Mechanical parameters are essential data for slope stability analysis of open pit mine,and in-situ direct shear test is an important method to obtain reliable mechanical parameters of rock and soil mass. Taking the open pit slope of Bayan Obo west mine in Inner Mongolia as engineering background, a modified apparatus of in-situ direct shear test was proposed to investigate the mechanical properties of rock and soil mass. This apparatus anchors the section steel in the earth to provide reaction force for ver-tical hydraulic jack,substituting the stacking load apparatus. Research shows that the cohesion has grea-ter deviation than friction angle in rock and soil mass sampling from different region. The micro tectonic and macro structure of the rock and soil mass affect the mechanical properties and failure mode of shear surface markedly. This modified apparatus of in-situ direct shear test is feasible in practical operation, and the test results can provide significant reference for the slope stability analysis of the mine.%岩土体力学参数是分析露天开采矿井边坡稳定的必要基础数据,原位直剪试验是获取岩土体可靠力学参数的重要方法.以内蒙古白云鄂博西矿露天边坡为工程背景,提出一种改进的原位直剪试验装置,即通过将型钢用锚杆锚固于岩土体内为垂直液压千斤顶提供作用反力的方式替代堆载装置,开展矿区典型岩土体力学特性研究.结果表明:不同区域及类型的岩土体,其内聚力的偏差较内摩擦角更大;岩土体的微观构造及宏观结构显著地影响着岩土体力学特性与剪切面破坏形态;这种改进的原位直剪试验装置在实际操作中是切实可行的,可为矿区边坡稳定性计算分析提供重要的参考依据.
展开▼
