Location

San Diego, California

Session Start Date

5-24-2010

Session End Date

5-29-2010

Abstract

This paper presents the numerical assessment of seismically-induced slope instability observed at Degirmendere Cape, Izmit Bay during Kocaeli (Izmit)-Turkey earthquake. As is evident from the name of the site, Degirmendere Cape site is located at the north of Degirmendere, on a small intrusion into the Bay of Izmit. At Degirmendere Cape, there existed a municipality owned hotel and recreational areas. During the earthquake following slumping of the fill material, the site was unindated. All the recreational facilities as well as the municipality hotel were lost to Marmara Sea with its residents. Failure mechanism was attributed to fault rupture/seismically induced slope instability and/or liquefaction of underlying fill materials. The site was sloping at an angle of 10–15 degrees towards the bay. For understanding the true failure mechanism, 2-D finite difference analysis of the slope is performed by using modified UBCSAND effective stress liquefaction model. In the original model, effects of static effective confining shear stresses on cyclic pore pressure response of saturated cohesionless soils were not fully addressed. Thus, additional Kα and Kσ corrections are applied explicitly and conveniently on SPT input values as opposed to conventional application of corrections on CSR. As a conclusion, the observed large ground deformations are compared with model predictions. Close agreements among failure modes and large deformations strains are concluded to be mutually supportive of the adopted numerical scheme and the constitutive model. Estimated high pore pressure ratios revealed that the major cause of instability of the slope was triggered by seismic soil liquefaction, more specifically flow liquefaction.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conferences on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics

Meeting Name

Fifth Conference

Publisher

Missouri University of Science and Technology

Publication Date

5-24-2010

Document Version

Final Version

Rights

© 2010 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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May 24th, 12:00 AM May 29th, 12:00 AM

Effective Stress Based Numerical Assessment of Liquefaction-Induced Landslide at Degirmendere Cape, Izmit Bay During Kocaeli (Izmit)-Turkey Earthquake

San Diego, California

This paper presents the numerical assessment of seismically-induced slope instability observed at Degirmendere Cape, Izmit Bay during Kocaeli (Izmit)-Turkey earthquake. As is evident from the name of the site, Degirmendere Cape site is located at the north of Degirmendere, on a small intrusion into the Bay of Izmit. At Degirmendere Cape, there existed a municipality owned hotel and recreational areas. During the earthquake following slumping of the fill material, the site was unindated. All the recreational facilities as well as the municipality hotel were lost to Marmara Sea with its residents. Failure mechanism was attributed to fault rupture/seismically induced slope instability and/or liquefaction of underlying fill materials. The site was sloping at an angle of 10–15 degrees towards the bay. For understanding the true failure mechanism, 2-D finite difference analysis of the slope is performed by using modified UBCSAND effective stress liquefaction model. In the original model, effects of static effective confining shear stresses on cyclic pore pressure response of saturated cohesionless soils were not fully addressed. Thus, additional Kα and Kσ corrections are applied explicitly and conveniently on SPT input values as opposed to conventional application of corrections on CSR. As a conclusion, the observed large ground deformations are compared with model predictions. Close agreements among failure modes and large deformations strains are concluded to be mutually supportive of the adopted numerical scheme and the constitutive model. Estimated high pore pressure ratios revealed that the major cause of instability of the slope was triggered by seismic soil liquefaction, more specifically flow liquefaction.