FORMER DE BURGH SCHOOL PLAYING FIELD CHETWODE ROAD ... FORMER DE BURGH SCHOOL PLAYING FIELD CHETWODE...

FORMER DE BURGH SCHOOLPLAYING FIELDCHETWODE ROADTADWORTHSURREY

Phase IIGeoenvironmental Investigation

ClientLondon Square Developments Limited

AgentBarnard & Associates

Report No. 4381-2

18th October 2016

CONTENTS

Section Page

SYNOPSIS 1

1 Site description 2

2 Development proposals 2

3 Geology 3

4 Field work 3

5 Laboratory testing 4

6 Ground conditions6.1 Stratigraphy 5

6.1.1 Overburden 66.1.2 Lewes Nodular Chalk Formation 6

6.2 Groundwater 7

7 Discussion7.1 General 77.2 Ground floor slabs 87.3 Excavations 87.4 Pavement construction 97.5 Surface water drainage 107.6 Contaminant analysis

7.6.1 Solid phase 117.6.2 Gas phase 127.6.3 Waste Acceptance Criteria (WAC) 137.6.4 Conclusion 14

7.7 Buried concrete 14

Procedural Notes

APPENDICES

A FiguresB Borehole RecordsC In Situ Permeability Test ResultsD Standpipe RecordsE California Bearing Ratio Test ResultsF Lankelma CPT Report, June 2016G Lankelma CPT Report, August/September 2016H Laboratory Test Results

Synopsis

An investigation has been carried out on the former De Burgh School Playing Fields in

Tadworth on the instructions of London Square. Technical direction was provided by

Barnard & Associates whilst specialist geotechnical advice was provided by Geotechnical

Consulting Group (GCG). A Phase I Environmental Assessment1 has been prepared for

the site and should be read in conjunction with this report.

The purpose of the investigation was to determine the ground conditions and to provide

recommendations in respect of foundation design and other geoenvironmental matters

for the proposed residential development.

Nine boreholes and two phases of investigation by Cone Penetration Testing were

carried out, supported by a programme of in situ and laboratory testing.

The results indicate that solution features are present within the underlying chalk and it

is anticipated that raft foundations will be utilised for pairs of houses whilst the flats will

be piled. Detailed recommendations relating to the proposed foundations forms part of

the GCG assessment. Chemical analysis revealed no significant contamination.

4381-2

FORMER DE BURGH SCHOOL PLAYING FIELDCHETWODE ROAD

TADWORTHSURREY

Phase II Geoenvironmental Investigation

1 Report No. 4381-1 Phase I Environmental Assessment. Former De Burgh School Playing Field,Chetwode Road, Tadworth, Surrey. AP Geotechnics Ltd., 8 January 2016

1

Site description

The area under investigation is an irregularly shaped portion of land extending to

approximately 6 hectares. The current general arrangement is presented on Figure 1 at

Appendix A.

The site is currently undeveloped and laid to grass. The site is fairly flat but levels drop from

around 177 m OD in the north to 167.5 m OD in the south. Trees and shrubs were generally

limited to the boundaries although a couple were present within the site itself. Japanese

Knotweed was noted on the northern boundary although outside the site itself.

A full site description is available in the Phase 1 report to which the reader is referred.

2

Development proposals

It is intended to construct 168 houses and 61 flats (in 11 blocks of 2½ to 3 storeys height)

along with associated roads, car parking, open space and other infrastructure, as shown on

Figure 2 at Appendix A.

The imposed loads were not known during preparation of this report but are expected to be

light to moderate.

4381-2 2

3

Geology

Published records of the British Geological Survey indicate the site to lie on Clay-with-flints

over Thanet Sand underlain by the Lewes Nodular Chalk Formation.

4

Field work

The extent of the field work was agreed with the Client and was originally scheduled to

comprise eight boreholes advanced by light percussive techniques; three to 10 m and three to

15 m depth. However, in view of the highly variable depth to chalk, nine boreholes were

drilled to depths ranging from 10 m to 35 m. In addition, two separate phases of investigation

by Cone Penetration Testing (CPT) techniques was carried out. The location of the boreholes

and CPTs is shown on Figure 3 at Appendix A.

Representative soil samples were recovered from the boreholes for subsequent laboratory

examination and testing; whilst Standard Penetration Tests (SPT) were carried out as

appropriate. Details of the strata encountered are provided on the Borehole Records at

Appendix B; together with particulars of the samples recovered, groundwater observations

and SPT results. The profile of SPT is also presented at Figure 4 of Appendix A.

Falling head permeability tests were undertaken in all boreholes except BHs 1, 4 and 4A with

the results available at Appendix C.

Standpipes were installed in boreholes 2, 4, 6 & 7 to permit monitoring of groundwater levels

and soil gas concentrations. The results are presented at Appendix D.

4381-2 3

To aid pavement design, eight in situ California Bearing Ratio (CBR) tests were carried out

with the results available at Appendix E. The location of the in situ CBRs is shown on Figure 5

at Appendix A.

The first investigation via CPT was carried out between 7 and 10 June 2016 using an 18.0

tonne tracked unit and is presented at Appendix F. Twenty two CPTs were undertaken and

included a magnetometer due to the potential threat posed by unexploded ordnance (UXO).

Mostap sampling was also carried out to confirm the ground conditions. A number of tests

were terminated at fairly shallow depth due to tip load. It was therefore decided to mobilise a

31.0 tonne wheeled CPT unit which could ‘dummy push’ through any obstacles and allow CPT

testing to continue beneath the obstacle. This field work was carried out between 30 August

and 2 September 2016 and was supervised by Geotechnical Consulting Group (GCG). Thirty

three CPTs with magnetometer and three video probe tests were carried out over the four

days. The report is presented at Appendix G.

5

Laboratory testing

The following laboratory tests were conducted on soil samples recovered during the field

work:-

Natural moisture content: to assess the in situ condition of the soil.

Liquid and Plastic Limits: to classify cohesive soil into behavioural groups.

Particle size distribution: by sieve analysis to classify granular material.

Unconsolidated undrained triaxial compression: to determine the shear

strength of cohesive material under immediate loading and thus to assess its

load bearing capacity.

4381-2 4

Soluble & total sulphate concentration and pH value: for the specification of

buried concrete.

Contamination: chemical analyses to detect the presence of contaminants as

indicated by the Phase 1 Assessment, viz:-

Total arsenic, cadmium, chromium, copper, lead, mercury,

nickel, zinc and selenium.

Hexavalent chromium and water soluble boron.

Total phenols, speciated Polycyclic Aromatic Hydrocarbons

(PAH), speciated Total Petroleum Hydrocarbons (TPH) and

polychlorinated biphenyls.

Asbestos screen and Waste Acceptance Criteria (WAC) full

solid waste suite and 2 stage leachate suite.

Results of these tests are presented at Appendix H and the variation of shear strength with

depth is shown at Figure 6 of Appendix A.

6

Ground conditions

6.1

Stratigraphy

The stratigraphy of the site as revealed by the boreholes is shown in detail at Appendix B and

is described in general terms hereafter. Ground conditions inferred from the CPTs are

provided in the reports at Appendix E & F.

4381-2 5

Although the BGS map the site as Clay-with-flints over Thanet Sand, the material above the

chalk revealed by the investigation is not considered entirely representative of either strata.

All material overlying the chalk has therefore been termed as overburden for the purposes of

this report.

6.1.1

Overburden

All boreholes were advanced through a surface layer of turf over topsoil which was observed

to a maximum depth of 0.85 m in BH2. Underlying the topsoil in all boreholes was a

succession of clays, sands and gravels.

Atterberg Limits performed on samples of clay indicates it to have a low to intermediate

plasticity. Visual assessment and triaxial testing indicates the clays to range from soft in the

upper reaches of BH1 and BH4 to stiff in BHs 4, 7 & 8.

The granular material ranged from a silty, fine to medium sand to a silty, very sandy gravel.

Standard penetration tests revealed the granular deposits to be generally in a medium dense to

dense state of compaction although loose conditions were noted locally. Of particular note is

the reduction in SPT N value with depth in granular material in BH1. Borehole 1 recorded a

drop in N values from 23 at 13.0 m to 5 at 19 m depth which is indicative of solution feature

infill.

6.1.3

Lewes Nodular Chalk Formation

This stratum was encountered at depths ranging from 5.30 m in BH5 to 27.80 m in BH4A and

continued to the limit of investigation by cable percussive means of 35 m. The samples

4381-2 6

produced by light percussive drilling only permit basic descriptions since the fabric of the rock

is destroyed by the action of drilling. Nevertheless, the SPT results give a fairly good indication

of its condition. Figure 4 shows the penetration resistance increasing with depth, albeit

gradually, which is consistent with a reduction in weathering over the depth of investigation.

Flints were recovered during the drilling process and these account for some of the scatter.

6.2

Groundwater

No groundwater was encountered during the investigation. The water sample recovered from

BH1 is likely to be remnants of water added to aid the drilling process. However, the speed of

drilling, the requirement to add water to aid the drilling process in granular material and the

use of casing to support the bore may have masked any small inflows and impinged upon the

accuracy of the observations.

Subsequent monitoring of the standpipes has recorded dry conditions on all occasions.

7

Discussion

7.1

General

The Phase I Assessment indicated that the site has not been previously developed, save for a

small portion just to the east of Marbles Pond which carried some huts associated with the

former De Burgh School campus. It is understood that the school was demolished and

redeveloped for housing in the late 1990s/early 2000s.

4381-2 7

The geotechnical specialists (GCG) are producing a report which will detail the foundation

solutions for the houses and flats at the site and below is a brief summary.

