In mid-July 2026, good news came from the construction of Hangzhou Metro Line 15: the left-line shield of the section from Longteng Street Station to Zhanjiaqiao Road Station in Bid Section SG15-15 successfully completed its underpassing of the Nanjing-Hangzhou High-Speed Railway. The operation lasted 18 days with a cumulative advance of 69 rings, achieving zero warnings and zero excessive settlement throughout. It pioneered the country's first non-obstacle-clearing pile grinding technology under the combined conditions of an elevated high-speed rail and sheet-pile walls, filling a domestic technical gap in construction under similar complex conditions.

As a core transportation artery of the Yangtze River Delta, the Nanjing-Hangzhou High-Speed Railway operates dense daily schedules under stringent standards, imposing extremely high requirements on settlement and vibration control for nearby construction. This shield underpassing was a high-risk controlling project for the entire line. The construction area combined the dual complex conditions of an elevated high-speed rail and road sheet-pile walls, with 8 road bored pile foundations remaining beneath the bridge and obstructing shield tunneling. The traditional obstacle-clearing construction method would easily disturb the high-speed rail foundation structure, triggering the risk of line settlement and directly threatening the safety of high-speed rail operations, making the construction extremely difficult.

To balance construction progress with high-speed rail operational safety, the project team abandoned the traditional obstacle-clearing tunneling scheme and innovatively adopted non-obstacle-clearing pile grinding technology. Without damaging the original high-speed rail structure or disrupting normal line operations, it precisely ground away all obstructing pile foundations beneath the bridge, perfectly adapting to the complex elevated bridge and sheet-pile construction scenario. The successful application of this technology provides a brand-new technical paradigm for metro shield construction in areas with dense high-speed rail operations and complex superimposed conditions in China.

The entire construction process relied on a smart construction site digital management and control system to build a comprehensive dynamic monitoring network. In the early stage, technical personnel accurately measured and located pile foundation positions, comprehensively assessed construction risks, and customized a dedicated tunneling scheme. During construction, tunneling parameters were dynamically adjusted, grouting quality was strictly controlled, and mortar testing and sample retention for traceability were carried out on a regular basis. Meanwhile, the project was equipped with clay-shield effectiveness equipment to reinforce the strata, calibrated the shield attitude in advance, and deployed high-density monitoring points. Through multiple measures such as advanced geological forecasting, multi-level grouting reinforcement, and automated settlement monitoring, it firmly safeguarded the bottom line of construction safety.

With the successful completion of this underpassing, ground settlement values throughout were stably controlled within the design standard range, without any impact on the normal operation of the Nanjing-Hangzhou High-Speed Railway. Next, the project team will continue to strictly uphold safety and quality standards, refine construction management and control processes, steadily advance subsequent tunnel boring, and make every effort to ensure the efficient and smooth progress of the Hangzhou Metro Line 15 project, laying a solid foundation for improving Hangzhou's urban rail transit network and facilitating citizens' travel.

Reference source: Hangzhou Net