Response of Soil-Foundation-Structure Systems to Multidirectional Seismic Motion: A Micromechanical Approach

摘要

In this study, a three-dimensional microscale framework utilizing the discrete element method (DEM) is presented to analyze the seismic response of soil-foundation-structure systems subjected to three-directional base motion. The granular soil deposit is idealized as a collection of spherical particles using DEM. The foundation is modeled as a rigid block composed of clumped particles and its motion is described by the resultant forces and moments acting upon it. The structure is modeled as a column made of particles that are clumped to idealize a rigid structure. Analysis is done in a fully coupled scheme in time domain. Simulations were conducted to investigate the response of the deposit with and without the structure to various scenarios of multidirectional shaking patterns. Vertical motion amplification in the free-field was similar to that of shear wave propagation. However, there was less nonlinearity for vertical motion compared to horizontal motion. Lateral motion had small impact on the amplification of vertical input motion. The inclusion of vertical motion did not influence the amplification of horizontal motion at frequencies far from the resonance frequency of vertical motion.