The thinnest and intelligent management in the world ...... This big country is full of Chinese wisdom!
Science and Technology Daily reporter Tang Ting
"On May 26, the first batch of units of Wudongde Hydropower Station started trial operation. This is another important progress in the construction of Wudongde Hydropower Station after the entire line of the main dam project was poured to the top. This also means that it is 7 years away from the plan. The goal of generating electricity from the first batch of units in July was a step closer. "Yang Zongli, director of the Three Gorges Group Udongde Engineering and Construction Department (hereinafter referred to as Udongde Construction Department), introduced that the dam of Udongde Hydropower Station is currently the thinnest 300m class in the world The ultra-high arch dam is also the world's first ultra-high arch dam using low-heat cement concrete.
With a flick of a finger, the project builders including Yang Zongli were not afraid of hardship and innovation, and witnessed the glorious moments in the construction of Wudongde Hydropower Station.
Lei Mingshan, Chairman and Secretary of the Party Group of China Three Gorges Group, stated that during the construction of Wudongde Hydropower Station, "Lei Mingshan, Chairman and Secretary of the Party Group of China Three Gorges Group, has carried out a series of technological and management innovations in the construction of Wudongde Hydropower Station, The world-class problems have improved the development level of hydropower technology in China and the world in underground engineering, dam engineering technology, equipment manufacturing, etc., and demonstrated the 'Chinese wisdom' of intelligent construction of large-scale hydropower projects worldwide. "
The thinnest arch dam "strong and healthy"
Wudongde Hydropower Station is the first cascade of the four cascade hydropower stations planned for the lower reaches of the Jinsha River. From Xiangjiaba and Xiluodu to Baihetan and Udongde, the river valley is narrower, the mountains on both sides are higher and higher, and the geological structure is more complicated.
Accurate survey is the premise of scientific design. As early as the beginning of the survey, the technicians of the Yangtze River Design Institute used remote sensing surveying, drone survey, three-dimensional geological laser scanning and other technologies to understand the situation of each mountain and each rock in detail, and strive to make the geological survey results accurate to the meter level .
The rock wall of nearly 90 degrees is directly inserted into the bottom of the river, the height of the slope on both sides of the bank is nearly 1800 meters, and the basic seismic intensity of the dam site is high ... The challenges facing dam construction are self-evident. "Unlike the Three Gorges, Xiangjiaba, etc., the natural slope is high and steep, the geological structure is complex, and the lithology of the layered strata changes greatly, which is a prominent difficulty in the design and construction of Wudongde Hydropower Station." Wudongde Hydropower Station Survey and Design Project Chief Engineer Weng Yonghong introduced.
The natural slope is high and steep, which means that the shallow surface mountains and slopes are at risk of collapsing at any time. Rocks in the dam site area include limestone, dolomite, marble and other types. To ensure the safety of design and construction and the stability of the dam structure, dam builders are looking for answers in innovation.
According to reports, the project design team for the first time adopted a new design method of "static design, dynamic adjustment" to create a "slim" and "sturdy" body shape for the dam of Wudongde Hydropower Station. As an ultra-high arch dam, the top of the dam crest of the Udongde Hydropower Station is 988 meters above sea level, the maximum dam height is 270 meters, the upstream arc length of the dam crest is 326.95 meters, and the thickness-to-height ratio is only 0.19, which is the thinnest 300 in the world Meter-level double-curved arch dam.
"Static design, dynamic adjustment" refers to the initial selection of body shape according to static conditions, and then the body shape is optimized according to the dynamic conditions to improve the seismic safety of the arch dam. Weng Yonghong introduced that practice has proved that through dynamic adjustment of body shape, the concrete volume of the dam construction of Wudongde Hydropower Station increased by only 3.1%, and under different working conditions, the maximum stress of the dam decreased by 32%.
Not only does it have a "slim" shape, but the dam of Wudongde Hydropower Station also adopted an innovative design without diversion bottom holes for the first time. The diversion bottom hole in the dam body to divert the river water is a traditional way in dam construction. The dam body of hydropower stations such as Ertan, Xiluodu and Xiaowan are all equipped with diversion bottom holes.
At the Wudongde Hydropower Station, through the technological innovation and joint demonstrations of many units such as the Yangtze River Design Institute and the Three Gorges Group, this normal has been changed, and the technical scheme of converting the diversion tunnel into a radial gate control outlet was creatively adopted. .
In the opinion of Liu Ke, deputy director of the Technical Department of the Ministry of Construction of Udongde, this program has achieved more than one benefit. While shortening the straight-line construction period, it is convenient for dam pouring and construction quality control. At the same time, it also simplifies the dam body structure and improves the dam body stress conditions.
Strive for the "perfect seamless" of the dam body
Not only is it the world's thinnest 300-meter-level ultra-high arch dam, but the Udongde Hydropower Station dam is also the world's first ultra-high arch dam that uses low-heat cement concrete. While pursuing design innovation, Wudongde Hydropower Station also took the lead in the application of new materials and technologies during construction.
Arch dam concrete generates a lot of heat in the process of pouring and hardening. Due to the large volume of concrete, the degree of thermal expansion and contraction is different between the inside and outside, and it is easy to form temperature cracks. How to ensure that the temperature after concrete pouring is within the design requirements to prevent cracks from occurring has always been a world-class problem faced by the construction of extra-high arch dams.
The dam of Wudongde Hydropower Station is a concrete double-curved arch dam, which is divided into 15 dam sections for pouring. The total amount of concrete pouring is about 2.7 million cubic meters. "Because it is located in the dry and hot valley of the Jinsha River, the climate is hot and rainy, the temperature difference between day and night is large, the wind is frequent in the construction area, and the temperature control and crack prevention of large-volume concrete is even more difficult." .
