露天矿边坡稳定性评价岩体力学参数修正

The Correction of the Rockmass Mechanics Parameters for the Strip Mine Slope Stability Evaluation

由于天然岩体中存在着层理、节理、弱面、断层面等,使得岩体的宏观力学参数与实验室获取的标准岩块的力学参数之间存在差异,因此需要将实验室得到岩块的宏观力学参数经过一系列修正以得到岩体的物理参数,才能将其运用到边坡稳定性评价中。通过Hoek-Brown经验法、地质力学法及RMI法对露天矿室内力学试验进行了修正,给出了边坡岩体力学参数建议值,同时考虑到露天矿边坡在开挖过程中岩体的风化、爆破震动、施工机具扰动尤其是冻融循环等不利因素对岩体强度的影响,给出了边坡稳定性计算岩体力学参数建议值。结论为:天然状态下,粘聚力最大值为3.22 MPa,最小值为1.84MPa,内摩擦角最大值为32.44°,最小值为24.42°;饱和状态下,粘聚力最大值为2.77 MPa,最小值为1.55 MPa,内摩擦角最大值为27.49°,最小值为21.35°。

In the process of open-pit slope stability analysis ,due to the existence of the layers ,joints ,weak interfaces and fault planes ,the macromechanical parameters of the rockmass are different from those of the laboratary standard rock . Therefore the parameters obtained in the laboratory should be corrected in order to derive the physical parameters of the rockmass and then applied to the stability evaluation of the slope At first ,the suggested mechanical parameters of the rockmass were obtained through the correction of Hoek Brown experience method ,geomechanical law and RMI method . And then ,the unfavorable factors of weathering ,blasting vibration ,construction disturbance and freeze-thaw cycle were taken into account to calculate the suggested mechanical parameter value of the slope stability .The results showed that under natural state ,the maximum value of the cohesion was 3 .22 MPa ,the minimum was 1 .84 MPa ;the maximum val-ue of internal friction angle was 32 .44° ,the minimum value was 24 .42° .Under the saturated state ,the maximum value of the cohesion was 2 .77 MPa and the minimum value was 1 .55 MPa ;the maximum value of internal friction angle was 27 .49° ,the minimum value was 21 .35° .