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This study outlines a probabilistic cyclic shear strain-based procedure for the determination of the minimum shear strain, γcl, required to initiate liquefaction in gravelly soils. The proposed formulation accounts for the influence of void ratio through the shear wave velocity and the grain size distribution through the coefficient of uniformity, Cu. Separate equations for γcl are derived considering four cyclic resistance models that rely on shear wave velocity as a measure of probabilistic liquefaction resistance. Similarities and differences in the resulting γcl for each of these models are identified. The accuracy and uncertainty of cyclic strain-based models in predicting liquefaction in gravelly soils are demonstrated using existing liquefaction case histories where grain size distributions are available. The excess pore pressure response of gravelly soils subjected to earthquake ground motions is evaluated using a subset of the available liquefaction case histories and the cyclic shear strain and energy-based frameworks and is compared to laboratory test specimens. Although the trends in excess pore pressure generation from critical layers in the case histories are comparable to laboratory-based responses, a greater rate of excess pore pressure generation is calculated for the field cases. The models presented in this study can help identify sites that have a high potential for ground failure when used together with other established models.
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Impact of Multiple Cyclic Loads on the Cyclic and Post-Cyclic Behavior of Fine-Grained Soils
Fine-grained soils subjected to seismic loading often exhibit instability or failure of slopes, foundations, and embankments. To understand the behavior of clay soils under multiple earthquake loads, kaolinite samples were prepared and tested in the laboratory using a cyclic simple shear device. Each sample was subjected to two cyclic events separated by different degrees of reconsolidation periods to simulate different levels of excess pore water pressure dissipation. The results indicated that the degree to which excess pore water pressure generated during the first cyclic event was dissipated affected the cyclic resistance of the soil during the second cyclic event. The post-cyclic undrained shear strength was also found to be a function of the degree to which excess pore water pressure from the first cyclic load was allowed to dissipate prior to the application of the second cyclic load.
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- PAR ID:
- 10514381
- Publisher / Repository:
- American Society of Civil Engineers
- Date Published:
- Volume:
- 349
- ISBN:
- 9780784485316
- Page Range / eLocation ID:
- 84 to 93
- Format(s):
- Medium: X
- Location:
- Vancouver, British Columbia, Canada
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1061/9780784485316.010
