A State-of-the-Practice Review of Three-Dimensional Laser Scanning Technology for Tunnel Distress Monitoring

Tunnel distress occurs often. Tunnel leakage, segment dislocation, and section deformation seriously affect tunnel construction safety and normal operation. Currently, mainly the traditional monitoring technology is used in tunnel distress monitoring. This kind of technology has the problems of low monitoring efficiency, slow speed, inaccurate measuring points, and so on. With the development of science and technology, three-dimensional laser scanning monitoring technology (3D LSMT) has fast acquisition speed, a comprehensive monitoring range, and high acquisition accuracy. This review collected the world’s more advanced monitoring technologies, such as optical fiber sensing technology (OFST), photogrammetry (PT), and so on. Firstly, these technologies were introduced and compared with 3D LSMT. Then the theoretical basis of 3D LSMT was analyzed. Three-dimensional LSMT uses the captured high-density point cloud to extract the tunnel structure information and realizes the rapid processing of point cloud data through automated software. Finally, the use of 3D LSMT for segment dislocation, tunnel deformation, and seepage water was discussed and analyzed further to understand the status of 3D LSMT in tunnel monitoring and provide a reference for tunnel distress monitoring.