At 9:18 a.m. on January 11, as the “CRRC No. 6” shield machine launched from the left line of Tengda Road Station and slowly began tunneling toward Passenger South Station, the left-line shield of the Tengda Road Station–Passenger South Station section in Section 7 was successfully launched, marking the start of tunneling in the last shield section of Section 7.

It is understood that the left-line shield section from Tengda Road Station to Passenger South Station is 1,904.15 m long, and the longitudinal gradient of the alignment forms a “V” shape. The construction difficulties of this section lie in crossing silt strata: the tunnel body stratum is dominated by flow-plastic silt with poor physical and mechanical properties, making shield posture control difficult and construction highly challenging; there are many buildings along the route and the overburden is relatively shallow, resulting in a high degree of construction difficulty; municipal pipelines of various types and depths are numerous along the route, making coordination difficult; and Wealth Avenue has heavy traffic and high public attention, creating a complex construction environment.

To ensure the early launch of the shield, the Section 7 project department adhered to the principle of neglecting neither epidemic prevention and control nor construction production, and grasped both simultaneously. Following the principle of “internal and external prevention of the epidemic and comprehensive efforts to expedite construction production,” it achieved the “five in place”: establishment of the epidemic prevention and control system in place, screening of returning employees in place, reserve of prevention and control materials in place, epidemic prevention and control publicity and education in place, and safety, quality and technical training in place. It raced against time to carry out all preparatory work before shield launch. At the same time, to ensure the safety and quality of shield launch, the project department strengthened shield machine tunneling parameter control and ground monitoring through early-stage ground reinforcement and later-stage secondary grouting, greatly reducing construction risks and ensuring safe shield tunneling.

Up to now, the right-line shield in the Tengda Road–Passenger South Station section has advanced 401 rings, with 791 rings remaining; the left line has a total of 1,190 rings and is expected to be completed in early July 2021. In the subsequent construction process, the Section 7 project department will continue to uphold the construction concept of “safety, efficiency, quality, greenness and intelligence” and promote the high-quality development of the urban railway S1 Line through technological innovation.