基于分形理论构建随机粗糙节理模型的方法研究

粗糙节理三维形貌特征是影响岩体沿节理面剪切力学性质的关键因素.采用3D扫描方法重构巴西劈裂试验得到的砂岩张节理表面形貌模型.根据粗糙节理表面统计自相似性质,引入地形学领域广泛应用的随机分形数字高程模型生成方法,通过调节不同的随机参数d,采用"菱形-正方形"算法迭代生成一系列不同形貌特征的分形粗糙表面数字高程模型,并将其...

Study on stochastic method for modeling rough joints based on fractal theory

The three-dimensional morphology is the key factor affecting the shear mechanical properties of rock joints.3 D scanning is performed to reconstruct the surface morphology model of the sandstone tension joint obtained by the Brazilian splitting test.The stochastic methodology of generating fractal digital elevation models,which is widely used in topography,is introduced to construct surface models with different rough morphological features based on the statistical self-similarity of rough joint surfaces.By adjusting the random parameter d,a series of fractal rough joints with different morphological features are generated using the"diamond-square"algorithm,and compared with the natural sandstone tension joint obtained by the Brazilian splitting test.3 D box-counting method is used to calculate the fractal dimensions of both kinds of joint surfaces,and the statistical distribution of apparent dip angles along a specific shear direction is analyzed.Considering the fractal dimension and the standard deviation of the statistical distribution of apparent dip angles as characterization parameters of 3 D joint roughness,it is confirmed that the morphological feature of the natural sandstone tension joint conform to that of the artificial surface with the random parameter d ranging from 2 mm to 3 mm,verifying the feasibility of the stochastic method of constructing digital elevation model based on fractal theory for modelling rough joints with different morphologies.