By Ashley Karen
CREC Yongning, the first domestically developed large-diameter and large-inclination inclined shaft TBM by China Railway Engineering Equipment Group, a subsidiary of China Railway Hi-Tech Industry, finished its excavation task on December 14th, with the final rock block of the No.1 diversion inclined shaft of Luoning Pumped Storage Power Station hitting the ground.
This hit marks a noteworthy milestone in the successful application of TBM technology in the pumped storage industry in China and fills the technical gap in TBM inclined shaft construction in China.
Henan Luoning Pumped Storage Power Station is the most considerable pumped storage power station under construction in central China, with a total installed capacity of 1.4 million kilowatts. The project started the task of optimizing the upper inclined shaft, the middle adit, and the lower inclined shaft into a primary one and created a new mode for the pumped storage power stations construction in China.
The CREC Yongning tunnel boring machine is responsible for the No.1 diversion inclined shaft construction, with a total length of 927 meters, a dip angle of 36.236 degrees, and a buried depth of 184-684 meters. Mainly, it is composed of moderately weathered fresh porphyritic granite and passes through two fault fracture zones, which are challenging to build.
To secure the project excavation, the technical service team of China Railway Engineering Equipment Group has designed new technologies such as variable angle inclined shaft starting and split assembly excavation to adapt to difficult working conditions, overwhelm many situations such as large inclination anti-slip car, material transportation and so on, and the excavation speed has been constantly enhanced, from the initial daily footage of 3-5 meters to the daily footage of 8-10 meters, and then to the daily footage of 16 meters. It has laid a solid foundation for the smooth implementation of the project.
In recent years, the large-scale pumped storage power stations construction in China has entered the fast lane, and the diversion inclined shaft is the pivotal part of the power station, which is a construction difficulty as well.
The traditional drilling and blasting method has low construction efficiency, and it is difficult to cope with the complicated super-large inclination environment, and the safety risk is high. The successful completion of the No.1 diversion inclined shaft TBM of Luoning Pumped Storage Power Station has collected valuable experience for the pumped storage power stations construction in China and has a demonstration effect on upgrading the high-quality development of pumped storage power stations in China and discovering technological autonomy and controllability.
