Discrete Element Modeling of the Resilient Behavior of Subgrade Sandy Soils

Abstract

Subgrade soils are very important materials to support highways. Current AASHTO pavement design procedures recommend the resilient modulus (Mr) of subgrade soils or pavement design and analysis. Laboratory repeated triaxial loading tests and field falling weight deflectometer (FWD) are two common ways to characterize the resilient modulus (Mr) of subgrade soils. The primary objective of this study is to conduct numerical simulations of the resilient behavior of subgrade sandy soils under repeated triaxial loading conditions using a commercial discrete elements code, e.g., particle flow code in two dimensions (PFC2D). Stress-controlled loading scheme is designed using a commercial DEM code, Particle Flow Code (PFC2D). One run with a confining stress of 41.4kPa and deviator stress of 12.4kPa is conducted for simulating the biaxial test of sandy soils under cyclic loading. Simulation results show that confining stress can be effectively applied to the testing sample. However, the error of axial stress is quite large. In addition, preliminary results of resilient behavior of sandy soils under cyclic loading are consistent with the classic results in real laboratories.