Estimation of the Mean Trace Length of Discontinuities in an Underground Drift using Laser Scanning Point Cloud Data

Abstract

Abstract In the drift of underground metal mines, the extraction of rock mass discontinuity characteristics from point cloud models generated by laser scanning has become the main approach. However, the exposure of discontinuities is restricted in the drift, and the size of discontinuities cannot be measured directly. Therefore, it is necessary to use a reasonable sampling tool to estimate the mean trace length of discontinuities that are mapped in the point cloud model. In this paper, a method to estimate the mean trace length of discontinuities in three-dimensional (3D) models of drift (3DM) is proposed. Through the point cloud data of drift obtained by 3D laser scanning, the information of discontinuities in the surrounding rock is extracted, and then the mean trace length is estimated by using 3DEC to set sampling windows on the roof and sidewall of the 3DM. By analyzing the difference between the circular sampling window and the rectangular sampling window using simulated cases, the estimation results show that the mean trace length obtained by circular measuring windows in 3DM is closer to the true trace length. Finally, the method is used on a practical engineering case in Jianshan Iron Mine, Panzhihua, Sichuan, China.