Recently, the slipform lining of the diversion vertical shaft at the Zhaoqing Langjiang Pumped Storage Power Station in Guangdong, in which Sinohydro Bureau 4 Co., Ltd. participated in construction, completed concrete pouring, marking an important achievement for China's first application of 500-meter-class large-diameter ultra-deep vertical shaft construction technology in the hydropower sector.

The Zhaoqing Langjiang Pumped Storage Power Station in Guangdong is the first variable-speed pumped storage power station in the Guangdong-Hong Kong-Macao Greater Bay Area and a key energy project of the national 14th Five-Year Plan. The station involves a total investment of about 8.67 billion yuan and has a total installed capacity of 1.2 million kilowatts (four 300,000-kilowatt units, one of which is a variable-speed unit independently developed by China). Once completed, the station will become a "super power bank" for the new-type power system of the Greater Bay Area, significantly enhancing the grid's peak-shaving and valley-filling capabilities, renewable energy accommodation, and safe and stable operation.

According to reports, the station's diversion system adopts an innovative design that coaxially combines the surge shaft and the diversion vertical shaft, turning the traditional two shafts of "surge shaft + vertical shaft" into a single coaxial deep shaft, forming an ultra-deep shaft with a total depth of 536 meters and a maximum diameter of 15.9 meters, equivalent to the height of a 180-story building. It is the deepest large-diameter vertical shaft among hydropower projects built or under construction in China.

The shaft lies in ultra-hard rock strata, with rock compressive strength reaching up to more than 200 megapascals, equivalent to a pressure of nearly 20,000 tonnes on one square meter. The completion of this highly difficult construction fills a gap in China's construction of ultra-deep vertical shafts of comparable scale.

Faced with complex conditions such as high in-situ stress and abundant groundwater during the ultra-deep shaft excavation stage, the construction team pioneered a "combined raise-and-sink shaft method" excavation technology, integrating the mining industry's "rapid raise shaft method" with the pilot-hole process of a raise boring machine. This achieved a single-cycle blasting excavation advance of 5 meters, an excavation-and-support cycle time of 17 hours, and a monthly excavation advance of 124.4 meters, improving overall efficiency by more than 60 percent compared with traditional hand-held pneumatic drill construction.

In addition, in response to high-difficulty challenges such as the difficulty of vertically conveying lining concrete over 500 meters, strict crack prevention requirements for high-strength concrete, and the high risk of stability control for the slipform system in a narrow deep shaft, the construction team efficiently coordinated a specially made hydraulic slipform system dedicated to ultra-deep vertical shafts with a mining shaft hoisting system, achieving efficient and continuous lining and greatly improving the integrity of the shaft's concrete structure.