岩体强度空间变异性与边坡可靠性研究

摘要

为分析岩体强度空间变异性对边坡可靠性的影响,引入理论变差函数的球状模型、高斯模型、指数模型来刻画岩体强度的空间变异性. 利用Visual Basic编写了上述模型对应的程序并结合现场点荷载试验数据进行拟合,得到了相关的模型参数,利用蒙特卡洛随机取样方法得到了混合岩岩体的强度参数的随机分布特征,最后利用BISHOP法进行边坡可靠性分析得到相应模型对应不同分条宽度的可靠性指标. 结果表明考虑岩体强度的空间变异性会使可靠性指标计算值增大,且当分条宽度小于相关距离时可靠性指标随分条宽度增大而增大,当分条宽度大于相关距离时随分条宽度的增大可靠性指标先减小后增大. 球状模型与高斯模型的可靠性指标的变化趋势与数值大小基本一致,均在指数模型之下.%In order to analyze the effect of rock mass strength spatial variation effect on the slope reliability,the theoreti-cal variation function''s spherical model,Gaussian model,index model are introduced to depict spatial variation of rock mass strength. Visual Basic is adopted to write the corresponding program to the model above,fitting with the on-site point load test data to get the related model parameters. Monte-Carlo random sampling method is used to get the stochastic distribution charac-teristic of migmatite strength parameters. BISHOP method is taken to analyze slope reliability to get the reliability index of mod-els corresponding to different slitting width. The results show that the spatial variation of rock mass strength will make reliability index increase,and the reliability index increases with slitting width increase when slitting width is smaller than the correlated distance,when the slitting width is greater than the correlated distance,the reliability index decrease first and then increase with the slitting width increase. The variation and trend of reliability index of Spherical model are almost the same as that of Gaussian model,and all are under the index model.