In view of the solution features identified in the chalk, GCG have recommended that pairs of

houses utilise stiff rafts as a foundation solution. They have advised that a net allowable

bearing capacity of 75 kPa should be used although this is subject to refinement following

further investigation.

Piled foundations are recommended for the 11 blocks of flats. CFA piles are recommended as

they avoid many of the installation difficulties that would otherwise be experienced, particularly

the need for casing through the granular material. Some negative shaft friction will be allowed

for in the overburden when calculating pile capacity.

7.2

Ground floor slabs

Where flats are located on clay subsoil, suspended ground floor construction is recommended.

A minimum void of 250 mm thickness should be incorporated beneath the suspended slab in

accordance with NHBC recommendations, assuming precast concrete flooring.

7.3

Excavations

The near surface soils were somewhat variable across the site, with both cohesive and granular

facies present. It is therefore recommended that all excavations are supported at all times,

unless battered to a safe angle of repose. In any event, excavations to greater than

1.2 m depth should be supported at all times.

4381-2 8

Provision of adequate support is especially important for the safety of personnel when

required to work in or close to excavations. Particular care should be exercised if excavations

are close to existing structures to ensure they do not experience any loss of support.

Temporary and permanent works should be designed to resist the additional lateral earth

pressures arising from any superimposed loads in addition to those generated by the soil itself,

without significant deformation.

Observations during the intrusive works and subsequent monitoring visits suggests that

groundwater inflows are unlikely within general construction excavations. However, a

perched water table may be established in the near surface material, especially after periods of

high rainfall. Conventional pumping from shallow sumps should be able to control any limited

inflows. Alternatively, any inflows may drain into the underlying material where granular

deposits are present.

The BGS maintain an online database of Borehole Records which has been searched in the

vicinity of the site. A 152 m deep borehole, drilled approximately 200 m to the north in

November 1979 struck water at a depth of 118 m. The top of the borehole is at a comparable

level to the north of the site (176.78 mOD).

7.4

Pavement construction

Where in areas of proposed pavement, it is recommended that the topsoil be removed and a

consistent formation level exposed.

The results of the eight in situ California Bearing Ratio (CBR) tests are presented at Appendix

D and show values ranging from 0.7 % to 6.0 %, depending on the particular composition and

moisture content of the material under test.

4381-2 9

It is well documented that CBR values decrease as soil moisture content increases. Unless

efficient sub - grade drainage is installed and can be guaranteed to perform throughout the life

of the proposed pavement, it is likely that the sub - grade moisture content will increase in

service, leading to a reduction in the CBR value. Therefore, although the test results may be

used as a guide for pavement design, it would be prudent to allow a reduction to reflect the

in - service condition beneath the pavement to a value of some 1 % for design purposes.

Where low CBR values are anticipated, consideration should be given to the use of a capping

layer of compacted granular fill. As a rule of thumb, a 300 mm thick layer of suitable granular

fill can double the design CBR.

The formation should be inspected on exposure and any unsuitable material replaced with

suitable compacted fill. Proof rolling of the formation will provide a more uniform surface for

construction, although this will not improve the properties of the material at depth.

It is recommended that flexible construction techniques such as block paving or wholly

bituminous materials are employed due to the possibility of post - construction movement.

This type of construction is better able to accommodate movement and can be more easily

realigned should deformations become unacceptable.

7.5

Surface water drainage

Surface water drainage will be via a piped system to three attenuation tanks which will

discharge via deep bored soakaways. Full details of size and location are yet to be finalised.

4381-2 10

Falling head permeability tests were undertaken in BHs 2, 3, 5, 6, 7 & 8 with the results

presented at Appendix C. Water could not be added fast enough or drained away too quickly

to be measured in BHs 6 and 7 and a deeper test in BH3. The results can be used to inform

the design of the surface water drainage system.

Chalk itself is impermeable and soakage rates rely on fissures, bedding planes and joints within

the chalk rock. Therefore, during construction of the bored soakaways, permeability tests

should be undertaken to ensure that the bottom of the bore is located where rapid soakage

can occur.

It is imperative that no surface water features are included within the proposed development.

In addition, every effort should be made to ensure that the drainage system is as watertight as

possible and to minimise leakage.

7.6

Contaminant analysis

7.6.1

Solid phase

Contaminant testing was undertaken on selected soil samples and the results compared with

the limited number of CLEA2 Soil Guideline Values (SGVs) for residential land use with plant

uptake that have been published to date. Where not available from that source, reference has

also been made to the to the LQM/CIEH S4ULs3. Appropriate trigger levels are given with the

results at Appendix G.

4381-2 11

3 The LQM/CIEH S4ULs for Human Health Risk Assessment. Land Quality Press, 2015

2 The Contaminated Land Exposure Assessment Model, Department for Environment, Food and RuralAffairs, The Environment Agency, R & D Publications SGV 1 et al., March 2002

Analysis for metals/metalloids revealed all results to be below the triggers for residential land

use with plant uptake.

No SGV exists for lead and reference has therefore been made to the Atkins SSVs derived

using CLEA. A concentration of 342 mg/kg lead has been calculated for 6 % SOM. No

samples recorded concentrations of lead above this value.

No phenols were recorded above the limit of detection for the test of 5 mg/kg.

Analysis for TPH recorded a maximum concentration of 12.4 mg/kg in BH3 at 0.90 m depth.

Fifteen samples were analysed for speciated PAH with 14 of the 15 not recording any

individual PAHs above the limit of detection for the test of 0.1m mg/kg. Only the sample from

BH8 at 0.10 m depth recorded any individual PAHs above the limit of detection, with a total

concentration of 2.8 mg/kg. No individual PAH was recorded above the relevant S4UL.

Analysis for polychlorinated biphenyls was carried out on one sample from BH2 (closest to

electricity substation on eastern boundary). No PCBs were detected above the limit of

detection for the test of 0.03 mg/kg.

No asbestos fibres were detected in the 15 samples analysed.

7.6.2

Gas phase

Six monitoring visits have been carried out to take readings of gas flow rate and concentrations

of oxygen, methane, carbon dioxide, carbon monoxide and hydrogen sulphide. A note was

4381-2 12

also being made of the weather conditions at the time of reading. The results are presented at

Appendix C.

No SGVs have been published for soil gas concentrations. However, a report published by the

NHBC4 describes a risk based approach to assessing potential hazards from ground gases

taking into account gas volume and flow rate. A Gas Screening Value (GSV) is calculated which

is compared to a series of ‘Traffic Lights’ which informs the level of protection required.

No positive flow rates have been recorded over the course of monitoring and a rate of

0.5 l/hr (potential calibration error) has been used to calculate the GSVs.

A GSV of 0.0055 l/hr has been calculated for methane and a GSV of 0.0265 l/hr has been

calculated for carbon dioxide. They result in a Green Traffic Light Classification and no

protection is considered necessary.

7.6.3

Waste Acceptance Criteria (WAC)

Six samples were subject to the WAC full solid waste suite and the WAC 2 stage leachate

suite. The results have been compared to the criteria contained in the Landfill Regulations

2002 as amended and are presented at Appendix E.

Within the solid waste suite, all results were within the Inert Waste Landfill classification.

Similarly, parameters determined on the compliance leaching test were also within the Inert

classification.

4381-2 13

4 Guidance on evaluation of development proposals on sites where methane and carbon dioxideare present. Report Edition No. 04. NHBC & RSK Group PLC, March 2007

The contamination test results and the WAC results should be forwarded to the contractor

appointed to remove arisings from site. Transfer notes and chain of custody sheets should be

retained for all spoil removed from site.

7.6.4

Conclusion

The investigation has revealed solution features within the Lewes Nodular Chalk Formation, as

shown on Figure 7 at Appendix A. The geotechnical specialist has recommended utilising a

rigid raft for pairs of houses and piles constructed by CFA means for the blocks of flats.

No contamination has been revealed by the laboratory analysis of soil samples recovered

during the investigation.

No remediation is therefore considered necessary.

A further phase of investigation by CPT with gamma cone and magnetometer is due to

commence shortly and will form the basis of a report in due course.

7.7

Buried concrete

Laboratory tests on soil samples yielded a maximum soluble sulphate concentration of 1.69 g/l.

However, the mean of the highest 20 % yielded a Characteristic Value of 0.74 g/l which results

in a Design Sulphate Class5 of DS-2.

4381-2 14

5 Concrete in aggressive ground. BRE Special Digest 1. Building Research Establishment, 2005

The groundwater is considered to be static and all pH determinations were greater than 3.5.

Therefore the Aggressive Chemical Environment for Concrete, ACEC, is classed as AC-1s.

R G ChapmanAP GEOTECHNICS LTD.18th October 2016

This report has been prepared for the sole and specific use of London Square for the purpose of the proposedresidential development on land known as De Burgh Playing Fields, Chetwode Road, Tadworth Surrey and shouldnot be relied upon by any third party. Any other persons who use any information contained herein without thewritten permission of AP GEOTECHNICS LTD. do so at their own risk. The copyright to this report remains the property of AP GEOTECHNICS LTD.

4381-2 15

PROCEDURAL NOTES for GROUND INVESTIGATIONS

General

This report is based upon data obtained from field descriptions of the strata and examination of the samples by anengineer, together with the results of in situ and laboratory tests as appropriate. Responsibility cannot be acceptedfor variations in ground conditions between and around any of the exploratory points that is not revealed by thedata. Whilst the report may offer an opinion on the ground conditions between exploratory points and below thedepth of investigation, this is for guidance only and no liability is accepted for its accuracy. Unless specificallyincluded in the report, it should be assumed that no testing has been carried out in respect of asbestos or JapaneseKnotweed and no liability is inferred or will be accepted.

