Kamai ± 400 kV converter station project is located in Mangkang County, Tibet Autonomous Region, invested by the Extra High Voltage Construction Branch of the State Grid Corporation of China, the geomorphology type of the station site belongs to the summit surface of the alpine landforms, the topography is relatively flat, adjacent to the mountain ranges in the south-west and the rest directions are steep slopes sloping to the Jinsha River or the valleys, the elevation is about 3,650 ~ 3,740 meters; the platform is narrow in the north-south direction, the south-west is high, the north-east is low, and the fields are terraced.
The project started on December 1, 2023 and completed on April 25, 2024, with a total of 3,941 rotary bored piles with pile diameter of 600 mm. After third party testing, the pass rate is 100%. As the project is located in ultra-high altitude area, the average altitude of the station site reaches 3,750 m. During the construction process, the lack of oxygen in the plateau leads to the inefficiency of rotary drilling rigs, which affects the construction progress, and it is a very big challenge for the bored piles construction. The project department collected data in the early stage, and after experiments, added monitoring equipment in the rotary drilling rig cartridge, improved the engine, added oxygen to the air intake, which improved the site construction efficiency, and at the same time formed the provincial-level construction method of “High Altitude Rotary Drilling Rig Construction Technique”.
During the construction period of this project, the site safety and civilized construction requirements put forward by the owner were strictly implemented, and the expected occupational safety and environmental management objectives were well achieved to meet the contract requirements. The environmental protection and civilized construction work during the construction has been praised by the supervisor and the owner.
