Abstract

A combination of Hoek–Brown strength criterion and geological strength index (GSI) rock mass classification is a common method to determine rock mass strength. However, the conventional method involving the determination of disturbance coefficient (D) cannot reflect the anisotropic characteristics of strength of jointed rock mass when considering mining damage. A numerical analysis method is proposed to determine the value of D using jointed rock damage tensor and mining damage evolution simulation. The anisotropy of rock mass strength at different mining depths for a high jointed rock slope in Dagushan open-pit mine was analyzed by mining damage simulation. Additionally, the Rosenblueth moment point estimation principle was combined with Monte-Carlo method to obtain the random strength of a jointed rock mass considering the effects of mining probability damage. The results show that the influence of the unloading due to excavation to stress state of rock mass is relatively obvious within 100 m away from the slope surface, however, the area of drastic change of damage is limited to a range of ∼50 m. Moreover, the reliability of local slope, analyzed using limit equilibrium method (Janbu), shows that consideration of spatiotemporal anisotropy of rock mass with mining damage is closer to reality.

摘要

Hoek-Brown强度准则和地质强度指数（GSI）岩体分类的组合是确定岩体强度的常用方法。但是，涉及扰动系数（D）确定的常规方法在考虑采矿损害时不能反映节理岩体强度的各向异性特征。提出了一种数值分析方法来确定D的值使用节理的岩石破坏张量和采矿破坏演化模拟。通过采矿破坏模拟，分析了大沽山露天矿高节理岩质边坡不同开采深度下岩体强度的各向异性。另外，考虑开采概率破坏的影响，将Rosenblueth矩点估计原理与蒙特卡洛方法相结合，获得节理岩体的随机强度。结果表明，开挖卸荷对岩体应力状态的影响在距坡面100m以内较为明显，但破坏的剧烈变化范围限制在50m左右。此外，使用极限平衡法（Janbu）分析了局部边坡的可靠性，