Discrete-Element Analysis of Influence of Granular Soil Density on Earthquake Surface Fault Rupture Interaction with Rigid Foundations

Abstract

Parametric analysis of the effects of soil relative density on earthquake surface fault rupture interaction with foundations having different contact pressures and positions was performed with the discrete-element method (DEM). DEM simulations provide insights into particle responses not possible with continuum methods. The relative density of soil has a significant impact on the interaction of surface fault rupture with a building foundation. The number of horizontally oriented contacts achieves a peak value before decreasing during reverse fault rupture through a dense particle assemblage due to its strain-softening response, and the number of horizontally oriented contacts tends to monotonically approach a constant value during reverse fault rupture through a loose particle assemblage. The mobilization of stresses reflects the trends seen with the contact forces and shows quantitatively the more brittle response of denser particle assemblages. Heavy foundations consistently alter the path of reverse fault rupture propagation while undergoing less rotation than light foundations. During normal fault rupture, heavy foundations can undergo more rotation when positioned on the footwall side of the free-field surface outcrop location.