close to the average maximum horizontal stress at depth. This approach is acceptable as it is plausible to assume generally low friction angles and high normal stresses for large-scale geological features such as brittle fault zones which extend to significant depths. The current Mohr-Coulomb fit to the Hoek-Brown failure criterion was determined according to an approximate depth of -300 m leading to a normal stress of ca. 4 MPa. This defined lower joint cohesions and higher friction angles.

Young’s modulus in brittle deformation zones varies between 8.2–56.9 GPa and compressive strength between 0.6–4.9 MPa.

The ONKALO tunnel mapping has increased the level of knowledge regarding the location and properties of brittle deformation zones. However the total amount of data is quite limited compared to the size of each deformation zones, and variation of parameters between different intersections inside a zone might be quite large. I.e. more data is needed for a better estimation of mechanical properties.

Direct shear tests results are missing from vertical major fracture sets and filled moderately dipping fractures. Laboratory joint shear and normal tests are recommended for filled and coated fractures, at least three tests per each type.

45

In further studies this approach to classify tunnel mapping data to major fracture sets should be evaluated carefully. The amount of fracture orientation data analysed for each tunnel section is large and the data are scattered, thus leaving a considerable portion of the fractures outside the defined major fracture sets.

47

REFERENCES

Aaltonen, I., (ed.), Lahti, M., Engström, J., Mattila, J., Paananen, M., Paulamäki, S., Gehör, S., Kärki, A., Ahokas, T., Torvela, T. & Front, K., 2010. Geological Model of the Olkiluoto Site - Version 2.0. Working Report 2010-70. Posiva Oy, Eurajoki.

Barton, N. 2002. Some new Q-value correlations to assist in site characterisation and tunnel design. International Journal of Rock Mechanics and Mining Sciences 39 (2002), 185-216.

Barton, N.R. & Bandis, S.C. 1990. Review of predictive capabilites of JRC-JCS model in engineering practice. In Rock joints, proc. int. symp. on rock joints, Loen, Norway, (eds N. Barton and O. Stephansson), 603-610. Rotterdam: Balkema.

Barton, N.R., Lien, R. & Lunde, J. 1974. Engineering classification of rock masses for the design of tunnel support. Rock Mech. 6(4), 189-239.

Deere, D.U., Hendron, A.J., Patton, F.D. & Cording, E.J. 1967. Design of surface and near surface construction in rock. In Failure and breakage of rock, proc. 8th U.S. symp. rock mech., (ed. C. Fairhurst), 237-302. New York: Soc. Min. Engrs, Am. Inst. Min. Metall. Petrolm Engrs.

Engström, J. & Kemppainen, K. 2008. Evaluation of the geological and geotechnical mapping procedures in use in the ONKALO access tunnel. Posiva Oy, Working Report 2008-77.

Hoek, E. 2007. Practical rock engineering. URL: http://www.rocscience.com/hoek/PracticalRockEngineering.asp course notes

Hoek, E., Carranza-Torres, C. T. & Corkum, B. 2002. Hoek-Brown failure criterion – 2002 edition. Proc. North American Rock Mechanics Society meeting in Toronto in July 2002.

Hudson, J. A., Cosgrove, J. & Johansson, E. 2008. Estimating the mechanical properties of the brittle deformation zones at Olkiluoto. Working Report 2008-67. Posiva Oy, Eurajoki.

Kuula, H., 2010. Geometrical and Mechanical Properties of the Fractures and Brittle Deformation Zones based on ONKALO Tunnel Mapping, 0-2400 m Tunnel Chainages. Working Report 2010-64. Posiva Oy, Eurajoki.

Løset, F. 1997. Practical Use of Q-method. NGI-report 592046-4. Norwegian Geotechnical Institute.

Mattila, J., Aaltonen, I., Kemppainen, K. Wikström, L., Paananen, M., Paulamäki, S., Front, K. Gehör, S., Kärki, A. & Ahokas, T. 2008. Geological model of the Olkiluoto Site. Version 1.0. Working Report 2007-92. Posiva Oy, Eurajoki.

Nordbäck, N., 2010. Outcome of the the geological mapping of the ONKALO underground research facility access tunnel, chainage 1980-3116. Working Report 2010-42. Posiva Oy, Eurajoki.

48

Ojala, I., Stenebråten, J. 2010. Mechanical and acoustic properties of the altered rock at Olkiluoto. Working Report 2008-27, Posiva.

Palmström, A. 1982. The volumetric joint count - a useful and simple measure of the degree of rock jointing. Proc. 4th congr. Int. Assn Engng Geol., Delhi 5, 221-228.

Posiva 2009. Olkiluoto Site Description 2008, Posiva Report 2009-01

Valli, J., Hakala, M., & Kuula, H. 2011 Modelling of the in-situ stress state at Olkiluoto. Working Report 2011-34. Posiva Oy, Eurajoki.

49

APPENDICES

The following four Appendices provide further supporting information to the main body of the Report with regard to the Q parameters, more fracture geometry detail, GSI BDZ information, and the details of the Hoek-Brown failure criterion.

APPENDIX 1 Classification of individual parameters used in the Tunnelling Quality Index Q

APPENDIX 2 Geological indications, the GSI values and Young’s modulus for the Brittle Deformation Zones

51

APPENDIX 1 Classification of individual parameters used in the Tunnelling Quality Index Q (Barton et al. 1974).

1 RQD (Rock Quality Designation) RQD

A Very poor 0-25 B Poor 25-50 C Fair 50-75 D Good 75-90 E Excellent 90-100

Note: i) Where RQD is reported or measured as 10 (including 0) the nominal value 10 is used to evaluate the Q-value

ii) RQD intervals of 5, i.e., 100, 95, 90, etc., are sufficiently accurate

2 Joint set number Jn

A Massive, no or few joints 0.5-1 B One joint set 2 C One joint set plus random joints 3 D Two joint sets 4 E Two joint sets plus random joints 6 F Three joint sets 9 G Three joint sets plus random joints 12 H Four or more joint sets, random, heavily jointed, .sugar-cube., etc. 15 J Crushed rock, earthlike 20

Notes: i) For tunnel intersections, use (3.0 × Jn ). ii) For portals use (2.0 × Jn ).

3 Joint roughness number Jr

a) Rock-wall contact, and b) Rock-wall contact before 10 cm shear A Discontinuous joints 4 B Rough or irregular, undulating 3 C Smooth, undulating 2 D Slickensided, undulating 1.5 E Rough or irregular, planar 1.5 F Smooth, planar 1.0 G Slickensided, planar 0.5

Notes: i) Descriptions refer to small-scale features and intermediate scale features, in that order.

52

b) No rock-wall contact when sheared

H Zone containing clay minerals thick enough to prevent rock-wall contact. 1.0

J Sandy, gravely or crushed zone thick enough to prevent rock-wall contact 1.0

Notes: ii) Add 1.0 if the mean spacing of the relevant joint set is greater than 3 m. iii) Jr = 0.5 can be used for planar, slickensided joints having lineations, provided the lineations are oriented for

minimum strength. iv) Jr and Ja classification is applied to the joint set or discontinuity that is least favourable for stability both

from the point of view of orientation and shear resistance, (where n tan-1 (Jr /Ja ).

4 Joint alteration number r approx. Ja

a) Rock-wall contact (no mineral fillings, only coatings)

A Tightly healed, hard, non-softening, impermeable filling, i.e., quartz or epidote. -- 0.75

B Unaltered joint walls, surface staining only. 25-35° 1.0

C Slightly altered joint walls. Non-softening mineral coatings, sandy particles, clay-free disintegrated rock, etc. 25-30° 2.0

D Silty- or sandy-clay coatings, small clay fraction (non-softening). 20-25° 3.0

E Softening or low friction clay mineral coatings, i.e., kaolinite or mica. Also chlorite, talc, gypsum, graphite, etc., and small quantities of swelling clays.

8-16° 4.0

b) Rock-wall contact before 10 cm shear (thin mineral fillings) F Sandy particles, clay-free disintegrated rock, etc. 25-30° 4.0

G Strongly over-consolidated non-softening clay mineral fillings (continuous, but < 5 mm thickness). 16-24° 6.0

H Medium or low over-consolidation, softening, clay mineral fillings (continuous, but < 5 mm thickness). 12-16° 8.0

J Swelling-clay fillings, i.e., montmorillonite (continuous, but < 5 mm thickness). Value of Ja depends on per cent of swelling clay-size particles, and access to water, etc.

