On August 29, 2024, China Railway First Bureau successfully completed the construction feat of the Laoqingshan Tunnel, a key part of the Dali Section II of the Central Yunnan Water Diversion Project. With the smooth breakthrough of the tunnel from the downstream of the No. 1 branch tunnel to the upstream section of the No. 2 branch tunnel, the Laoqingshan tunnel with a total length of 11,824.268 meters has achieved full penetration, which not only marks that the tunnel has become the first comprehensive breakthrough tunnel with a length of more than 10 kilometers in the Dali section of the central Yunnan water diversion project, but also highlights the remarkable achievements of China's technical strength and engineering progress in the field of water conservancy construction.

The total length of the downstream section from No. 1 branch tunnel to the upstream section of No. 2 branch tunnel is 4657.027 meters, and the geological conditions are extremely complex and the construction is extremely difficult. The 6th bid project department of the second section of the Dali Water Diversion in Central Yunnan of China Railway First Bureau followed the principle of all work to the face of the tunnel, cooperated with a number of units, overcame multiple landslides, and solved the water inrush problem of the No. 1 branch tunnel and the geological problem of the soft rock large deformation section of the No. 2 branch tunnel.

The project continuously strengthens the construction of the internal control system and the implementation of on-site standardization: first, strictly implements safety management, and achieves zero safety accidents and zero quality defects in the first half of 2024; The second is to vigorously carry out technical research, two QC achievements won the Yunnan Construction Industry Association Class II Achievement Award, two construction methods passed the expert review of Yunnan Water Conservancy Engineering Association, four scientific and technological papers were published, and three software copyrights were obtained; the third is to vigorously carry out labor competition to ensure the progress of construction; Fourth, strengthen process control to ensure that construction quality and safety are fully controlled.

After 4 years and 4 months of joint efforts of the builders, the tunnel breakthrough from the No. 1 branch tunnel of the Laoqingshan Tunnel to the No. 2 branch of the Laoqingshan Tunnel was realized as scheduled, laying a solid foundation for the safe, high-quality, efficient and ecological construction of the Central Yunnan Water Diversion Project.

As a landmark project among the 172 key water conservation and water supply major water conservancy projects identified by the State Council, the Central Yunnan Water Diversion Project has an overall line of 664.326 kilometers, of which the core water diversion tunnel is 611 kilometers long. Once realized, the project will have the extraordinary ability to deliver up to 3.4 billion cubic metres of high-quality water per year to a given area, with far-reaching implications covering a vast 37,000 square kilometres of land and unprecedented water benefits for the region.Editor/Jiang Mingyue