某水电站坝肩随机块体稳定系数敏感性影响分析

针对复杂的地质条件,运用三维极限平衡法对某水电站坝肩随机块体的稳定性进行分析,并研究了块体稳定系数Fs的敏感性影响因子。通过敏感性计算,确定了结构面抗剪强度参数(包括粘聚力C、抗剪断摩擦系数f)和结构面产状(包括倾向和倾角)两组主要影响因子,分析了以上影响因子与Fs的变化规律。根据主要影响因子的变化规律比较,得出结构面产状是影响随机块体稳定性主导因素的结论。敏感性影响因子的变化规律分析,为坝肩抗滑设计和治理提供了一定的理论依据。

STABILITY SENSIBILITY ANALYSIS ON DAM ABUTMENT BASE BY RANDOM BLOCK THEORY

There are lots of discontinuities whose geometry exhibits a random behavior in rock excavated slopes,and the failure surface of the slope is normally consisted of the joints and rock-bridges.The rock mass of dam abutment is enclosed by faults,joint fissures and bedding planes,and it is necessary to carry out stability sensibility analysis in order to make the abutment withstand potential slide.In the paper,three-dimensional limiting equilibrium method is employed for stability analysis on the dam abutment.The factor influencing the dam abutment stability is numerous.The leading factor can be found out through the sensitivity analysis,which offered the basis for administration and design of the dam abutment.The sensitivity study indicates that the two main influencing factors are shear strength parameters and occurrences of rock mass structure.The change laws of Fs under different conditions are analyzed and it is concluded that the occurrences of rock mass structure are the most sensitive one of the two.The analysis of sensitivity influencing factors can provide a theoretical basis for the dam abutment stability analysis.