DEM investigation of the effect of coarse content and size ratio on the local shear behavior at gap-graded soil-structure interface

Abstract

Gap-graded soils are widespread as naturally sedimentary soils, and their interaction with structures is crucial for assessing the workability of the geo-structures. The effect of coarse content and size ratio on the local shear behavior at soil-structure interface is investigated using Discrete Element Method (DEM). The shear band thickness increases with increasing coarse fraction within the transitional coarse content while falling due to the reduction of structural relative roughness beyond the transitional value. The variation of microscopic parameters and contact force network is consistent with the evolution of the shear band thickness and the macroscopic mechanical parameters, e.g., the peak friction angle. Three types of failure modes are defined according to the local shear behavior, i.e., thin fines failure, mixed thick failure, and mixed thin failure. The insights drawn from this work provide a reference for assessing the mechanical behavior at the interface between gap-graded soil and structure.