Toward Model-Based Simulation of Earthquake-Induced Soil Liquefaction Effects

Rensselaer Polytechnic Institute, Troy NY

Investigators

Abstract

A new framework will be developed for reliable computational simulations of earthquake-induced soil liquefaction effects on soil and soil-structure systems. This is an important problem of great economic implications, which remains largely unsolved due to its complexity. Water-saturated sands and other soils that liquefy are characterized by particle interactions at their contacts as well as with pore water and with structural surfaces. The pore water changes in pressure and moves within the soil mass and out of it during and after earthquake shaking. When the sand liquefies the particles separate and the physics change. Other changes of physics include the formation of water interlayers at soil and soil-structure boundaries, instances of nonlaminar flow, and formation of shear bands, separation and other localized phenomena in the soil and at soil-structure boundaries. In the current state-of-the-art, typically homogenized constitutive relations are used in a Biot-type phase-coupled formulation. The proposed new simulation framework will be multiphysics, multiscale and adaptive, with two coupled scales used for the soil. One of these scales will remain homogenized, while the second scale will explicitly consider the particle scale in the critical regions, such as shear bands and boundary layers. The investigation will include strong experimental, mathematical and computational components, linked by a systematic use of system identification techniques, adaptive analysis techniques, and feedback loops as well as comparative visualizations of computational and physical simulations, and synthesized within a general framework. Both mathematical and computational components will include micromechanical studies needed for both homogenized and micro-scale model development and simulation, including treatment of pore water and its interaction with the soil particles. This study will initiate the development of an operational adaptive multiscale multiphysics computational simulation framework based on first principles for the study of earthquake-induced soil liquefaction and its effects.