Lead the quality innovation of testing engineering and help improve the quality of traffic engineering

Recently, the joint stress test of the top and bottom joints of the partition wall in the shield tunnel of the airport link line of Shanghai City Railway was undertaken by the joint research and development of the railway and Tongji University. The bottom joints have accumulated fatigue loading 600,000 times.

The Shanghai Rail Transit Airport Link is an east-west urban line in the Shanghai rail transit network. After the completion of the full line, it will realize the rapid connection between Hongqiao Airport and Pudong Airport, further enhance the core function of Shanghai as a global city, and accelerate the process of transportation integration in the Yangtze River Delta.

                                                                                                             Shanghai airport link project route plan

      As the first demonstration line with fully prefabricated internal structure, the former cast-in-place structure is replaced by prefabricated parts such as middle partition wall and curved parts in the large diameter shield section of the airport line. In the construction of this project, the fourth Survey and Design Institute of China Railway is faced with a problem, its design of the middle partition wall in 100 years of service life, to withstand the train wind load of about 6 million times of repeated action, Shanghai quality inspection Station has to worry about how to ensure the fatigue performance of its upper and lower joints.

  Interior structure rendering of shield tunnel

   Internal structure assembly

Therefore, the joint test project of the middle partition wall, initiated by Tiensiyuan and jointly carried out by Professor Liu Xuezeng of Academician Zhu Hehua's team of Tongji University, needs to verify the stress characteristics of the top and bottom joints of the middle partition wall under fatigue load and dynamic load, based on the most unfavorable working conditions of the airport line. Due to the large size and many loading times of the full scale test, it is necessary to rely on the three-dimensional reaction wall, embedded channel, high-precision electro-hydraulic servo fatigue test and the detection ability of on-site processing tools and accessories. As a well-known fatigue test expert in the industry, with more than 20 years of deep cultivation of fatigue testing machine and its testing technology, it has a test site located at the foot of Mount Tai, a production workshop, and a professional fatigue test guidance team, Professor Liu Xuezeng of Tongji University decided to choose Force Test. At present, the bottom node test of the project has reached 600,000.

        In the same period, the fatigue performance test of large-tonnage 2200MPa prestressed system assembled by China Academy of Railway Sciences has been carried out more than 1.66 million times, and the test has been widely concerned by the domestic prestressed industry and heavy-load fatigue test field. The test equipment is the fully closed-loop micro-computer-controlled electro-hydraulic pulse fatigue tester PAM1600, which is newly developed for force support test. The successful verification of the test will once again prove that China's heavy-duty pulsation fatigue test technology in the world's leading position.