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岩石结构面形貌特征直接影响其宏细观剪切破坏特征和剪切强度,因此,清楚地认识在不同点云数据采样间隔下结构面形貌特征和各向异性特征的统计参数稳定性,对于定量认识结构面剪切破坏机制并建立合理的抗剪强度准则十分重要。为此,借助三维白光面扫描系统对3组不同粗糙度的岩石结构面进行测量,并根据稀疏点云数据密度的原理得到其15种采样间隔的点云数据;在此基础之上,研究了2D统计参数坡度均方根Z_2、粗糙度指数R_p和θ_(max)~*/(C+1)_(2D)以及其所对应的3D坡度均方根Z_(2s)、3D粗糙度指数R_s和3D统计参数θ_(max)~*/(C+1)_(3D)随采样间隔的变化规律。研究发现,上述统计参数随着采样间隔的增大而减小,且衰减幅度逐渐增大,并与采样间隔存在二次多项式的拟合关系;同时,研究还发现,不同采样间隔下结构面的各向异性特征也具有间隔效应。为定量描述这种结构面各向异性特征的采样间隔效应,利用所构造的无量纲参数结构面各向异性系数DAC和各向异性特征参数K_α对其度量,结果表明,结构面的各向异性与间隔效应呈现正相关的关系。最后,综合岩石自然结构面分析形貌特征参数和各向异性特征参数的稳定性,在采样间隔取为0.1~0.5 mm之间表现较好的稳定性,其参数值偏差不大于3%,因此,建议一般情况下岩石自然结构面三维扫描的采样间隔可取为0.5 mm。
Therefore, it is clear that the stability of the statistical parameters of the morphological and anisotropic features of the structural plane under different sampling intervals of the cloud data points clearly shows that the rock-surface morphological characteristics of the rock face directly affect the characteristics of the macroscopic shear failure and the shear strength. It is very important to quantitatively understand the mechanism of shear failure of structural plane and establish a reasonable shear strength criterion. Therefore, three-dimensional white-light surface scanning system is used to measure three groups of rock facets with different roughness. According to the data density of sparse point cloud, 15 kinds of point cloud data are obtained. On this basis, The 2D statistical parameters of the slope root mean square Z_2, the roughness indices R_p and θ_max ~ * / (C + 1) _ (2D) and their corresponding 3D slope root mean square Z_ (2s), the 3D roughness index R_s And the variation rule of 3D statistical parameters θ_ (max) ~ * / (C + 1) _ (3D) with sampling interval. The results show that the above statistical parameters decrease with the increase of sampling interval, and the attenuation amplitude increases gradually, and there is a quadratic polynomial fitting relationship with the sampling interval. At the same time, the study also found that the structural parameters Anisotropic features also have a spacer effect. In order to quantitatively describe the sampling interval effect of the anisotropy of structural planes, we measure the anisotropy coefficients by using the dimensionless parametric structural plane anisotropy coefficient DAC and anisotropy characteristic parameter K_α. The results show that anisotropy of structural planes And the interval effect showed a positive correlation between the relationship. Finally, the stability analysis of the morphological and anisotropic parameters of the integrated natural rock mass surface shows good stability between sampling intervals of 0.1-0.5 mm, and the deviation of the parameter values is not more than 3% , It is suggested that the sampling interval of three-dimensional scanning of rock’s natural structural plane should be 0.5 mm in general.