基于岩体损伤模拟的露井联采边坡稳定性

Slope stability in surface and underground combined mining based on rock mass damage simulation

岩体是具有初始几何损伤的多裂隙介质,露天和井工开采导致应力场发生改变,进而节理扩展,损伤增加,强度降低。根据Kawarnoto损伤张量概念、等效应变原理及断裂力学理论,对安太堡煤矿露井联采条件下的节理岩体损伤演化进行了模拟,得到了边坡岩体在露采与井采时损伤张量的时空分布演化特征。建议应用反映采动效应的损伤张量或截面损伤度作为岩体扰动参数,根据岩体质量分类RMR值,确定Hoek-Brown强度参数m和s,体现了岩体强度的各向异性和时空变化。应用到安太堡煤矿露井联采条件下的边坡稳定性分析中,安全系数为1.89~2.32,说明发生剪切破坏的可能性较小,边坡岩体的破坏主要由井工采空区坍塌引起。

The rock mass is a kind of multiple joint medium with initial geometrical damage. Surface and underground mining result in the change of stress field,thereby rock joints grow,rock damage increases,and rock strength decreases. According to Kawarnoto damage tensor concept,the equivalent strain principle and fracture mechanics theory,the joint damage evolution of rock mass was simulated at Antaibao coal mine under the condition of combined mining.Time-space distribution feature of damage tensor was obtained. It is recommended to use the damage tensor or damage degree on a cross section on mining effect as rock mass disturbance parameters. According to the RMR values of rock mass quality classification,the strength parameters m and s of Hoek Brown Theory was determined. It reflects the anisotropy of rock mass strength and time-space variation. Applied to slope stability analysis on Antaobao coal mining,the safety factor is 1. 89- 2. 32. It suggests that the possibility of shear failure is low,the rock mass damage of slope is mainly caused by mining cavity collapse.