Underwater High-speed Railway Shield Tunnel In Soft Ground Train Vibration Response Analysis

With the shield tunneling technology has matured, shield method is widely used in the construction of under water tunnel.The disadvantages of shield tunnel are jointy, poor structural integrity and dynamic response of complex. What's more, the geological conditions of underwater tunnel are generally more complicated than the common, so the dynamic response of the train loads is more complicated than the common tunnel.The scientific research and development project (2006G007-B) from the Ministry of Railways is as the support to this article.The Shi Ziyang shield tunnel in high-speed railway which from Guangzhou to Shenzhen to Hong Kong is the engineering background. The numerical method is used to analysis the dynamic response characteristics of the high-speed railway tunnel underwater by the train load. The key study are the characteristics of the tunnel structure and the accumulated settlement in sand or soft soil.The main contents are:(1)The research literatures were extensive investigated and survey. The simulation method of the train load, the evaluation criteria of liquefaction of sand layer, the train vibration on the existing structure and the accumulation deformation of soil under cyclic loading are summarized;(2)Two places where have the possibility of the soil liquefaction and the soft soil seismic subsidence were selected to analyze the the dynamic response characteristics of the tunnel structure and soil in the soft ground under vibrating load;(3)Through the contrast of a variety of reinforcement method around the tunnel and the contrast of having or having no secondary lining, the vibration performance effects of different foundation parameters and with or without secondary lining in the tunnel structure are Investigated;(4) Three dimensional model of space crossing structure by which working shaft is connected with tunnel shield and open cut tunnel is established. Displacement and stress response rule of key point in the supporting structure of joint between working shaft and tunnel is gained. Convergence displacement of the supporting structure of joint between working shaft and tunnel,principal stress of key point is analyzed in the process of high speed train loading, then antivibration characteristic of the structure is evaluated;(5)The different long-term settlement under uneven tunnel basement strata is predicted by introducing the empirical accumulative plastic strain model.The analysis results have significance not only for the dynamic stability evaluation of tunnel structures for high-speed railway but also for the control of uneven settlement.Above results have been used to guide the design and construction.