"Zhai model" helps speed up China's high-speed rail
2022-07-26
The speed of 350 kilometers per hour is the highest design standard of high-speed railway in China at present. How much is the maximum operating speed of high-speed railway suitable? This is a common concern of the world, and Chinese scientists are giving the answer. "The design speed is 400 kilometers per hour, and the curve parameters are feasible." On July 20, Zhai Wanming, an academician of the Chinese Academy of Sciences, a foreign academician of the National Academy of engineering and the chief professor of southwestjiaotonguniversity, led the team in the State Key Laboratory of traction power of southwestjiaotonguniversity to use the "Zhai model" to simulate and verify the design parameters of the 400 km / h line. "Zhai model" is a new theoretical system of "vehicle track coupling dynamics" initiated by Zhai Wanming. Its core model "vehicle rail coupling" has become the basic method of rail transit dynamics research at home and abroad, and it is also an important theoretical support for the continuous improvement of China's high-speed rail speed. "Vehicle rail coupling", a doctoral student created a new model. In the summer of 1990, Zhai Wanming, a 27 year old doctoral student at southwestjiaotonguniversity, pioneered a fast explicit numerical integration method to solve the dynamics of complex large-scale systems, and successfully solved the longitudinal dynamics of long and heavy haul trains. This method was later praised as "Zhai method" by international peers. That year, Zhai Wanming had a bigger research stage when the country launched the key scientific and technological research project of the eighth five year plan. "The train should be overloaded and the damage to the line should be reduced." As the specific executor of the key project "Research on reducing the interaction between heavy haul trains and lines", Zhai Wanming felt very thorny. In the field of railway engineering, vehicle and track have always been two independent research systems, which belong to the classical theoretical system of vehicle dynamics and track dynamics. However, these two theories are difficult to solve the problems in tackling. "When the vehicle runs on the track, the two interact and couple with each other, forming an interdependent dynamic system." After repeated thinking, Zhai Wanming's inspiration suddenly appeared. Can we couple the "vehicle track" and build a unified model? The idea of stone shattering the sky is like a stone thrown into the lake, causing layers of ripples. On the basis of absorbing the achievements of vehicle and track dynamics, Zhai Wanming created a "vehicle track" unified model. The resulting large-scale dynamic calculation problem was just solved by the "Zhai method". The road of scientific research is winding. The subsequent debugging program gave Zhai Wanming a blow - because the calculation results were inconsistent with the reality, in the simulation calculation, the vehicle running on the track actually flew off the track. "Zhai Wanming, you drove the train to heaven!" There were voices of doubt and ridicule. In addition to being shocked, Zhai Wanming was not discouraged. He thought again and again, convinced that the research direction was correct. It seems that the calculation program is wrong. After checking thousands of programming statements one by one, Zhai Wanming finally found a parameter error in the programming statement late one night more than 20 days later. In 1992, "Zhai model" broke out of the cocoon, providing a theoretical method for reducing the interaction between heavy haul trains and lines, and ensuring the smooth completion of national key scientific and technological projects. In the absence of standards, the "Zhai model" worked out the optimal plan. In 2004, China's high-speed rail began to start. Without design standards, the project construction faces a series of challenges. "Which design is feasible?" One day in 2005, the technical director of the design unit was uneasy with four route selection design schemes for the Guangzhou Shenzhen Hong Kong (Guangzhou Shenzhen Hong Kong) high-speed railway crossing the lion ocean. Guangzhou Shenzhen Hong Kong high-speed railway is one of the main frameworks of China's high-speed railway network. It needs to cross the lion ocean in the waters of the Pearl River Estuary, and the terrain conditions are complex. After more than a year of survey, the design unit has put forward four route selection schemes, and for the first time, it involves a large gradient profile of more than 30 ‰. Can the high-speed train pass through such a large longitudinal slope safely and smoothly at a speed of 300 kilometers per hour? This major engineering and technical problem has never been encountered before in the history of high-speed railway line design in the world. The design director found zhaiwanming. The parameters of the four route selection schemes were input into the "Zhai model" one by one. After computer simulation and analysis, coupled with dynamic safety assessment, Zhai Wanming found the best one: the design scheme of the long tunnel passing through shazai island. This scheme was finally adopted by the design unit. In December, 2011, the Guangzhou Shenzhen section of Guangzhou Shenzhen Hong Kong high speed railway was officially put into operation. The operation practice of more than 10 years has shown that the high-speed EMU runs safely and smoothly in Shiziyang section. In the spiral process of theory experiment application theory, the "Zhai model" has been continuously enriched and improved, and has been successfully applied to various engineering sites of China's high-speed railway, solving a series of practical problems. Field tests, theory and practice promote each other. "In the past, there were few opportunities for field tests, but with the six major speed increases of China's railways and the subsequent development of high-speed railways, such opportunities are increasing." Zhai Wanming said that no matter how good the theory is, it can only be on paper unless it is tested in practice. In order to verify his research, Zhai Wanming often followed railway safety officers one sleeper, one sleeper, to the scene to find the answer and carry out tests on the scene. In 2008, on the eve of the opening of China's first high-speed railway, the Beijing Tianjin Intercity Railway, Zhai Wanming was very excited: he was finally able to collect high-speed railway test data! This is too important to enrich the theoretical research of "Zhai model". In order to collect the high-speed driving dynamics performance indicators of a super large bridge, he took the test team and stayed on the site for 35 days. "The data of every train passing is very valuable." Zhai Wanming remembered that the maximum speed of the train had reached 390 km / h, which was the highest speed of the Chinese railway at that time. In early 2011, at the test site of a section of the Beijing Shanghai high-speed railway, the train ran at a speed of more than 430 kilometers per hour. Zhai Wanming's team measured the track dynamics and the surrounding ground vibration characteristics. The research papers published on this basis are still exclusive in the world and widely cited by international peers. Beijing Tianjin Intercity Railway, Beijing Shanghai high speed railway, Chengdu Chongqing railway, Daqin Heavy Haul Railway... Through on-site investigation and repeated tests, Zhai Wanming also obtained a large number of first-hand precious data while solving engineering problems. Calculation, simulation and test confirm each other, "Zhai model" has been constantly enriched and improved, which has promoted China's railway technology to gradually overcome the vibration problems of high-speed driving and move towards the forefront of the world. China has laid out and developed new high-speed trains with higher speed per hour and built lines with higher speed operation conditions reserved. In Zhai Wanming's view, China's high-speed rail will be faster and more intelligent in the future. The 400 km / h high-speed rail may roar. (Xinhua News Agency)
Edit：Li Jialang Responsible editor：Mu Mu
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