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 construction beneath the Nanjing-Hangzhou High-Speed Railway. The construction lasted 18 days with a cumulative advance of 69 rings, achieving zero warnings and zero excessive settlement throughout the entire process. It pioneered the country's first non-obstacle-clearing pile grinding technology under the combined working conditions of an elevated high-speed railway and sheet piles, 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 has dense daily schedules and stringent operating standards, imposing extremely high requirements on settlement and vibration control for surrounding construction. This shield underpassing operation is a high-risk control project for the entire line. The construction area combines the dual complex conditions of an elevated high-speed railway and road sheet piles, with 8 road bored pile foundations remaining beneath the bridge obstructing shield tunneling. If the traditional obstacle-clearing construction method were adopted, it would easily disturb the high-speed railway's foundation structure, triggering the risk of line settlement and directly threatening the safety of high-speed railway operations, making the construction extremely difficult.

To balance construction progress with high-speed railway 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 structure of the high-speed railway or interfering with 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 railway operations and complex superimposed working conditions in China.

The entire construction process relied on a smart construction site digital management and control system to build a comprehensive dynamic supervision 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. At the same time, 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 construction, ground settlement values throughout the process 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 comply with safety and quality standards, refine construction management and control processes, steadily advance subsequent tunnel tunneling operations, 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