The main tunnel section of the largest inclined shaft in the Chuxiong section of Yunnan Central Yunnan Water Diversion Project was successfully connected – China Daily

The main tunnel section of the largest inclined shaft in the Chuxiong section of Yunnan Central Yunnan Water Diversion Project was successfully connected (Photo by Gao Zhan)

On November 11, the downstream section of the No. 2 inclined shaft of the Longtan Tunnel of the Chuxiong 8th Water Diversion Project in Central Yunnan and the upstream section of the Longtan Tunnel No. 3 branch were successfully connected, marking a major breakthrough in the construction of the Chuxiong 8th Water Diversion Project in Central Yunnan and laying a solid foundation for subsequent construction. .

The total length of the main downstream section of Longtan Tunnel No. 2 is 3,672 meters, and the deepest tunnel burial depth is more than 330 meters. The tunnel passes through “Middle Yunnan Red Bed” muddy rock interspersed with sandstone. Soft rock and fault zones account for 61%, and it crosses multiple faults. Zone, the surrounding rock is broken, and the surrounding rock conditions are generally poor. During the construction process, Class IV and V surrounding rock accounted for 70%. The overall surrounding rock is easily weathered and easily dissolved when exposed to water, and there is high external water pressure. During the construction process, there are There are risks such as sudden mud and water intrusion and large deformation of soft rock. Construction is difficult and safety risks are high. Moreover, Longtan Tunnel No. 2 Branch is a long-distance, steep-slope inclined shaft, making it difficult to remove slag and causing high safety risks.

In order to ensure construction safety and ensure construction quality, the project department of China Railway No. 8 Bureau scientifically formulated construction plans and continuously strengthened construction organization. In order to improve efficiency and speed up the construction progress, the project department continuously improved the process and construction methods, vigorously carried out labor competitions, and set off a rush to work on the construction site. At the same time, it arranged party members and leading cadres and construction technical backbones to perform 24-hour follow-up operations, and combined advanced horizontal drilling and advanced geology Forecast results, monitor construction safety and quality in real time, and be “well-prepared and foolproof”. Through the joint efforts of all construction personnel, the construction cycle time of the downstream main tunnel of the No. 2 branch of Longtan Tunnel was successfully shortened from 36 hours to 25 hours. In addition, the project department attaches great importance to technological innovation, and has compiled “A Rollover Unloading System and Unloading Method”, “A Device for Processing and Forming of Concrete Transport Chute for Large-Slope Inclined Shafts”, and “An Inclined Shaft Concrete Transportation System” , “Incline Shaft Unloading System” and many other scientific research achievements have obtained national utility model patents.

After the main tunnel section is connected, it will bring great convenience to the lining concrete construction of the main tunnel section of the inclined shaft No. 2 of the Longtan Tunnel, further reduce the construction difficulty of the main tunnel section of the inclined shaft, improve construction efficiency, and reduce construction safety risks.

It is reported that the Central Yunnan Water Diversion Project ranks first among the top ten landmark water conservancy projects in the country’s “13th Five-Year Plan” and is currently the largest and most heavily invested water resources allocation project in southwest my country. The main water source draws water from the Shigu River section of the Jinsha River, and receives water from Lijiang, Dali, Chuxiong, Kunming, Yuxi and Honghe along the way. The total length of the line is 664 kilometers. After the project is completed, it will alleviate the problems of urban production and living water in central Yunnan, improve the ecological and water environment conditions of rivers and lakes in the region, benefit 35 counties (cities, districts) in 6 states (cities) along the route, and benefit a land area of ​​36,900 square kilometers. , benefiting more than 11 million people. (Reporter Li Yingqing/Gao Zhan, China Daily Yunnan Reporter Station)

[Editor in charge: Xu Dan]