Experimental Investigation on Shear Mechanical Behavior of Sandstone Containing a Pre-existing Flaw Under Unloading Normal Stress with Constant Shear Stress

Excavation, river incision and anchor cable relaxation would result in unloading of stress in at least one direction of rock masses in caverns or slopes, and the unloading failure is prominent and it even shows remarkable tensile failure. The previous direct shear tests with constant normal stress can no longer meet these circumstances. However, the experimental study of rock shear behavior under unloading normal stress condition is rare. This...