露天矿高陡边坡岩体参数获取与稳定性评价方法研究

针对露天矿高陡边坡岩体参数难获取和稳定性易变化的问题,本文以攀枝花露天矿高陡边坡为研究对象,采用非接触式无人机摄影测量技术获取研究区域的三维模型,统计结构面的分布情况,结合室内岩石力学试验数据,采用国家BQ标准进行岩体质量分级,并给出边坡岩体强度力学参数建议值。在此基础上,通过有限单元法分析了矿区在开采条件下边坡的稳定性动态演化特征,并对开挖过程边坡的稳定性做出了评价。结果表明:随着矿区的开采,边坡在开挖面附近由于卸荷作用发生位移回弹,最大位移增量为33.2 mm；塑性区主要集中在断层和矿岩界面附近,以剪切屈服为主；边坡稳定性随着矿区的开采逐渐降低,直至达到临界稳定状态。采用锚索对边坡进行加固,并采用塑性区面积占比对加固前后的稳定性进行评价,评价系数α由加固前的0.4降低至加固后的0.05,证明了加固措施的有效性。本文相关研究可为露天矿高陡边坡岩体参数取值和稳定性评价提供参考。

Study on parameter acquisition and stability evaluation method of high steep slope rock mass in open-pit mine

In response to the difficulty in obtaining rock mass parameters and the instability of steep slopes in open-pit mines, this paper focuses on the high steep slope of the Panzhihua open-pit mine. Non-contact unmanned aerial vehicle photogrammetry technology was employed to obtain the three-dimensional model of the study area, and the distribution of structural planes was statistically analyzed. Combined with rock mechanics test data, the national BQ standard was used for rock mass quality grading, and the recommended values of strength mechanical parameters of the slope rock mass were given. Based on this, the dynamic evolution characteristics of slope stability in the mining area were analyzed by the finite element method under mining conditions, and the stability of the slope during the excavation process was evaluated. The results show that with the exploitation of the mining area, the slope near the mining face rebounded due to unloading, with a maximum displacement increment of 33.2mm. The plastic zone mainly concentrated near the fault and the interface between the ore and the rock, with shear yielding as the main form. The factor of safety of the slope decreased gradually with the exploitation of the mining area until reaching the critical stability state. Anchors were used to reinforce the slope, and the stability before and after reinforcement was evaluated by the proportion of the plastic zone area, which decreased from 0.4 before reinforcement to 0.05 after reinforcement, demonstrating the effectiveness of the reinforcement measures. The relevant research in this paper can provide reference for rock mass parameter estimation and stability evaluation of steep slopes in open-pit mines.