The Zhejiang Jingning Pumped Storage Power Station is located in Shawan Town and Wutong Township, Jingning She Autonomous County, Lishui City, Zhejiang Province. It is a key energy project under the national 14th Five-Year Plan and the largest single project in Jingning's history. With a total investment of approximately 9.2 billion yuan and a total installed capacity of 1,400 MW (4×350 MW), it is designed to generate 1.4 billion kWh of electricity annually and to consume 1.867 billion kWh of pumped-storage electricity per year.

It is understood that the project features high water head, high slopes, complex geological conditions and high seismic fortification requirements, and the construction of its underground cavern group faces the challenges of high rock hardness and strict excavation precision requirements. The core process of raise boring machine shaft construction is to drill a pilot hole downward from the top, continuously removing cuttings and cooling, until it penetrates the lower tunnel; then reaming is carried out in reverse, with a reaming bit of the same diameter as the shaft installed below to break the rock from bottom to top, and the rock cuttings fall by their own weight to the lower level for removal.

3D animation demonstration of large-diameter raise boring machine shaft construction

Faced with high water head, high slopes, complex geology and high seismic fortification requirements, the construction of the underground cavern group of this pumped storage power station is constrained by high rock hardness and strict excavation precision. Its powerhouse exhaust shaft has a depth of 319.7 meters and a circular cross-section diameter of 7 meters, and was ultimately formed in a single reverse reaming pass by a custom-built 7-meter-class ultra-large-diameter raise boring machine from China Railway Engineering Equipment Group. This equipment is dedicated to large-diameter ultra-deep shafts and was put into use in China for the first time.

The core significance of large-diameter raise boring machine construction lies in breaking through the technical bottlenecks of traditional shaft construction and providing more efficient and safer solutions for ultra-large-diameter and ultra-deep shaft projects under complex conditions.It overcomes the limitations of traditional drill-and-blast construction and achieves "one-pass forming" of large-diameter, ultra-deep shafts, greatly improving construction precision and quality.