On January 31, 2024, the Baihetan Engineering Construction Department of the Three Gorges Construction Engineering Co., Ltd., a subsidiary of the Three Gorges Corporation, officially handed over the Baihetan Hydropower Station dam to the Baihetan Power Plant of the Yangtze River Electric Power Plant, a subsidiary of the Three Gorges Corporation, to take over the operation. The completion of the handover of this dam project, which ranks second in the world after the Three Gorges Project, means that the Baihetan Hydropower Station project has fully entered the operation period from the construction period and will usher in a new stage of formal operation.
The dam is the core building of the hydropower hub project, which undertakes the task of retaining water and discharging floodwater, and its quality and safety directly determine the life of the hub project. The Baihetan Hydropower Station Dam is a 300-meter-level concrete double-curved arch dam, which began to be poured in the first warehouse on April 12, 2017, and was poured to the top on May 31, 2021, lasting 1,511 days and nights.
- In 2017, the Baihetan Hydropower Station project was completed to intercept the flow of the river
- On April 12, 2017, the first warehouse of the Baihetan Hydropower Station dam was concreted
- On August 4, 2018, the first section of the Baihetan Hydropower Station dam was poured over 100 meters
- On April 1, 2019, the Baihetan Hydropower Station dam borehole coring quality inspection, and the world's longest normal concrete core sample was taken out
- On October 15, 2019, the first flood discharge deep hole of the Baihetan Hydropower Station Dam was successfully poured to the top, successfully achieving the goal of passing through the deep hole in 100 days
- On December 31, 2019, the Baihetan Hydropower Station Project exceeded 2.7 million cubic meters of concrete poured for the dam throughout the year, setting a world record
- On June 6, 2020, the foundation pit of the Baihetan Hydropower Station dam was flooded, and the dam had the conditions to hold back the flood
- On September 15, 2020, the diversion bottom hole of the Baihetan Hydropower Station dam overflowed
- On November 26, 2020, the first batch of dam sections of the Baihetan Hydropower Station dam was poured to the top
- On April 6, 2021, the diversion bottom hole of the Baihetan Hydropower Station Dam was lowered, and the Baihetan Hydropower Station project began to store water
- On May 1, 2021, the flood discharge deep hole of the Baihetan Hydropower Station Dam began to overflow
- On May 31, 2021, the dam of Baihetan Hydropower Station was poured to the top
The problem of temperature control and crack prevention of large-volume concrete has always been a worldwide problem, and the industry says that "no dam does not crack", but in Baihetan Hydropower Station, there is not a single crack on the dam, "this is a miracle of dam construction!"
In the process of dam construction, a series of world-class problems such as columnar jointed basalt and safe and efficient operation of cable groups under windy conditions have been overcome, and technological innovations such as the use of low-heat cement and intelligent construction have been carried out to build a seamless and high-quality dam.
In order to check the concrete construction quality of the dam, the whole dam was drilled 848 meters, and a total of 6 long cores of more than 20 meters were taken out, and at the top of the dam section of the No. 11 dam section, through 12 pouring silos, 74 pouring billet layers, and 24 layers of cooling water pipes, the world's longest normal concrete core sample with a length of 36.74 meters was taken out. After careful on-site testing, the concrete core sample is complete and beautiful, the surface is smooth and flat, the aggregate is evenly distributed, and the interlayer combination is good.
Earlier, CCTV reported
How does the Baihetan Hydropower Station Dam prevent temperature cracks?
It can be said that it is China and the world
The highest level of crack prevention technology for large-volume concrete
The Baihetan Hydropower Station dam is 289 meters high
It is divided into 31 dam sections
共浇筑混凝土800多万m³
Temperature-controlled crack prevention for bulk concrete
It has always been a problem for the engineering community
In order to get from the source
Ensure that the dam does not have temperature crack problems
The whole dam of Baihetan was used for the first time
A new type of special cement independently developed by the mainland——
Low-heat Portland cement concrete
Conventional dam construction requires pouring a large amount of concrete, and the cement hydration reaction in the concrete generates heat, which causes the temperature of the concrete to rise after pouring, and then slowly cool to ambient temperature. If effective temperature control measures are not taken, cracks will inevitably occur if the concrete is allowed to expand and contract. The temperature of the heat of hydration of low-heat cement concrete is lower than that of medium-heat cement and ordinary cement, and the adiabatic temperature rise is much lower than that of medium-heat cement and ordinary cement. It can greatly reduce the possibility of dam cracks caused by thermal expansion and cold contraction, and low-heat cement has the advantages of good dry shrinkage resistance, erosion resistance, impact resistance and wear resistance, as well as high strength and continuous strength growth in the later stage.