Drilling procedure

Boring by light cable percussion drilling allows the ground conditions to be reasonably well established. However, acertain amount of disturbance is inevitable and some mixing of soils can occur.

Sampling procedure

"Undisturbed" samples of predominantly cohesive soils are taken with a 100mm diameter open tube sampler,generally in accordance with BS 5930: 1999.

Where appropriate, or where an undisturbed sample is unsuccessful, disturbed samples are recovered and sealedinto polythene bags.

Groundwater samples are taken when water is encountered in sufficient quantity.

Standard penetration tests

The test is conducted generally in accordance with BS 1377: Part 9: 1990. The sampler tube is subject to a seatingdrive of 150mm into the soil at the base of the borehole. Results are given on the Borehole Records as the numberof blows required to drive the sampler tube a further 300mm and this is known as the “N” value. Where thedriving resistance is such that full penetration is not achieved, the test is generally terminated after 50 blows and theactual distance penetrated is recorded.

Groundwater

Groundwater observations necessarily reflect the conditions encountered at the time of the exploratory work.Long term monitoring of standpipes is usually required to establish an equilibrium water level since the normal rateof boring is too fast to permit steady state conditions to be achieved.

Groundwater levels are subject to variations caused by changes in drainage conditions and seasonal climaticchanges.

Water may necessarily be added to advance the bore whilst casing may be required to maintain an open hole.These can both mask subsequent groundwater observations and are therefore noted on the individual BoreholeRecord.

July 2007

APPENDICES

A Figures

Figure 1: Site PlanFigure 2: Proposed DevelopmentFigure 3: Borehole and CPT locationsFigure 4: SPT ProfileFigure 5: Approximate CBR locationsFigure 6: Shear Strength ProfileFigure 7: Top of Chalk/Solution features

B Borehole Records

Symbols and AbbreviationsBorehole Records

C In Situ Permeability Test Results

HVORSLEV'S TIME LAG

D Standpipe Records

Gas Emissions and Water Levels

E California Bearing Ratio Test Results

F Lankelma CPT Report, June 2016

G Lankelma CPT Report, August/September 2016

H Laboratory Test Results

Summary of Geotechnical TestsParticle Size DistributionContaminants in SoilWaste Acceptance Criteria

FIGURES

APPENDIX A

© AP GEOTECHNICS LTD. Figure 4

0 50 100 150

SPT N Value

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

Dep

th, m

BH1

BH2

BH3

BH4

BH5

BH6

BH7

BH8

N values >50 extrapolated to 300 mm penetration

SPT PROFILEDe Burgh Playing Fields

Tadworth

© AP GEOTECHNICS LTD. Figure 6

0 50 100 150 200 250

Undrained cohesion, kPa

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

32

Dep

th, m

BH1 BH4 BH7 BH8

SHEAR STRENGTH PROFILEDe Burgh Playing Field, Tadworth

BOREHOLE RECORDS

APPENDIX B

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er

LegendDescriptionDepth

(m)(Thickness)

Depth(m)

Level(mOD)Sample / Tests Field Records

Remarks Scale(approx)

LoggedBy

Figure No.4381.BH1

1:50 ljs

150mm cased to 11.00m

FORMER DE BURGH PLAYING FIELD, CHETWODE ROAD, TADWORTH, SURREY, KT20 5LU

London Square Developments Limited


BH1

4381

See site plan16/06/2016-17/06/2016

Produced by the GEOtechnical DAtabase SYstem (GEODASY) (C) all rights reserved

Boring Method Casing Diameter

Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Small amount of water at 10.1 m depth0.75 hrs filling water bowser

0.20 D1(0.30) 0.30

Turf over TOPSOIL with rootlets

Backfilled with arisings

0.35 D2(0.50)

0.80

Firm grey brown and orange mottled slightly sandy gravelly CLAY with rootlets

0.85 D3 (0.20) 1.00

Soft grey brown and orange very sandy CLAY1.00 D4

1.50-1.95 SPT N=22 2,3/4,5,6,7DRY1.50 D5

2.00 D6

2.50-2.95 SPT N=27 1,3/5,6,8,8DRY2.50 D7

3.50-3.95 SPT N=34 3,6/6,9,9,102.50 DRY

(3.00)

4.00

Medium dense to dense orange very clayey SAND with occasional gravel

4.10-4.50 B1

4.50-4.95 SPT(C) N=31 2,5/7,8,7,94.40 DRY (1.20)

5.20

Dense orange silty very sandy GRAVEL

5.20 D8

5.50-5.95 SPT(C) N=50 9,14/17,13,15,55.40 5.005.50-6.00 B2

(1.20)

6.40

Dense to very dense grey brown slightly sandy GRAVEL. Gravel is fine to coarse subangular to rounded flint

6.40 D9

7.00-7.45 U1 6.60 MM 100 blows

7.50 D10

7.80 W1

8.50-8.95 SPT N=31 2,4/6,6,9,106.60 DRY8.50-8.95 D11

(2.80)

9.20

Stiff orange brown, brown and grey mottled CLAY, locally sandy

(0.90)

Firm brown very sandy CLAY with sand layers9.20 D12

10.00-10.45 SPT N=24 3,4/4,6,7,76.60 DRY

Water added from 5.20m to 6.20m. Excavating from 0.00m to 1.20m for 1.0 hour.

1/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH1

1:50 ljs





BH1

4381

See site plan16/06/2016-17/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Firm brown very sandy CLAY with sand layers(0.90) 10.10

(0.40) 10.50 Firm orange, brown, red and black mottled sandy CLAY

16/06/2016:DRY—————————17/06/2016:DRY

11.50-11.95 U1 11.00 DRY 100 blows

(1.10)

11.60

Stiff grey and orange slightly sandy CLAY

12.00 D13

13.00-13.45 SPT N=23 2,3/5,6,6,611.00 DRY

14.50-14.95 SPT N=18 1,2/3,5,4,611.00 DRY

16.00-16.45 SPT N=11 1,2/3,3,2,311.00 DRY

17.50-17.95 SPT N=8 1,2/2,2,2,211.00 DRY17.50-18.50 B3

19.00-19.45 SPT N=5 1,0/1,1,1,211.00 DRY

(8.40)

20.00

Medium dense orange and grey silty fine to medium SAND, becoming loose with depth

2/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH1

1:50 ljs





BH1

4381

See site plan16/06/2016-17/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

20.00 D14

(10.45)

White CHALK recovered as gravel sized intact fragments in structureless melange

20.50-20.95 SPT N=22 4,5/6,5,5,611.00 DRY

22.00-22.45 SPT N=21 3,4/5,5,6,511.00 DRY

23.00-23.45 SPT N=21 2,3/4,5,6,611.00 DRY

24.50-24.95 SPT N=26 3,4/6,7,6,711.00 DRY

26.00-26.45 SPT N=50 3,5/7,23,2011.00 DRY

27.50-27.95 SPT N=27 3,6/5,6,8,811.00 DRY

29.00-29.45 SPT N=33 3,5/7,8,8,1011.00 DRY

17/06/2016:DRY—————————

3/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH1

1:50 ljs





BH1

4381

See site plan16/06/2016-17/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

30.00-30.45 SPT N=34 3,4/6,9,8,1111.00 DRY(10.45)

30.45

Complete at 30.45m

4/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er

Legend InstrDescriptionDepth

(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH2

1:50 ljs





BH2

4381

See site plan21/06/2016-22/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

1 hr falling head permeability testBorehole dry and backfilled with arisings

0.50 D1(0.85)

0.85

Turf over clayey TOPSOIL with rootlets

0.90 D2

1.20-1.65 SPT N=10 1,1/2,2,3,3(1.15)

2.00

Firm orange brown and brown mottled slightly sandy CLAY with occasional gravel and rootlets at top

2.00-2.45 U1 45 blows

2.50 D3

3.00-3.45 SPT N=19 3,3/4,5,5,52.50

...becoming orange brown3.80 D4

4.00-4.45 SPT N=21 4,4/5,5,6,52.50

5.00-5.45 SPT N=27 4,5/5,7,7,83.00

6.50-6.95 SPT N=22 4,4/5,5,7,54.50

(5.50)

7.50

Medium dense orange silty to very silty fine to medium SAND

7.50 D5

8.00-8.45 SPT N=13 2,3/3,3,4,34.50

9.00-9.45 SPT N=21 3,4/11,2,5,39.00

(2.50)

10.00

White structureless CHALK with occasional flints

Excavating from 0.00m to 1.20m for 1.0 hour.

1/1

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH3

1:50 ljs





BH3

4381

See site plan17/06/2016-20/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

3.5 hrs falling head tests

0.10 D1

2 hrs filling water bowser for falling head tests

(0.30) 0.30


0.30 D2

Water added throughout drilling

0.50 D3 (0.60)

0.90

Firm light brown sandy clay with occasional flints

0.90 D4

1.20-1.65 SPT N=6 1,0/1,1,2,2

2.00-2.45 U1 37 blows

(1.60)

2.50

Firm orange and grey mottled very sandy CLAY with rare gravel

2.50 D5(0.40) 2.90

Brown silty fine SAND

2.90 D63.00-3.45 SPT N=17 2,2/4,3,4,62.50 NIL

4.00-4.45 U2 4.00 76 blows

4.50 D7

5.00-5.45 SPT N=19 2,3/3,4,6,64.00 NIL

(3.40)

6.30

Firm to stiff brown sandy CLAY with occasional sand layers

6.30 D8

6.50-6.95 U3 5.50 92 blows

(1.50)

7.80

Dense light brown very silty SAND

White CHALK with brown clay inclusions at top7.80 D9

8.00-8.45 SPT N=10 1,2/2,3,2,38.00 NIL

9.50-9.95 SPT N=11 2,2/3,2,3,39.50 8.50

Breaking out from 0.00m to 1.20m for 1 hour.

