Deformation Monitoring for Subway Tunnels Based on TLS

The paper studies Terrestrial Laser Scanning used in subway tunnel deformation monitoring. For special narrow subway tunnel structure, the accumulated error between the adjacent station can be eliminated by global registration pattern which is to set the common control point within the section ends. Point cloud slicing is used to calculate the radius of the circle by multi-point coordinate, deformation is fitted to curve to show the monitoring result by analyzing the center coordinates sequence trends and mean curvature. Three-dimensional model of subway tunnel not only improves the accuracy of deformation monitoring, but also reflects the overall deformation trend. This method is applied to monitor deformation for Shanghai Metro Line twelve, comparing with the total station method, high precision of deformation monitoring meet the need.