Recently, good news has kept coming from the Phase II project of the Liangshan Prefecture Daqiao Reservoir Irrigation District, constructed by the China Railway Construction Bridge Engineering Bureau Group — the Xiao'ao, Moyushan, and Ayuegou tunnels have been successfully holed through one after another. This marks another phased achievement in the project's construction, laying a solid foundation for the follow-up work and the smooth water conveyance of the entire line.

Xiao'ao Tunnel successfully holed through

On the evening of October 2, after more than two years of unremitting efforts by the project team, the Xiao'ao Tunnel was successfully holed through. The tunnel is located in Xiao'ao Village, Ruoshui Town, with a total length of 1,972.5 meters, a cross-section bottom width of 2.7 meters and a straight wall height of 1.48 meters, and a maximum buried depth of about 85 meters. It was constructed by excavation from both ends. The main stratum lithology is carbonaceous mudstone, dominated by Class V surrounding rock. The surrounding rock has generally poor stability, abundant groundwater, and softens upon contact with water, posing risks of rockfall, collapse, water inrush, and mud inrush.

Moyushan Tunnel successfully holed through

On October 3, after about three months of arduous efforts, the Moyushan Tunnel was successfully holed through. The tunnel is located in Younian Village, Youjun Town, with a total length of 235 meters, a cross-section bottom width of 2.75 meters and a straight wall height of 1.85 meters, and a maximum buried depth of about 20 meters. The tunnel was constructed by single-end excavation. Thanks to the careful organization and unremitting efforts of the project team, the tunnel was holed through 24 days ahead of schedule.

Ayuegou Tunnel successfully holed through

On the same day, the Ayuegou Tunnel was successfully holed through. The tunnel is located in Ayue Village, Mali Town, with a total length of 1,278 meters, a cross-section bottom width of 2.7 meters, a straight wall height of 1.93 meters, and a top arch radius of 1.69 meters, and a maximum buried depth of about 50 meters. It was constructed by single-end excavation. The project strictly followed the construction principles of advanced pipe forepoling, strict grouting, short advance per round, strong support, and frequent measurement, ensuring the smooth holing-through of the tunnel.

The Phase II project of the Liangshan Prefecture Daqiao Reservoir Irrigation District is a long, large-scale linear water conservancy project, characterized by a long construction line, small tunnel cross-sections, a large number of tunnels, scattered work sites, and high construction difficulty. Once completed, it will deliver life-giving water to 450,000 mu of farmland, benefiting the three counties (cities) of Mianning, Xichang, and Dechang, solving the problems of high-quality drinking water and irrigation for a million people along the route, further improving production and living conditions in the Anning River Valley area of Liangshan Prefecture, promoting the adjustment of the local agricultural industrial structure and the development of specialty agriculture, raising the level of urban and rural domestic water supply security, and powerfully boosting Liangshan Prefecture's implementation of rural revitalization and consolidation of poverty alleviation achievements.