Umur Salih OKYAY - PRESENTATION 07-OKYAY-U-S-20130408-CFMS

7/30/2019 Umur Salih OKYAY - PRESENTATION 07-OKYAY-U-S-20130408-CFMS

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UTILISATION DES SOLS TRAITES A LA CHAUX ET AU CIMENT POUR

LE RENFORCEMENT DES SOLS AVEC INCLUSIONS RIGIDES

Prsent par Umur Salih OKYAY

Paris, le 08/04/2013


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ISBN : 978-2-85978-462-1, 2012 - 384 p., 17 x 24 cm, broch, Presses des Ponts

Institut pour la recherche applique et l'exprimentation en gnie civil (IREX)


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Use of lime and cement treated soils as pile supported load transfer platform

Okyay, U.S., Dias, D., 2010., Use of lime and cement treated soils as pile supported load transfer platform,

Engineering Geology, Volume 114, Issues 12, 23 June 2010, Pages 3444, DOI: 10.1016/j.enggeo.2010.03.008


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Particle size distribution of Goderville soil3 Tons of Goderville silt

Particles smaller than 0.063 mm and larger than 0.002 mm constitute 70% of the soil. 25% of the particles are smaller than 0.002 mm.


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Soil Lime Cement

SL3%

SC6%

SLC12%3%

SLC22%5%


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Notation of the tested materials and optimum Proctor values

Variation of reduction in water content due to

hydration at different curing time

The addition of cement/lime has an influence in increasing

the optimum water content and decreasing the maximumdry unit weight of the naturel soil.

Proctor tests & Treatment formulations


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250 tests at 7, 28, 90 and 350 days

In the experimental program, the

Goderville soil was characterised by

laboratory tests and appropriate

treatment formulations were chosen.

Mechanical soil tests were conductedto deduce the strength characteristics

of soils at 7, 28, 90 and 350 days after

treatment.

Mechanical performance of treated soil : Laboratory tests


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Evolution of cohesion

Direct shear tests

The value of the cohesion reaches at least 25 kPa at the first week treatment and above

60 kPa at 28 days after the treatment in presence of cement.

The evolution of cohesion for the soil treated with lime is quite slow and the cohesion

does not exceed 45 kPa in long term.

The tests were performed with 50mm height and 60 mm diameter cylindrical specimens at constant

shearing speed (0.1 mm/min).

The shearing tests were carried on normal stress range from 50 to 100 kPa.


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Evolution of compressive strength

Unconfined compressive strength test : uniaxial compression

In presence of cement, more than 80% of the final compressive strength was obtained at 90 days after the treatment.

This ratio is 70% for the treatment with only lime. The highest strength value is obtained with the combined treatment

SLC2.

The tests were carried out with 100 mm height and 50 mm diameter cylindrical specimens at a constant

loading speed of 0.1 mm/min.

The untreated soil (S) has ductile strain hardening failure behaviour.

On the other hand, ductile strain softening behaviour is observed for lime treated soil (SL).

Addition of cement ----- specimens become more brittle.

For the cement treated soil (SC), the failure occurs suddenly at the end of the test.

The addition of lime to the treatment provides a residual resistance at the end of the test

and the specimens behave in a more ductile manner.

Stress vs strain @ 90 days


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Evolution of tensile strength Evolution of Young's modulus

Bending resistance of the specimen is equal to 3FL/2a3 where a is the section of the specimen. Then the Young's modulus of the

specimen is calculated E=FL3/48Iy where I is the second moment of area and y is the deflection at the centre of the beam.

Bending test on 4 x 4 x 16 cm specimens

3% Lime 6% Cement


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Summary of the results at 90 days after the treatment and comparisons

The tests indicate that almost 90% of total resistance is gained at 90 days of curing after treatment.


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Numerical analysis of treated soils with rigid piles


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Differential settlements

Variation of the material characteristics

Total principal stresses under 60 kPa of loading on the foundation

Soft soilPileSoft soilPile

Soft soilPile Soft soilPile

Soft soilPile


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Influence of platform height

Total principal stresses for 60 kPa of loading on the foundation.