1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH3

1:50 ljs





BH3

4381

See site plan17/06/2016-20/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

White CHALK

11.00-11.45 SPT N=18 5,4/3,5,5,511.00 10.50

12.50-12.95 SPT N=18 3,4/4,4,5,511.50 NIL

14.00-14.45 SPT N=17 4,3/4,4,4,511.50 NIL

(7.20)

15.00

15.00-15.45 SPT N=50 4,4/5,4511.50 NIL

Complete at 15.00m

2/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4

1:50 ljs





BH4

4381

See site plan20/06/2016-21/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

No chalk encountered and BH depth at practical limit in ground conditions. BH4A therefore drilled adjacent in 200 & 150 mm diameter casing

D

Borehole dry

D

0.20 D1(0.40) 0.40

Turf over TOPSOIL

0.50 D2

1.20-1.65 SPT N=7 1,1/2,1,2,2

2.00-2.45 U1 50 blows

(2.10)

2.50

Soft orange brown sandy CLAY

2.50 D3

3.00-3.45 SPT N=12 2,3/3,2,3,4

4.00-4.45 U2 60 blows

4.50 D4

5.00-5.45 SPT N=17 1,2/3,4,5,5

6.50-6.95 U3 80 blows

(4.30)

6.80

Firm to stiff orange and locally red slightly sandy to sandy CLAY

Medium dense orange brown very silty SAND 7.00 D57.00-7.50 B1

8.00-8.45 SPT N=20 2,3/5,5,5,53.00

8.50 D6

9.50-9.95 SPT N=20 2,3/4,5,5,63.00


1/3

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4

1:50 ljs





BH4

4381

See site plan20/06/2016-21/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Medium dense orange brown silty fine SAND with occasional gravel

11.00-11.45 SPT N=22 1,2/4,5,6,73.00

12.50-12.95 SPT N=22 2,3/5,5,6,63.00

(6.70)

13.50

13.50 D7

14.00-14.45 SPT N=50 3,6/11,12,15,123.00

15.50-15.95 SPT N=50 4,8/13,15,12,103.00

(2.50)

16.00

Dense orange clayey sandy GRAVEL

16.00 D8

(0.70)

16.70

Soft light brown sandy CLAY

16.70 D9

17.00-17.45 SPT N=32 3,5/7,8,8,93.00

18.50-18.95 SPT N=27 3,4/5,7,8,73.00

(3.00)

19.70

Stiff orange brown and green slightly sandy CLAY

Firm light grey slightly sandy CLAY19.70 D1020.00-20.45 SPT N=27 4,4/5,6,8,83.00

2/3

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4

1:50 ljs





BH4

4381

See site plan20/06/2016-21/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Firm light grey slightly sandy CLAY

(1.80)

21.50

21.50-21.95 SPT N=50 3,5/10,16,18,63.0021.50 D11

23.00-23.45 SPT N=50 7,10/14,20,163.00

24.50-24.95 SPT N=50 6,10/15,17,183.00

(4.50)

26.00

Very dense orange brown fine SAND with rare rounded flint gravel

26.00-26.45 SPT N=50 6,8/10,12,15,133.00

Complete at 26.00m

3/3

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4A

1:50 ljs

200mm cased to 10.50m150mm cased to 23.00m




BH4A

4381

See site plan22/06/2016-23/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Borehole dry and backfilled with arisings0.5 hr reducing casing

(0.40) 0.40

Turf over sandy TOPSOIL

(2.80)

3.20

Soft orange brown sandy CLAY

(7.80)

Orange slightly clayey slightly gravelly SAND with pockets of clay

...very gravelly from 7.40m to 11.00m


1/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4A

1:50 ljs





BH4A

4381

See site plan22/06/2016-23/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Orange, slightly clayey, slightly gravelly SAND, with pockets of clay

(7.80)

11.00

(1.70)

12.70

Stiff brown, black and grey CLAY

...very sandy from 13.50m

(4.20)

16.90

Stiff orange, dark brown and green slightly sandy CLAY

Orange grey slightly clayey SAND

...just orange from 17.20m

2/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4A

1:50 ljs





BH4A

4381

See site plan22/06/2016-23/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Orange grey slightly clayey SAND

...light brown grey from 22.30m

(7.00)

23.90

23.90 D1

...sand and chalk fragments from 27.30m27.30 D2

27.50-27.95 SPT(C) N=15 5,8/5,3,4,323.00 DRY

(3.90)

27.80

Stiff dark grey and brown mottled slightly sandy CLAY with coarse angular flints

White CHALK27.80 D3

29.00-29.45 SPT N=13 2,3/3,4,3,323.00 DRY

30.00-30.45 SPT N=16 2,3/4,3,5,423.00 DRY

3/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH4A

1:50 ljs





BH4A

4381

See site plan22/06/2016-23/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

White CHALK

31.50-31.95 SPT N=21 3,5/4,5,6,623.00 DRY

33.00-33.45 SPT N=29 3,5/7,9,7,623.00 DRY

34.50-34.95 SPT N=45 5,7/13,13,16,323.00 DRY

(7.20)

35.00

Complete at 35.00m

4/4

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH5

1:50 ljs





BH5

4381

See site plan20/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Borehole dryand backfilled with arisings0.5 hr falling head test

0.20 D1(0.40) 0.40


0.50 D2 (0.40) 0.80

Loose orange clayey gravelly SAND

0.80 D3

1.50-1.95 SPT N=10 1,1/2,2,3,3DRY

2.50-2.95 SPT N=15 1,2/3,3,4,52.40 DRY

2.80 D4

3.50-3.95 SPT N=18 3,3/3,5,5,52.50 DRY3.50-4.00 B1

4.50-4.95 SPT N=17 2,3/3,4,5,54.00 DRY

(4.50)

5.30

Loose to medium dense brown and light brown very silty fine to medium SAND

White structureless CHALK5.30 D5

5.50-5.95 SPT N=12 1,2/3,2,4,35.30 DRY

7.00-7.45 SPT N=17 2,2/4,4,4,56.90 DRY

8.50-8.95 SPT N=12 1,1/2,3,3,47.00 DRY

10.00-10.45 SPT N=26 4,6/7,8,6,57.00 DRY


1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH5

1:50 ljs





BH5

4381




Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

White structureless CHALK

11.50-11.95 SPT N=19 2,3/4,3,7,57.00 DRY

13.00-13.45 SPT N=14 3,3/3,4,4,37.00 DRY

14.50-14.95 SPT N=18 2,3/5,4,4,57.00 DRY

(9.70)

15.00

Complete at 15.00m

2/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH6

1:50 ljs





BH6

4381




Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

1 hr filling water bowser

0.15 D1

Borehole dry

(0.30) 0.30

Turf over brown sandy TOPSOIL with rootlets

0.30 D2

0.50 D3

1.50-1.95 SPT N=11 1,1/3,2,3,3DRY1.50-2.00 B1

2.50-2.95 SPT N=6 1,1/2,1,2,1DRY

(2.90)

3.20

Medium dense brown very silty gravelly SAND

3.20 D4 (0.30) 3.50

Firm dark brown sandy CLAY

3.50-3.95 SPT N=8 1,2/1,2,2,33.40 DRY3.50 D5

4.50-4.95 SPT N=8 1,1/2,1,2,34.40 DRY

5.50-5.95 SPT N=9 1,1/2,2,2,35.40 DRY

(3.40)

6.90

Loose brown silty fine SAND with occasional clay layers

7.00-7.45 SPT N=6 4,3/2,1,1,25.90 DRY7.00 D6

8.50-8.95 SPT N=12 2,1/2,3,3,48.40 DRY

(1.80)

8.70

Loose brown silty very sandy GRAVEL

8.70 D7

(1.30)

10.00


10.00-10.45 SPT N=12 1,2/2,3,4,39.00 DRY


1/1

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH7

1:50 ljs





BH7

4381

See site plan21/06/2016-22/06/2016



Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Borehole dry1 hr filling water bowser

0.20 D1

0.50 D2(0.80)

0.80

Turf over brown TOPSOIL with rootlets

0.80 D3

1.50-1.95 U1 DRY 35 blows

2.00 D4

2.50-2.95 SPT N=12 1,1/3,2,3,4DRY

3.50-3.95 U2 2.50 DRY 50 blows

(3.10)

3.90

Stiff orange, green and brown mottled slightly sandy CLAY with rootlets at top. Locally very sandy

4.00 D5

4.50-4.95 SPT N=18 1,3/4,4,5,53.50 DRY4.50-5.00 B1

5.50-5.95 SPT N=21 1,2/5,5,5,65.00 DRY

7.00-7.45 SPT N=14 1,1/3,4,3,46.00 DRY

(3.20)

7.10

Medium dense orange brown silty fine SAND

7.10 D6

8.50-8.95 SPT N=20 2,3/5,5,6,48.00 DRY (2.90)

10.00


10.00-10.45 SPT N=23 4,4/7,6,5,59.00 DRY


1/1

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH8

1:50 ljs





BH8

4381




Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

1 hr falling head test

0.10 D1(0.15) 0.15

Turf over dark grey TOPSOIL with rootlets

0.5 hr filling water bowser

0.20 D2

Borehole dry and backfilled with arisings

(0.85)