6-12° 8-12

c) No rock-wall contact when sheared (thick mineral fillings) KL M

Zones or bands of disintegrated or crushed rock and clay (see G, H, J for description of clay condition). 6-24° 6, 8, or

8-12

N Zones or bands of silty- or sandy-clay, small clay fraction (non-softening). -- 5.0

OP R

Thick, continuous zones or bands of clay (see G, H, J for description of clay condition). 6-24° 10, 13,

or 13-20

53

5 Joint water reduction factor approx. water pres. (kg/cm2)

Jw

A Dry excavations or minor inflow, i.e., < 5 l/min locally. < 1 1.0

B Medium inflow or pressure, occasional outwash of joint fillings. 1-2.5 0.66

C Large inflow or high pressure in competent rock with unfilled joints. 2.5-10 0.5

D Large inflow or high pressure, considerable outwash of joint fillings. 2.5-10 0.33

E Exceptionally high inflow or water pressure at blasting, decaying with time. > 10 0.2-0.1

F Exceptionally high inflow or water pressure continuing without noticeable decay. > 10 0.1-0.05

Notes: i) Factors C to F are crude estimates. Increase Jw if drainage measures are installed. ii) Special problems caused by ice formation are not considered.

iii) For general characterization of rock masses distant from excavation influences, the use of Jw = 1.0, 0.66, 0.5, 0.33 etc. as depth increases from say 0-5m, 5-25m, 25-250m to >250m is recommended, assuming that RQD /Jn is low enough (e.g. 0.5-25) for good hydraulic connectivity. This will help to adjust Q for some of the effective stress and water softening effects, in combination with appropriate characterization values of SRF. Correlations with depth-dependent static deformation modulus and seismic velocity will then follow the practice used when these were developed.

6 Stress Reduction Factor SRF

a) Weakness zones intersecting excavation, which may cause loosening of rock mass when tunnel is excavated

A Multiple occurrences of weakness zones containing clay or chemically disintegrated rock, very loose surrounding rock (any depth).

10

B Single weakness zones containing clay or chemically disintegrated rock (depth of excavation 50 m). 5

C Single weakness zones containing clay or chemically disintegrated rock (depth of excavation > 50 m). 2.5

D Multiple shear zones in competent rock (clay-free), loose surrounding rock (any depth). 7.5

E Single shear zones in competent rock (clay-free), (depth of excavation 50 m). 5.0

F Single shear zones in competent rock (clay-free), (depth of excavation > 50 m). 2.5

G Loose, open joints, heavily jointed or .sugar cube., etc. (any depth) 5.0 Notes: i) Reduce these values of SRF by 25-50% if the relevant shear zones only influence but do not intersect the

excavation. This will also be relevant for characterization.

54

b) Competent rock, rock stress problems c / 1 / c SRF H Low stress, near surface, open joints. > 200 < 0.01 2.5 J Medium stress, favourable stress condition. 200-10 0.01-0.3 1

K High stress, very tight structure. Usually favourable to stability, may be unfavourable for wall stability.

10-5 0.3-0.4 0.5-2

L Moderate slabbing after > 1 hour in massive rock. 5-3 0.5-0.65 5-50

M Slabbing and rock burst after a few minutes in massive rock. 3-2 0.65-1 50-

200

N Heavy rock burst (strain-burst) and immediate dynamic deformations in massive rock. < 2 > 1 200-

400 Notes: ii) For strongly anisotropic virgin stress field (if measured): When 5 1 / 3 10, reduce c to 0.75 c. When

1 / 3 > 10, reduce c to 0.5 c, where c = unconfined compression strength, 1 and 3 are the major and minor principal stresses, and = maximum tangential stress (estimated from elastic theory).

iii) Few case records available where depth of crown below surface is less than span width. Suggest an SRF increase from 2.5 to 5 for such cases (see H).

iv) Cases L, M, and N are usually most relevant for support design of deep tunnel excavations in hard massive rock masses, with RQD /Jn ratios from about 50 to 200.

v) For general characterization of rock masses distant from excavation influences, the use of SRF = 5, 2.5, 1.0, and 0.5 is recommended as depth increases from say 0-5m, 5-25m, 25-250m to >250m. This will help to adjust Q for some of the effective stress effects, in combination with appropriate characterization values of Jw. Correlations with depth - dependent static deformation modulus and seismic velocity will then follow the practice used when these were developed.

c) Squeezing rock: plastic flow of incompetent rock under the influence of high rock pressure / c SRF

O Mild squeezing rock pressure 1-5 5-10 P Heavy squeezing rock pressure > 5 10-20

Notes: vi) Cases of squeezing rock may occur for depth H > 350 Q1/3 according to Singh 1993. Rock mass compression strength can be estimated from SIGMAcm 5 Qc

1/3 (MPa) where = rock density in t /m3, and Qc=Qx c /100, Barton, 2000.

d) Swelling rock: chemical swelling activity depending on presence of water SRF

R Mild swelling rock pressure 5-10 S Heavy swelling rock pressure 10-15

55

APPENDIX 2 Geological descriptions, the GSI values and Young’s modulus for the Brittle Deformation Zones

OL- BFZ-011

Figure A2 - 1. Brittle deformation zone OL- BFZ-011. According to Q-classification, interpreted rock mass quality is “Poor”.

The interpreted GSI value for OL-BFZ011 is 54 and interpreted Young’s modulus is 24.5 GPa. Geological description of OL-BFZ011 is following (Aaltonen et al. 2010):

VGN and a cross-cutting narrow pegmatite. Fractured, slickensides, sulphide-fillings and porosity. Fractures are quite parallel. No open fracture resistivity.

OL_KR40_BFI_49896_50066: The intersection locates in VGN - DGN, and consists of 10 fractures of which 4 are slickensided and with chlorite, pyrite and clay-filled. The non-slickensided fractures are also chlorite/clay filled and occasionally show small signs of movement. The core of the intersection is poorly defined at 499.45 - 499.80 m and consists of three slickenside fractures. The lineations show a shallow dip to direction 215 degrees. The rock contains small amounts of pyrrhotite. At the end of the section there is a very narrow SFI.

Table A2 - 1. Intersections OL-BFZ011 at drill cores. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view

Hole_id Geological intersection

m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR9 147.33 149.56 49 149.00 149.30

OL-KR40 499.56 499.80 67 499.45 499.80

56

20

40

60

80

OL-

KR9

OL-

KR40

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth

Figure A2 - 2. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ011. Blue dashed line presents the interpreted GSI-value of the deformation zones core (GSI =54).

Table A2 - 2. Lower quartile, median value and upper quartile of Young’s modulus calculated from seismic P-wave velocities.

Lower quartile (GPa) Median (GPa) Upper quartile (GPa)

24.5 48.4 49.6

Table A2 - 3. Intersections OL-BFZ011 at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR9 147.33 149.56 149.00 149.30 1.0

OL-KR40 499.56 499.80 499.45 499.80 0.6

57

OL-BFZ016

Figure A2 - 3. Brittle deformation zone OL-BFZ016. According to Q-classification, interpreted rock mass quality is “Poor”.


The fault is within the diatexitic gneiss (DGN), with some short sections of mafic gneiss (MFGN). Old and welded fractures where calcite is present. These old fractures have partly been reactivated later. The intersection contains 50 joints. The rock is most fractured in section 379.18-379.80, containing 18 fractures Dip directions of the fractures are towards the NNW, with moderate to steep dip. Numerous slickenside surfaces with a NE-SW striation trend. The movement on surfaces is random.

Table A2 - 4. Intersections OL-BFZ016 at drill cores. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core

GSI

Core

m_from

Core

m_to

OL-KR8 376.00 383.00 49 379.2 379.8

58

20

40

60

80

OL-

KR8

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width

Figure A2 - 4. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ016. Interpreted GSI-value of deformation zones core is 49.



29.4 30.2 30.6

Table A2 - 6. Intersection OL-BFZ016 at drill core. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR8 376.00 383.00 379.20 379.80 1.0

59

OL-BFZ019a

Figure A2 - 5. Brittle deformation zone OL-BFZ019a. According to Q-classification, interpreted rock mass quality is “Fair”.

The interpreted GSI value for OL-BFZ019a is 58 and interpreted Young’s modulus is 14.6 GPa. Geological description of OL-BFZ019a is following (Aaltonen et al. 2010):

OL-BFZ019a is a gently dipping thrust fault with an approximate dip of c. 15 degrees towards the SE. The thickness of the fault core varies from 0.1 to 4 m. The fault is located a few tens of meters above fault OL-BFZ019c and is subparallel to it. Predominantly fracture-controlled kaolinisation, illitisation and sulphidisation are observed along the zone, although sporadically the alteration is also pervasive. As a result of re-examination of the geological data, the lateral extent of the fault is limited only to the ONKALO area in the current model. The core is characterized mainly by RiIII-IV-sections according to the RG-classification and the core of the fault is also hydraulically conducting in most of the drillhole intersections.

60

Table A2 - 7. Intersections OL-BFZ019a at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.

