Lateral Behavior of Pile Foundations during Partial Liquefaction

Abstract

Pile foundations in liquefiable soils need to be checked for the bending moments due to the liquefaction induced stresses to arrest the plastic hinge formation. Recent studies reveal that the bending moments in the pile are significantly higher during the partial liquefaction stage (excess pore water pressure ratio <1.0) than at the fully liquefied condition. This study proposes a method to estimate the pile bending moments during partial liquefaction. Advanced multi-stage cyclic triaxial tests are conducted on sandy soil to understand the partial liquefaction behavior. The test results are then utilized to model the soil pile interaction in partially liquefiable soils following the Beams on Nonlinear Winkler Foundation (BNWF) approach. The method is based on mobilized strength design concept. The developed numerical model is analyzed using the traditional lateral soil springs along with the proposed springs. It is understood from this study that the bending response of pile foundations in partially liquefiable soils can be effectively estimated with the proposed methodology compared to the existing models.