降雨作用下三维矿山边坡的力学状态响应

Mechanical response of 3D mining slopes under effect of rainfall

矿山边坡稳定性是影响矿山开采的重大安全生产难题,安全的环境是进行矿山开采的重要前提,因此,开展矿山边坡稳定性分析,对矿山的安全生产具有重要的指导意义。以重庆皇华石灰岩矿山边坡为例进行数值建模分析,首先利用无人机倾斜摄影得到矿山边坡几何形状并识别出岩体结构面,基于摄影识别结果建立三维地质模型,然后采用有限元强度折减法对边坡进行数值计算,对比分析天然工况及暴雨工况下矿山边坡稳定性,揭示降雨作用对于边坡稳定性的影响规律。结果表明,暴雨工况下边坡变形和应变比天然工况下的更大,安全系数更小;暴雨工况下的变形和应变分别比天然工况高30%、40%~60%,安全系数减小了5%~7%,数值模拟结果基本合理;该矿山边坡稳定性较高,整体滑移破坏的可能性较低,但需防范局部块体掉落的风险,还需要进一步研究是否需要进行局部边坡加固。研究结果验证了现场调查、室内试验、三维模型判定、二维剖面重点分析的综合研究方法对岩质边坡稳定性进行评价的适用性与可靠性。

The stability of mine slope is a major safety and production problem that affects mining practice.A safe environment is an important prerequisite for mining.Therefore,mine slope stability analysis has important guiding significance for safety production.This paper takes the Huanghua limestone mine slope in Chongqing as an example to perform a numerical modeling analysis.Firstly,the unmanned aerial vehicle(UAV)was used to obtain the geometric shape of the mine slope and identify the rock structure surface,and a 3D geologic model was created based on photographic identification results.Then,the finite element strength reduction method was used to compare the stability of the slope of the mine under natural condition and heavy rain condition,and the influences of rainfall on slope stability were revealed.The results show that under the condition of heavy rain,the slope deformation and strain are larger than those under natural conditions,and the safety factor is smaller.Specifically,the deformation and strain under heavy rain are 30%and 40%-60%higher than that under natural condition.The safety coefficient decreased by 5%-7%,and the numerical simulation results were basically reasonable.The stability of the mine slope is high,and the possibility of overall slip failure is low.However,the risk of local block falls should be prevented,and further research is needed to determine whether local slope reinforcement is required.In addition,the research results of this article verified the applicability and reliability of the comprehensive research methods of on-site investigation,lab testing,preliminary determination of 3D models,and key analysis of 2D profiles for evaluating the stability of rock slopes.