1.00

Brown silty fine SAND with occasional gravel

1.00 D3

1.50-1.95 SPT N=11 1,1/2,2,3,4DRY

2.50-2.95 U1 2.20 DRY 50 blows

3.00 D4

3.50-3.95 SPT N=10 1,1/3,2,3,22.20 DRY

4.50-4.95 U2 2.20 DRY 60 blows

5.00 D5

5.50-5.95 SPT N=12 1,2/2,3,3,42.20 DRY

(5.10)

6.10

Firm to stiff brown grey mottled very sandy CLAY

(4.90)

Firm to stiff brown and black mottled sandy CLAY with coarse flints

6.10 D6

7.00-7.45 SPT N=12 2,2/2,2,4,42.20 DRY

...chalk fragments from 8.40m8.40 D78.50-8.95 SPT N=7 1,1/2,2,1,22.20 DRY

10.00-10.45 SPT N=9 1,2/2,3,2,22.20 DRY


1/2

Location

Ground Level (mOD)

Dates

Site

Client

Engineer

Number

JobNumber

Sheet

Wat

er


(m)(Thickness)

Depth(m)



LoggedBy

Figure No.4381.BH8

1:50 ljs





BH8

4381




Borehole

CasingDepth

(m)WaterDepth

(m)

Cable Percussion

Firm to stiff brown and black mottled sandy CLAY with coarse flints

(4.90)

11.00

11.00 D8

11.50-11.95 SPT N=7 1,0/1,2,2,22.20 DRY

13.00-13.45 SPT N=18 4,10/4,4,5,512.00 DRY

14.50-14.95 SPT N=19 2,4/4,5,4,613.50 DRY

(4.00)

15.00


Complete at 15.00m

2/2

IN SITU PERMEABILITY TEST RESULTS

APPENDIX C

Project: FORMER DE BURGH PLAYING FIELD, CHETWODE ROAD, TADWO Project No: 4381Client: London Square Developments Ltd Sheet No: 1/1Agent: Barnard & Associates

Location: BH 2Test depth from 9.00 m

to 10.00 m in borehole

Height of casing above g.l., m 0.00 Description of stratum under testDepth of casing below g.l., m 9.00Diameter of casing, m 0.15 Lewes Nodular Chalk FormationDepth to water at start of test, m b.g.l. 10.00

Elapsed Depth to Water, m H HTime from from Homin Casing GL

0.00 3.40 3.40 6.60 1.0000.50 3.50 3.50 6.50 0.9851.00 4.80 4.80 5.20 0.7881.50 5.95 5.95 4.05 0.6142.00 6.65 6.65 3.35 0.5082.50 7.05 7.05 2.95 0.4473.00 7.15 7.15 2.85 0.4323.50 7.30 7.30 2.70 0.4094.00 7.40 7.40 2.60 0.3944.50 7.50 7.50 2.50 0.3795.00 7.55 7.55 2.45 0.37110.00 7.95 7.95 2.05 0.31115.00 8.20 8.20 1.80 0.27320.00 8.40 8.40 1.60 0.24225.00 8.40 8.40 1.60 0.24230.00 8.45 8.45 1.55 0.23540.00 8.55 8.55 1.45 0.22050.00 8.65 8.65 1.35 0.20560.00 8.80 8.80 1.20 0.182

k = A/FTA = 0.018 m²F = 2.420 mT = 5 mink = 2.43E-005 m/s

© AP GEOTECHNICS LTD

0 10 20 30 40 50 60 70

Time, minutes

0.10

1.00

H/H

o

Head Ratio vs Elapsed Time

0.37

IN SITU PERMEABILITY

HVORSLEV'S TIME LAG






0.00 0.90 0.90 8.10 1.0001.00 2.74 2.74 6.26 0.7732.00 4.80 4.80 4.20 0.5193.00 5.90 5.90 3.10 0.3834.00 6.60 6.60 2.40 0.2965.00 7.10 7.10 1.90 0.2356.00 7.30 7.30 1.70 0.2107.00 7.40 7.40 1.60 0.1988.00 7.45 7.45 1.55 0.1919.00 7.50 7.50 1.50 0.18510.00 7.55 7.55 1.45 0.17915.00 7.70 7.70 1.30 0.16020.00 7.80 7.80 1.20 0.14825.00 8.00 8.00 1.00 0.12330.00 8.00 8.00 1.00 0.12345.00 8.20 8.20 0.80 0.09960.00 8.35 8.35 0.65 0.080



0 10 20 30 40 50 60 70

Time, minutes

0.01

0.10

1.00

H/H

o


0.37


HVORSLEV'S TIME LAG






0.00 2.20 2.20 9.80 1.0001.00 5.40 5.40 6.60 0.6732.00 6.80 6.80 5.20 0.5313.00 7.65 7.65 4.35 0.4444.00 8.30 8.30 3.70 0.3785.00 8.90 8.90 3.10 0.3166.00 9.10 9.10 2.90 0.2967.00 9.15 9.15 2.85 0.2918.00 9.20 9.20 2.80 0.2869.00 9.45 9.45 2.55 0.26010.00 9.50 9.50 2.50 0.25515.00 10.30 10.30 1.70 0.17320.00 11.00 11.00 1.00 0.102



0 10 20 30 40 50 60 70

Time, minutes

0.01

0.10

1.00

H/H

o


0.37


HVORSLEV'S TIME LAG






0.00 2.20 2.20 5.80 1.0001.00 3.20 3.20 4.80 0.8281.50 3.90 3.90 4.10 0.7072.00 4.40 4.40 3.60 0.6212.50 4.80 4.80 3.20 0.5523.00 5.10 5.10 2.90 0.5003.50 5.30 5.30 2.70 0.4664.00 5.50 5.50 2.50 0.4314.50 5.70 5.70 2.30 0.3975.00 5.85 5.85 2.15 0.3716.00 6.05 6.05 1.95 0.3367.00 6.30 6.30 1.70 0.2938.00 6.45 6.45 1.55 0.2679.00 6.65 6.65 1.35 0.23310.00 6.70 6.70 1.30 0.22411.00 6.80 6.80 1.20 0.20712.00 6.90 6.90 1.10 0.19013.00 6.95 6.95 1.05 0.18114.00 7.03 7.03 0.97 0.167



0 10 20 30 40 50 60 70

Time, minutes

0.10

1.00

H/H

o


0.37


HVORSLEV'S TIME LAG






0.00 10.50 10.50 4.50 1.0001.00 10.60 10.60 4.40 0.9782.00 11.20 11.20 3.80 0.8442.50 11.50 11.50 3.50 0.7783.00 11.70 11.70 3.30 0.7333.50 12.00 12.00 3.00 0.6674.00 12.30 12.30 2.70 0.6004.50 12.50 12.50 2.50 0.5565.00 12.65 12.65 2.35 0.52210.00 13.10 13.10 1.90 0.42215.00 13.20 13.20 1.80 0.40020.00 13.25 13.25 1.75 0.38930.00 13.40 13.40 1.60 0.35645.00 13.50 13.50 1.50 0.333



0 10 20 30 40 50 60 70

Time, minutes

0.10

1.00

H/H

o


0.37


HVORSLEV'S TIME LAG

STANDPIPE RECORDS

APPENDIX D

Project: FORMER DE BURGH PLAYING FIELD, CHETWODE ROAD, TADWORTHClient: London Square Developments Ltd Project No: 4381-2

Sheet No: 1/2

Date Measurement Units Location

05/07/2016 BH2 BH4 BH6 BH7

Weather conditions Initial Steady Initial Steady Initial Steady Initial Steady

Temp. °C 19 Flow rate l/hr 0.0 0.0 0.0 0.0 0.0 0.0 -1.3 0.0Atmos. mb 999 Methane % 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Carbon dioxide % 1.2 1.1 1.4 1.4 3.4 3.5 4.2 5.3Cloud 90 % Carbon monoxide ppm 0 0 0 0 0 0 0 0Sun 10 % Hydrogen sulphide ppm 0 0 0 0 0 0 0 0

Rainfall nil Oxygen % 19.6 19.7 18.1 18.0 18.1 16.2 13.5 12.5PID reading ppm 0 0 0 0 0 0 0 0Water level m bgl Dry @ 4.35 m Dry @ 4.30 m Dry @ 4.20 m Dry @ 4.10 m


18/07/2016 BH2 BH4 BH6 BH7


Temp. °C 23 Flow rate l/hr 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Atmos. mb 1005 Methane % 1.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0




29/07/2016 BH2 BH4 BH6 BH7






12/08/2016 BH2 BH4 BH6 BH7





Readings taken with GFM435 manufactured by Gas Data Ltd.

© AP GEOTECHNICS LTD.

STANDPIPE RECORDS

GAS EMISSIONS AND WATER LEVELS

Project: FORMER DE BURGH PLAYING FIELD, CHETWODE ROAD, TADWORTHClient: London Square Developments Ltd Project No: 4381-2

Sheet No: 2/2


22/08/2016 BH2 BH4 BH6 BH7


Temp. °C 18 Flow rate l/hr 0.0 0.0 0.0 0.0 0.0 0.0 -1.3 0.0Atmos. mb 1005 Methane % 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0




06/09/2016 BH2 BH4 BH6 BH7







Temp. °C Flow rate l/hr

Atmos. mb Methane %

Carbon dioxide %

Cloud Carbon monoxide ppm

Sun Hydrogen sulphide ppm

Rainfall Oxygen %

PID reading ppm

Water level m bgl



Temp. °C Flow rate l/hr

Atmos. mb Methane %

Carbon dioxide %

Cloud Carbon monoxide ppm

Sun Hydrogen sulphide ppm

Rainfall Oxygen %

PID reading ppm

Water level m bgl

Readings taken with GFM435 manufactured by Gas Data Ltd.


