Recently, good news came again from the north extension project of Chongqing Rail Transit Line 18: the shield on the right line of the Shibati Station–Qixinggang Station section (referred to as the "Shiqi section") of the project was successfully launched, marking that the section has officially entered the shield construction stage.

Construction site of the Shibati Station–Qixinggang Station section of the Line 18 north extension project

　　The right line of the Shiqi section has a total length of 993.832 meters, of which the shield-driven section is 963.832 meters long. The minimum turning radius of the section is 350 meters, the maximum gradient is 44‰, and the burial depth is approximately 18.3 meters to 67.3 meters. At both ends of the section, 15-meter mined pass-through drifts are provided to enable the shield's reception, translation and blind thrusting in the receiving (launching) shaft; the receiving (launching) shaft can also serve as the station's civil air defense section or the station-end wastewater pump house.

　　It is understood that the "Yuxing No. 1" shield machine undertaking this tunneling task has functions such as digital information processing and automated control of tunneling parameters. Its cutterhead excavation diameter is 6.9 meters, the machine body is about 83 meters long in total, and its total weight reaches 684 tons. It is mainly electrically driven and can meet the requirements of tunneling in complex strata.

　　To ensure the smooth launch of the shield, in view of the characteristics of the Shiqi section such as complex water conditions and complex surface and underground environments, the project team adopted a series of targeted measures, including: organizing all parties in advance to carry out a comprehensive inspection and acceptance of the shield machine, checking every link from cutter bolt tightening torque testing, non-destructive weld inspection, and pressure testing of pipeline and oil connections, so as to comprehensively guarantee the shield machine's assembly quality; sorting out the pre-launch work list and resource allocation, formulating special construction plans, and using two-dimensional drawings and three-dimensional modeling to conduct fitting analysis of the shield launch plan, ensuring the smooth reception, blind thrusting and launch of the shield machine in the mined station; arranging various construction operations in an orderly manner, and carrying out the station main structure construction and shield construction simultaneously in different zones, so as to minimize the impact of cross-operation between the station main structure construction and shield construction; systematically summarizing shield construction experience, and, in view of the weak points and risk points existing in shield tunneling, organizing all participating parties to hold construction seminars to concentrate efforts on overcoming key and difficult points, etc.

The shield on the right line of the Shibati Station–Qixinggang Station section of the Line 18 north extension project was successfully launched recently

　　With the close cooperation of all parties, the project safely and efficiently completed key links such as the blind thrusting, translation, installation and commissioning of the "Yuxing No. 1" shield machine, and the pre-launch node acceptance, realizing the launch of the shield on the right line of the Shiqi section.

　　The north extension project of Chongqing Metro Line 18 starts from Xiaoshizi Station in the east and ends at Fuhua Road Station of Phase I of Line 18 in the west, with a total length of about 10 kilometers and 8 underground stations. After completion, the line will further densify the rail transit network in Yuzhong District and alleviate traffic congestion in areas such as Hualongqiao, Daping and Caiyuanba.