Study On Rock Mass Structural Plane Identification And Rock Mass Integrity Evaluation Based On 3D Laser Scanning Technology

The staggered structural plane constitutes the weakest part of the rock mass and is the key control factor of rock mass deformation and failure.Different from the traditional manual measurement,3D laser scanning technology can obtain the coordinate information of rock mass surface in a long distance,non-contact,fast and accurate way,and show the real situation of rock mass structural plane of reservoir bank slope in a comprehensive and detailed way.Based on the reliable point cloud data,accurate and efficient rock mass structural plane identification and feature information extraction can provide an important basis for rock mass stability evaluation.Based on many point cloud data obtained by 3D laser scanning technology,this paper deeply studies the identification,segmentation and information extraction technology of rock mass structural plane.Taking the structural rock mass of Mangshezhai slope on the left bank of the Yangtze River in the Three Gorges reservoir area as an example,based on the comprehensive field investigation and the information of structural plane,the rock mass quality evaluation in line with the characteristics of 3D laser scanning technology is established,and the complete process from 3D laser structural plane point cloud data acquisition to rock mass quality evaluation is realized.The main research results of this paper are as follows:（1）The research methods of rock mass structural plane are summarized.The principle and characteristics of three-dimensional laser scanning technology are introduced comprehensively.The application scope of different structural plane identification and extraction methods is analyzed in detail.（2）A method of rock mass structural plane recognition and segmentation based on 3D point cloud data is proposed.In this paper,the spatial relationship between the point cloud position of the rock mass structural plane and its neighborhood is considered.The regional growth segmentation parameters are modified by multiple eigenvalues.The KD-tree data structure is used to perform the nearest neighbor search voxel down-sampling,and the structural plane is segmented according to the difference between the point cloud normal vector and the surface change degree.Based on the robust random Hough transform,the regional growth algorithm is improved to realize the identification and segmentation of the bedding plane.Based on the principle of the algorithm,the feature final value is proposed to describe the point cloud characteristics of joint fissures according to the multi-dimensional feature values,and RGBA coloring is performed on different feature final value intervals to complete the joint fissure identification and segmentation.（3）The influence of the main parameters of the proposed method is studied.The influence trend of the main parameters K and the angle thresholdθ_th on the recognition and segmentation effect is analyzed respectively,and the change rule is summarized.The general calculation method of parameter K is proposed,and the setting standard of other parameters in the application is given.（4）The specific meaning of the five kinds of geometric information of rock mass occurrence,spacing,ductility,area and joint parameters in the point cloud data of rock mass structural plane is analyzed.The spatial relationship of whether the scale gap between different structural planes is too large to be integrated and incompletely paralleled is considered,and the extraction of geometric information of complex structural planes is realized.Based on the obtained geometric information,a 3D DRMR structural plane classification evaluation method is proposed based on the 2D DRMR classification.（5）The method proposed in this paper is used to identify and segment the different types of rock mass structural planes exposed in the Mangshezhai slope on the left bank of the Yangtze River in the Three Gorges Reservoir area.The information of the occurrence,spacing,ductility,area and joint fissures of each group is extracted.The intersection relationship between the structural plane and the slope is analyzed according to the pole is density map and the stereographic projection map.Based on the three-dimensional DRMR classification evaluation,the integrity and stability of the rock mass structure in the Mangshezhai study area are judged.Based on the three-dimensional laser scanning technology,a complete process from data acquisition to preliminary evaluation of rock mass integrity and stability is realized.