岩溶弱发育对围岩力学参数的影响规律研究

Study on the influence of weak karst development on mechanical parameters of surrounding rock

为了研究岩溶弱发育对围岩整体变形与强度参数的影响,确定岩溶弱发育的溶洞直径分布规律和分析模型,基于蒙特卡罗法建立溶洞随机分布的三维数值模型,对不同体岩溶率的围岩进行了加载试验模拟研究。研究结果表明:该方法可灵活准确地生成符合实际分布特征的岩溶岩体模型;在相同体岩溶率的情况下,围岩级别越好,弹性模量折减越小而抗压强度折减越大;弹性模量和抗压强度的折减系数可根据非线性回归方程进行计算;岩溶弱发育情况下,各级围岩弹性模量下降不超过15%;Ⅴ级围岩抗压强度下降不超过5%,Ⅲ和Ⅳ级围岩抗压强度下降不超过10%。

In order to study the influence of karst weak development on the overall deformation and strength parameters of rock mass, this article determined the diameter distribution law and the analytical model for karst coves. The Monte Carlo method was used to establish the three-dimensional numerical model of karst cave and different rates of karst development were simulated. The results show that the method can generate the karst rock model flexibly and accurately according to the actual distribution characteristics. Under the same karst rate, the better the elastic modulus, the smaller the elastic modulus reduction and the greater compressive strength reduction. The elastic modulus and compressive strength of the reduction coefficient can be calculated according to nonlinear regression equation; when the karst is weakly developed, the elastic modulus of surrounding rock decreases by no more than 15%. The compressive strength of Grade V shall be less than 5% and the compressive strength of Grade III and IV shall not exceed 10%.