The largest shield tunneling machine in Guangdong Comprehensive pipe Corridor project

Recently, the shield tunnel section of no.18 to no.17 comprehensive well of Shenzhen Tube profile of China Railway Guangzhou Bureau Urban Rail Company has been successfully transfixed. The shield machine with a diameter of 8830mm is one of the largest shield machines of comprehensive pipe corridor project in Guangdong province, as well as the largest shield machine of China Railway Guangzhou Bureau.

The interval between 18# and 17# comprehensive well is 765 meters in length, and the shield construction starts from the small mileage end of 18# comprehensive well. The line is laid from east to west along the green belt and sidewalk of Longxiang Avenue, and successively passes through the ailian River box culvert, sewage lifting pump house and reaches the large mileage end of 17# comprehensive well through karst area. The tunnel mainly passes through the strata of medium-breezed limestone and medium-weathered sandstone, with the maximum slope of 6.61‰ and the tunnel burial depth of 18.4 ~ 26.8 meters.

The interval shield tunnel penetrates through hard rock strata and karst cave zone, which has large space, large number and complex stratum structure. Along the way, the shield traverses sub-high-pressure gas pipes, Xiamen-Shenzhen high-speed railway, Changguang Industrial Park printing plant, pedestrian culvert, Shenhai Expressway, Jihe Expressway, high-pressure water supply pipeline of waterworks, pedestrian bridge of Hong Kong University of Information Technology and other major risk sources. The construction environment is complicated and the construction is difficult.

In order to ensure the safety and rapid progress of the construction, the project department took the initiative to take multiple measures to overcome numerous difficulties: First, before the launch of the shield machine, facing the narrow construction site of the 18# comprehensive well and difficulties in lifting and assembling the 8830mm large shield machine, the project department made careful planning, overcame difficulties and optimized the construction scheme to adopt large separation to start the construction; Second, in the tunneling process, the shield tunneling machine passes through complex strata, breezy limestone (high hardness, karst strongly developed), fracture zone (rich groundwater), upper soft and lower hard strata, etc. Underground structure (building) built close outside the tunnel contour, the sewage pump room and minimum clear distance tunnel 1.5 meters, the project department for construction scheme optimization than choose meticulously, targeted selection tool, karst strata grouting in ahead of time, choose reasonable tunneling parameters and dynamically adjust, significantly improved the tunneling effect, created a one-month drivage 150 good grades; Third, strictly implement the provisions of the company, strictly observe the safety and quality red line, constantly optimize the construction plan, do a good job of safety technology disclosure, effectively ensure strict control of the process, fine management responsibility to the person, each process closely connected. Fourth, the project department shall strictly monitor the major risk sources 24 hours a day, and monitor the stratum changes in real time, strengthen the structural protection of risk sources, and synchronize grouting to improve geological conditions, so as to ensure the safety and quality of the project.