考虑锚杆锚固段从岩体中拔出、拉杆拉断、拉杆从注浆体中拔出等失效模式,利用系统可靠性原理和极限平衡分析方法,并基于Monte.Carlo抽样原理提出双滑块岩质边坡锚固系统破坏概率的直接求解方法。同时考虑锚杆钢筋的腐蚀与软弱滑动面抗剪强度c、φ的时变性,建立了考虑锚杆多失效模式双滑块岩质边坡锚固系统的时变可靠性模型。算例计算结果表明:软弱滑动面上的强度参数c、φ的时变性和注浆体与围岩之间的抗力时变性对锚固系统的破坏概率的影响较大,而锚杆的腐蚀对锚固系统破坏概率的影响不明显。
Considering the multiple failure modes of anchor system such as pulling out of grouting mass from surrounding rock, the tensile failure of the pull rod and the shearing failure of interface between pull rod and grouting mass, etc., applying systematical reliability principle and limit equilibrium method, a direct solution of failure probability of anchor system of rock slope with double slide blocks is proposed based on Monte Carlo sample principle. Meanwhile, taking the time variation of shear strength indices of soft sliding surface c and φ and the erosion of anchor bars into account, a time-variation reliability model of anchor system of rock slope with double slide blocks in consideration of multiple failure modes of anchor is established. The calculation results of examples show that the time-variations of shear strength indices of soft sliding surface c, φ and the resistance between grouting body and surrounding rock have great impact on failure probability of anchor system, while erosion of anchor bars has less impact on it.