Baozuo Tunnel, Longest on Xining-Chengdu Railway Sichuan Section, Breaks Through; 11 of 14 Tunnels Completed

The Baozuo Tunnel, the longest on the Sichuan section of the Xining-Chengdu Railway, has been fully completed. Located in Songpan County, Aba Tibetan and Qiang Autonomous Prefecture, Sichuan Province, the tunnel is a single-tube double-track railway tunnel with a design speed of 200 km/h, a total length of 11,795 meters, an average altitude of 3,500 meters, and a maximum altitude of nearly 3,700 meters. The tunnel is situated in a strong tectonic compression zone on the eastern edge of the Qinghai-Tibet Plateau, with 98.5% of the tunnel's length in fractured surrounding rock classified as Grade IV or above.

During construction, the project team carried out zonal stripping, centralized storage, and maintenance of native turf, which was later restored and replanted in place after project completion. Production and domestic wastewater was treated through a fully closed-loop circulation system. The spoil disposal sites strictly followed the standard of 'retaining first, then filling, and layered protection,' achieving a cumulative ecological restoration area of over 120,000 square meters. Special passages were reserved along the railway line for wildlife migration and herder livestock passage.

Currently, 11 of the 14 tunnels on the Sichuan section of the Xining-Chengdu Railway have been successfully completed, 62 bridge projects are 92.4% complete overall, subgrade works are 85.6% complete, and the overall project construction progress exceeds 55%.