On July 31, the dam filling work for the upper reservoir of the Yunyang Jianquan Pumped Storage Power Station, constructed by Sinohydro Bureau 5 Co., Ltd., was successfully completed, achieving the major milestone goal of upper reservoir construction on schedule and sounding the "charge bugle" for subsequent concrete face slab construction and power station impoundment.

The upper reservoir dam of the Yunyang project adopts a concrete face rockfill dam, with a crest elevation of 685 meters, a dam height of 99 meters (at the plinth), a crest length of 382.5 meters, a crest width of 10 meters, and a total filling volume of approximately 3.54 million cubic meters.

Since the start of dam filling construction, the project department has successively overcome a series of difficulties, including tight land acquisition and delivery timelines, unstable material source supply, transportation layout, and a tight construction schedule. It organized multiple dam scheme discussion meetings and special technical briefings. In light of the valley terrain and dam structure characteristics, the construction area was divided into several independent work units, with construction tasks and progress requirements clearly defined for each unit and construction organized separately, thereby improving construction efficiency while ensuring dam construction quality. In the face of crisscrossing rock fissures in the borrow area, fragmented structure, poor stability of dam material particle size supply, complex and changeable construction area environment, limited layout of construction equipment, and frequent interference from cross operations, collaborative work faced enormous challenges. The project team established a "material source identification and tracking" mechanism covering the entire extraction process, focusing mainly on refined blasting control, three-dimensional excavation and support construction organization, and precise supply of dam materials. This achieved dynamic optimization of blasting parameters and adopted a "spatiotemporal replacement" strategy to realize collaborative extraction across multiple work faces. Through this mechanism, extraction paths were adjusted based on real-time monitoring data to avoid unfavorable rock strata and reduce secondary weathering of stone materials during extraction, successfully breaking through the material source quality bottleneck. In the dam material transportation works, road layout was continuously optimized, and an innovative planning approach combining "permanent and temporary integration" with "open roads + tunnels" was proposed to solve problems such as the intersection and interconnection between dam construction in the narrow V-shaped valley and existing rural roads, ensuring the stability and continuity of transportation routes.

During dam filling, the project also established a "Dam Intelligent Safety Management Center" and successfully put into use an unmanned vibratory roller intelligent compaction system and a digital compaction monitoring system, which calculate key parameters such as compaction passes, travel speed, and excitation force in real time, making the dam compaction process visual and ensuring the precision and quality of dam construction compaction. Using the "three-machine coordinated paving" construction mode (an integrated paving, compaction, and curing machine, a fleet of unmanned bulldozers, and a fleet of unmanned rollers), and connected via the BeiDou satellite system and 5G network, the project achieved precise positioning and efficient collaborative operation, improving construction efficiency. In the face of severe weather, the project promptly activated early warning and emergency systems, seizing opportunities to advance construction on the basis of ensuring safety; established a 24-hour shift duty system to promptly resolve on-site problems; and before rain arrived, pre-paved the transport roads on the downstream pressure slope body with higher-strength rockfill materials to ensure timely resumption of dam filling works after rain.

As a key project in China's 14th Five-Year Plan, the Yunyang Jianquan Pumped Storage Power Station will, once completed, provide 1,200 megawatts of regulating power to the Chongqing and northeastern Chongqing power grids, effectively alleviating the medium- and long-term power capacity and peak-shaving capacity gaps in Chongqing and northeastern Chongqing, and helping to build a clean, low-carbon, safe, and efficient modern energy system.