"The overall difficulty of the Xiaowan Hydropower Station is the world's first," said Yi Kui, chief engineer of Huaneng Xiaowan Hydropower Station, on the opening ceremony of the nationwide hydropower installed 200-kilowatt-hour flagship unit on August 25.
According to Yi Kui, the Xiaowan Hydropower Station has created several of the world's largest hydropower stations. The dam with a height of nearly 300 meters is the largest in the world, with a capacity of 700,000 kilowatt-hours in a single aircraft. It is the world's largest in terms of installation difficulty, and it is the first in the world to build dams. The world's number one in terms of reinforcement difficulty and engineering quantity, Xiaowan Hydropower Station's comprehensive difficulty is the world's first. The research funding for concrete pouring alone amounts to tens of millions. In addition, the earthquake resistance of the dam reached 9 degrees, and the vanadium-containing steel used more than 10,000 tons.
As a challenging world-class project, the construction of the Huaneng Xiaowan Hydropower Station brings together many world problems. Yi Kui said: "The world's first 300-meter-high arch dam built in the area of ​​high seismic intensity, as well as the manufacture and installation of high-capacity, high-head, high-parameter hydro-generating units, are rare in the world's hydropower project construction. The construction field offers many experiences. â€
Design and Construction of 300m High Arch Dam Xiaowan Arch Dam is one of the highest arch dams under construction in the world. It was built in a high-seismic-cracking area, with peak horizontal acceleration of base rock, arch length of the crest, total water thrust, and other data. , ranking first in the world arch dam construction. The layout and body shape of the arch dam are subject to specific geological and topographic conditions, the general layout of the hub, and the stability of the dam foundation. It is difficult for the body shape design to simultaneously meet the stress standards during the construction period, normal operation period and earthquake. For this reason, in addition to the traditional multi-arch beam method, thick shell element method, finite element method, etc. are also introduced to optimize the shape of the arch dam and solve the safety and economic problems of the Xiaowan arch dam's shape design. . Regarding the problem of dam damming in high arch dams that has not yet been covered in the current hydropower construction code, a variety of analytical methods developed at home and abroad have been used to conduct in-depth research from different perspectives and engineering measures have been proposed to solve this problem.
Solved the problem of flood discharge with high head and discharge capacity The discharge flow of the Xiaowan Hydropower Station was the highest at 20,745 cubic meters per second, coupled with a large drop in flood discharge, with a discharge power of up to 46 million kilowatts; the valley in the dam site was narrow, the bank slope was steep, and flood discharge energy was eliminated. The area is located within the abutment resistance rock mass, and the layout of flood discharge energy dissipation facilities is greatly limited. To this end, a large number of numerical analyses and model tests have been carried out around these issues, and flood discharge safety has been ensured by the use of dam-body tables, meso-holes, and flood discharge tunnels at the shore. The flood discharge from the dam body has been vertically and horizontally separated. The principles and methods of body diffusion, air collision energy dissipation, and overall dispersion and slotting achieve the ideal energy dissipation effect.
Successfully excavated the large-scale underground cavern group. The underground diversion power generation system of the Xiaowan Hydropower Station is of large scale. The main and auxiliary workshops, the main transformer room, the tailrace surge chamber and the gate room are arranged in parallel. The main plant is 323 meters long and 30.6 meters wide. The maximum height of 82 meters is like a 30-storey underground palace. There is no pillar in the middle, equivalent to a 1 million cubic meters of underground space. In the construction, a large number of engineering measures were adopted to stabilize the rock caverns of underground caverns. At the same time, the domestic and international trials of the mechatronics hydraulic transition process with model units were first carried out. For such excavation of underground caverns, Huaneng Xiaowan Hydropower Station is the first attempt in China.