STANDPIPE RECORDS

GAS EMISSIONS AND WATER LEVELS

CALIFORNIA BEARING RATIO TEST RESULTS

APPENDIX E

Project: FORMER DE BURGH PLAYING FIELD, TADWORTH Project No: 4381-2Agent: London Square Developments Limited Sheet No: 1/8

Loc'n Sample Depth (m)

CBR 1 0.5

DescriptionOrange SAND

Sample PreparationIn situ

Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg

Penetration Load Dial Gauge, divmm top bottom

0.00 00.25 30.50 40.75 41.00 41.25 51.50 51.75 52.00 52.25 62.50 62.75 63.00 63.25 63.50 63.75 64.00 74.25 74.50 74.75 85.00 85.25 85.50 85.75 96.00 96.25 106.50 106.75 107.00 117.25 117.50 12

Surcharge, kg 9

Seating Load, N 50Proving Ring Factor, N/div 26.327Particles larger than 20 mm may be presentwithin the test area.

CBR at 2.5mm = (Dial reading x ring factor)/132.4 Moisture Density, Mg/m³ % retained C Penet'n Top Bottom

CBR at 5.0mm = (Dial reading x ring factor)/199.6 Cont. % Bulk Dry at 20mm B % 2.5mm 1.214 R 5.0mm 1.1


0.0 2.5 5.0 7.5 10.0

Penetration of plunger, mm

0

5

10

15

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration

CALIFORNIA BEARING RATIO



CBR 2 0.5

DescriptionOrange sandy CLAY


Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 50.50 70.75 81.00 81.25 81.50 81.75 82.00 82.25 82.50 92.75 93.00 93.25 93.50 93.75 94.00 94.25 94.50 94.75 95.00 105.25 105.50 105.75 116.00 116.25 116.50 116.75 117.00 117.25 117.50 11

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

5

10

15

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration




CBR 3 0.5

DescriptionSandy CLAY with stone


Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 10.50 20.75 21.00 31.25 31.50 31.75 32.00 42.25 42.50 42.75 43.00 43.25 43.50 43.75 54.00 54.25 54.50 54.75 55.00 55.25 55.50 55.75 56.00 66.25 66.50 66.75 67.00 67.25 67.50 6

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

2

4

6

8

10

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration




CBR 4 0.5

DescriptionSandy CLAY


Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 20.50 20.75 21.00 31.25 31.50 31.75 32.00 32.25 32.50 32.75 33.00 33.25 43.50 43.75 44.00 44.25 44.50 54.75 55.00 55.25 55.50 55.75 56.00 56.25 56.50 56.75 57.00 57.25 57.50 5

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

2

4

6

8

10

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration




CBR 5 0.5



Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 30.50 40.75 61.00 61.25 71.50 71.75 72.00 82.25 102.50 112.75 133.00 143.25 153.50 163.75 174.00 174.25 174.50 174.75 185.00 185.25 185.50 195.75 196.00 196.25 196.50 196.75 207.00 207.25 207.50 20

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

5

10

15

20

25

30

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration




CBR 6 0.5



Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 60.50 90.75 111.00 131.25 141.50 151.75 162.00 172.25 182.50 182.75 193.00 193.25 203.50 203.75 204.00 214.25 214.50 214.75 215.00 215.25 215.50 215.75 216.00 216.25 216.50 216.75 227.00 227.25 227.50 22

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

5

10

15

20

25

30

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration




CBR 7 0.5



Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 60.50 80.75 91.00 111.25 131.50 151.75 162.00 182.25 202.50 212.75 223.00 233.25 243.50 263.75 274.00 304.25 334.50 354.75 385.00 405.25 415.50 425.75 446.00 456.25 466.50 476.75 477.00 477.25 477.50 48

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

10

20

30

40

50

60

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration




CBR 8 0.5



Undisturbed

Remoulded

Recompacted 2.5kg

4.5kg


0.00 00.25 120.50 150.75 181.00 211.25 231.50 251.75 262.00 272.25 292.50 302.75 313.00 323.25 333.50 343.75 354.00 364.25 384.50 394.75 395.00 405.25 405.50 415.75 426.00 446.25 456.50 466.75 477.00 487.25 487.50 49

Surcharge, kg 9





0.0 2.5 5.0 7.5 10.0


0

10

20

30

40

50

60

Load

dia

l gau

ge r

eadi

ng, d

ivis

ions

Load vs Penetration


LANKELMA CPT REPORT, JUNE 2016

APPENDIX F

LANKELMA Limited

Cold Harbour Barn, Cold Harbour Lane, Iden East Sussex, TN31 7UT

T: +44 (0)1797 280050 E: [email protected]

www.lankelma.com

Project Ref.: P-106427-4

TADWORTH

SOIL INVESTIGATION

CPT REPORT

Cone Penetration TestMOSTAP Sampling

UXO Clearance CertificateStandard Data Interpretation

TADWORTH

Report No. P-106427-4R00CP

PROJECT: Tadworth

CLIENT: A P Geotechnics

FIELDWORK

CPT Rig 18.0 tonne tracked CPT unit (UK8)Date Fieldwork Started 7th June 2016Date Fieldwork Completed 10th June 2016Lankelma’s Representative Emma Stickland Client’s Representative Richard Chapman

REPORT

Status Revision Action Date Name

Final 00Completed 20/06/16 Chris PlayerChecked 21/06/16 Emma SticklandApproved 21/06/16 Joseph Hobbs

TADWORTH


CONTENTS

1 INTRODUCTION ........................................................................................... 1 1.1 COMPLETED WORKS.............................................................................. 1 2 FIELDWORK................................................................................................. 1 2.1 CONE PENETRATION TESTING ............................................................. 1 2.2 MAGNETOMETER TESTING ................................................................... 1 2.3 MOSTAP SAMPLING................................................................................ 2 2.4 FIELD LOGISTICS.................................................................................... 2 3 RAW DATA REDUCTION AND PRESENTATION........................................ 2 4 INTERPRETATIVE DATA ............................................................................. 2 4.1 IN-SITU STRESS CONDITIONS............................................................... 2 4.2 IDENTIFICATION OF CHALK ................................................................... 3 4.3 S OIL BEHAVIOUR TYPE......................................................................... 3 4.4 SOIL BEHAVIOUR TYPE – IC INDEX....................................................... 3 4.5 GEOTECHNICAL PARAMETERS............................................................. 4

4.5.1 RELATIVE DENSITY .................. ERROR! BOOKMARK NOT DEFINED. 4.5.2 UNDRAINED SHEAR STRENGTH ......................................................... 5

4.5.3 OVERCONSOLIDATION RATIO............................................................. 5

4.5.4 SENSITIVITY.......................................................................................... 6

5 CPT DATA INTERPRETATION NOTES ....................................................... 7 6 REFERENCES .............................................................................................. 9

SUMMARY TABLESTable 1 CPT Test Summary .................................................................................... 10 Table 2 MOSTAP Summary Table .......................................................................... 12

APPENDICESAPPENDIX A General InformationAPPENDIX B Cone Penetration Test Results – Raw Data PlotsAPPENDIX C Standard Interpretation ResultsAPPENDIX D MOSTAP Core Photos and Sample DescriptionsAPPENDIX E UXO Clearance Certificate

TADWORTH

1Report No. P-106427-4R00CP

1 INTRODUCTION

At the request of A P Geotechnics, a CPT led soils investigation was carried out on project Tadworth.

Site location:

De Burgh Gardens,Tadworth,Surrey,KT20 5LU

1.1 COMPLETED WORKS

22 nr. Cone Penetration Tests (CPT) with magnetometer;12 nr. MOSTAP Samples; andFactual report plus standard geotechnical data interpretation.

The Summary Tables section details the field records.

2 FIELDWORK

2.1 CONE PENETRATION TESTING

Cone Penetration Tests were performed with an 18.0 tonne tracked CPT unit (UK8) equipped with a 12.5 tonne capacity hydraulic ram set.

An electric penetrometer of a type conforming to the requirements of BS ISO 22476-1:2012 was used on this project. Cone measurements included cone tip resistance, friction sleeve resistance and dynamic pore water pressure (Piezometer) sampled at a 10mm resolution. Cone maintenance, checks and calibrations were carried out in accordance with recommendations of BS8422:2003, and ASTM E74-13a as referenced by the British Standard. The management of calibration records is in accordance with ISO10012. Copies of all calibration certificates for the cones used are presented in Appendix A. Refer to the cone calibration certificates for the cone type and dimensional data.

The piezometer filter element was located in the u2 position between the cone and friction sleeve and was replaced after every test. The pore pressure system was saturated with de-aired 1000 cSt silicone fluid.

2.2 MAGNETOMETER TESTING

The magnetometer used in the Lankelma Magcone system comprises a Bartington Instruments 3 Axis Flux Gate magnetometer that is capable of measuring disturbances in the Earth’s field of less than 1 part in a million. Buried ferrous items, such as UXO, result in localized distortions

TADWORTH


of the magnetic field. The detection radius of the works undertaken was dependent upon the level of magnetic field distortion noise and the size of the ferrous object(s) of interest.

The magnetometer probe was pushed into the soil using a standard CPT rig up to a maximum applied pressure of 15 Tonnes.

The third party Site Safe report / Magnetometer test results as required are presented in Appendix E – UXO Clearance Certificate.

