On May 5, the shield machine "Kaituo" (Pioneer) for the right-line shield-driven section of Civil Construction Section 3 of Tianjin Binhai New Area Rail Transit Line B1, constructed by China Railway No. 10 Engineering Group, broke through the soil and successfully completed its tunneling task, taking a solid step toward the early realization of the goal of full-line breakthrough. The right-line tunnel of the section from Guoxiang Xidao Station to Binhai West Station has a total length of approximately 1,122 meters, comprising 749 rings in total, with a maximum overburden depth of 16.4 meters. One cross passage combined with a pump room is provided in the section. The geology of the section mainly consists of mucky silty clay and silty clay.

The tunnel in this section requires close-distance parallel construction and crossing various risk sources such as pipelines. The greatest construction difficulty lies in the close-distance parallel construction of the tunnels, with a minimum horizontal clear distance of 3.5 meters, making them parallel shield tunnels in a near-adjacent state, which entails high construction risk. To this end, the project team established a special technical group for shield tunneling, carried out advance overall planning and deployment targeting the high-risk sources, and organized multiple expert reviews, ultimately forming a feasible implementation plan that provides strong guarantees for the shield machine to cross the risk sources.

To ensure that the "Kaituo" shield machine completes its breakthrough operation safely and smoothly, the project improved the safety and quality management system, strictly followed shield tunnel construction specifications, clarified the division of responsibilities during tunneling, and gave priority to guaranteeing the resource requirements for shield operations. In addition, comprehensive tracking and monitoring of the shield machine was carried out through an information platform, and a monitoring system for the internal forces and deformation of segment linings was installed inside the tunnel to reduce interference between the construction of the left and right lines. The project successfully overcame difficulties such as shield attitude control, upward floating of segments in the completed tunnel, close-distance parallel construction, and crossing various pipelines, achieving a maximum single-section tunneling rate of 19 rings per day and a maximum monthly tunneling rate of 336 rings (504 meters).