天然岩体结构面三维粗糙度的多尺度取样影响规律研究

基于三维激光扫描技术,在单一大尺度天然岩体结构面点云数据上开展多尺度窗口取样时,取样窗口中心位置的选取对结构面三维粗糙度的准确表征具有显著的控制作用,然而该控制机制与影响规律的研究十分匮乏.为此,以青海祁连县黄藏寺水利枢纽右岸坝址边坡大尺度天然岩体结构面为研究对象,以结构面三维激光扫描点云数据和Grasselli三维粗糙度计算方法为基础,开展了单一大尺度结构面上窗口取样中心位置对三维粗糙度多尺度特征影响与控制规律的深入研究.结果表明:窗口取样中心位置对结构面三维粗糙度的尺寸效应影响显著,取样中心位置的不同导致尺寸效应具有显著差异;同一剪切方向上结构面三维粗糙度的差异性随取样窗口尺寸的增大而减小;窗口取样中心位置对分析含结构面岩质边坡的潜在滑动方向的影响较小,当取样窗口尺寸增大到特征尺寸后,潜在滑动方向将被限定在一定角度范围,天然结构面的角度区间为110°～130°.最后基于上述研究,建立了窗口取样中心位置选取的基本原则,改进了天然大尺度结构面三维粗糙度取样方法.

Research on the Influence Law of Multi-scale Sampling of Three-Dimensional Roughness of Natural Rock Mass Structure Plane

Based three-dimensional laser scanning technique, to carry out multi-scale window samples on a single large-scale natural rock structure surface point cloud data, the sampling window center positions of the characterization results for the three-dimensional roughness features of rock mass structural plane have a significant controlling effect, but study the control mechanism and the influence law is scarce. In order to understand this law of influence, the large-scale structure of natural surface on right bank slope about Huang Temple Water Control Project dam site in Qilian, Qinghai Province as the research object, based on the three-dimensional laser scanning point cloud data of the structural plane and the Grasselli three-dimensional roughness calculation method, to carry out a depth study about large-scale single sampling window center position for the influence of multi-scale features of the control law. The results show that the center position of the sampling window has a significant influence on the dimensional effect of the roughness of the structural surface.The difference of 3D roughness of structural surface in the same shear direction decreases with the increase of sampling window size.The central position of the sampling window has little influence on the analysis of the potential sliding direction of the rock slope containing structural plane. When the sampling window size increases to the characteristic size, the potential sliding direction will be limited to a certain angle range, which is 110°~130° for the natural structural plane adopted in this paper. Finally, based on the above research, this article establishes the basic principles of window sampling center location selection, improves the natural large-scale structural surface 3D roughness sampling method.