Numerical Study on the Liquefaction Resistance of Rectangular Closed Diaphragm Walls in Gently Sloping Liquefiable Deposits

Rectangular closed diaphragm walls (RCDWs) serve as a new type liquefaction mitigating foundations recently, however, their mechanisms of liquefaction mitigating have been studied scantly. This paper proposed a 2D numerical method to simulate a dynamic centrifuge test with OpenSees, on the basis of Biot`s coupled theory and u-p formulation considering the dynamic interactions between fluid and soil particles in the saturated sands. The validity of the method was proved by comparing the results of the dynamic centrifuge test. Furthermore, four different earthquake events with three PGAs were applied to this numerical model to study the capacity to liquefaction mitigating of RCDWs. The results show that RCDWs can mitigate soil liquefaction effectively under all the earthquake events, and the characteristics of excess pore water pressure (EPWP) developed in far field and soil core are different: 1) the development of EPWP in soil core were restrained by RCDWs under small shaking events; 2) liquefaction was restrained in soil core though large EPWP generated under moderate shaking events; and 3) the onset of liquefaction was delayed in soil core under extreme large shaking events.