Learned on December 1 that the shield tunneling construction on the right line of the Shenzhen Mawan Cross-Sea Passage, undertaken by the Shenzhen Transport and Public Facilities Construction Center, China Railway South, and China Railway Tunnel Group, has successfully exceeded 500 meters. The project is expected to officially begin "entering the sea" for excavation at the end of this month.

The Shenzhen Mawan Cross-Sea Passage starts at the intersection of Mawan Avenue and Yueliangwan Avenue in the Mawan Port Area of Qianhai and connects with the Yantian Expressway Dachan Bay Toll Station and the Jinwan Avenue-Xixiang Avenue intersection. It is divided into above-ground and underground road sections, with a total length of 8.05 kilometers. The shield tunnel section of the Mawan Cross-Sea Passage Section 2 project has a total length of 2,063 meters, including 1,100 meters in the sea area. A domestically made shield machine named "Mawan" was tailor-made for the project, with a diameter of 15.53 meters. Its excavation cross-section is six times that of a conventional metro shield machine, making it the largest-diameter shield machine used in underwater tunnel construction in China.

According to reports, more than 50% of the strata encountered by "Mawan" consist of uneven soft-over-hard ground, with the highest rock strength reaching 193 MPa. The repeated variability of the strata posed severe challenges to the project. During construction, the builders relied on the intelligent shield TBM engineering big data platform to achieve real-time intelligent monitoring and automatic warning of tunneling parameters. Technologies such as digital BeiDou positioning, informatized BIM, 5D, and intelligent monitoring were used to comprehensively perceive the surrounding environment of the project construction, changing the traditional methods of manual supervision and manual setting-out, and greatly improving construction accuracy and monitoring efficiency.

According to reports, while the project team operated this "major national equipment" standing more than five stories tall and struggled through complex uneven soft-and-hard strata, it also attached great importance to environmental protection. It adopted a zero-emission slurry collection design with extended shield machine pipelines, achieving zero leakage and zero pollution of slurry, ensuring the overall construction environment of the tunnel, and practicing the concept of green development.

As Shenzhen's first large-diameter cross-sea shield tunnel, the Mawan Cross-Sea Passage is expected to be completed and opened to traffic by the end of 2023. Once completed, it will play an important role in improving the external road network structure of Qianhai, the "special zone within the special zone," linking the port-related freight traffic of the Nanshan Port Area, and promoting transportation connectivity in the Guangdong-Hong Kong-Macao Greater Bay Area.