Three Dimensional Modeling And Safety Analysis Of Complex Karst Cave Based On 3D Laser Scanning

The existence of underground complex karst cave brings great security risks to tunnel construction so that traditional measuring method cannot obtain cave' s deposition and size precisely.This thesis adopts field investigation?theoretical analysis?on-site detection and 3D modeling etc.,basing on 3D laser scanning to carry out the research of 3D modeling and safety analysis of complex tunnel,which has significant realistic meaning to the layout and construction of tunnel engineering.By comparing the traditional measurement technology and 3D laser scanning technology,analyzing the shortcomings of the traditional measurement technology and the superiorities of 3D laser scanning technology,thesis expounds the principles of 3D laser scanning technology for underground caverns or empty space spatial shape scanning.Using laser scanning system C-ALS,we finished the detection of Xiangjiabao No.2 karst cave and obtained karst cave point cloud data through No.1 and No.2 borehole respectively.Through point cloud data filtering and splicing,we established a 3D model of the cave,then calculated the volume size and made a comprehensive analysis of the spatial shape,including the plane graph analysis,cross section analysis and longitudinal section analysis of the karst cave etc.After the 3D modeling construction of Xiangjiabao No.2 tunnel surface,borehole,karst cave and tunnel,we conducted a multifaceted analysis of the relationship between the karst cave and the tunnel,and figured out the development direction.Furthermore,we made the subdivision and dissection of the karst cave from the parallel direction?vertical direction and along the karst cave extending direction respectively to know the whole shape in order to analyze the safety and stability of karst cave.Research shows,in view of the complex karst staff cannot reach,C-ALS 3D laser scanning system can be used to construct completed complex karst cave 3D model.Through a multifaceted analysis,we can figure out the development direction and relative influence of complex karst cave that providing reliable data for the safety and stability of the late tunnel construction.