Rock Block Identification and Block Size Determination of Rock Mass

摘要

In this paper, the topological properties of 3D blocks are described, and 3D topological data model is proposed. An algorithm of automatically identifying rock blocks is then presented. Based on object-oriented approach, a block tracing program is developed to identity rock blocks. In the program, the discontinuities in rock mass are treated as flat planes with or without finite size. Using the geometrical and topological information of joints as input data, the block tracing program can identify all possible 3D blocks (convex or concave) through four steps, namely, intersection calculation, tree cutting, 2D block tracing and 3D block tracing. The volume of rock blocks can be easily calculated by using of 3D simplex integration without dividing it into small blocks. An example is used to demonstrate and verify the effectiveness and accuracy of block tracing program that can identify both convex and concave polyhedron and calculate their volume. This block tracing program can be used as a pre-process for discrete element method (DEM), block theory, discontinuous deformation analysis (DDA) and manifold method (MM).