The interfaces in bedding rock slopes are regarded as weak planes

which are equivalent to equal-interval collinear multi-joint mechanical model. The anchorage model of the slope reinforced by prestressed anchor cable is equivalent to plane problem of the rock mass joints with finite width. The original stresses and additional dynamic stresses caused by seismic loads are regarded as far field effect

and the force of the anchored slopes is the superposition of far field effect and effect of concentrated force of joint surface. The stress intensity factor of crack tip subjected to seismic loads is calculated based on superposition principle. It is found that the prestressed anchor cable whose anchor point located close to the crack tip can greatly reduce the stress intensity factor of the mode I crack. The reinforcement mechanism of bedding rock slopes reinforced by prestressed anchor cable subjected to seismic loads is interpreted using stress intensity factor as an important parameter of compression and shear failure criterion of rock mass

which can well explain the failure features of slopes in Wenchuan earthquake.