Prediction of seismic compression of saturated sand considering the ground motion characteristics and variable permeability

Abstract

A one dimensional shear beam numerical model was firstly established to calculate the seismic compression in free-field site of saturated sand by using OpenSees program. Based on the established model, the influence of permeability coefficient on the liquefaction-induced settlement of saturated sand was investigated by introducing a variable permeability coefficient model. The modified model was verified by comparison with results from centrifuge model test. The correlation between seismic compression and seismic load parameters was studied, and a velocity spectrum intensity (VSI) based prediction function was proposed to estimate the compression of saturated sand by considering both the characteristics of seismic motion and the sand properties. The results show that the modified variable permeability model significantly improves the accuracy of the simulation results. Direction of seismic motion has a significant effect on the seismic compression and excess pore water pressure of sand, and the simplification of using one-dimensional load in a certain direction to represent the two-dimensional loads underestimates the seismic compression of sands. The proposed VSI-based prediction function provides a means for estimating seismic compression of saturated sand, and the prediction accuracy improves with increasing the relative density of sand.