抄録
The authors have performed a set of numerical loading tests in terms of the Granular Element Method. The tests exhibit mechanical behaviors which are common among real behaviors of geological materials. These test results are very suggestive to know the internal mechanism hidden behind the macroscopic behaviors. This paper mainly concerns the plastic behavior whose mechanism has its main origin on the slipping between grains. A theoretical yielding condition, which explains the result obtained by the simulation, is derived from non-slipping condition for stable assemblies of rigid particles. Performing eigen-value analyses of the instantaneous stiffness matrix which is utilized in the Granular Element Method, the authors demonstrate the similarity of displacement fields accompanied by plastic deformations for different loading directions. This similarity explains why the common direction of plastic strain is assumed in the flow rule.