Hole_id Geological intersection m_from

Geological intersection m_to

Core GSI

Core m_from

Core m_to

OL-KR4 81.50 82.40 69 81.50 82.40 OL-KR7 26.00 42.55 67 36.16 37.39

OL-KR22 138.80 146.05 72 144.9 145.6 OL-KR24 94.02 94.35 49 92.02 94.35 OL-KR25 94.45 97.30 62 96.09 96.73 OL-KR28 154.50 155.50 71 154.50 155.50 OL-KR30 52.22 53.88 69 52.20 53.88 OL-KR34 78.32 78.83 52 78.30 78.80 OL-KR35 94.40 94.60 64 94.40 94.60 OL-KR36 154.69 155.90 61 154.70 155.90 OL-KR37 123.32 123.83 73 123.30 123.80 OL-KR38 88.10 88.75 57 88.10 88.70 OL-KR48 93.90 101.00 60 96.10 96.39 ONK-PH4 84.00 85.68 40 85.53 85.68 CL 15cm ONKALO 931.90 963.00 62 932.80 937.90 Q_median

20

40

60

80

ON

K-PH

4

OL-

KR

24

OL-

KR

34

OL-

KR

38

OL-

KR

48

OL-

KR

36

OL-

KR

25

OL-

KR

35

OL-

KR

7

OL-

KR

30

OL-

KR

4

OL-

KR

28

OL-

KR

22

OL-

KR

37

ON

K-B

FI-9

3190

-963

00

GSI

0

1

2

3

4

5

core

wid

th

GSI

width

Figure A2 - 6. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ019a. Blue dashed line presents the interpreted GSI-value of the deformation zones core (GSI =58).

61



14.6 20.8 29.6

Table A2 - 9. Intersection OL-BFZ019a at drill core. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 81.50 82.40 81.50 82.40 0.6

OL-KR7 26.00 42.55 36.16 37.39 1.0

OL-KR22 138.80 146.05 114.90 145.60 1.0

OL-KR24 94.02 94.35 no data

OL-KR25 94.45 97.30 96.09 96.73 1.0

OL-KR28 154.50 155.50 154.50 155.50 1.0

OL-KR30 52.22 53.88 52.20 53.83 0.6

OL-KR34 78.32 78.83 78.30 78.80 0.6

OL-KR35 94.40 94.60 94.40 94.60 0.6

OL-KR36 154.69 155.90 154.70 155.90 0.6

OL-KR37 123.32 123.83 123.30 123.80 0.6

OL-KR38 88.10 88.75 88.10 88.70 0.6

OL-KR48 93.90 101.00 96.10 96.39 1.0

ONK-PH4 84.00 85.68 no data

ONKALO 931.90 963.00 no data

62

OL-BFZ019c

Figure A2 - 7. Brittle deformation zone OL-BFZ019c. According to Q-classification, interpreted rock mass quality is “Fair”.

The interpreted GSI value for OL-BFZ019c is 64 and interpreted Young’s modulus is 32.0 GPa. Geological description of OL-BFZ019c is following (Aaltonen et al. 2010):

OL-BFZ019c is a moderately dipping thrust fault with an approximate dip of c. 10 - 25 degrees towards the SSE. The fault is located a few tens of meters beneath fault OL-BFZ019a and is subparallel to it. The thickness of the fault core is approximately 0.1 – 1.4 m and the core zone is also frequently hydraulically conducting. Fracture-controlled kaolinisation, illitisation and sulphidisation are typical for the zone although occasionally illitisation is also pervasive. The core of the zone is characterized by RiIII-IV-sections or core loss in most of the drillhole intersections, although in a few drillholes significant geological evidence is lacking. However, the fault is inferred to intersect these drillholes on the basis of its general geometry, geophysical data and/or hydraulic connections. The geometry of the fault is based mainly on Mise-a-la-masse results in combination with geological observations in the drillholes and in the ONKALO tunnel.

63

Table A2 - 10. Intersections OL-BFZ019c at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core GSI

Core m_from

Core m_to

Obs.

OL-KR4 116.10 116.30 --- No fractures OL-KR10 76.70 77.60 75 76.70 77.60 OL-KR14 50.00 51.00 74 50.00 51.00 OL-KR22 188.45 200.50 66 188.50 191.30 OL-KR23 195.33 196.11 61 195.33 196.10 OL-KR24 112.55 116.20 62 155.30 155.80 OL-KR25 149.70 154.15 67 151.80 152.99 OL-KR27 277.51 284.40 40 280.75 284.60 OL-KR28 170.21 178.30 62 172.60 172.70 OL-KR30 81.09 83.48 58 82.17 82.72 OL-KR31 174.60 175.40 60 174.60 175.40 OL-KR36 197.40 201.10 65 197.40 197.90 OL-KR38 123.95 125.13 64 123.95 125.13 OL-KR40 273.64 282.25 36 273.87 273.96 OL-KR42 57.70 58.18 --- No data OL-KR45 607.42 608.56 68 607.77 608.56 ONK-PH5 57.09 57.20 45 57.09 57.20 CL 11cm ONKALO 1045.4 1045.7 64 1045.4 1045.7 ONK-BFI-104500-110850

20

40

60

80

ON

K-B

FI-1

0450

0-11

0850

ON

K-P

H5

OL-

KR

40

OL-

KR

27

OL-

KR

30

OL-

KR

31

OL-

KR

23

OL-

KR

24

OL-

KR

28

OL-

KR

38

OL-

KR

36

OL-

KR

22

OL-

KR

25

OL-

KR

45

OL-

KR

14

OL-

KR

10

OL-

KR

4

OL-

KR

42

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width

Figure A2 - 8. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ019c. Blue dashed line presents the interpreted GSI-value of the deformation zones core (GSI =64).

64



32.0 42.4 48.5

Table A2 - 12. Intersections OL-BFZ019c at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 116.10 116.30 116.10 116.30 0.6 OL-KR10 76.70 77.60 76.70 77.60 1.0 OL-KR14 50.00 51.00 50.00 51.00 1.0 OL-KR22 188.45 200.50 194.40 195.50 1.0 OL-KR23 195.33 196.11 no data OL-KR24 112.55 116.20 no data OL-KR25 149.70 154.15 151.80 152.99 1.0 OL-KR27 277.51 284.40 283.00 283.50 1.0 OL-KR28 170.21 178.30 172.60 172.70 1.0 OL-KR30 81.09 83.48 82.50 83.20 0.6 OL-KR31 174.60 175.40 174.60 175.40 0.6 OL-KR36 197.40 201.10 197.40 197.90 0.6 OL-KR38 123.95 125.13 123.95 125.13 0.6 OL-KR40 273.64 282.25 273.87 273.96 0.6 OL-KR42 57.70 58.18 57.70 58.18 0.6 OL-KR45 607.42 608.56 607.77 608.56 0.6 ONK-PH5 57.09 57.20 no data ONKALO 1045.4 1045.7 no data

65

OL-BFZ020a

Figure A2 - 9. Brittle deformation zone OL-BFZ020a. According to Q-classification, interpreted rock mass quality is “Poor”.

The interpreted GSI value for OL-BFZ020a is 54 and interpreted Young’s modulus is 21.4 GPa. Geological description of OL-BFZ020a is following (Aaltonen et al. 2010):

OL-BFZ020a is a moderately dipping thrust fault with an approximate dip of c. 20 degrees towards the SE. It is the main splay of another subparallel fault zone OL-BFZ020b, located at the maximum of a few tens of meters beneath OL-BFZ020a. The thickness of the fault core of OL-BFZ020a is approximately 0.1 – 2.7 m thick, with an average thickness of 1 m. Geologically OL-BFZ020a is not as distinct as OL-BFZ099 or OL-BFZ021. According to the RG-classification system, the fault core of OL-BFZ020a consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in most of the intersecting drillholes. In some drillholes, the fault core is characterized by pervasive or fracture-controlled illitisation, kaolinisation and sulphidisation or weathering. Its geometry is strongly based on Mise-a-la-masse results, seismic reflectors revealed by VSP, 3D and 2D reflection surveys and Sampo Gefinex conductors (see Mattila et al. 2008 for more details). The thickness of the influence zone of OL-BFZ020a is in average 40 m, varying from 15 m to 73 m. It is usually characterized by increased fracturing, slickenside fractures, elevated hydraulic conductivity and sporadic alteration.

66

Table A2 - 13. Intersections OL-BFZ020a at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.



Core GSI

Core m_from

Core m_to

Obs.