To solve the problem, the material is one of the keys. On March 16, 2017, as the first tank of grayish-grey concrete poured out from the cable crane hoisting tank and fell on the first storage surface of the No. 8 dam section, the dam project of Wudongde Hydropower Station was fully converted from foundation excavation Enter the main concrete pouring stage.
Don't underestimate the concrete, the cement used in it is low-heat cement. Unlike ordinary cement or medium-heat cement, low-heat cement has a low calorific value, can significantly reduce the maximum temperature of concrete, reduce the temperature stress of concrete, and help prevent dam temperature cracks from occurring.
"Low-heat cement is also known as dam 'fever medicine'. As early as during the construction of the Three Gorges Project, the Three Gorges Group began low-heat cement research. Through continuous testing and improvement, the first dam application on the dam of Wudongde Hydropower Station was realized for the first time. It is a pioneering work in the history of world dam construction. "Yang Zongli said.
Dam has "stronger brain"
Compared with the gravity dam represented by the Three Gorges Dam, the structure and stress conditions of arch dams, especially high arch dams, are more complicated. During the entire construction process, the stress status and self-stress of the dam body are constantly being adjusted. Therefore, the ultra-high arch dam is also considered to be the most complex building in the hydraulic world.
In order to realize the real-time perception of the dam condition, the dam builders turned their attention to the application of intelligent technology. In the construction of Xiluodu Hydropower Station, technicians conducted research and application of key technologies for the intelligent construction of 300-meter super-high arch dams, and developed an intelligent arch dam construction and operation information platform (iDam) to effectively support on-site production management.
If Xiluodu Hydropower Station opened the 1.0 era of intelligent large-scale hydropower, the Udongde Hydropower Station under construction is further moving towards the era of intelligent hydropower 2.0. According to reports, the iDam2.0 system explored and constructed by Wudongde Hydropower Station, with the help of big data, Internet of Things, cloud computing and other technologies, establishes a shared, collaborative and interactive intelligent dam business management platform that can sense basic data in real time and carry out real Analysis, and finally achieve intelligent temperature control, intelligent grouting, intelligent spray, etc.
"Technicians can understand its 'headache and brain fever' at any time through the iDam2.0 system, and make dynamic adjustments in time to keep the dam in a healthy state," said Qiao Yu, an engineer at the Udongde Construction Department.
Taking the hydropower engineering machine vision intelligent construction project as an example, by introducing non-contact infrared thermal imaging temperature measurement equipment in the construction of hydropower projects, relevant technical personnel have developed binocular heavy monitoring that combines visible light and infrared lenses in concrete construction PTZ, build a model of the concrete surface temperature, outlet temperature, and pouring temperature, which can perform real-time, online, continuous, high-precision monitoring and fast and accurate measurement of the temperature, pouring temperature, and surface temperature of the dam concrete outlet, and With over-temperature warning and forecasting function.
Memorabilia of Wudongde Hydropower Station
The Wudongde Hydropower Station, located on the main stream of the Jinsha River at the junction of Luquan County in Yunnan and Huidong County in Sichuan, is another 10 million-kilowatt-level hydropower station built after the Three Gorges Project and Xiluodu Hydropower Station.
The main project is fully started
On December 16, 2015, the Executive Meeting of the State Council decided to approve the Jinsha River Wudongde Hydropower Project.
On December 24, 2015, the Three Gorges Group held a construction mobilization meeting at the site of Wudongde Hydropower Station, marking the full start of construction of the main project in Wudongde. So far, after more than 10 years of scientific research, survey, design and preparation, Wudongde Hydropower Station project has entered the construction period of the main project.
The total installed capacity of Wudongde Hydropower Station is 10.2 million kilowatts, and the total project dynamic investment is about 100 billion yuan. After the completion of the power station, the average annual power generation is 38.91 billion kwh, and the average annual standard coal consumption can be reduced by more than 12.2 million tons, and carbon dioxide emissions by more than 30.5 million tons.
Complete some key nodes
In July 2016, with the filling of the upstream cofferdam to the design elevation of 873 meters, the construction of the dam cofferdam of the Wudongde Hydropower Station was completed, and the goal of cofferdam water blocking was successfully achieved, meeting the requirements of flood control and flood control, and serving as the foundation for the dam follow-up Pit excavation and concrete construction have created good conditions.
In December 2016, the foundation pit of the dam was excavated to a design elevation of 718 meters, and the quality of the foundation surface fully met the design requirements. The excavation of the dam foundation was completed as scheduled and is a key node in dam construction.
The unit entered the final assembly stage
In December 2019, the left and right bank underground power stations of Wudongde Hydropower Station successively realized the successful hoisting of the rotor of the first 850,000-kilowatt hydroelectric generating set. The smooth hoisting of the rotor marks that the installation of the left and right bank units has fully entered the final assembly stage.
On May 4, 2020, the concrete of the last warehouse of the No. 7 dam section of Wudongde Hydropower Station was completed, and the main project of the dam was poured to the top. After pouring the whole line to the top, the dam entered the finishing stage of surface hole metal structure installation and surface hole beam construction.
At present, all 5 diversion tunnels of Wudongde Hydropower Station have been closed and the closure construction has been completed. The reservoir is steadily storing water, and another high gorge Pinghu is ready to come out. On May 26, the first batch of units of Wudongde Hydropower Station started trial operation. According to plan, the first batch of generating units will be put into operation in July this year.