节理岩体数值模拟及力学参数确定

Numerical modeling and mechanical parameters determination of jointed rock mass

采用FLAC3D程序和离散裂隙网络技术构建的遍布节理岩体模型能同时考虑节理岩体中节理和岩体的作用,具有概念清晰、建模快捷、计算效率高等特点.首先对现场结构面测绘数据进行统计分析,获得其概率分布特征参数,在此基础上分两尺度考虑节理并确定其离散裂隙网络模型;其次基于离散裂隙网络模型构建相应的节理岩体模型,研究其强度特征并获取工程岩体单轴抗压强度;结合Hoek-Brown、Mohr-Coulomb准则及最大围压拟合综合确定节理岩体力学参数;最后将拟合所得参数用于边坡稳定性分析,分别运用强度折减法和极限平衡法计算两种模型的安全系数,对比发现计算结果基本一致,表明所提出的研究思路用于确定节理岩体参数是可行的.

A ubiquitous jointed rock mass（ UJRM） model constructed by combining the FLAC3D software and discrete fracture network（ DFN） technique,which takes the features of rock and joints into account,has a clear concept,high efficiency of modeling and calculation,and so on. Firstly,the in-situ survey results of joints were statistically analyzed to obtain their probability distribution parameters,on the basis of which the joints were considered in two scales and their DFN models were determined. Secondly,based on the determined DFN models,the jointed rock mass was modeled and the strength characteristics were researched to get the uniaxial compressive strength（ UCS） of engineering rock mass,then the mechanical parameters of jointed rock mass were fitted and determined by the Hoek-Brown and Mohr-Coulomb criteria while considering the max confining stress. Finally,the determined parameters were applied to slope stability analysis,the safety factors of the two kinds of criterions solved by the limit equilibrium method（ LEM） and the strength reduction method（ SRM） are basically the same,indicating that using the proposed approach to determine the mechanical parameters of jointed rock mass is practicable.