OL-KR1 141.18 143.95 40 142.57 143.25 OL-KR2 107.70 107.9 74 107.70 107.90 OL-KR3 46.30 48.80 51 48.50 49.02 OL-KR4 313.40 316.15 55 313.40 314.00 OL-KR7 227.01 228.80 51 227.00 228.53 OL-KR8 450.47 454.60 45 452.70 453.10 OL-KR9 444.20 445.10 59 444.20 445.10 OL-KR10 260.47 260.65 59 260.47 260.65 OL-KR11 300.61 305.39 55 304.00 305.00 OL-KR12 144.00 150.54 71 144.00 146.00 OL-KR13 113.49 115.31 68 113.49 115.31 OL-KR14 183.00 184.20 39 183.15 183.30 OL-KR15 148.20 148.80 30 148.20 148.80 OL-KR16 147.4 148.2 40 148.09 148.34 CL 25 cm OL-KR17 123.50 130.92 52 128.90 129.20 OL-KR20 37.36 39.48 --- OL-KR20B 39.50 42.15 63 39.50 41.67 OL-KR22 390.76 393.06 72 390.80 391.50 OL-KR23 427.60 428.50 72 427.60 428.50 OL-KR24 330.8 331.8 80 330.80 331.80 OL-KR25 347.00 352.25 52 350.56 350.80 OL-KR27 547.38 459.59 72 547.38 549.59 OL-KR28 388.00 389.80 63 388.00 388.65 OL-KR29 322.71 325.58 67 324.00 325.00 OL-KR32 86.79 88.07 82 86.79 88.07 OL-KR38 319.28 323.53 68 320.48 320.85 OL-KR39 146.88 148.83 59 147.00 148.00 OL-KR40 604.77 607.70 59 604.77 606.30 OL-KR41 150.00 151.00 --- No data OL-KR42 183.03 198.83 --- No data OL-KR44 652.00 665.00 62 653.05 653.36 OL-KR46 285.00 286.00 60 285.00 286.00 OL-KR48 338.99 342.15 53 339.60 340.20 ONKALO 3157 3158 54 ONK-BFI-3159

67

20

40

60

80

100

ON

K-B

FI-3

159

OL-

KR

15

OL-

KR

14

OL-

KR

1

OL-

KR

16

OL-

KR

8

OL-

KR

3

OL-

KR

7

OL-

KR

17

OL-

KR

25

OL-

KR

48

OL-

KR

11

OL-

KR

4

OL-

KR

10

OL-

KR

39

OL-

KR

40

OL-

KR

9

OL-

KR

46

OL-

KR

44

OL-

KR

20B

OL-

KR

28

OL-

KR

29

OL-

KR

13

OL-

KR

38

OL-

KR

12

OL-

KR

22

OL-

KR

23

OL-

KR

27

OL-

KR

2

OL-

KR

24

OL-

KR

32

OL-

KR

20

OL-

KR

41

OL-

KR

42

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width

Figure A2 - 10. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ020a Blue dashed line presents the interpreted GSI-value of the deformation zones core (GSI =54).



21.4 30.4 39.3

68

Table A2 - 15. Intersections OL-BFZ020a at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 141.18 143.95 142.00 143.00 1.0 OL-KR2 107.70 107.90 107.70 107.90 1.0 OL-KR3 46.30 48.80 47.40 48.50 1.0 OL-KR4 313.40 316.15 313.40 314.00 1.0 OL-KR7 227.01 228.80 227.10 228.50 1.0 OL-KR8 450.47 454.60 452.70 453.10 1.0 OL-KR9 444.20 445.10 444.20 445.10 1.0 OL-KR10 260.47 260.65 260.47 260.65 1.0 OL-KR11 300.61 305.39 304.00 305.00 1.0 OL-KR12 144.00 150.54 144.00 146.00 1.0 OL-KR13 113.49 115.31 113.49 115.31 1.0 OL-KR14 183.00 184.20 183.00 184.00 1.0 OL-KR15 148.20 148.80 148.20 148.80 1.0 OL-KR16 147.4 148.2 147.40 148.20 1.0 OL-KR17 123.50 130.92 no data OL-KR20 37.36 39.48 37.36 39.48 1.0 OL-KR20B 39.50 42.15 39.50 41.67 1.0 OL-KR22 390.76 393.06 390.80 391.50 1.0 OL-KR23 427.60 428.50 no data OL-KR24 330.8 331.8 330.80 331.80 1.0 OL-KR25 347.00 352.25 350.50 350.80 1.0 OL-KR27 547.38 459.59 547.38 549.59 1.0 OL-KR28 388.00 389.80 388.00 389.80 1.0 OL-KR29 322.71 325.58 324.00 325.00 0.6 OL-KR32 86.79 88.07 86.79 88.07 0.6 OL-KR38 319.28 323.53 320.50 320.90 0.6 OL-KR39 146.88 148.83 147.00 148.00 0.6 OL-KR40 604.77 607.70 604.99 605.02 0.6 OL-KR41 150.00 151.00 no data OL-KR42 183.03 198.83 193.40 194.37 0.6 OL-KR44 652.00 665.00 653.05 653.36 0.6 OL-KR46 285.00 286.00 285.00 286.00 0.6 OL-KR48 338.99 342.15 339.60 340.20 0.6 ONKALO 3157 3158 no data

69

OL-BFZ020b

Figure A2 - 11. Brittle deformation zone OL-BFZ020b. According to Q-classification, interpreted rock mass quality is “Poor”.

The interpreted GSI value for OL-BFZ020b is 55 and interpreted Young’s modulus is 20.5 GPa. Geological description of OL-BFZ020b is following (Aaltonen et al. 2010):

OL-BFZ020b is the lower splay of OL-BFZ020a with an approximate dip of c. 20 degrees towards the SE (Figure 4 32). The thickness of the fault is approximately 0.2 to 8.6 m, with an average thickness of c. 1 m. The fault is cross-cut by OL-BFZ020a to the SE. According to the RG-classification system, the core consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in all of the intersecting drillholes. Hydraulic conductivity is commonly also elevated. There are not many indications of hydrothermal alteration related to the core of the fault. Kaolinisation is the most common type of alteration (pervasive as well as fracture-controlled). Sporadic illitisation and sulphidisation are also present. The geometry of the zone is strongly based on Mise-a-la-Masse and Sampo Gefinex results and VSP reflectors. The seismic reflectors detected from the ground surface are strongly concentrated to fault zone OL-BFZ020a.

70

Table A2 - 16. Intersections OL-BFZ020b at drill cores. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.


m_from


m_to

Core GSI

Core m_from

Core m_to

Obs

OL-KR4 370.08 370.6 70 370.10 370.60 OL-KR7 285.70 287.80 52 287.44 287.70 OL-KR8 542.00 562.00 39 552.37 552.60 OL-KR9 473.70 474.70 74 473.70 474.70

OL-KR10 326.00 327.45 58 326.00 326.40 OL-KR12 271.87 282.97 59 271.87 272.97 OL-KR22 423.35 425.65 77 423.90 425.30 OL-KR24 380.73 385.55 55 380.83 381.45 OL-KR25 369.31 373.2 72 369.90 370.90 OL-KR28 445.4 445.7 49 445.40 445.70 OL-KR29 333.55 337.75 55 336.50 336.70 OL-KR38 372.53 392.62 56 383.48 384.08 OL-KR40 630.45 631.90 59 630.40 631.20 OL-KR42 272.83 274.36 --- No data OL-KR44 668.50 674.80 58 668.72 668.95 OL-KR48 376.35 382.85 57 378.22 382.85

20

40

60

80

OL-

KR

8

OL-

KR

28

OL-

KR

7

OL-

KR

24

OL-

KR

29

OL-

KR

38

OL-

KR

48

OL-

KR

10

OL-

KR

44

OL-

KR

12

OL-

KR

40

OL-

KR

4

OL-

KR

25

OL-

KR

9

OL-

KR

22

OL-

KR

42

GSI

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

core

wid

th

GSI

width

Figure A2 - 12. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ020b Blue dashed line presents the interpreted GSI-value of the deformation zones core (GSI =55).



20.5 28.9 42.8

71

Table A2 - 18. Intersections OL-BFZ020b at drill cores. Young’s modulus is calculated from data between depths Core m_from and core m_to.


m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 370.08 370.6 370.10 370.60 1.0 OL-KR7 285.70 287.80 285.70 287.80 1.0 OL-KR8 542.00 562.00 552.80 555.30 1.0 OL-KR9 473.70 474.70 473.70 474.70 1.0

OL-KR10 326.00 327.45 326.00 326.40 1.0 OL-KR12 271.87 282.97 271.80 272.97 1.0 OL-KR22 423.35 425.65 423.90 425.30 1.0 OL-KR24 380.73 385.55 380.73 785.55 1.0 OL-KR25 369.31 373.2 369.90 370.90 1.0 OL-KR28 445.4 445.7 445.40 445.70 1.0 OL-KR29 333.55 337.75 336.50 336.70 0.6 OL-KR38 372.53 392.62 374.04 375.55 0.6 OL-KR40 630.45 631.90 630.40 631.20 0.6 OL-KR42 272.83 274.36 273.50 273.85 0.6 OL-KR44 668.50 674.80 668.72 668.95 0.6 OL-KR48 376.35 382.85 380.25 380.55 0.6

72

OL-BFZ021

Figure A2 - 13. Brittle deformation zone OL-BFZ021 (c. 200 m below ONKALO). According to Q-classification, interpreted rock mass quality is “Very Poor”.


