On February 1, with a loud blast, the breakthrough was successfully achieved between the exit of the Yujiashan Tunnel and the large mileage of the No. 2 inclined shaft, both constructed by the Second Company of China Railway 11th Bureau Group on the Wuhan–Shiyan High-Speed Railway, marking another stage victory in the construction of the Yujiashan Tunnel.
The Yujiashan Tunnel has a designed total length of 10,125 meters and is the longest tunnel on the entire Wuhan–Shiyan High-Speed Railway. The tunnel passes through low mountain areas, where geological structures and hydrogeological conditions are complex. It crosses four faults, passes beneath the Yunshi Expressway, and traverses an artificial landfill area. With great construction difficulty and poor construction conditions, it is a key, difficult and controlling project on the entire line. As an extra-long tunnel, the Yujiashan Tunnel has a long single-head excavation construction period. To meet the overall construction schedule requirements of the entire line, the tunnel was provided with two inclined shafts, No. 1 and No. 2, as auxiliary adits for simultaneous construction, greatly accelerating the construction progress of the Yujiashan Tunnel.
Since construction began on November 20, 2015, the Project Department of Section 4 of the Wuhan–Shiyan High-Speed Railway has carried out comprehensive construction organization planning for the Yujiashan Tunnel. Through scientific and reasonable construction management, advanced construction equipment and techniques were adopted. During construction, a complete set of tunnel lining construction technologies was actively used, together with shaped-charge hydraulic smooth blasting technology and the micro-short bench rapid excavation construction method, effectively improving tunnel construction quality and ensuring the successful breakthrough between the Yujiashan Tunnel exit and the large mileage of the No. 2 inclined shaft.
During tunnel construction, the construction principles of “short advance, weak blasting, strong support, early closure and frequent measurement” were strictly followed, ensuring smooth progress of tunnel construction. In the construction management process, due to the complex geological conditions, long tunnel length, poor ventilation conditions, high temperatures inside the tunnel in summer and poor air quality, the project department actively carried out various special seminars and proposed practical and feasible solutions to difficulties encountered during construction. As the longest tunnel on the entire line, before construction began, the project department actively organized expert review meetings to review the tunnel entry and exit construction plans, special safety plans and others, providing reliable technical support for tunnel construction. During construction, due to the high risk level, the project department implemented a leadership responsibility system and a night inspection system. For key procedures, two-level leadership from the project department and the sub-department jointly supervised operations on duty. Through control of key procedures such as construction methods, blasting excavation, initial support, lining construction and concrete pouring, the successful completion of tunnel safety and quality objectives was ensured, and the successful breakthrough between the Yujiashan Tunnel exit and the large mileage of the No. 2 inclined shaft was guaranteed.
The successful breakthrough between the Yujiashan Tunnel exit and the large mileage of the No. 2 inclined shaft has laid a solid foundation for the full breakthrough of the Yujiashan Tunnel, marking another stage victory in the tunnel's construction and bringing it one step closer to full breakthrough.