Abstract:The application of 3D visual laser scanning technology in deep softrock roadway is mainly to identify the deformation and failure of wallrock during stoping and eliminate defects of conventional monitoring, including limited amount of measured data, low level of visualization and low utilization rate of data. 3D laser scanning technology was applied to obtain 3D point cloud data of the roadway surface in order to build a 3D visual model of roadway with high precision and high-resolution. Tunnelkey 3D Point Clouds Processing & Analyzing System(TK-PCAS), a 3D point cloud processing software, was adopted to process the point cloud profile data of actual roadway section and roadway design profile data and analyze intrusion beyond clearance limit of roadway; In order to fully master the deformation of steel support in the deformed section, a 3D cloud model of roadway was constructed. Point cloud data of the steel support section were extracted directly for comparison with the steel support section analysis in preliminary survey, so as to quantify the subsidence of steel support and deformation of sidewalls. In order to prove the accuracy of monitoring data, comparative demonstration was made in terms of value and development trend between the monitoring data collected by total station and that by the scanner. The results show that 3D laser scanning technology can accurately and scientifically evaluate the over intrusion of the initial support structure to roadway clearance limit, which offers guidance to the rectification of under-excavated therein; Regarding deformation monitoring, data obtained by 3D scanning technology were generally consistent with conventional monitoring in terms of value and development trend. What’s more, 3D laser scanning technology broke through limitations of conventional single-point monitoring, which made the monitoring information of the roadway more complete in both longitudinal and annular directions with higher visualization. It provides data support for determining the deformation magnitude of wallrock and optimizing roadway support system.
