露天边坡局部失稳特征的数值分析及监测

以金川集团露天石英石矿边坡监测项目为依托,利用监测数据成果,以台阶局部滑坡部位作为研究对象,通过分析其台阶周围及滑坡剖面上台阶监测点的累积水平位移值,研究了采动卸荷效应造成的集中应力反复作用下边坡的变形破坏机制。利用RFPA强度折减法,数值模拟过程再现了1 768 m平台开采过程中典型剖面多台阶的渐进失稳过程,宏观裂缝在细观上的"破裂-应力转移-破裂"的循环中不断发育,最终形成贯通的滑动面。破坏的整个过程中伴随着由应力集中、释放、转移过程造成的应变局部化现象。监测结果表明:局部化损伤发展过程是从采动平台向上部台阶边坡岩体转移,各台阶边坡内部7~11 m位置处受荷载转移影响程度较大。

Numerical Analysis and Monitoring of Local Instability Characteristics of the Open Pit Slope

Based on slope monitoring project of Open Pit Quartz Mine of Jinchuan Group as background，with the use of the monitoring data，and taking local landslide of the beach as the research object，the deformation and failure mechanism of the slope under the stress concentration action caused by unloading effect is studied through analyze the cumulative horizontal displacement values of the monitoring sites around the beach and on the landslide.With RFPA strength subtraction method，the gradual instability process of typical profile and multi-steps during the mining process of 1 768 mm platform is reproduced.macro-cracks on the meso cycle of “rupture-stress transfer-rupture” is developed constantly，eventually forming a cut-through sliding surface.The strain localization phenomenon caused by stress concentration，release，and transfer process is accompanied by the whole process of failure.The monitoring results show that:the process of localized damage is migrated from mining step to the upper bench slope rock mass，and 7~11 m point of each beach slope is greatly affected by load transfer.