The Yellow River and the Yangtze River "shake hands" here after crossing the Qinling Mountains for nearly 100 kilometers

February 22, 2022 11:20

With TBM (Tunnel Boring Machine) cutterhead

Breaking out of the rock

The Qinling Water Diversion Tunnel for the Han-Wei Diversion Project

Achieve full line connection

Photo by Xinhua News Agency reporter Zhang Bowen

The Qinling Water Conveyance Tunnel is the largest water conservancy project in human history.

The first project to cross the Qinling Mountains from the bottom

Water Resources in the Han River Basin in Southern Shaanxi

It will be introduced into Guanzhong area through Qinling Tunnel

It is the Shaanxi version of "Water Diversion from South to North"

Image source: CCTV News Client

How difficult is the Qinling water diversion tunnel?

The Qinling Water Diversion Tunnel is a key controlling project of the Han-Wei Water Diversion Project, and it is also the first attempt by humans to cross the Qinling Mountains from the bottom.

The tunnel is 98.3 kilometers long, with a maximum burial depth of 2012 meters, a designed flow rate of 70 cubic meters per second, and a longitudinal slope of 1/2500. The Qinling Water Conveyance Tunnel passes through an area with extremely complex geological conditions, with temperatures exceeding 40°C all year round, relative humidity as high as 90%, and various geological disasters occurring in combination. Many academicians and experts have commented that the "comprehensive construction difficulty is rare in the world."

Image source: CCTV News Client

Due to the limitations of geological and topographical conditions, the Qinling water diversion tunnel was constructed by a combination of drilling and blasting and tunnel boring machines (TBMs), of which 63.3 kilometers were constructed by drilling and blasting and 35 kilometers by TBM. In particular, the TBM construction section encountered geological disasters such as strong rock bursts, super strong rock bursts, fault collapses, sudden water gushing, high temperature and humidity, and harmful gases. According to statistics, there have been more than 4,000 rock bursts, including more than 3,000 of medium grade or above, with the largest magnitude of 1.6.

In order to solve the ventilation problem of the ultra-long Qinling water diversion tunnel, the Han-Wei Water Diversion Project has established a complete new set of construction ventilation technology for ultra-long tunnels using the TBM and drilling and blasting methods, setting world records of 7.2 kilometers for ventilation distance of drilling and blasting trackless transportation construction and 16.5 kilometers for TBM single-headed excavation construction.

How important is it to divert water from Han River to Wei River?

Shaanxi has a shortage of water resources and uneven distribution. Water shortage is a major bottleneck restricting the economic and social development of Guanzhong and northern Shaanxi. Therefore, Shaanxi launched the South-to-North Water Diversion Project in the province - the Han River to Wei River Diversion Project. This is one of the major water conservancy projects in my country's "13th Five-Year Plan". The project spans the two major river basins of the Yellow River and the Yangtze River, with an average annual water diversion scale of 1.5 billion cubic meters. After the completion of the project, the water of the Han River will be transferred to the Guanzhong area of ​​Shaanxi through the Qinling water diversion tunnel to meet the water needs of cities such as Xi'an and Xianyang and areas along the route.

"The Han-Wei Water Diversion Project will solve the contradiction between water supply and demand in Guanzhong, improve the water ecological environment quality in the Weihe River basin, and provide strong 'water power' for the economic and social development of the Guanzhong urban agglomeration." Wei Wenzhu, director of the Provincial Water Resources Department, said that in addition, through water rights replacement, the northern Shaanxi region can obtain more water use indicators in the Yellow River and provide water resources guarantee for the construction of the northern Shaanxi national energy and chemical base.

Line design to avoid protection areas

Changing construction plans for ecological protection

The Han-Wei River Diversion Project passes through many national and provincial nature reserves, including Crested Ibis, Tianhua Mountain, Zhouzhi, and Heihe. The project has many points, a wide area, and rich regional biological resources, making construction and environmental protection management extremely difficult. Doing our best to protect the ecological environment of the Qinling Mountains and building an ecological civilization project that can stand the test of time has become an important issue throughout the Han-Wei River Diversion Project.

Sun Ping'an, former chief engineer of the Shaanxi Provincial Water Resources Department, who participated in and presided over the planning and design of the Han-Wei Diversion Project, said that the nearly 100-kilometer water supply line was selected from nearly 10 lines inspected by the expert group that year. In addition to comprehensively considering factors such as economy and maximizing utilization, the planning and design put the ecological protection of the Qinling Mountains first.

In order to avoid the animal's activity range as much as possible, the design team also made partial reroutes and optimizations to the route.

Li Lingzhi, chief designer of the Han-Wei Water Diversion Tunnel of China Railway First Survey and Design Institute Group Co., Ltd., told reporters: "At the beginning of the scheme research, in order to meet the construction needs, we first adopted a 1,500-meter-deep vertical shaft scheme for Lingnan. After a detailed investigation, the construction area of ​​the entrance of this vertical shaft is relatively close to the wildlife habitat. In order to avoid the habitat and reduce the impact on animals, we finally adopted the No. 4 inclined shaft scheme. The No. 4 inclined shaft is 5,800 meters long, and the investment is greatly increased compared to the 1,500-meter vertical shaft, but the impact on wildlife is minimized."

Wastewater recycling

Environmental protection first, water use second

The Han-Wei Diversion Project implements the concept of "saving water first, then transferring water, treating pollution first, then allowing water to flow, and protecting the environment first, then using water". In order to harmlessly treat the "drainage" generated by tunnel construction, the project built a large-scale water quality "purifier" combining "sedimentation tank + filtration tank + activated carbon" at the branch tunnel entrance.

In addition, the Han-Wei Diversion Project uses an advanced DH wastewater recycling system, and the sand and gravel processing system has achieved "zero emissions". Through transformation, the landslide body has been transformed into a water conservation demonstration area, and a series of innovative environmental management models and efficient and innovative measures such as waste slag backfilling "land creation", "Sky Eye" environmental monitoring, and "Crowned Ibis UAV" surprise inspections have effectively reduced the impact of water conservancy development on the ecological environment.

The Jade Belt passes through the Qinling Mountains, and the clear water moistens Guanzhong. The Han-Wei River Diversion Project is like a ribbon, crossing the Qinling Mountains to connect the Yangtze River and the Yellow River. It is an important part of the national water network construction and an important supplement to the national South-to-North Water Diversion Project. This is the largest water conservancy project in Shaanxi in history, and a significant contribution to the history of water management by the Qin people.

"The Han-Wei Water Diversion Project will be a project that will leave a legacy to the world and can be compared with water conservancy projects such as the Dujiangyan Irrigation System and the Zhengguo Canal that have benefited generations to come." Wang Hao, an academician of the Chinese Academy of Engineering, said that the project has added an important connecting channel between the Yangtze River Basin and the Yellow River Basin, crossing the geographical dividing line between north and south China. It is an important part of the national water network construction and an important supplement to the national South-to-North Water Diversion Project. It plays a supporting and guaranteeing role in promoting ecological protection and high-quality development in the Yellow River Basin.

Comprehensive sources: Xinhuanet, CCTV News, Xi'an News, West China Network, etc.