开挖条件下含陡倾结构面顺层岩质边坡破坏模式与稳定性预测

Failure pattern and stability prediction of bedding rock slope with steep structural plane under excavated condition

顺层岩质边坡易发生失稳破坏,当边坡中发育有顺坡向陡倾结构面时,更不利于边坡稳定。以贵州某水电站大坝左岸含陡倾结构面顺层边坡为例,在综合分析地质条件及开挖扰动的基础上,结合离散元软件UDEC,分析了边坡的变形破坏模式和稳定性。研究结果表明,边坡可能发生的变形破坏模式主要有滑移、拉裂—滑移两种;自然状况下及开挖后,边坡都有沿断层f_9、卸荷裂隙L_1及岩层面发生滑移的趋势,且工程开挖导致边坡沿该结构面发生内部滑动;对边坡采用预应力锚索加固后,变形得到有效控制,位移数值计算值与实际监测值基本吻合。

Unstable failure occurred easily in bedding rock slope,especially in the slope with steep structural plane which along slope. Taking bedding rock slope with steep structure plane of left bank for a hydroelectric power station in Guizhou for example,based on comprehensive analyze of geological conditions and excavating disturbance,and combined with Universal Distinct Element Code in 2-dunebsion（ UDEC）,deformation failure mode and stability of the slope is analyzed. The results show that,deformation and failure mode of the slope may mainly includes sliding and tension crack-sliding. Under natural conditions and after excavation,the deformation trend of slope may along fault f_9,unloading fracture L_1 and rock levels,and excavation lead to slope inner sliding along these structure plane. After reinforcement of prestressed anchor cable,deformation of slope is controlled effectively,and numerical calculating value of displacement is relatively anastomosed with the practical monitoring value.