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


CONFERENCE


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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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


Cardboard


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Compressible inclusion

Pipe or culvert


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


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


Swelling

Pressure: 192 kPa

Swelling

Percentage:%94.01


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Last

Test (10


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

XVIII EYGEC 18th EUROPEAN YOUNG … european young geotechnical engineers’ conference the...

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