Yinzishan Tunnel on Yan'an-Yulin High-Speed Railway, Built by China Railway Tunnel Group under China Railway, Achieves Breakthrough

en.Wedoany.com Reported - On November 10, the Yinzishan Tunnel on the Yan'an-Yulin High-Speed Railway, constructed by China Railway Tunnel Group under China Railway, achieved breakthrough within Qingjian County and Suide County in Yulin City, Shaanxi Province. The tunnel has a total length of 5,035.04 meters and adopts a single-tube double-track structure. The drill-and-blast method with bidirectional excavation was used in construction, completing the work two months ahead of the guiding construction organization plan.

The Yinzishan Tunnel has a maximum burial depth of 148 meters and a minimum burial depth of only 2 meters, crossing the loess ridge and gully region. The terrain along the route is highly undulating, with sinkholes at the tunnel crown, and unfavorable geological conditions such as loess landslides, landslides, and surface slumps distributed on both sides of the gullies. Collapsible loess is also present in the portal section, and the construction risk in the shallow-buried section and broken surrounding rock is relatively high. During construction, the project team adjusted blasting parameters and excavation advance according to surrounding rock conditions, strengthened advanced geological forecasting and monitoring measurement, and dynamically adjusted support parameters to control surrounding rock deformation and collapse risks during tunnel excavation.

The tunnel was organized with bidirectional excavation from the inlet and outlet. During drill-and-blast construction, the cyclic advance was improved by optimizing process connections, with the fastest monthly advance reaching 150 meters in the Class III surrounding rock construction section. The project also relied on an intelligent management and control platform for informatized management of the construction site, adjusting work arrangements based on geological forecasting, monitoring measurement, and on-site construction data. The Yinzishan Tunnel is the third tunnel to achieve breakthrough in Section 7 of the Yan'an-Yulin High-Speed Railway.

The Yan'an-Yulin High-Speed Railway has a total length of approximately 238.7 kilometers and a design speed of 350 kilometers per hour. It starts from Yan'an Station on the Xi'an-Yan'an High-Speed Railway, passes through Yan'an New Area, Yanchuan, Qingjian, Suide, Mizhi, and other places, and connects to Yulin South Station, with 7 stations along the entire line. The bridge-tunnel ratio of the line is approximately 94.3%, with 68 new bridges and 50 tunnels. After the project is completed, the railway travel time from Yan'an to Yulin is expected to be shortened to approximately 1 hour, and the fastest travel time from Xi'an to Yulin will be approximately 2 hours.