2.3 MOSTAP SAMPLING

MOSTAP soil samples were taken at depth specified by the client’s representative on site. The sampler was hydraulically pushed and recovered 1.2 m samples comprising 1.00 m length 66mm diameter stocking wrapped tube sample retained in a UPVC liner and a 0.20 m disturbed pot sample (cutting shoe sample). The MOSTAP sampler has an outside diameter of 90 mm.

2.4 FIELD LOGISTICS

The client was responsible for the positioning and re-survey of all investigative locations.

The target depth for the investigation was 21 m. Table 1 details the final test depths and reasons for test termination (Refusal Factor). Termination depths were advised to, and agreed with, the client’s on-site representative.

3 RAW DATA REDUCTION AND PRESENTATION

The CPT results are presented in Appendix B. The corrected cone resistance (qt), local side friction, pore water pressure, friction ratio and inclination are all presented against depth and elevation in accordance with recommendations of the BS ISO 22476-1:2012. CPT data and the associated derived geotechnical parameters are included in the AGS 3.1 and 4.0 data filesprovided.

Penetration length readings are corrected for inclination and sleeve readings are depth corrected for the dimensional offset between cone tip and sleeve during post processing. An additional shift of -80mm is applied to the sleeve to account for tip failure zone offset (see ‘CPT Interpretation Notes’). ‘Rod spikes’ (artefacts of the 1 m interval pause for rod string addition) are filtered from the cone tip and sleeve data.

4 INTERPRETATIVE DATA

4.1 IN-SITU STRESS CONDITIONS

The in-situ total and effective stress states are calculated based on an assumed total unit weight of soil (17 kN/m3 above the inferred piezometric surface and 18 kN/m3 below) and a hydrostatic pore pressure state. The depth of the piezometric surface has been assumed at a generic 1.0

TADWORTH


mBGL across the site based on interpretation of piezocone measurements or other observationsby Lankelma. The data are applied in calculation of stress normalised geotechnical parameters.

In the event that complex groundwater regimes are clearly identified, multiple piezometric surfaces are applied.

4.2 IDENTIFICATION OF CHALK

Identification of chalk was obtained by the analysis of CPT logs together with verification fromtargeted MOSTAP sampling at the identified interface.

The chalk interface is generally recognised by a horizon of cohesive material having a characteristically high friction ratio and/or followed by high positive excess pore pressures in the underlying material. An example of this can be seen for CPT10 at 10.50 m as shown below.

The signature response shown above is sometimes less obvious or absent (due to absence of chalk or not). Where the interface has not been verified by sampling, the reported depths representour best estimate and should be independently verified where possible. The estimated depths to chalk are provided in Table 1 – CPT Test Summary.

The results are presented on the plots of Appendix C – Standard Interpretation Results.

4.3 S OIL BEHAVIOUR TYPE

The Soil Behaviour Type (SBT) has been interpreted using the Robertson 1990 classification system based on the stress normalised cone resistance (Qt) and normalised friction sleeve resistance (Fr).

(See glossary of terms and symbols Appendix A)


4.4 SOIL BEHAVIOUR TYPE – Ic INDEX

The Soil Behaviour Type (SBT) is presented as the Soil Behaviour Type Index, IC, for both stress-normalised and non-normalised evaluations according to the charts of Robertson (1998 & 2010)applicable to predominantly silicate soils.

The Ic provides a continuous profile of SBT variation with depth such that the end user may choose appropriate stratigraphic subdivisions. The basis of Ic and its approximation of the original

Chalk

Overburden

Friction (Red) & Tip Resistance Dynamic Pore PressureFriction Ratio

TADWORTH


chart classification zones may be seen from Appendix A figure ‘CPT Soil Behaviour Type Chart’.The loss of fidelity is dominantly in zones 1 (sensitive fine grained) and zones 8 & 9 (overconsolidated or cemented). To account for this approximation a profile of sensitivity and OCR is provided in the Standard Interpretation Results (see section ‘Geotechnical Parameters’).

Non-stress normalised SBT index IC:

= 3.47 log ( ) + ( + 1.22) .Stress-normalised SBT index IC:= ((3.47 log ) + (log + 1.22 ) ) .(See glossary of terms and symbols Appendix A)


4.5 GEOTECHNICAL PARAMETERS

4.5.1 RELATIVE DENSITY

The relative density of sands is calculated based on an empirical relationship proposed by Jamiolkowski et al. (2001) based on a large database of undisturbed frozen samples and calibration chamber tests. The expected accuracy may be evaluated from the figures presented below.

= 100 0.268 ln(See glossary of terms and symbols Appendix A – General Information)

= Compressibility dependant constant. For medium compressibility = -0.675 (applied genericvalue), for high compressibility and sands with significant carbonate or calcareous composition <=1, for low compressibility >=-2.0

Figure 4-1 Relative density with normalised tip stress and sand compressibility from calibration chamber tests (left) and undisturbed frozen samples (right). Jamiolkowski et al. (2001) (Reproduced from NCHRP Synthesis 368

(2007)).

TADWORTH



4.5.2 UNDRAINED SHEAR STRENGTH

Su is estimated from the net cone tip resistance using the following equation:

k

vocu N

qs )((Lunne et al. (1981))

where Nk is an empirical cone factor.

Research has shown that the cone factor Nk varies between 11 and 21 for normally to moderately overconsolidated soils with an average value of 14. The Nk factor tends to increase with plasticity and decrease with sensitivity. SU values are presented for Nk factors of 15 and 20.


4.5.3 OVERCONSOLIDATION RATIO

The preconsolidation stress of clays is calculated based on the method proposed by Mayne (1995) and Demers and Leroueil (2002):

= ( ) = 0.33( )= /(See glossary of terms and symbols Appendix A)

The factor may be expected to lie within the range 0.2 to 0.5 with 0.33 representing theaverage. Higher values of are recommended for aged heavily overconsolidated clays (Robertson, 2009) and may be calibrated accordingly. The figure below demonstrates the expected accuracy of the above methods in prediction of preconsolidation stress, of particular note is the under prediction for fissured clays.

Figure 4-2 Preconsolidation stress from net cone resistance in clays (Reproduced from Mayne (2007)).

TADWORTH


4.5.4 SENSITIVITY

The sensitivity of the soil, as defined by the ratio of undrained shear strength to remoulded shear strength, is calculated using the factored normalised cone resistance (Su) and remoulded shear strength taken as equal to the direct friction sleeve measurement:= 0.073 (Mayne (2007))

(See glossary of terms and symbols Appendix A – General Information)


TADWORTH


5 CPT DATA INTERPRETATION NOTES

Provided below is an inexhaustive set of cautionary notes on interpretation of the acquired CPT data with reference to examples within the dataset where appropriate.

SOIL BEHAVIOUR TYPE

The soil behaviour type (SBT) as defined by Robertson et al. (1986) is not intended to replace soil classification based on particle size fractions. Rather, the SBT will generally show bias in the classification towards the soil fraction that dominates soil behaviour in response to cone penetration (Cone tip: analogous to bearing capacity failure, friction sleeve: analogous to remoulded Su or simple shear). In general the stress-normalised SBT will be more accurate, but may be less reliable at very shallow depths (1-2 m) due to low confining stresses.

DRAINED AND UNDRAINED SOIL BEHAVIOUR

Geotechnical parameters appropriate for drained and undrained cone penetration conditions are derived for drained and undrained soil behaviour types (SBTs) respectively, however to account for uncertainty in the SBT correlation with drainage behaviour, all parameters are derived over the range of mixed soil types ‘Silt Mixtures’ and ‘Sand Mixtures’ or Ic 2.05-2.95 (Robertson, 2010). For partially drained conditions, or for partially saturated low permeability soils, error will be introduced within derived parameters.

Piezocone dynamic pore water pressures behaviour, dissipations or other site specific observations may be used to identify the appropriate limits of application. Dissipations to t50

exceeding 30 seconds indicate undrained penetration behaviour (Kim et al., 2010).

DYNAMIC PORE PRESSURE DATA

During penetration, strong dilation in shear at the cone shoulder may result in cavitation and desaturation of the piezo system and may take time to recover (up to 1 m penetration). Penetration through soils of partial saturation will provide unrepresentative readings and may desaturate the piezo system introducing variable error.

CONE TIP AND SLEEVE OFFSET

The accuracy of the SBT, over thin layers and at layer boundaries, is sensitive to offset error in the friction ratio. Penetration through zones of anisotropic soil stiffness may lead to offset of the cone tip and sleeve readings due to variation in the tip failure zone shape/depth. The friction ratio is often inaccurate in heavily disturbed soils with a ‘blocky’ macro fabric.

For this investigation a friction sleeve depth offset correction of -80mm was applied together with a 5 data point moving average on the friction ratio to minimise the influence of this effect on derived parameters.

TADWORTH


CONE TYPE

The reference cone type has a 10 cm2 projected cone tip area and 150 cm2 friction sleeve area, however it is common to use the larger 15 cm2 cone with 225 cm2 friction sleeve area for improved sensitivity and penetration depth potential. Use of the 15 cm2 cone will have the following known influences on data with respect to the reference 10 cm2:

More pronounced transitions zones and thin layer effects (larger zone of influence and failure zone).

Possible marginal increase in u2 position dynamic pore pressures during undrained/partially drained penetration.

TRANSITION ZONES AND THIN LAYER EFFECTS

During penetration at the boundary between soils of contrasting stiffness, a transition zone is often evident prior to mobilization of the true soil stiffness. These should be cautiously ignored in assessment of soil behaviour type and parameter evaluation. Where the stiff layer is thin (<~0.5m) the true stiffness will not be fully mobilised. The effect for thin low stiffness layers is less significant. Procedures for thin-layer effect correction are provided by Robertson and Wride (1998). In choosing characteristic values of the tip, sleeve and derived parameter results, large scale peak and trough values may be more representative of the local value.