During the construction of the dam
It was jointly developed by the Three Gorges Corporation and Tsinghua University
Intelligent water supply equipment and multi-terminal control system
By sensing the concrete temperature in real time
Dynamic control of water flow
The intelligent and precise control of the concrete temperature process is realized
Since April 12, 2017, the main body of the dam began to be concreted, and it has lasted 1,510 days and nights, and a total of 2,253 warehouses and 8 million square meters of concrete have been poured into the dam body. In the more than 4 years of dam pouring, all parties involved in the construction worked day and night, and the overall balance of the dam continued to rise, and the pouring volume was more than 2 million square meters for three consecutive years, creating a world record of 2.7 million square meters per year, 273,000 square meters per month, and 100 days of deep holes.
The new special cement prevents temperature cracks in the dam
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CCTV reporter Zhang Wei: At the Baihetan construction site, high temperatures above 35 degrees Celsius are the norm. We calculated that it would take about 7 minutes for the concrete poured from the Baihetan Dam to come out of the mixing building, drive to the feeding platform by dump truck, and then transport the concrete to the pouring site of the dam by cable car, and the temperature of the concrete arriving at the site will not exceed 8 degrees Celsius in the changing environment and hot weather.
Xu Yinlin, Chairman of China Water Resources and Hydropower Fourth Engineering Bureau Co., Ltd.: First of all, in the operation of the mixing system, we must first pass the fruit through one cold and two cold, so as to ensure that the temperature of the fruit is reduced to the required range of temperature, so that the outlet is guaranteed to be 7 degrees. The concrete is introduced into the cable machine tank by means of an insulated truck, and the concrete is quickly put into the warehouse. In the pouring process, we spray and moisturize, and then keep warm immediately during the pouring process so that the temperature does not rise.
During the construction of the dam, the Three Gorges Corporation and Tsinghua University jointly developed a complete set of intelligent water access equipment and a multi-terminal control system, which realized the intelligent and accurate control of the concrete temperature process by sensing the concrete temperature in real time and dynamically controlling the water flow.
Zhang Jianqing, Director of Baihetan Construction Bureau of China Hydropower Eighth Bureau: This is our intelligent temperature control system, which reflects the temperature of the warehouse surface and the temperature of the cooling water pipe to our background platform in a timely manner, and then adjusts the water temperature and water flow through the pre-set temperature control strategy to ensure that the maximum temperature and cooling speed inside the concrete are completely in accordance with the set target, so that the score is exactly right.
The quality of the dam project has been fully affirmed and highly praised by the National Energy Administration and the quality expert group for many times. According to the safety appraisal opinion on the completion of the hub project, "the quality of the project is excellent, the operation of the main buildings, mechanical and electrical and metal structure equipment is safe, the project has achieved the scheduled power generation, flood control and other goals, and the hub project has safe operation conditions". According to the special acceptance quality supervision opinion of the completion of the hub project, the construction process of the project is controlled, the quality of the project entity is excellent, and the design and specification requirements are met.
The Baihetan Hydropower Station was opened on April 6, 2021 to store water, and was fully put into operation on December 20, 2022. The dam has been tested in three flood seasons, the reservoir has been impounded to the normal water storage level twice, and the operating indicators such as temperature stress, deformation and displacement, seepage and pressure of the dam body are better than the design level, and the working condition is good. Next, the Baihetan Engineering Construction Department will be cautious from the beginning to the end, do a solid job in the contract acceptance, and lay a solid foundation for the special acceptance of the hub project in the completion stage.