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Numerical Simulation of Pile Foundations in

Liquefiable Soils with a Frozen Crust

AUTC Project #309011

Zhaohui (Joey) Yang, Ph.D.

Associate Professor

University of Alaska Anchorage

May, 2010

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Acknowledgement

Sponsors Alaska ni!ersity "ransportation #enter (A"#) Alaska Dept. o$ "ransportation and Pu%lic &acilities

Alaska 'PS#o

#o*orkers Pro$. J. +eroy ulsey (A&) Dr. &eng -iong, Dr. tpal Dutta, Dr. Jens unk (&aculty,

S/' o$ AA) r. 0iang +i, r. 1ang -u, and r. uel 2inonwangan

(1raduate Students)

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/utline

3ntroduction

Soil #onstituti!e odel

#ali%ration o$ &' model

Da!is centri$uge test description 4 Simulation results

odel Description

esh '$$ects

Simulation esults#onclusion

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3ntroduction

+andslide in the "urnagain

eight in the 5678 1reat

Alaska 'arth9uake:

+ateral spreading o%ser!ed

in the ;

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3ntroduction

+ateral spreading is particularly damaging i$ a nonli9ue$ia%lecrust rides on top o$ the li9ue$ied soil. *hen the ground crust

is $ro=en, it will greatly impact the li9ue$action o$ underlying

soils as well as the conse9uences o$ li9ue$action $or two

reasons

the $ro=en ground crust $orms a sti$$ and almost impermea%le mass

that restricts upward $low o$ water: and

the $ro=en crust will likely impose large lateral loads on the %ridge

$oundation during shaking as well as postli9ue$action lateral

spreading

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Soil #onstituti!e odel

&or cohesionless soil, the constituti!e model used in

/penSees is de!eloped %ased on the multiyield

sur$ace plasticity theory (Pre!ost, 56>?).

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#ali%ration o$ &' model

Description o$ #entri$uge "est

A centri$uge e@periment identi$ied

as PDS

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#ali%ration o$ &' model

Description o$ #entri$uge "est

Soil and model parameters $rom the e@periment were used in thesimulation.

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#ali%ration o$ &' model

Description o$ #entri$uge "est

#omparison was made $or the displacement time history o$ pile head."he trend o$ results $rom e@periment and &' modeling is in good

agreement.

"he pile head de$lection o%tained $rom e@periment and &' model is

88 and 5 cm, respecti!ely.

< ? 5< 5? ;< ;? B< B? 8 m depth

5< ;< B< 8< ? 5< 5;

?

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&inite 'lement odel

Pile esponse

+ateral displacement time histories o$ pile at the

ground sur$ace $or %oth cases

< 5< ;< B< 8< ?< 7 7 8 ; < ; 8 7;?

; 7 8 ; < ; 8 7;?

;