顺层岩质边坡预应力锚索抗震加固机制研究

将顺层岩质边坡的层面考虑为弱面，将其等效为等间距共线多节理的力学模型。预应力锚索加固边坡的锚固模型等效为平面有限宽度岩体节理问题。并将初始应力和地震荷载引起的附加动应力视为远场作用，锚固边坡的受力问题视为远场作用效果和节理面集中力作用效果的叠加。根据叠加原理计算地震荷载作用下裂纹端部应力强度因子，发现位于裂纹端部的预应力锚索能大幅度降低I型裂纹的应力强度因子。以应力强度因子作为岩体的压剪破坏判据解释顺层岩质边坡预应力锚索的抗震加固机制，能很好地解释汶川地震边坡破坏特点。

Reinforcement mechanism of bedding rock slopes with prestressed anchor cable subjected to seismic loads

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.