Seismic performance evaluations of earth dams are essential to characterize the geotechnical risk implied by slope stability failures. There are a large number of case histories compiled in the international technical literature, which report failures of these types of earthen structures caused by moderate to large magnitude earthquakes. The observed damage is more important when liquefaction occurs on the dam body and foundation, which often leads to cracking, settlements, tilting, and general distortion of the dam geometry. Analyses based on limit equilibrium are generally sufficient to establish hazard zones. However, numerical models with solution schemes formulated in the time domain, which are capable of taking into account the kinematics of the soil movement more realistically, are needed to quantify the geotechnical risk. This paper describes the application of a practice-oriented simplified constitutive model, which implemented in a lagragian finite difference platform, is capable of predicting the accumulation of pore pressure due to earthquake loading in finegrained saturated materials, the reduction of shear strength, and its effect on the development of permanent displacements. The model uses a bilinear Mohr-Coulomb type failure criterion coupled with an incremental pore pressure generation scheme. The pore pressure is accumulated as a function of the number of stress cycles. The tangent soil stiffness and hysteretic damping are modified with the loading history. The model capability to evaluate the seismic response of earth dams is illustrated through the analysis of a case history comparing the model predictions with actual field measures. The model is able to properly capture the kinematics of the slope failure and the observed damage. The measured permanent displacements after liquefaction and those computed with the model are in good agreement.
[1]
I. M. Idriss,et al.
SIMPLIFIED PROCEDURE FOR EVALUATING SOIL LIQUEFACTION POTENTIAL
,
1971
.
[2]
W. D. Liam Finn,et al.
An Effective Stress Model for Liquefaction
,
1977
.
[3]
W. F. Marcuson,et al.
Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils
,
2001
.
[4]
Izzat M. Idriss,et al.
The slides in the San Fernando Dams during the earthquake of February 9, 1971
,
1975
.
[5]
Kenneth L. Lee,et al.
ANALYSIS OF THE SHEFFIELD DAM FAILURE
,
1969
.
[6]
Gonzalo Castro,et al.
Re‐Examination of Slide of Lower San Fernando Dam
,
1985
.
[7]
H. Bolton Seed,et al.
PORE-WATER PRESSURE CHANGES DURING SOIL LIQUEFACTION
,
1976
.
[8]
Jean-Pierre Bardet,et al.
Engineering observations on ground motion at the Van Norman Complex after the 1994 Northridge earthquake
,
1996
.
[9]
Jean-Pierre Bardet,et al.
PERFORMANCE OF SAN FERNANDO DAMS DURING 1994 NORTHRIDGE EARTHQUAKE
,
1996
.
[10]
H. Bolton Seed,et al.
Closure of "Soil Liquefaction and Cyclic Mobility Evaluation for Level Ground during Earthquakes"
,
1979
.
[11]
John Egan,et al.
Practical applications of a nonlinear approach to analysis of earthquake-induced liquefaction and deformation of earth structures
,
2006
.
[12]
G Mesri,et al.
Closure of "Undrained Shear Strength of Liquefied Sands for Stability Analysis"
,
1992
.