岩体蠕变对露天矿边坡稳定性的影响

为了研究岩体蠕变对边坡稳定性的影响,评价露天矿边坡服务周期内的安全性,根据时效边坡理论及岩体蠕变规律,分析了边坡岩体力学参数的长期强度表达式;基于极限平衡法中的简化Bishop法,推导出了圆弧滑坡时效稳定系数的计算公式;得出了稳定系数随蠕变时间增长呈指数递减的规律。对哈尔乌素露天矿端帮靠帮开采过程的时效稳定性进行研究的结果表明:在相同岩性参数的基础上,随着边坡角的不断增大,端帮边坡的整体稳定系数呈线性下降,剪应变及应力集中于高陡台阶底部,塑性贯通区呈圆弧状;随着蠕变时间的增长,不同几何形状边坡的稳定系数均呈现相同的衰减规律。岩体蠕变特性会造成岩体抗剪强度及边坡稳定系数随时间延长而呈指数规律衰减。准确把握岩体蠕变特性,可预测边坡的有效服务时间,具有非常重要的工程价值。

Influence of Rock Mass Creep on Slope Stability in Surface Mine

In order to study the effect of rock mass creep on slope stability，as well as to evaluate the safety of open-pit slope during service period，and according to the timeliness slope theory and rock mass creep rule，the expression of long-term strength for mechanics parameters of slope rock mass was analyzed.Also，on the basis of simplified Bishop method in the limit equilibrium method，the calculation formula of circular sliding timeliness stability coefficient was deduced.In addition，the rule was found that the stability coefficient decreased in an exponential fashion with creep time climbing.By studying the timeliness stability of end-slope in the process of steep mining at Haerwusu open-pit mine，results were achieved that with the same lithologic parameters，the integral stability factor of end-slope reduced following a linear fashion with slope angle increasing，the shear strain and shear stress concentrates on the bottom of high and steep steps，and plastic transfixion area shows as circular shape.In addition，as creeping time grows，the timeliness stability factor follows the same rule regardless of different geometric shapes.Rock mass creep property will cause the shear strength and the slope stability factor decreased in an exponential fashion with creep time climbing.Grasp the creep characteristics of rock mass can predict the effective service time of slope，which has very important engineering value.