Successfully developed and installed a hydroelectric generator set and metal structure for the installation of a high head high capacity hydroelectric generator set metal structure Xiaowan Hydropower Station, with the characteristics of “high, large, and fullâ€, that is, from the perspective of the hydroelectric generating set, the hydraulic turbine operation head High, high unit speed, high operational stability, large stand-alone capacity, large amplitude of head, is the world's largest single unit with the largest capacity in the head section of the world. After the model test and study, it was decided to increase the rated head of the turbine and increase the suction height and the rated voltage of the generator, and adopt the cooling method of the whole air-cooled generator; from the perspective of the metal structure, due to the high dam, high head, large water thrust, head Larger amplitudes and large flood discharges have brought great difficulties in the design, manufacture and installation of metal structures. As far as gates are concerned, there are as many as hundreds, including various types of gates, of various types, and the size of many gates is the largest among similar gates. In particular, the structure of large orifices, high head gates, earthquake resistance, sealing of water seals, hydraulics for doorways, anti-cavitation, and support for heavily loaded sprocket gates are among the world's best.
The selection of high-strength concrete and large-area concrete temperature control and crack prevention new method arch dam concrete raw material selection and temperature control problems of concrete placement is one of the key technical problems of the Xiaowan Project. In particular, the length of the largest concrete pouring block in the lower middle of the arch dam is more than 90 meters, and the temperature control and crack prevention is very difficult, and many process specifications exceed the existing standards. Through in-depth and meticulous experimental research on concrete raw materials, the optimal mix ratio was optimized; a series of concrete temperature control standards were proposed and formulated to ensure that the dam concrete reached high strength, high ultimate tensile value, bullet bomb, low heat, no The overall specification of shrinkage performance.
Successfully solved the problem of the stability of a 700-meter complex high slope. The Huaneng Xiaowan Hydropower Station artificially handles the high slope, the difference in slope stability conditions, and the difficulty of technical treatment. It is rare in hydropower construction at home and abroad and even in other industries. At present, the governance of high slopes at home and abroad is still in the exploratory stage. There is no consensus on the analysis theory, calculation methods, and associated safety and control indicators. In the absence of strong operability rules and regulations, The successful practice of Huaneng Xiaowan Hydropower Station has also played a pioneering role in many aspects.
According to Yi Kui, the Xiaowan Hydropower Station has created several of the world's largest hydropower stations. The dam with a height of nearly 300 meters is the largest in the world, with a capacity of 700,000 kilowatt-hours in a single aircraft. It is the world's largest in terms of installation difficulty, and it is the first in the world to build dams. The world's number one in terms of reinforcement difficulty and engineering quantity, Xiaowan Hydropower Station's comprehensive difficulty is the world's first. The research funding for concrete pouring alone amounts to tens of millions. In addition, the earthquake resistance of the dam reached 9 degrees, and the vanadium-containing steel used more than 10,000 tons.
As a challenging world-class project, the construction of the Huaneng Xiaowan Hydropower Station brings together many world problems. Yi Kui said: "The world's first 300-meter-high arch dam built in the area of ​​high seismic intensity, as well as the manufacture and installation of high-capacity, high-head, high-parameter hydro-generating units, are rare in the world's hydropower project construction. The construction field offers many experiences. â€
Design and Construction of 300m High Arch Dam Xiaowan Arch Dam is one of the highest arch dams under construction in the world. It was built in a high-seismic-cracking area, with peak horizontal acceleration of base rock, arch length of the crest, total water thrust, and other data. , ranking first in the world arch dam construction. The layout and body shape of the arch dam are subject to specific geological and topographic conditions, the general layout of the hub, and the stability of the dam foundation. It is difficult for the body shape design to simultaneously meet the stress standards during the construction period, normal operation period and earthquake. For this reason, in addition to the traditional multi-arch beam method, thick shell element method, finite element method, etc. are also introduced to optimize the shape of the arch dam and solve the safety and economic problems of the Xiaowan arch dam's shape design. . Regarding the problem of dam damming in high arch dams that has not yet been covered in the current hydropower construction code, a variety of analytical methods developed at home and abroad have been used to conduct in-depth research from different perspectives and engineering measures have been proposed to solve this problem.
