Shakedown analysis of soil materials based on an incremental approach

In this paper, an incremental technique based on cyclic loading is developed to implement shakedown analysis for soils in the framework of elastic-plastic analysis without utilization of the classical shakedown theorems. A finite element model together with the use of ABAQUS is established for soil structures subjected to cyclic loads, where the Mohr-Coulomb yield criterion with associated plastic flow is assumed to capture the plastic behavior of soil materials. A criterion based on the plastic dissipation energy is suggested to distinguish shakedown and non-shakedown status. Meanwhile, the evolution of residual stresses during the whole process is examined for the better understanding of shakedown phenomenon. The investigation of the plastic dissipation energy and the residual stresses via elastic-plastic analysis provides a deep insight to the classical kinematic/static shakedown theorems. The effect of soil parameters on shakedown limit is studied with the application to both one-layered and two-layered soil foundations. Some possible failure modes of this soil structure under cyclic loads have also been found. The proposed approach can bridge the gap between the traditional elastic-plastic incremental analysis and the classical shakedown analysis and also provide the better understanding of shakedown phenomenon. Moreover, this technique can be easily extended for nonstandard materials such as non-associated or strain-hardening materials.