On May 9, as the last meter of rock was drilled through, the Daping Mountain Tunnel of the newly built Chengdu-Dazhou-Wanzhou High-Speed Railway (hereinafter referred to as the "Chengda-Wan HSR") was officially completed and opened, marking the official breakthrough of another "bottleneck" in the Changgangling-Yuanbaoshan section of the Nanchong segment of the Chengda-Wan HSR.

It is reported that the Daping Mountain Tunnel is located in Xixing Subdistrict, Jialing District, Nanchong City, with a total length of 624.83 meters and a maximum burial depth of 108 meters. It is a single-tube double-track tunnel.

According to the introduction, the Daping Mountain Tunnel section mainly consists of argillaceous sandstone and sandy mudstone, with fractured rock masses that soften easily upon contact with water. The tunnel portal and exit sections pass through Quaternary residual slope deposits and strongly weathered sandy mudstone layers, where the surrounding rock stability is poor and roof collapse is likely, resulting in high construction risks. The project adhered to the principles of advance forecasting, controlled overbreak, short advance per round, weak blasting, strong support, rapid sealing, and frequent measurement. The secondary lining adopted the nine-step rebar method and the window-by-window vibration process to ensure efficient construction progress under the premise of safety and quality.

The Chengda-Wan HSR is an important component of the Yangtze River corridor of China's "Eight Vertical and Eight Horizontal" high-speed railway network. It starts from Chengdu and passes through Suining, Nanchong, and Dazhou to Wanzhou, Chongqing, with a total length of over 400 kilometers and a designed speed of 350 kilometers per hour. This year, the Nanchong segment plans to complete an investment of 2.886 billion yuan, and all projects are progressing steadily.