Micro-mechanical analysis of residual stresses in cohesive-frictional particulate materials under moving surface loads

This study focuses on the build-up of residual stresses of cohesive-frictional materials under moving surface loads, and corresponding micromechanisms are studied in particle scales using discrete element methods. The numerical procedure is validated with macroscopic residual stresses obtained by experimental tests and finite element methods. It is found that residual stresses are dominated by normal contact and normal bond forces, and strong force chains make a leading contribution to build-ups of residual stresses. A further study indicates that the increase of averaged interparticle forces is a critical factor to growths of residual stresses, which is generally accompanied with decreased proportions of contacts carrying small forces. Simultaneously, the averaged magnitude of interparticle forces belonging to single orientations generally grows with developments of residual stresses, and for resultant forces it distributes almost isotropically. Nevertheless, because of gradual developments of residual stresses, macroscopic stress fields should be anisotropic, which is subsequently validated to be dominated by the fabric anisotropy.