On July 12, the section from the exit of the Wujiayuan Tunnel to the large-chainage direction of No. 3 inclined shaft on the Xi'an-Yan'an High-Speed Railway was successfully holed through, marking another important milestone in the construction of a long tunnel on the entire Xi'an-Yan'an High-Speed Railway line and laying a solid foundation for subsequent ballastless track construction.

It is understood that, according to length classification, a long tunnel refers to a tunnel exceeding 1,000 meters in length. The Wujiayuan Tunnel on the Xi'an-Yan'an High-Speed Railway has a total length of 9,736.34 meters and is located in Yijun County, Tongchuan City, Shaanxi Province. The tunnel generally has a burial depth of 50–100 m, with a maximum burial depth of 190 m and a minimum burial depth of 2.3 m. The tunnel soil is soft, with low cohesion and poor self-stabilization capacity, posing high safety risks.

To ensure tunnel construction safety, the project team, through a combination of advanced geological forecasting, surrounding rock monitoring and measurement, and other means, conducted comprehensive analysis and judgment to identify the location, nature, and scale of unfavorable strata in advance, and optimized support parameters and dynamically adjusted blasting parameters. At the same time, blasting combined with mechanical and manual excavation was adopted, shotcrete was used to promptly seal the excavation face, and advanced small pipe support, steel arch support, and wire mesh hanging were used to enhance the self-stabilization capacity of the surrounding rock. Real-time monitoring was carried out on the tunnel interior and ground surface as well as the surrounding rock conditions at the tunnel face, ensuring the smooth holing-through of the tunnel.

The Xi'an-Yan'an High-Speed Railway is the first high-speed railway in the old revolutionary base area of northern Shaanxi, an important component of the Baotou (Yinchuan)-Haikou high-speed railway corridor in the national high-speed railway network, and together with the Xi'an-Chongqing High-Speed Railway under construction, forms a major north-south corridor. It is an important constituent of the main framework of Shaanxi Province's "米"-shaped high-speed railway network and a key construction project during the 14th Five-Year Plan period. The line has a total length of 299.8 kilometers, with a construction standard of a double-track high-speed railway and a design speed of 350 km/h. After the line is completed and put into operation, the travel time from Xi'an to Yan'an will be shortened from the current 2.5 hours to about 1 hour, which is of great significance for accelerating the construction of the Baotou-Haikou high-speed railway corridor, further improving and optimizing the layout of the national high-speed railway network, enhancing Shaanxi Province's locational advantages and its hub status in the national railway network, supporting rural revitalization in the old revolutionary base areas, and shaping a new pattern of large-scale development of the western region.