OL-BFZ021 is a moderately dipping thrust fault, with an approximate dip of 20 degrees towards the SSE. OL-BFZ021 and OL-BFZ099 are considered as two splays of a one single zone, combining into a single zone in the central part of the site volume. Similarly to OL-BFZ099, OL-BFZ021 is geologically well-pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of incohesive fault breccia and gouge (i.e. crushed rock). The thickness of the fault core varies from 1 to 8 m. the average thickness being approximately 4 m. As for the OL-BFZ099, the majority of the core intersections fall into the RiIII-category of the RG-classification, but in a few intersections RiIV and RiV-sections also occur. Again, this corresponds to the variation in the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone shows evidence of recurrent movements within the brittle regime as ductile and semi-ductile precursors are in many drill cores overprinted first by welded fractures and cohesive breccias and later by younger fractures.

73




Core GSI

Core m_from

Core m_to

Obs

OL-KR1 611.00 618.00 51 616.05 616.75

OL-KR2 600.00 607.00 42 605.38 605.68 OL-KR3 470.00 473.00 72 471.65 472.65 OL-KR4 756.00 764.00 37 760.95 761.40

OL-KR5 481.00 483.50 45 481.75 483.27

OL-KR6 468.00 471.00 52 469.00 469.70 OL-KR7 689.90 692.02 34 691.00 692.12

OL-KR11 623.00 627.00 42 625.02 626.40 OL-KR12 664.80 673.00 55 670.90 671.75 OL-KR19 464.00 766.00 70 464.75 465.35 OL-KR29 776.51 781.02 32 776.98 777.39 OL-KR43 340.00 345.93 --- No data

available OL-KR47 523.18 535.99 43 524.65 525.14

20

40

60

80

OL-

KR

29

OL-

KR

7

OL-

KR

3

OL-

KR

1

OL-

KR

11

OL-

KR

47

OL-

KR

5

OL-

KR

4

OL-

KR

6

OL-

KR

12

OL-

KR

19

OL-

KR

2

OL-

KR

43

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width

Figure A2 - 14. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ021 Blue dashed line presents the interpreted GSI-value of the deformation zones core (GSI =41).

74



17.4 22.9 30.3



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 611.00 618.00 no data OL-KR2 600.00 607.00 no data OL-KR3 470.00 473.00 no data OL-KR4 756.00 764.00 756.00 764.00 1.0 OL-KR5 481.00 483.50 no data OL-KR6 468.00 471.00 no data OL-KR7 689.90 692.02 no data

OL-KR11 623.00 627.00 no data OL-KR12 664.80 673.00 no data OL-KR19 464.00 766.00 no data OL-KR29 776.51 781.02 no data OL-KR43 340.00 345.93 no data OL-KR47 523.18 535.99 524.65 525.14 0.6

75

OL-BFZ039

Figure A2 - 15. Brittle deformation zone OL-BFZ039. According to Q-classification, interpreted rock mass quality is “Fair”.


The intersection in KR29 is composed of VGN and DGN, with some short sections of PGR. The feldspars are often altered to illite. The intersection contains a few old and welded fractures with calcite and pyrite infillings, especially in the PGR. Several of the fractures contain kaolinite and illite infillings. Accordingly, a majority of the fractures show signs of water conductivity and some of them also have green-grey clay infillings. There is, however, no indication of water flow in the flow measurements. The intersection exhibits 61 fractures, with a dip direction towards SE with a moderate dip. The rock is more fractured in section 543.80-547.12 m (37 joints). The intersection exhibit 29 fractures with a slickenside surface, which have a striation direction varying from SE to SW, with a moderate plunge.




Core GSI

Core m_from

Core M_to

Obs.

OL-KR7 473.92 473.92 --- 1 fracture OL-KR29 533.00 548.55 60 543.80 546.4

76

20

40

60

80

OL-

KR

29

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth

Figure A2 - 16. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ039. The interpreted GSI-value of the deformation zones core is 60.



35.9 38.6 41.6



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR7 473.92 473.92 no data OL-KR29 533.00 548.55 543.80 546.40 0.6

77

OL-BFZ043

Figure A2 - 17.. Brittle deformation zone OL-BFZ043. According to Q-classification, interpreted rock mass quality is “Good”.


A set of parallel quite steeply-dipping slickensides in KR10, which cross-cut the foliation. Slight pyrite coatings on fracture surfaces.

The first intersection in ONKALO is composed of one main fault (87/100°), which crosscuts the whole tunnel. This fault contains a ca. 15 cm wide section of epidote altered rock around the fracture in the left wall. As fracture filling it contains calcite, quartz, epidote and unidentified clays with a maximum thickness of 30 mm. Striation could not be determined from the slickenside surface, but the fracture has faulted to MGN inclusions dextrally when viewed from south to north in the left wall. In addition to the main fault the intersection contains several conjugate fractures either combining with the main fault or in the near vicinity of it. These fractures mainly have an undulating smooth profile and mainly contain calcite and epidote as fracture filling. This gives an indication of some kind of a hydrothermal alteration within this zone. The intersection contains a ca. 1.40 m wide “damage zone” with approximately equal extent on both sides of the main fault.

The second intersection in ONKALO is composed of two tunnel crosscutting undulating slickensided fractures and some shorter fractures near them. Filling minerals are calcite, quartz, some epidote, chlorite, illite, pyrite and galena also exists. The width of these fracture infillings changes between 2-50 mm. The surrounding rock is weakly banded, slightly fractured and unaltered veined gneiss.

78

Table A2 - 25. Intersections OL-BFZ043 at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.



Core GSI

Core m_from

Core m_to

Obs.

OL-KR10 271.41 271.60 49 271.5 271.6

ONKALO 1364.80 1366.00 62 ONK-BFI-136480-136600

ONKALO 2232.90 2234.50 73 ONK-BFI-223290-223450

20

40

60

80

ON

K-B

FI-1

3648

0-13

6600

ON

K-B

FI-2

2329

0-22

3450

OL-

KR10

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth




56.9 56.9 57.2



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR10 271.41 271.60 271.50 271.60 1.0 ONKALO 1364.80 1366.00 no data ONKALO 2232.90 2234.50 no data

79

OL-BFZ045b

Figure A2 - 19. Brittle deformation zone OL-BFZ045b. According to Q-classification, interpreted rock mass quality is “Poor”.

The interpreted GSI value for OL-BFZ045b is 48 and determined Young’s module is 27.04 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ045b is the average value of all determined brittle deformations zones. Geological description of OL-BFZ045b is following (Aaltonen et al. 2010):

A narrow zone outlined by two parallel, slickenside fractures. A white calcite vein between the fractures (about 1.5 cm); the vein shows step-like small-scale faulting with movement of about 1 cm/step (3-4 cm total); right-handed from above the core. Graphite present in the fractures. Resembles the "storage hall fault” OL-BFZ100.

Table A2 - 28. Intersections OL-BFZ045b at ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.



Core GSI

Core m_from

Core m_to

Obs

ONKALO 3350 3352 56 ONK-BFI-3350

ONKALO 4377.3 4389 41 ONK-BFI-4377

80

20

40

60

ON

K-B

FI-4

377

ON

K-B

FI-3

350

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth

Figure A2 - 20. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ045b. Interpreted GSI-value of the deformation zones core is 48.

81

OL-BFZ084



KR1: Fractures parallel with foliation are abundantly present as well as fractures perpendicular to foliation. Macadam-looking core sample, however, show some slickenside surfaces. TV-image shows 2 – 3 clear open fractures. Fracture surfaces carry powder-like clay minerals. Porosity and seriticisation (zinnwaldite) are detected. Two remarkable water-flow anomalies are situated in this section.

KR3: Pegmatite containing voluminous mica-rich parts, around which the rock has slipped and plenty of slickensides were born. Slight alteration, some pyrite on fracture surfaces and sporadic illite-coatings.

KR7: A short breakage, which is strongly aided by drilling. Strong geophysical anomalies, except water-conductivity are insignificant. Older strong ductile shear is visible.

TK2: Dextral fault zone upon a high-grade ductile shear zone precursor. The ductile shear zone has been reactivated and the resulting fractures are subsequently healed and welded by calcite and pyrite.

KR39: The intersection locates in varying VGN/DGN/PGR rock. It consists of three densely fractured zones with less fractured rock between them. The depths of the three core zones are: 178.94 - 179.26 m. 182.84 - 183.87 m and 186.51 - 187.52 m. The densely fractured sections are mostly in VGN. while DGN and PGR are less fractured. The main fracture direction is at 25-50/160. The fillings are chlorite, graphite, clay, pyrite and calcite. The intersection is altered with chloritization and graphitization at core zones. The less fractured parts of the section are only very weakly altered.

82

ONK-PH10: A densely fractured section (fracture spacing from 0.5-15 cm) with a very broken core zone (BFI_3540), where the core has broken up into pieces (rubble) of about 4 cm and less in diameter. Fracture-fillings are rather thin.

