露天矿山岩体力学参数估算法的应用研究

露天矿山边坡稳定性分析中岩体力学参数的取值至关重要,Hoek-Brown强度准则可以充分反映岩石的非线性破坏的特点,广泛应用于工程实践;结构面作为岩体的一部分,其对岩体的影响不可忽略;结构面的稳定性由抗剪强度决定,对结构面力学参数的估计同样是评价岩体强度的重要组成部分。利用轮廓曲线法和回弹法量取结构面粗糙度和壁岩强度量化地质强度指标GSI,并对潜在滑移结构面抗剪强度精准取值。结合广义Hoek-Brown强度准则估算和兴矿山II-B边坡岩体力学参数,通过极限平衡法分析其整体稳定性系数;利用Barton-Bandis模型线性拟合,计算结构面抗剪强度,对滑体落岩的稳定性进行分析。计算结果表明,整体边坡安全系数F_s=1.285,稳定性较好;含有潜在滑移结构面的岩体安全系数F_s=0.911,局部存在单平面滑移可能。计算结果符合现场实际情况,经反算法验证后,证明通过该方法估算得到的岩体强度参数及结构面抗剪强度是合理的。

Application Research of Rock Mass Mechanics Parameter Estimation in Open-Pit Mines

The mechanical parameters of rock mass are significant in slope stability analysis of open-pit mines. Hoek-Brown strength criterion can fully reflect the characteristics of nonlinear failure of rock mass and it is widely used in engineering practice. Structural plane is a part of rock mass, and how to estimate the shear strength of structural plane in an exact way is also a worthy question to explore. The GSI index was quantified by the contour curve and pressure-resistance test. Using generalized Hoek-Brown strength criterion to calculate the mechanical parameters of the rock mass in II-B slope of Hexing mine. According to the Barton-Bandis theory, the shear strength of structural plane and the stability of sliding rock mass were figured out. The calculation results showed that the safety factor of the slope is Fs=1.285, and the safety factor of the potential slip plane is Fs=0.911. That means the stability of the overall slope is well, but the partial rock mass has the potential to slip along with the structural plane. The analysis results are in accord with the actual situation. It is demonstrated that the strength parameters of rock mass and the shear strength of the structural plane obtained by this method are reasonable.