高海拔区千枚岩质高陡边坡稳定性分析与评价

A Stability Analysis of High Steep Slopes Made of Phyllite In High-Altitude Areas

以某矿高海拔千枚岩质高陡边坡为工程背景,开展了工程地质调查和岩石力学测试,采用RMR法和CSMR法岩体分级2种主要岩体均为Ⅳ级/差等级;采用赤平投影方法分析不同边坡分区破坏模式,该矿边坡主要破坏模式为圆弧复合型破坏;采用简化Bishop方法分析了3种工况条件下不同边坡分区稳定性,除风化带边坡分区略小于许用安全系数1.15,其他各边坡分区其安全系数均满足边坡许用安全系数的要求;为满足《非煤露天矿边坡工程技术规范》安全系数要求,将风化带边坡可容许最大边坡角优化为56°;采用蒙特卡洛方法分析各剖面破坏概率和安全系数可靠性,分析结果表明:各分区代表性剖面失稳概率都低于标准值5%,表明角度选取合理。

On the engineering background of a high-altitude and steep slope made of phyllite in a certain mine,engineering geological surveys and rock mechanics tests were conducted.The RMR and CSMR methods were used to classify the rock mass,and both indicated that the main rock mass was Grade IV/Poor quality.The stereographic projection method was employed to analyze the failure modes of different slope zones,revealing that the main failure mode of the mine slope was circular-arc compound failure.The simplified Bishop method was used to analyze the stability of different slope zones under three working conditions.Except for the weathered zone,where the safety factor was slightly below the allowable value of 1.15,the safety factors of all other slope zones met the required safety standards.To satisfy the safety factor requirements specified in the“Non-Coal Open Pit Mine Slope Engineering Technical Specification,”the allowable maximum slope angle of the weathered zone was optimized to 56°.Monte Carlo analysis was applied to assess the failure probability and reliability of the safety factors for each profile.The results indicated that the instability probabilities of the representative profiles in each zone were below the 5%threshold,indicating that the selection of angles was reasonable.