A modified method of discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces

This paper presents an automated method for discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces. Specifically, the method consists of five steps: (1) detection of trace feature points by normal tensor voting theory, (2) contraction of trace feature points, (3) connection of trace feature points, (4) linearization of trace segments, and (5) connection of trace segments. A sensitivity analysis was then conducted to identify the optimal parameters of the proposed method. Three field cases, a natural rock mass outcrop and two excavated rock tunnel surfaces, were analyzed using the proposed method to evaluate its validity and efficiency. The results show that the proposed method is more efficient and accurate than the traditional trace mapping method, and the efficiency enhancement is more robust as the number of feature points increases.