XVIII EYGEC 18th EUROPEAN YOUNG … european young geotechnical engineers’ conference the...
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XVIII EYGEC18th EUROPEAN
YOUNG GEOTECHNICAL ENGINEERS’ CONFERENCE
Portonovo, Ancona
(Italy) June
17-20th 2007
18th EUROPEAN YOUNG GEOTECHNICAL ENGINEERS’
CONFERENCE
18th EUROPEAN YOUNG GEOTECHNICAL ENGINEERS’
CONFERENCE
www.www.ktuktu..edu.tredu.tr
THE VARIATION of
SWELLING CHARACTERISTICS with
EPS GEOFOAM
in
EXPANSIVE SOILS
S. B. İkizler, M. Aytekin
& E. NasKaradeniz Technical
University, Trabzon, Turkey
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WhatWhat
areare
ExpansiveExpansive
SoilsSoils??TheyThey havehave volume change because volume change because of changing water contentof changing water contentThey swell when the moisture They swell when the moisture content is increased and shrink content is increased and shrink when the moisture content is when the moisture content is decreaseddecreased
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18th EUROPEAN YOUNG GEOTECHNICAL ENGINEERS’
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18th EUROPEAN YOUNG GEOTECHNICAL ENGINEERS’
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Expansive soils are generally in unsaturated stateExpansive soils are generally in unsaturated state
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Expansive soils are generally located in arid and semi-arid regions
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What are the Effects of Expansive Soils?
The swelling of expansive soils cause major damage and distresses without taking enough measure in the structure as, slab-on-grade, residential structures, roadways, light structures, highways, railways, airport slabs, water channels, pipe lines, earth retaining walls, dams, bridges and waste disposal areas
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Polygonal pattern of surface cracks in the dry season
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Damages Damages ffromrom
Expansive Soils in the BuildingsExpansive Soils in the Buildings
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Structural damage due to ground heave at Al-Khod
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Shrinkage Cracks in Poured Concrete Slabs
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What is the Swelling Pressure?
ASTM ASTM definedefiness
sswelling pressure as the welling pressure as the pressure which prevents the specimen pressure which prevents the specimen from swelling or that pressure which is from swelling or that pressure which is required to return the specimen back to required to return the specimen back to its original state (void ratio, height) its original state (void ratio, height) after swellingafter swelling
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Tension reinforcement
Retaining wall Compressible material
Using compressible material in geotechnical applications
glass-fiber insulation and cardboard
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Grade beam or structural slab
Compressible inclusion
Deep foundation
Using compressible material in geotechnical applications
Cardboard
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Compressible inclusion
Pipe or culvert
Using compressible material in geotechnical applications
bales of hay
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Disadvantages
of Compressible Material of Compressible Material for Using in Geotechnical Applicationsfor Using in Geotechnical Applications
their stress-strain behavior is unpredictable and uncontrollable.
if it occurs in a confined space, can result in a potential explosion hazard as a result of the methane gas generation that accompanies the anaerobic decomposition of organic material.
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EXPANDED POLYSYTRENE SYTROFOR (EPS)GEOFOAM
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Advantages
of EPS Geofoam
EPS geofoam is an inexpensive geofoam material
It can be produced within a range of densities between 11 and 30 kg/m3
It is a lightweight material with a good insulation and energy absorption characteristics.
Selected EPS Geofoam Applications
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Application Density Compressibility Damping Insulation CohesionSlope
StabilizationEmbankments
Bridge Approaches
Earth Retaining Structures
Bridge AbutmentsBuried PipesFlood Control
LeveesLandscape
ArchitecturalPlaza DecksBasement
InsulationRailways
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MATERIALS AND METHODS
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SWELLING PARAMETERS
Swelling Percentage Swelling Pressure
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ASTM D 4546 (2003)
The magnitude of swell or settlement under known vertical (axial) pressure
The magnitude of vertical pressure needed to maintain no volume change of laterally constrained, axially loaded specimens.
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Grain density (kN/mGrain density (kN/m33)) 23.223.2Liquid limit (%)Liquid limit (%) 284.5284.5
Plastic limit (%)Plastic limit (%) 55.655.6Plasticity index (%)Plasticity index (%) 228.9228.9Shrinkage limit (%)Shrinkage limit (%) 36.5536.55Optimum water content Optimum water content (%)(%)
11.611.6
Maximum dry density Maximum dry density (kN/m(kN/m33))
8.638.63
Coefficient of Coefficient of permeability (mm/sec)permeability (mm/sec)
17.8x1017.8x10--99
Physical properties of the expansive soil from laboratory testing
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Thicknesses
of EPS Geofoam in the
Experiments
1.1.
002.2.
2.2 mm2.2 mm
3.3.
4.3 mm4.3 mm4.4.
7.15 mm7.15 mm
5.5.
10 mm 10 mm
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P Okuma saati
Yükleme başlığPoroz taşFiltre kağıdıGeofoamNumune alma hFiltre kağıdı Poroz taş
Zemin
Su
Load Device Porous Stone Filter Paper EPS GeofoamRing Filter Paper Porous Stone
Load Device Porous Stone Filter Paper EPS Geofoam RingFilter Paper Porous Stone
Dial Gage
Water
Specimen
Consolidation test apparatus for swelling test with EPS Geofoam
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1.00 10.00 100.00 1000.00
Swelling Pressure, kPa
1.5
2.1
2.7
3.3
1.2
1.8
2.4
3.0
Voi
d R
atio
, e
e 0
σp = 465 kPa
First
Test (without
EPS Geofoam)
Swelling
Pressure: 465 kPaSwelling
Percentage:%133.25
Void Ratio -
Log Pressure Curve
of Expansive
Soil
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Second
Test (2.2 mm thick layer of EPS geofoam)
Swelling
Pressure: 435 kPa
Swelling
Percentage:%116.34
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Third
Test (4.3
mm thick layer of EPS geofoam)
Swelling
Pressure: 401 kPa
Swelling
Percentage:%99.30
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Fourth
Test (7.15
mm thick layer of EPS geofoam)
Swelling
Pressure: 192 kPa
Swelling
Percentage:%94.01
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Last
Test (10
mm thick layer of EPS geofoam)
Swelling
Pressure: 101 kPa
Swelling
Percentage:%73.24
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Thickness of
EPS
Geofoam(mm)
W0 (%)Initial
Water
Content
γdo (kN/m3)Maximum
Dry
Density
Free Swell
(%)
σp (kPa)Swelling Pressure
0 11.6 8.63 133.25 465
2.2 11.6 8.63 116.34 435
4.3 11.6 8.63 99.30 401
7.15 11.6 8.63 94.01 192
10 11.6 8.63 73.24 101
Swelling pressures and swelling percentage of expansive soil for different thickness of EPS geofoam
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CONCLUSIONS
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Different thickness of EPS geofoam (density of 12 kg/m3) that was inserted between the expansive soil and the top porous stone was effective in reducing the swelling pressure and the swelling percentage.
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0
100
200
300
400
500
600
0 1 2 3 4 5 6 7 8 9 10 11 12
Thickness of EPS Geofoam (mm)
Swellin
g Pr
essu
re (kP
a)
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40
60
80
100
120
140
0 1 2 3 4 5 6 7 8 9 10 11 12
Thickness of EPS Geofoam (mm)
Free
Swe
ll (%
)
THANKSTHANKS