Simplified effective stress simulation of shear wave propagation in saturated granular soils
Kai Zhao, Qiannian Wang, Q. Chen, Haiyang Zhuang, G. Chen
Abstract
This paper improves a simplified soil hysteresis model for one-dimensional fully coupled effective stress analysis of site seismic response that addresses the limitations of existing hyperbolic soil models to simultaneously capture the hysteretic stress–strain behaviour and the accumulated volumetric strain of soil skeleton. In particular, emphasis is placed on coupling the pore-water pressure buildup and the soil-skeleton volumetric deformation based on the Biot's dynamic consolidation theory. A newly observed cyclic shear-volume coupling equation is included as the source term for residual pore-pressure accumulation, which represents the plastic volume change induced by cyclic shearing. The proposed framework is implemented into an explicit time matching finite difference platform with embedded Biot equations of consolidation, and validated against the cyclic shearing test on saturated sand in the laboratory. Overall, good agreement demonstrates the prediction reliability of shear wave propagation in saturated granular soils. Then, the paper highlights the potential of the proposed framework to simulate the seismic wave propagation in a liquefiable site, based on the recordings of the Port Island borehole array station site during the 1995 Kobe Earthquake. The results indicate that the basic features of the non-linear seismic response of liquefiable site can be well captured by the proposed framework.