节理岩体关键块体稳定的概率分析  

A probabilistic analysis of key block stability in jointed rock masses

作　　者：张瑞新[1,2] 李泽荃[1] 赵红泽[1] 杨曌[1] 白玉奇[1] 

机构地区：[1]中国矿业大学(北京)资源与安全工程学院,北京100083 [2]国家安全生产监督管理总局通信信息中心,北京100013

出　　处：《岩土力学》2014年第5期1399-1405,共7页Rock and Soil Mechanics

基　　金：国家重点基础研究(973)计划项目(No.2010CB732002)

摘　　要：基于地下岩体受节理面的控制,节理面的几何和力学参数随机分布,从而导致岩体系统具有高度不确定性,提出以关键块体理论为基础,考虑节理几何和力学参数随机性的岩体开挖可靠度分析方法,并给出了块体稳定的总失效概率评价模型。以澳大利亚阿德莱德地区一铜矿地质条件为例,以节理面倾角、倾向、摩擦系数和黏聚力为随机变量,通过Monte Carlo模拟和概率图方法,进行了岩体可靠度和失效概率的计算。最后,采用条件概率的分析方法,计算了单面滑动块体的总失效概率。计算结果表明,块体沿单面滑动并且出现的概率为11.0%,总的失效概率为3.85%,超过一般岩体工程可允许的风险水平,认为该方法可以作为评价块体可靠性的依据。As known to all, the fact that the stability of undergrotmd rock is mainly controlled by joint; and the stochastic distribution of geometric and mechanical parameters of joint causes high degree of uncertainty; a reliability analysis method about stability of rock blocks considering uncertainty in geometric parameters and mechanical parameters of joint combined with key block theory is presented; and a proper, combined evaluation model for failure probability is developed. The main objective of this research is to develop a probabilistic approach that can be implemented to assess the probabilistic occurrence and probability of failure of wedges within excavations. This approach is based on the use of stochastic fracture networks FracSim3D to simulate the fracture network and key block theory to identify the wedges and calculate the factor of safety. A programming code based on Fortran 95 has been implemented to perform the main probabilistic wedge occurrence and wedge failure analysis. To evaluate the feasibility of this new probabilistic approach, the procedure is applied to a practical example, a cooper mine in Adelaide, Australia, with considering the uncertainty of dip angle, dip direction, cohesion and friction angle. Finally, the analysis method of conditional probability is proposed to find the failure probability of wedge in plane failure. The calculation results show that the occurrence probability of wedge in plane failure is 11.0%, and the probability of failure is 3.85%, which is greater than the general engineering acceptable risk level. Results of the probabilistic method indicate that the method can be used as a basis model to evaluate the reliability of wedge.

关 键 词：岩石力学 关键块体理论 楔体可靠度 条件概率 蒙特卡洛法 

分 类 号：TU457[建筑科学—岩土工程]