On March 12, the pilot shaft of the surge well of the Lake Tana HPP in Nepal, which was designed by the company affiliated Chengdu Research Institute and undertaken by the 11th Bureau of Hydropower, was successfully completed, marking the shift in the excavation of the surge well from the construction of the pilot shaft to the expansion of the wellbore.

The impedance-type water diversion surge chamber of the Tana Lake HPP adopts an underground buried layout. The shaft body consists of two parts: the shaft and the vertical shaft. The diameter of the shaft after the initial support is about 25 meters, and the design depth is 68.9 meters. meters, the design depth is 17.43 meters, the total design depth of the shaft is 86.33 meters, and the design excavation volume is about 40,000 cubic meters. As the slag discharge channel for wellbore expansion, the pilot well plays a key role in the excavation of the surge well.

In order to ensure the scheduled breakthrough of the pilot well, the Chengdu Research Institute and the Project Department of the 11th Bureau of Hydropower have carefully studied and carried out early warning of geological risks. In the weak and broken surrounding rock zone in the middle of the well depth, measures such as backfilling and grouting have been adopted to solve the problem of pilot wells under unfavorable geological conditions. During the construction, there were problems such as slag failure and hole collapse in the hole, and the pilot well penetration operation was completed ahead of schedule.

The power station hub project consists of a 140-meter-high concrete gravity dam, diversion tunnel, surge shaft, pressure steel pipe, underground powerhouse, tailwater tunnel and tailwater outlet, with an installed capacity of 140.25 MW. The project is in the peak period of construction, and the concrete pouring of the underground powerhouse, the grouting of the tailrace tunnel, the excavation of the water diversion tunnel and the surge shaft are carried out. After the completion of the power station, it will effectively increase the total capacity of power generation equipment throughout Nepal, and greatly alleviate the power supply shortage in the western mountainous area of Nepal and the famous tourist city of Pokhara. At the same time, the construction of the project has also promoted local employment, providing more than 1,500 jobs for local people.