Soft soilPile Soft soilPile

Soft soilPileSoft soilPile

SLC2

Influence of pile spacing

SLC2 h=60 cm 90%

55%

Bending moments and shear forces in the foundation.


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Geotechnical centrifuge of LCPC Nantes

12 x g & 20 x g


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Experimental Apparatus


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MALAXAGE TRAITEMENT COMPACTAGE

COMPACTAGE STOCKAGE TRANSPORTATION

Fabrication des galettes du sol trait :

SL & SC Diamtre = 90 cm Hauteur = 42 cm 60 cm


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-12

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-8

-6

-4

-2

0

0 15 30 45 60 75 90 105 120 135

Temps coul (min)

Dplacementvertical(mm)

0

10

20

30

40

50

60

70

80

90

100

Pression(kPa)

12xg - 20xg Fin de remplissage

Descente du plateau

Fin de lessai

ESSAI TYPE : Droulement dun essai


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0

10

20

30

40

50

60

70

80

90

100

0,00 0,10 0,20 0,30 0,40 0,50

Ratio Tassement / Diamtre (

z/D)

Efficacitnormalise(%)

Emax = 100 %

E = 85 % E = 86 %

E31 - H/s = 0,25

E32 - H/s = 0,18

E > 85%

Efficacit avec un matelas trait la chaux ( = 1,23%) 12 x gD = 30 cm

s = 240 cm

H = 60 cm

H = 42 cm

La valeur defficacit ne descend pas en dessous de 85% pour les 2 hauteurs de matelas testes.

La baisse defficacit seffectue plus tt avec une hauteur de matelas faible quavec une hauteur de

matelas plus importante.


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0

10

20

30

40

5060

70

80

90

100

0.00 0.10 0.20 0.30 0.40 0.50

Ratio Tassement / Diamtre (

z/D)

Eff

icacitnormalise(%)

E33 - H/s = 0,18E34 - H/s = 0,25

E > 90%

Efficacit avec un matelas trait au ciment( = 1,23%) 12 x gD = 30 cm

s = 240 cm

H = 42 cmH = 60 cm

Pour les deux hauteurs de matelas testes, lefficacit maximale de 100% est atteinte au cours des

essais.

Lefficacit maximale est atteinte rapidement pour une hauteur de matelas faible.

La moyenne des contraintes en tte des inclusions rigides est denviron 6 MPa.


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0

200

400

600

800

1000

1200

1400

1600

0 100 200 300 400 500

Temps coul (min)

Force

(N)

monotone

cyclique

z/D = 0,15

z/D = 0,28

z/D = 0,52

Cycles de chargement / dchargement


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0

200

400

600

800

1000

1200

1400

1600

0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80

Ratio Tassement / Diamtre (z/D)

Force(N)

E28

E29

monotone

cyclique

Cycles de chargement / dchargement

Dun point de vue global, la courbe de chargement cyclique prsente la mme allure que

celle du chargement monotone.

A la fin de chaque srie, les valeurs deffort issues dun chargement cyclique finissent par

atteindre les valeurs deffort de lessai monotone.


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Rupture dans le matelas


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Effet de vote


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Chapiteaux en tte des inclusions rigides


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Surfaces de rupture sur les chapiteaux en tte des inclusions rigides


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Dcollement entre les couches de compactage


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Chaux : comportement mcanique souple et radoucissant

Lefficacit augmente progressivement Les contraintes sont rparties entre les inclusions rigides et le

sol compressible par flexion du matelas

Ciment : comportement mcanique fragile et cassant

Lefficacit augmente rapidement Comme une dalle sur les ttes des inclusions rigides

Conclusions

E > 85% aprs la rupture

Le matelas de faible hauteur se fissure et se dtruit plus

facilement quun matelas pais.

Malaxage et compactage


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UTILISATION DES SOLS TRAITES A LA CHAUX ET AU CIMENT POUR

LE RENFORCEMENT DES SOLS AVEC INCLUSIONS RIGIDES

Prsent par Umur Salih OKYAY

Paris, le 08/04/2013Merci pour votre attention.

Umur Salih OKYAY - PRESENTATION 07-OKYAY-U-S-20130408-CFMS

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