Tunnel Automated Monitoring

▋A Certain Subway Tunnel Monitoring project

The south end construction area of a certain underground space in Shenzhen is located directly above and on the east and west sides of the existing station section of Metro Line 10. The burial depth of the subway tunnel is approximately 17.5 meters, the excavation depth of the foundation pit at the south end is about 13.7 meters, and the minimum vertical clear distance between the foundation pit bottom slab and the subway tunnel is 3.47 meters. This construction has a significant impact on the existing subway line; to evaluate the impact degree, the project adopts intelligent vision gauges to conduct safety monitoring on the deformation status of existing rail transit facilities in the impact area.

The project has set up 11 monitoring cross-sections in the monitoring section. According to the survey line length and line-of-sight conditions, 2 intelligent vision gauges are installed on each of the left and right side walls of the tunnel. In addition, 4 transfer points and 3 reference points are arranged to verify the monitoring data, with a total of 4 intelligent vision gauge and 51 reflective targets used.

▋Existing Tunnel Monitoring Project for Reconstruction and Expansion of a Highway

The existing tunnel has a total length of 2140 meters and a cross-sectional width of 10.25 meters. A new tunnel is under construction adjacent to the right tunnel of the existing one. Excavation of the new tunnel will cause stress redistribution of the surrounding rock of the existing tunnel, which may lead to additional deformation. Therefore, it is necessary to monitor the settlement and convergence of the existing tunnel within the construction impact area.

The project covers a 150-meter monitoring section, and 4  intelligent vision gauge are used for relay measurement. In total, 4 measuring instruments, 48 monitoring targets, 4 light measurement points, and 2 transfer point targets have been installed.

Since the monitoring system was installed, the equipment has been operating well, and the monitoring data remains stable. The settlement and convergence of the tunnel are no more than 2 mm, which are within the control range, indicating the stable structure of the tunnel.