Fluid-Solid Fully Coupled Seismic Response Analysis of Layered Liquefiable Site with Consideration of Soil Dynamic Nonlinearity

Abstract

The seismic response study of a layered liquefiable site is crucial in the seismic design of both aboveground and underground structures. This study introduces one-dimensional dynamic site response processes with advanced nonlinear soil constitutive models for non-liquefiable and liquefiable soils in the OpenSees computational platform. The solid-fluid fully coupled plane-strain u-p elements are used to simulate the soil elements. This study investigates the seismic response of a layered liquefiable site with specific focus on the development of excess pore water pressure, acceleration and post-earthquake ground surface settlement under two typical earthquake excitations. The numerical results show that the ground motion characteristics as well as the site profile have significant effects on the dynamic response of the layered liquefiable site. The loose sand layer with 35% relative density is more prone to liquefaction and contractive deformation under the same intensity of ground motion, resulting in irreversible residual deformation and vertical settlement. The saturated soil layer may efficiently filter the high-frequency components of ground motions while amplifying the low-frequency components. Meanwhile, during the post-earthquake excess pore pressure dissipation, the soil produce a large consolidation settlement.