Solved the problem of flood discharge with high head and discharge capacity The discharge flow of the Xiaowan Hydropower Station was the highest at 20,745 cubic meters per second, coupled with a large drop in flood discharge, with a discharge power of up to 46 million kilowatts; the valley in the dam site was narrow, the bank slope was steep, and flood discharge energy was eliminated. The area is located within the abutment resistance rock mass, and the layout of flood discharge energy dissipation facilities is greatly limited. To this end, a large number of numerical analyses and model tests have been carried out around these issues, and flood discharge safety has been ensured by the use of dam-body tables, meso-holes, and flood discharge tunnels at the shore. The flood discharge from the dam body has been vertically and horizontally separated. The principles and methods of body diffusion, air collision energy dissipation, and overall dispersion and slotting achieve the ideal energy dissipation effect.
Successfully excavated the large-scale underground cavern group. The underground diversion power generation system of the Xiaowan Hydropower Station is of large scale. The main and auxiliary workshops, the main transformer room, the tailrace surge chamber and the gate room are arranged in parallel. The main plant is 323 meters long and 30.6 meters wide. The maximum height of 82 meters is like a 30-storey underground palace. There is no pillar in the middle, equivalent to a 1 million cubic meters of underground space. In the construction, a large number of engineering measures were adopted to stabilize the rock caverns of underground caverns. At the same time, the domestic and international trials of the mechatronics hydraulic transition process with model units were first carried out. For such excavation of underground caverns, Huaneng Xiaowan Hydropower Station is the first attempt in China.
Successfully developed and installed a hydroelectric generator set and metal structure for the installation of a high head high capacity hydroelectric generator set metal structure Xiaowan Hydropower Station, with the characteristics of “high, large, and fullâ€, that is, from the perspective of the hydroelectric generating set, the hydraulic turbine operation head High, high unit speed, high operational stability, large stand-alone capacity, large amplitude of head, is the world's largest single unit with the largest capacity in the head section of the world. After the model test and study, it was decided to increase the rated head of the turbine and increase the suction height and the rated voltage of the generator, and adopt the cooling method of the whole air-cooled generator; from the perspective of the metal structure, due to the high dam, high head, large water thrust, head Larger amplitudes and large flood discharges have brought great difficulties in the design, manufacture and installation of metal structures. As far as gates are concerned, there are as many as hundreds, including various types of gates, of various types, and the size of many gates is the largest among similar gates. In particular, the structure of large orifices, high head gates, earthquake resistance, sealing of water seals, hydraulics for doorways, anti-cavitation, and support for heavily loaded sprocket gates are among the world's best.
The selection of high-strength concrete and large-area concrete temperature control and crack prevention new method arch dam concrete raw material selection and temperature control problems of concrete placement is one of the key technical problems of the Xiaowan Project. In particular, the length of the largest concrete pouring block in the lower middle of the arch dam is more than 90 meters, and the temperature control and crack prevention is very difficult, and many process specifications exceed the existing standards. Through in-depth and meticulous experimental research on concrete raw materials, the optimal mix ratio was optimized; a series of concrete temperature control standards were proposed and formulated to ensure that the dam concrete reached high strength, high ultimate tensile value, bullet bomb, low heat, no The overall specification of shrinkage performance.
Successfully solved the problem of the stability of a 700-meter complex high slope. The Huaneng Xiaowan Hydropower Station artificially handles the high slope, the difference in slope stability conditions, and the difficulty of technical treatment. It is rare in hydropower construction at home and abroad and even in other industries. At present, the governance of high slopes at home and abroad is still in the exploratory stage. There is no consensus on the analysis theory, calculation methods, and associated safety and control indicators. In the absence of strong operability rules and regulations, The successful practice of Huaneng Xiaowan Hydropower Station has also played a pioneering role in many aspects.
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