Abstract
In this paper, we propose maximum frictional shear fracture criterion, which explains mode II type crack extension in geomaterials under the compressive loads. It is important to elucidate the fracture criterions under compressive loads such as the explanation of the existence and the creation of long faults, landslide in slope ground and so on. We examine an implicit soil/water coupling elastic-plastic calculation algorithm with contact conditions on the crack surfaces in order to obtain stress fields near a crack tip under the biaxial compressive loads. We find that the maximum frictional shear stress causes a crack extension with the same direction of an initial crack in any condition and the tensile cracks never extend from the upper side of a crack near the tip.