Table A2 - 29. Intersections OL-BFZ084 at drill core and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.



Core GSI

Core m_from

Core m_to

Obs.

OL-KR1 108.51 110.36 62 108.51 109.25

OL-KR3 158.20 162.75 42 158.20 158.60

OL-KR7 409.25 410.40 55 409.30 410.40

OL-KR39 178.05 187.60 45 186.40 187.55 CL 40 cm

ONKALO 3540.40 3543.80 50 ONK _BFI_3540

20

40

60

80

ON

K-B

FI-3

540

OL-

KR3

OL-

KR

39

OL-

KR7

OL-

KR1

GSI

0

0,5

1

1,5

2

2,5

3co

re w

idth

GSIwidth




27.4 37.7 43.0

83



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 108.51 110.36 108.60 109.90 1.0 OL-KR3 158.20 162.75 159.00 161.70 1.0 OL-KR7 409.25 410.40 409.30 410.40 1.0

OL-KR39 178.05 187.60 186.40 187.50 0.6 ONKALO 3540.40 3543.80 no data

84

OL-BFZ099

Figure A2 - 23. Brittle deformation zone OL-BFZ099. . According to Q-classification, interpreted rock mass quality is “Very Poor”.


OL-BFZ099 is a site-scale, moderately dipping thrust fault with an approximate dip of 40 degrees towards the SE. The fault zone is geologically well-pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, hydrothermal fracture-controlled/pervasive illitisation and kaolinisation and variable amounts of incohesive fault breccia and gouge (i.e. crushed rock). The thickness of the fault core varies from 1 to 13 m, the average thickness being 5 metres. A majority of the core intersections fall into the RiIII-category of the RG-classification (fracture-structured with minor fracture filling), but in few intersections also RiIV (crush-structured with clay fracture fillings) and RiV (clay-structured) sections occur. This corresponds to the variation on the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone also shows evidence of recurrent movements within the brittle regime, as ductile and semi-ductile precursors are in many drill cores overprinted first by cataclasites and later by younger fractures.

The thickness of the fault zone (core zone plus influence zone) is on average about 44 m but varies between 11 and 103 m in different drillholes. Characteristic features of the influence zone are the abundance of slickensides, pervasive illitisation, kaolinisation and sporadic occurrence of fracture-controlled sulphidisation and, in many cases, subsidiary fault core sections.

85



m_from

Geologiclal intersection

m_to

Core GSI

Core m_from

Core m_to

Obs.

OL-KR1 524.00 526.20 55 525.65 526.20 OL-KR2 471.00 473.00 49 471.23 472.27 OL-KR3 470.00 473.00 72 470.00 473.00 OL-KR4 756.00 764.00 37 758.27 758.45 OL-KR5 278.00 283.00 40 279.48 280.25 CL 77 cm OL-KR6 162.8 166.5 66 162.80 164.80 OL-KR7 689.90 692.02 34 691.00 692.12

OL-KR11 623.00 627.00 42 625.02 626.40 OL-KR12 581.00 584.10 61 582.40 584.10 OL-KR13 445.50 468.00 51 453.20 453.62 OL-KR19 253.00 261.00 54 259.00 259.65 OL-KR20 410.59 424.45 50 416.29 417.70 OL-KR20 426.90 431.14 43 426.90 428.59 OL-KR29 776.51 781.02 32 776.98 777.39 OL-KR33 275.50 280.43 42 275.90 276.30 OL-KR43 97.10 102.10 --- No data

available OL-KR47 324.44 343.80 40 330.74 330.9

20

40

60

80

OL-

KR

29

OL-

KR7

OL-

KR4

OL-

KR5

OL-

KR

47

OL-

KR

11

OL-

KR

33

OL-

KR

20

OL-

KR2

OL-

KR

20

OL-

KR

13

OL-

KR

19

OL-

KR1

OL-

KR

12

OL-

KR6

OL-

KR3

OL-

KR

43

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

thGSI

width


86



24.0 32.0 43.6



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR1 524.00 526.20 524.00 526.20 1.0 OL-KR2 471.00 473.00 471.00 473.00 1.0 OL-KR3 470.00 473.00 470.00 473.00 1.0 OL-KR4 756.00 764.00 756.00 764.00 1.0 OL-KR5 278.00 283.00 no data OL-KR6 162.8 166.5 162.80 164.80 0.6 OL-KR7 689.90 692.02 no data

OL-KR11 623.00 627.00 623.00 627.00 1.0 OL-KR12 581.00 584.10 581.00 584.00 1.0 OL-KR13 445.50 468.00 451.04 459.23 1.0 OL-KR19 253.00 261.00 no data OL-KR20 410.59 424.45 416.50 420.60 1.0 OL-KR20 426.90 431.14 426.90 428.59 1.0 OL-KR29 776.51 781.02 777.00 781.00 0.6 OL-KR33 275.50 280.43 275.50 279.00 0.6 OL-KR43 97.10 102.10 98.63 99.64 0.6 OL-KR47 324.44 343.80 330.74 330.90 0.6

87

OL-BFZ100

Figure A2 - 25. Brittle deformation zone OL-BFZ100. According to Q-classification, interpreted rock mass quality is “Very Poor”.


The fault consists of a clearly definable core and transition zone; the core has a varying width of 0.15 to 2 metres and has in places strongly developed schistose fabric with associated slickensided surfaces. Quartz, pyrite, chalcopyrite, graphite, galena and talc mineralisations can be observed within the fault core. Pyrite mineralisation occurs within cavities associated with quartz-filled tension veins. Chalcopyrite seems to be associated with calcite-filled fractures/tension veins. The fault zone shows sinistral sense of movement by numerous kinematic indicators.

88

Table A2 - 35. Geological indications for the OL-BFZ100 intersections. Core m_from and core m_to are the depths of the selected GSI value of intersection in question.

Hole_id


m_from


m_to

Core GSI

Core m_from

Core m_to

OL-PH1 151.64 154.32 26 152.38 152.62

ONK-PH4 27.10 30.57 70 28.76 29.6 OL-KR22 337.65 340.45 67 338.20 339.60 OL-KR23 372.5 373.02 67 372.50 373.02 OL-KR25 216.5 222.05 43 217.65 218.31 Ol-KR26 95.80 98.25 70 96.82 97.9 OL-KR28 170.21 178.30 62 172.60 173.20 OL-KR34 48.38 53.77 43 48.38 49.46 OL-KR37 56.23 57.5 47 56.19 56.71 OL-KR42 183.03 198.83 --- No data ONKALO 128.50 129.30 RiIV ONK_BFI_12850-12930 ONKALO 521.50 523.00 RiIV ONK_BFI_52150-52300 ONKALO 900.20 906.40 RiIV ONK_BFI_90020-90640 ONKALO 1592.90 1595.00 40 ONK_BFI_159290_159500 ONKALO 1819.00 1831.00 43 ONK_BFI_181900_183100 ONKALO 2481.50 2482.00 56 ONK-BFI-248150-248200 ONKALO 2931.50 2937.50 46 ONK-BFI-293150-293750

20

40

60

80

ON

K_BF

I_15

9290

_159

500

ON

K_BF

I_18

1900

_183

100

ON

K-BF

I-293

150-

2937

50

ON

K-BF

I-248

150-

2482

00

ON

K_BF

I_12

850_

1293

0

ON

K_BF

I_52

150_

5230

0

ON

K_BF

I_90

020_

9064

0

OL-

PH1

OL-

KR25

OL-

KR34

OL-

KR37

OL-

KR28

ON

K-PH

4

OL-

KR22

OL-

KR23

OL-

KR26

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width

Figure A2 - 26. Minimum GSI values and width of minimum GSI section in the tunnel and drillhole intersections of brittle deformation zone OL-BFZ100. The blue dashed line presents the interpreted GSI-value of the core (GSI =43).



32.0 44.9 50.1

89



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-PH1 151.64 154.32 no data ONK-PH4 27.10 30.57 27.01 30.57 0.6 OL-KR22 337.65 340.45 338.20 339.60 1.0 OL-KR23 372.5 373.02 no data OL-KR25 216.5 222.05 217.32 218.31 1.0 Ol-KR26 95.80 98.25 96.82 97.90 1.0 OL-KR28 170.21 178.30 177.02 178.02 1.0 OL-KR34 48.38 53.77 49.23 50.17 0.6 OL-KR37 56.23 57.5 56.23 57.50 0.6 OL-KR42 183.03 198.83 197.70 198.10 0.6 ONKALO 128.50 129.30 no data ONKALO 521.50 523.00 no data ONKALO 900.20 906.40 no data ONKALO 1592.90 1595.00 no data ONKALO 1819.00 1831.00 no data ONKALO 2481.50 2482.00 no data ONKALO 2931.50 2937.50 no data

90

OL-BFZ101


The interpreted GSI value for OL-BFZ101 is 45 and determined Young’s module is 27.04 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ0101 is the average value of all determined brittle deformations zones. Geological description of OL-BFZ101 is following (Aaltonen et al. 2010):

Brittle fault intersection, which is visible across the whole tunnel, has a trace length of more than 40 meters. The fault plane has an average dip/dip direction of 10/151. The width of the zone is approximately 2 meters. The fault has partly a semi-brittle character as the foliation near the fault shows well-developed deflection and thus indicating that the hanging wall of the fault has moved towards west (reverse fault). The fault plane crosscuts the foliation. Accordingly, sense-of-movement viewed from south is sinistral. The fault has a well-developed 10-30 cm wide core, which contains of intensively crushed rock (0.1-30 mm in diameter) and greenish clay. The core can be defined as fault breccia, as most of the material consists of rock pieces (70-80%).The fault has also an intensively altered "transition intersection" in which the rock is quite homogenous K-feldspar porphyric tonalite/granodiorite; the K-feldspar phenocrysts are 5-50 mm in diameter and are both eu- to subhedral. The width of this K-feldspar porhyritic zone is 0.2-2 m in the hanging wall and approximately 1 meter in the footwall.

