随机节理岩体变形与强度参数及其尺寸效应的数值模拟研究

节理岩体力学参数及其尺寸效应一直以来都是岩体研究的热点和难点,但对于基于结构面网络模型进行数值模拟的研究尚未见报道。笔者以小湾坝基卸荷岩体为例,在对现场节理进行大量统计的基础上,分析出节理特征值的分布函数,再运用蒙特卡罗方法建立了其结构面网络模型。在此基础上,利用编制的接口程序和现有的FLAC3D岩土分析软件,实现了对随机节理结构面网络模型的不连续位移数值模拟。模拟结果表明:小湾坝基卸荷岩体变形模量与岩体尺寸的关系服从负指数分布,而强度参数与岩体尺寸的关系基本服从负幂函数分布,其结果与现场斜面载荷试验及经验评估参数结果较为接近。

Deformation and strength parameters and size effect of random jointed rock mass by numerical simulation

The mechanical parameters and the size effect of the jointed rock masses are one of the hotspots and a difficult task in the field of the rock mass research work.It is known that the numerical analysis for rock discontinuity network model has not been published yet and that in Xiaowan Hydro-power Dam Station(in China),there are so many rock joints and their mechanical parameters should be characterized.For this purpose,a numerical analysis is done.After analyzing the eigen-values of the joints distributing function,the discontinuity network modeling is established by the Monte Carlo method.The discontinuity displacement numerical simulation for the network modeling is achieved by elaborating an interface program which is injected into a computer program FLAC3D of geotechnical analysis.According to different rock mass samples,the results of the numerical analysis reveal that the deformation modulus of the unloaded rock masses presents a negative exponential function,whereas,basically,the curve of the strength parameters c,? and the rock mass size give a negative power function.The numerical simulation results correlate well with the inclined plane loading test results and the Hock Brown results.