柱状节理岩体地质成因特殊,地质结构特点与常见岩体有很大不同,成规则或不规则柱状排列,其裂隙统计及节理的随机模拟方法也与常见岩体采用的方法不尽相同。根据白鹤滩水电站柱状节理岩体的地质构造特点及现场统计资料,以其中最为常见的一类柱状节理为例,引入Voronoi方法对其进行随机模拟,并将随机模型导入3DEC,生成三维随机柱状节理模型进行数值试验,得出其表征单元体(REV)尺度约为典型节理迹长的3~4倍。同时数值试验结果表明,平行于柱轴向(y方向)与垂直于柱轴向(x-z方向)的弹性模量及泊松比值相差较大,柱状节理显示有强烈的各向异性。x-z方向弹性模量及泊松比值相差较小,在REV尺度下可近似认为x—z方向材料性质相同,将柱状节理视为横观各向同性体进行计算和分析。
The geological origin of columnar jointed rock mass is very complicated, its geological structure arranges regularly or irregularly, which is not same as common rock mass, so different methods should be adopted in fracture statistics and random simulation of joints. According to the geological structure of the columnar joints and in-situ data, columnar joints are simulated randomly by Voronoi method, which can effectively solve the problem in the random simulation of columnar joints. With the introduction of random model into 3DEC, 3D random columnar joint model can be set up: and then the numerical test is carried out. Following conclusions can be drawn. (1) The size of representative elementary volume(REV) is about 3 to 4 times of the typical joint size. (2) Elastic modulus and Poisson's ratio show great differences in the horizontal and vertical directions, which indicates that the columnar joints have strong anisotropy. Elastic modulus and Poisson ratio in horizontal direction show little differences, so the material property can be considered same in REV scale; and columnar joints can be computed and analyzed as transversely isotropic material.