China Railway No.5 Engineering Group Co., Ltd. Completes Breakthrough of the 25.3 km Haidong Tunnel on the Central Yunnan Water Diversion Project

en.Wedoany.com Reported - On September 8, the Haidong Tunnel of the Central Yunnan Water Diversion Project in Dali, constructed by China Railway No.5 Engineering Group Co., Ltd., was successfully holed through. With a total length of 25.313 kilometers, the Haidong Tunnel is located east of Erhai Lake in Dali Prefecture, Yunnan Province. It is the fifth longest tunnel along the entire Central Yunnan Water Diversion Project and one of the key challenging tunnels in the Dali section of Phase I water conveyance works. By June 25, 2025, the cumulative excavation of the main tunnel of Haidong had reached 24,631 meters, completing 97% of the total length. At that time, the remaining critical section was the main tunnel segment from the downstream of No. 2 adit to the upstream of No. 3 adit. This breakthrough completed the remaining construction of the Haidong Tunnel main tunnel.

The construction section of the Haidong Tunnel traverses 11 fault fracture zones and 1 active fault zone, facing risks such as fractured surrounding rock, water inflow, and deformation during construction. Previous construction data show that the tunnel was equipped with 6 construction adits, including 4 horizontal adits and 2 inclined shafts, with a total adit length of approximately 4.94 kilometers. After China Railway No.5 Engineering Group Co., Ltd. entered the main tunnel construction in November 2019, it adopted measures such as advanced geological prediction, advanced probe holes, deepened blast holes, and adjusted construction techniques according to different surrounding rock conditions to organize excavation. In March 2023, the excavation of the Haidong Tunnel main tunnel exceeded 20,000 meters; in April 2024, it exceeded 23,000 meters; and in June 2025, after the 4,076-meter main tunnel section from the downstream of No. 3 adit to the upstream of No. 4 adit was holed through, the main tunnel excavation progress reached 97%.

The Phase I project of the Central Yunnan Water Diversion consists of a water source project and water conveyance works. According to project data released in 2026 by the Yunnan Provincial Central Yunnan Water Diversion Project Construction Administration Bureau, the main conveyance canal starts from Shigu Town, Yulong County, Lijiang City, and ends at Xinpobei, Honghe, with a total length of 664.236 kilometers. It is divided into six sections: Dali Section I, Dali Section II, Chuxiong Section, Kunming Section, Yuxi Section, and Honghe Section. The Phase I water conveyance works include 58 tunnels with a combined length of 612 kilometers. The water source project includes one pumping station with an installed capacity of 480 megawatts and an average pumping head of 219 meters. The total investment in the Phase I project is 82.576 billion yuan, with construction commencing in October 2018.

By the end of 2025, the water source project of Phase I of the Central Yunnan Water Diversion had fully entered the equipment installation stage, and the water conveyance works had achieved a cumulative breakthrough of 627.9 kilometers, accounting for 94.6% of the total 664 kilometers. The Yunnan Provincial Central Yunnan Water Diversion Project Construction Administration Bureau has designated 2026 as the year for concentrated advancement of both Phase I and Phase II projects, with the Phase I annual plan including 23 kilometers of excavation and 59 kilometers of lining. The project's average annual water diversion volume is 3.403 billion cubic meters, covering water supply areas including Lijiang, Dali, Chuxiong, Kunming, Yuxi, and Honghe.