91

Table A2 - 38. Intersections OL-BFZ101 at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.

Hole_id

Geological intersection m_from


Core GSI

Core m_from

Core m_to

Obs

ONKALO 65.6 68.00 71 ONK-BFI-6560-6575 Q_median

OL-PH1 98.59 99.76 45 98.59 99.76

20

40

60

80

OL-

PH1

ON

K-BF

I-656

0-65

75

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth (Q

_med

ian)


92

OL-BFZ106



KR22: Inside the section lies the semi-ductile intersection SFI_OL_KR22_04335-06530. A few old, “welded” fractures with calcite infilling are present. The intersection contains several slickensides between 46.00-48.00 m. Slickensides follow the foliation. The slickenside surfaces often contain graphite and chlorite. The beginning of this section is badly crushed (partly mechanical). Signs of water conductivity were observed in sections 50.00-51.20 m and 66.53-67.12 m. The fractures in the former section contains greenish clay (1 mm thick, unidentified) and the latter graphite, kaolinite and some unidentified greenish clay.

KR27: The intersection contains mostly VGN with short sections of PGR and a grey-red, fine-medium grained, sheared rock that resembles VGN at 86.31-88.03 m and 92.80-94.25 m. The VGN is greenish in colour, due to propable illite alteration. The PGR exhibits a red (paleo)oxidation. The intersection is strongly altered and shows a paleoshearing, which probably later has been reactivated. The rock is partly porous because of the mineral leaching. The rock exhibits in one joint a black mineral (goethite?) and a few gouges with unidentified clay minerals. Water flowing has been determined in following fractures: 84.60 m, 86.40 m, 88.00 m, 89.80 m, 92.75 m and 95.50 m. The intersection also contains old, randomly oriented “welded” fractures; fractures are welded by calcite.

KR40: Short intersection in PGR, with fractures mainly in dip direction 030/60. Fracture fillings are clay, carbonate and yellowish mineral (epidote/sericite?). The PGR around fractures is weakly altered with epidotization/sericitization.

93



Geolocical intersection m_to

Core GSI

Core m_from

Core m_to

OL-KR22 42.80 73.15 40 46.00 46.27 OL-KR27 84.50 96.50 33 95.40 95.70 OL-KR40 395.10 395.75 60 395.10 395.75

20

40

60

80O

L-KR

27

OL-

KR22

OL-

KR40

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width




23.1 28.8 32.4



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR22 42.80 73.15 46.00 48.00 1.0 OL-KR27 84.50 96.50 86.70 87.50 1.0 OL-KR40 395.10 395.75 395.10 395.75 0.6

94

OL-BFZ118


The interpreted GSI value for OL-BFZ118 is 60 and determined Young’s module is 27.04 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ0118 is the average value of all determined brittle deformations zones. Geological description of OL-BFZ118 is following (Aaltonen & al. 2010):

ONK-BFI-71310-71805: Six single slickenside surfaces that cut the tunnel. Only few SS surfaces combine. Fracture fillings (1-40 mm): pyrite, calcite, kaolinite, quartz, chlorite, hornblende and chalcopyrite. Thick (~5 cm) calcite and quartz filling in one fracture. Fracture orientations: 83/081, 82/073, 72/086 (right wall). Orientations are similar in the left wall. Left-handed movement observed in PGR vein on the right wall.

Table A2 - 42. Intersections OL-BFZ118 at drill cores and ONKALO. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view



Core GSI

Core m_from

Core m_to

Obs

ONKALO 713.10 718.05 72 ONK-BFI-71310-71805 Q_median

ONK-PH3 19.2 21.8 60 20.35 21.8

95

20

40

60

80

OL-

PH

3

ON

K-B

FI-7

1310

-718

05

GSI

0

1

2

3

4

5

6

core

wid

th

GSI

width

(Q_m

edia

n)


96

OL-BFZ146



“Liikla shear zone”, a major ductile shear zone detected in TK14 and lineament interpretation (SURFMAGN0003 and SURFMAGN0068). In TK14, the zone is characterised by strongly foliated, pervasively altered and weathered veined gneiss. The mesosome is totally chloritised and hematised and the neosome kaolinitised and illitised. Most foliation planes are weathered open, which gives the rock a densely fractured look. The sense-of-shear remains ambiguous but the rock contains some sub-horizontal lineations plunging slightly towards the WSW. The upper parts of drillholes KR27, KR40 and KR45 are highly fractured (numerous RiIII-RiIV zones), indicating that also brittle deformation may be related to this zone. The zone has also been fixed to highly fractured sections in drillholes KR49 and KR50, showing slickenside fractures, alteration and indications of semi-brittle deformation. According to the recent magnetic interpretation, the zone may be cut by several N-S trending fault zones.




Core GSI

Core m_from

Core m_to

OL-KR27 10.91 11.96 --- OL-KR27B 14.45 15.53 67 14.45 15.53 OL-KR40 22.93 23.39 ---

OL-KR40B 16.20 23.20 60 20.50 23.20 OL-KR45 58.10 62.55 63 61.10 61.75 OL-KR49 323.62 324.49 58 323.62 324.49 OL-KR50 391.28 391.77 49 391.28 391.77

97

20

40

60

80

OL-

KR50

OL-

KR49

OL-

KR40

B

OL-

KR45

OL-

KR27

B

OL-

KR27

OL-

KR40

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width




12.8 23.3 32.0



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR27 10.91 11.96 no data OL-KR27B 14.45 15.53 14.45 15.53 1.0 OL-KR40 22.93 23.39 22.93 23.39 0.6

OL-KR40B 16.20 23.20 19.28 19.64 0.6 OL-KR45 58.10 62.55 60.76 61.53 0.6 OL-KR49 323.62 324.49 323.62 324.49 0.6 OL-KR50 391.28 391.77 391.28 391.77 0.6

98

OL-BFZ152



The zone is based on magnetic lineament NEWSURFMAGN18. It is observed as a magnetic minimum.

OL_KR44_BFI_79108_79556: The intersection locates in moderately banded VGN, between a PGR+MGN (hanging wall) and TGG (roof wall) sections. It consists of 29 fractures of which 12 are slickensided. Fracture fillings consist mostly of chlorite, kaolinite, illite and pyrite, with occasional clay and calcite. Main fracture directions are a subvertical fracture direction (also core direction) dipping 70-90 degrees to directions 105 and 285, and fracture directions 70/220 and 15/320. The measured lineations are quite variable, showing several drends and dips. The core of the intersection locates at 793.30 - 793.68 m, and consists of densely fractured rock (mostly slickensides), but no real fault breccia. Outside the core there are less fractures and the outer borders of the intersection is defined by lack of slickensided/chlorite filled fractures. The alteration in the intersection is local weak illitization with pinitization of cordierite.

OL_KR45_BFI_6858_7121: The intersection locates at the upper contact of VGN to underlying KFP. The transition of rock types occur at 68.20 - 68.10 m. The intersection consists of 21 logged fractures of which one is grain filled and two have weak lineations, suggesting more a weak BFI type than clear BJI type intersection. The fracture fillings are mainly clay, chlorite and illite with occational calcite, pyrite and

99

epidote. There is a dominating fracture direction 30/360 and minor directions: 50/330 and 10/220. The core of the intersection locates at 68.89 - 69.16 m and consists of one grain filled fracture at 68.89 m and densely fractured rock below it. The intersection shows weak to moderate illitization, epidotization and chloritization, as also the wall rock. The outer borders of the intersection are defined by lack of chlorite filled fractures.




Core GSI

Core m_from

Core m_to

OL-KR44 791.08 795.56 60 793.30 793.68 OL-KR45 68.58 71.21 68 68.89 69.16

20

40

60

80

OL-

KR44

OL-

KR45

GSI

0

0,5

1

1,5

2

2,5

3co

re w

idth

GSIwidth




8.2 43.0 43.4

100



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR44 791.08 795.56 793.30 793.68 0.6 OL-KR45 68.58 71.21 68.89 69.16 0.6

101

OL-BFZ159

Figure A2 - 37. Brittle deformation zone OL-BFZ159. According to Q-classification, interpreted rock mass quality is “Good”.


