On August 1, the Xinjiangmen No. 2 Tunnel of the Longchang-Huangtong Railway Longchang-Xuyong Section Capacity Expansion and Renovation Project was successfully holed through. With this, 20 of the 23 tunnels along the entire line have been completed, pressing the "accelerator key" for the project's completion and opening to traffic.

Xinjiangmen No. 2 Tunnel of the Longchang-Xuyong Section of the Longchang-Huangtong Railway Holed Through

The Xinjiangmen No. 2 Tunnel is located in Yongsheng Village, Jiangmen Town, Xuyong County, Luzhou City, with a total length of 1,291 meters and a maximum buried depth of approximately 165.2 meters. It is a single-track tunnel. The tunnel site lies in a low hilly area with considerable topographic relief. The terrain at the tunnel portal is steep and stepped, while the exit connects directly to the Xinfangzi rigid-frame medium bridge. In the shallow-buried section of the tunnel body, there are multiple natural gullies on the surface in some local areas, and the water volume is clearly controlled by the seasons; in particular, the water inflow inside the tunnel is relatively large during the rainy season. The entire tunnel is constructed on a reverse slope, and the exit section passes beneath an existing water diversion tunnel. The surrounding rock joints are developed, and water seepage and leakage are severe.

According to reports, since construction began, measures such as strengthening advanced geological forecasting and monitoring measurement, all-weather observation of water seepage and leakage inside the tunnel, and strict implementation of in-tunnel drainage and surrounding rock monitoring measurement have been adopted to ensure safe construction. At the same time, the excavation method and tunnel exit scheme have been continuously optimized, adhering to the principle of "advance detection, advanced pipe roof support, short advance per round, weak disturbance, strong support, rapid closure, and frequent measurement" to overcome difficulties in construction such as broken surrounding rock, developed joints, and passing beneath the existing water diversion tunnel.

The Longchang-Huangtong Railway Longchang-Xuyong Section Capacity Expansion and Renovation Project starts from Longchang Station of the Chengdu-Chongqing Railway in the north and ends at Xuyong North Station in the south, with a total length of 138.6 kilometers, a design speed of 120 kilometers per hour, and 11 stations. After the project is completed, it will connect with the already operational Xuyong-Bijie Section of the Longchang-Huangtong Railway, further improving the regional railway system and enhancing the comprehensive regional transport efficiency. It is of great significance to accelerating the construction of the Chengdu-Chongqing Twin-City Economic Circle.