DEM study on the development of the earth pressure of granular materials subjected to lateral cyclic loading

Abstract

The discrete element method (DEM) is adopted to study the development of the lateral earth pressure of granular materials subjected to lateral strain-controlled cyclic loading, which is imposed by integral abutments due to temperature variation. Clumped particles are used to simulate the nonspherical granular particles. The simulation results show that there is continuing buildup of lateral stresses with cycling for both loose and dense samples, while the loose sample experiences a substantial decrease in volume and the dense sample shows slight dilation. The simulated macro-response is qualitatively consistent with the laboratory observations. The micro-response is further investigated, and a unique relationship is revealed between the deviator stress ratio on the macro-scale and the deviator fabric of strong contacts on the micro-scale, which is not influenced by the initial porosity, vertical stress, or loading path. Although the cyclic lateral strain is small, a number of cycles can result in a certain micro-structure that can support large lateral stresses, which can also be achieved by lateral monotonic loading to large strains. The influence of the particle shape on the macro- and micro-responses of an assembly is highlighted by performing lateral cyclic loading test on a sample with spherical particles.