The model of moment of force is introduced to the rock shearing failure; and the shearing failure process is analyzed. The moment model is used to explain the formation of low-angle structural-plane. When the rock has the shearing failure

the shear band has a certain width. On the shear band

shear stress and the support strength are not the even distribution. There is a process alignment procedure in cuts; and the stress concentrated in some part caused the existence of shearing moment. Along with increasing of

the supports strength and the shearing force all increase; the non-uniform distribution appears. The stress is concentrated partially; and the rock appears the partial failure. When the shearing moment is bigger than the support moment

the macroscopic shearing failure appears. Based on the destruction effect of groundwater

the change of interface with the variety of groundwater is analyzed. Along with the increasing of hydraulic pressure

the effective pressure and the contacted area rate of the structural surface and under the crag body changes slightly

the critical angle of the steady destruction reduces. So the rock block is easy to lose its steadily.