GRAVELS

The presence of gravel or larger clasts in a soil is often characterised by short peaks in the CPT tip and sleeve readings, possibly with associate inclinometer ‘shake’ and/or sharp reductions in pore water readings due to dilation effects. Frequent gravels in soft or loose soils may generate highly erroneous friction ratio values. Where gravels are matrix supported the tip and sleeve peaks may be ignored or filtered in choosing characteristic values for bulk behaviour.

TADWORTH


6 REFERENCES

Agrawal, G., Pekin, O. & Chandra, D. 2010. Evaluating relative compaction of fills using CPT. 2nd International Symposium on CPT, Huntington Beach, CA, USA. Volume 2&3: Technical Papers, Session 3: Applications, Paper No. 3-46.

ASTM E74-13a (2013), Standard Practice of Calibration of Force-Measuring Instruments for Verifying the Force Indication of Testing Machines, ASTM International, West Conshohocken, PA.

Baldi, G., Bellotti, R., Ghionna, V.N., Jamiolkowski, M. and Pusqualini, E. (1986) “Interpretation of CPT’s and CPTU’s, 2nd Part: Drained Penetration of Sands”. Proceedings of the 4th International Geotechnical Seminar, Singapore. pp. 143-156.

British Standards Institution (2003) BS 8422:2003, Force measurement – Strain gauge load cell systems – Calibration method. London: British Standards Institution.

Houlsby, G.T. and Teh, C.I. (1988) “Analysis of the Piezocone in Clay”. Proceedings of the International Symposium on Penetration Testing (ISOPT-1), Orlando, Vol. 2, pp. 777-783. Balkema Pub., Rotterdam.

ISO 10012:2003 Measurement management systems - Requirements for measurement processes and measuring equipment. New Delhi: Bureau of Indian Standards (2003).

ISO 22476-1:2012 Geotechnical investigation and testing - Field testing - Part 1: Electrical cone and piezocone penetration test. New Delhi: Bureau of Indian Standards (2012).

ISSMGE, 1999. International reference test procedure for the cone penetrometer test CPT and the cone penetration test CPTU, Report of ISSMGE TC16 on Ground Property Characterisation for In situ Testing, In Proceedings of the 12th European conference on Soil Mechanics and Geotechnical Engineering 3:2195-222 (1999).

Jamiolkowski, M., LoPresti, D.C.F., and Manassero, M. (2001) “Evaluation of Relative Density and Shear Strength of Sands from Cone Penetration Test and Flat Dilatometer Test”. Soil Behaviour and Soft Ground Construction (GSP119), American Society of Civil Engineers, pp. 201-238. Reston, Va. 2001

Kim, K., Prezzi, M., Salgado, R., and Lee, W. (2008) “Effect of Penetration Rate on Cone Penetration Resistance in Saturated Clayey Soils”, Journal of Geotech. Geoenviron. Eng., Vol. 134(8), pp. 1142-1153.

Kulhawy, F.H. and Mayne, P.W. (1990) “Manual on Estimating Soil Properties for Foundation Design”. Report EPRI EL-6800Research Project 1493-6, Electric Power Research Institute, Palo Alto, CA, pp. 306.

Ladd, C.C. and DeGroot, D.J. (2003) “Recommended Practice for Soft Ground Site Characterization: Arthur Casagrande Lecture”. Soil & Rock America 2003 (Proceedings. 12th Pan American Conference on Soil Mechanics and Geotechnical Engineering, Boston, MA). Verlag Glückauf, Essen, Germany. pp. 3–57.

Lunne, T., Robertson, P.K. and Powell, J.J.M. (1997) “Cone Penetration Testing in Geotechnical Practice” Blackie Academic, New York 1997.

Lunne, T. and Kleven, A. (1981) “Role of CPT in North Sea Foundation Engineering”. Session at the ASCE National Convention: Cone Penetration Testing and Materials. pp. 76-107. American Society of Engineers (ASCE).

Mayne, P.W. and Campanella, R.G. (2005) “Versatile Site Characterisation by Seismic Piezocone”. Proceedings of the 16th

International Conference on Soil Mechanics and Geotechnical Engineering, Vol. 2. Millpress, Rotterdam, The Netherlands 2005. pp 721-724.

Mayne, P.W. (2007) “Cone Penetration Testing – A Synthesis of Highway Practice”. NCHRP Synthesis 368, Transportation Research Board, Washington, D.C.

Robertson, P.K., Campanella, R.G., Gillespie, D. and Greig, J. (1986) “Use of Piezometer Cone Data”. Proceedings of the ASCE Specialty Conference, In Situ ’86: Use of In-Situ Testing in Geotechnical Engineering. Blacksburg, pp. 1263-1280, American Society of Engineers (ASCE).

Robertson. P.K., (2010) “Soil Behaviour Type from the CPT: an update”. 2nd International Symposium on Cone Penetration Testing. Huntingdon Beach, CA, USA.

Robertson, P.K. (2012). Interpretation of in-situ tests – some insights, Proc. 4th Int. Conf. on Geotechnical & Geophysical Site Characterization, ISC’4, Brazil, 1.

Schmertmann, J., Baker, W., Gupta, R. & Kessler, K. 1986. CPT/DMT OC of Ground Modification at a Power Plant. Geotechnical Special Publication 6:985-1001. ASCE.

Sully, J.P., Robertson, P.K., Campanella, R.G. and Woeller, D.J. (1999) “An approach to evaluation of field CPTU dissipationdata in overconsolidated fine-grained soils”. Canadian Geotechnical Journal. Vol. 36, pp. 369-381.

TADWORTH


SUMMARY TABLES

Table 1 CPT Test Summary

TEST ID FIN

AL D

EPTH

(m

BGL)

Cone ID {C=Cone tip; F=Friction Sleeve; I= Inclination; P = Piezo; S=Subtraction cone; 15/10 = cone projected area (cm2) )} CP

T RI

G

PRE

DRIL

LED

/ IN

SPEC

TIO

N P

IT

(m)

CASI

NG

DEPT

H (m

)

REFU

SAL

FACT

OR

SAM

PLES

EAST

ING

NO

RTHI

NG

ELEV

ATIO

N (m

)

DATE

OF

TEST

REMARKS ESTIMATED DEPTH TO CHALK (mBGL)

CPT01 3.80 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. <3.80 m based on observation of chalk on cone tip. Characteristic signature not observed.

CPT02 10.28 S15-CFIP.1151 UK8 Tip load 08/06/2016 >10.28 m. Refusal assumed to be at or close to chalk interface, based on friction ratio signature.

CPT03 10.27 S15-CFIP.1151 UK8 Tip load 08/06/2016 7.20 – 8.20 m.

CPT04 7.86 S15-CFIP.1151 UK8 Tip load 07/06/2016 No interpretation available – characteristic signature not observed.

CPT05 10.09 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. 8.00 – 8.50 m.

CPT06 9.95 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. 6.00 - 6.50 m. MOSTAP sample confirmed chalk at 6.45 m.

CPT07 11.48 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. >11.48 m. Refusal assumed to be at chalk interface, based on friction ratio signature and chalk on cone tip observed.




CPT11 9.92 S15-CFIP.1151 UK8 Tip load 07/06/2016 Chalk on tip. 3.80 – 4.20 m. MOSTAP sample confirmed chalk interface at 4.30 m.


CPT13 10.87 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. 6.50 – 7.50 m. MOSTAP sample confirmed chalk interface at <6.50 m.


CPT15 13.38 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. 9.50 – 10.50 m. Uncharacteristic piezo response – high associated uncertainty.

CPT16 9.45 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. <9.45 m based on observation of chalk on cone tip. Characteristic signature not observed.

CPT17 8.04 S15-CFIP.1151 UK8 Tip load 07/06/2016 Chalk on tip. 6.80 – 7.20 m. MOSTAP sample confirmed chalk interface at <7.00 m.

TADWORTH


CPT18A 12.95 S15-CFIP.1151 UK8 Tip load 08/06/2016 Chalk on tip. 10.20 – 11.70 m.




Note; MOSTAP locations are between 1-2 m from the original CPT location. Note: “Chalk on tip” means that chalk residue was observed on the cone tip following extraction of the cone at the end of the test. Note: For an example of “Characteristic signature” see report section 4.2.

CPT Test Plots are presented in Appendices B & C

TADWORTH


Table 2 MOSTAP Summary Table

TEST IDDEPTH TOP

(mBGL)DEPTH BOTTOM

(mBGL) RECOVERY (%) REMARKSCPT02 3.8 5.0 0 Dense sands and no recovery.CPT05 7.0 8.2 0 Dense sands and no recovery.CPT06 5.5 6.7 50 CPT07 10.5 11.7 100

CPT11 3.5 4.7 40 Obstruction, possible flints from chalk deposits.

CPT12 3.0 4.2 100


CPT17 7.0 8.2 100 CPT18 11.5 12.7 0 Refused on total reaction load.CPT19 3.0 4.2 80 CPT19 4.2 5.4 100


Note; MOSTAP locations are between 1-2 m from the original CPT location.

MOSTAP core photos and sample descriptions are presented in Appendix D

TADWORTH


APPENDIX A GENERAL INFORMATION

LIST OF FIGURES

Description Pages Included

Cone Calibration Certificate: S15-CFIP.1151 1

Data Sheet: 18.0 Tonne “Bog-Skipper” CPT Unit (UK8) 1

CPT Soil Behaviour Type Chart 1

Glossary of Terms 1

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