The zone is based on topographic lineament TOPO0117 There are also some magnetic indications (magnetic lineament SURFMAGN 0116). The intersection is located mainly in PGR. The intersection is characterized by fractures oriented 035/60. The fractures have thin fillings of carbonate, pyrite, chlorite and clay. Part of the fractures is closed. The core of the intersections locates at 385.73 - 386.36 m. The amount of visible fragments is > 90 % so material could be classified as fault breccia. In the core there is possibly a weak older SFI shown as an epidotized/sericitized network of healed fractures and weak breccia. Around the core there is weak epidotization/sericitization.

Table A2 - 49. Intersections OL-BFZ159 at drill core. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.



Core GSI

Core m_from

Core m_to

OL-KR40 385.40 387.67 73 385.40 386.40

102

20

40

60

80

OL-

KR40

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth




22.5 30.3 39.0



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR40 385.40 387.67 385.40 386.40 0.6

103

OL-BFZ160



The zone is based on topographic lineament TOPO0465 correlated to drillhole intersection OL_KR45_BFI_17809_19536. The intersection is weakly mineralized in low temperature, and a large portion of the fractures (locally also fault breccia) are loosely closed with calcite, pyrite and graphite. The BFI consists of 152 logged fractures of which 14 have clearly slickensided surfaces. Most other fractures have clay or crushed rock as filling, showing clear fault type intersection. Typical fracture filling minerals are: chlorite, graphite, pyrite, calcite, illite and clay minerals. The core of the intersection locates at 185.05 - 185.45 m and consists of fault breccia/gouge that is washed away during drilling (core loss). The fracture directions are variable but three fracture directions can be observed: 15/330, 30/200 and 45/290. The number of measured lineations is small but 2 measurements each show following lineations: 25/345, 20/030 and 5/090. The intersection is moderately to strongly altered with sulphidization, illitization and carbonatization. The borders of the intersection are defined by lack of severe KL filled fracturing.

Table A2 - 52. Intersections OL-BFZ160 at drill core. Core m_from and core m_to are the depths of selected GSI value of intersection in question i.e. the core from rock mechanical point of view.



Core GSI

Core m_from

Core m_to

OL-KR45 176.02 195.36 46 183.60 184.07

104

20

40

60

80

OL-

KR

45

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth




37.4 42.0 44.2



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR45 176.02 195.36 176.02 180.51 0.6

105

OL-BFZ161

Figure A2 - 41. Brittle deformation zone OL-BFZ161. According to Q-classification, interpreted rock mass quality is “Good”.


OL-BFZ161 is a subhorizontal potential fault zone with an approximate orientation of 145/16º. The modeled dimensions of this feature are ca. 2650 x 500 m. The zone is initially based on 3D reflection seismics: reflective features at the depth of ca. 730 – 780 m in the 2006 survey and 1050 – 1300 m in the 2007 survey were combined into a single unit. The zone intersects drillhole OL-KR4 at the depth of ca. 808 – 810 m and is characterised by intense fracturing, a few slickenslided fractures, pervasive illitisation and fracture-controlled kaolinitisation.




Core GSI

Core m_from

Core m_to

OL-KR4 808.30 809.95 65 808.30 809.95

106

20

40

60

80

OL-

KR

4

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSI

width




39.8 41.7 46.1



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR4 808.30 809.95 808.30 809.95 1.0

107

OL-BFZ175



OL-BFZ175 is a gently dipping fault zone with an approximate orientation of 150/27º. The zone is based on MAM results with a grounding in OL-KR11 at the depth of 418 m. It combines the following drillhole sections: OL-KR11 413.08 – 413.27 m (RiIII), OLKR42 297.99 – 298.36 (BFI), OL-KR46 411.7 – 412.17 (BFI), OL-KR47 220.87 – 221.50 (BFI) and OL-KR9 547.74 – 549.23 (RiIII). The core intersections are typically characterised by slickenside fractures with a moderate dip to the SSE. Geologically and geophysically the zone is not very significant. However, occasionally P-wave and hydraulic anomalies are related to it. The fault is located in the eastern part of the site as a possible extension or an extra splay of OL-BFZ020B (See Figure 9-34).




Core GSI

Core m_from

Core m_to

Obs.

OL-KR9 547.74 549.23 68 547.74 549.23 OL-KR11 413.08 413.27 53 413.08 413.27 OL-KR42 297.03 302.67 -- No data OL-KR46 411.68 412.17 46 411.66 412.06 OL-KR47 216.80 238.31 55 217.10 217.49

108

20

40

60

80

OL-

KR46

OL-

KR11

OL-

KR47

OL-

KR9

OL-

KR42

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth




32.9 40.3 41.7



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR9 547.74 549.23 547.74 549.23 1.0

OL-KR11 413.08 413.27 413.08 413.27 1.0

OL-KR42 297.03 302.67 297.99 298.36 0.6

OL-KR46 411.68 412.17 411.70 412.17 0.6

OL-KR47 216.80 238.31 220.87 221.5 0.6

109

OL-BFZ214


The interpreted GSI value for OL-BFZ214 is 40and determined Young’s module is 27.04 GPa. No seismic data were available from drillhole intersections and determined Young’s modulus for OL-BFZ0214 is the average value of all determined brittle deformations zones. Geological description of OL-BFZ214 is following (Aaltonen et al. 2010):

This zone is modelled by combining the long highly fractured section at the lower end of OL-KR47 and a major bounding lineament north of Olkiluoto island. The lineament has been detected by acoustic soundings. Based on fracture intensity and remarkable core loss the main core of the fault is fixed at 926.74 – 927.2 although there are no oriented fracture data.

OL_KR47_BFI_82852_100876: This is a very long brittle fault intersection that may be composed of several independent fault intersections blending to each other. The whole drillcore from 828.53 m downwards is fractured by slickensided fractures (194 of 499 fractures logged), and therefore it is impossible to defined stricter outer borders to the intersection(s). The natures of the several fault intersection cores are quite similar suggesting that they may be of same origin though. No borehole image exists and there is practically no oriented sample of the core sections, so their same/different attitude cannot be verified. There are three common fracture directions, counted over the whole length of the intersection. The dominant is dipping to direction 180 degree with dip of ~45 degrees (almost parallel to foliation). One fracture direction is almost vertical 80-90 degrees dip with a strike 360/180. Third fracture direction dips to direction 230 degrees with a dip of ~40 degrees. The intersection locates in variable rocks, PGR from start to ~868 m, continuing with VGN, intersected by few short PGRs to the end of the drillhole at 1008.76 m. The uppermost fault core locates at 896.52 - 897.55 m and consist of frequent sl. fractures and at 896.82 - 896.89 m compacted fault breccia. The breccia has been compacted with unidentified white mineral (possibly nacrite?) The first core seems to dip to direction 170 degrees with a dip of 50 degrees. The second fault core locates at 915.42 - 915.83 m and consist of fault breccia with clay, graphite and pyrite. The attitude of the core is unknown. Third fault core locates at 926.74 - 927.20 m and consist of fault breccia. There are also several other less pronounced section of intensive fracturing and minor breccia (eg. 925.93 m. 956.60 m and 957.00 m). The core zones are altered with strong graphitization, chloritization and locally sulphidization and weak

110

illitization. The zones of influence are mainly unaltered or weakly altered. The PGR sections below 959 m contains locally core discing.




Core GSI

Core m_from

Core m_to

OL-KR47 828.53 1008.76 40 926.74 927.20

20

40

60

80O

L-K

R47

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth


111

OL-BFZ219



The intersection is composed of VGN and PGR. PGR sections have old welded calcite bearing fractures. Fractures have dip direction towards NW with a nearly horizontal dip. The intersection contains 8 slickenside surfaces but the orientation of the striation varies. Some of the fractures are water -conducting. These fractures contain kaolinite and grayish clay infillings. The intersection contains ca 40 joints, with 13 fractures/0.7 m (576.21-576.91). Some mechanical fracturing has occurred during the drillings.




Core GSI

Core m_from

Core m_to

OL-KR25 517.55 578.00 51 572.24 572.50

112

20

40

60

80

OL-

KR

25

GSI

0

0,5

1

1,5

2

2,5

3

core

wid

th

GSIwidth




28.1 28.8 29.4



m_from


m_to

Core

m_from

Core

m_to

Distance btw

transm and recvr

OL-KR25 517.55 578.00 571.70 572.50 1.0

Geometrical and Mechanical Properties of the Fractures and ... · brittle deformation zones,...

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Transcript of Geometrical and Mechanical Properties of the Fractures and ... · brittle deformation zones,...