Numerical Simulation Method And Application Of Vehicle-tunnel Dynamic Coupling System

With the rapid growth of China economics and the acceleration of urbanization, the rail transportation system construction comes into a great growth period, in which the tunnel becomes the important construction projects because of the increasingly crowded ground surface space. Therefore, it is necessary to study the dynamic coupling system of train and tunnel. The numerical simulation techniques can simulate the complex problems to get a satisfactory answer that are used to can't be effectively carried out by scientific experiments or theoretical analysis. Much time could be saved. The vehicle-tunnel dynamic coupling system is considered as a whole system. Based on high performance computer, the numerical simulation method of the vehicle-tunnel dynamic coupling system is studied and applied to projects. The main contents include:Numerical modeling method of the vehicle-tunnel dynamic coupling system is studied. The orthotropic equivalent model of shield tunnel is established by numerical simulation experiments, which takes the different horizontal and vertical mechanical properties of shield into account. The finite element method is used to define the multi-body vehicle model, which makes the connection of vehicle and structure model easily. Different non-linear dynamic coupling methods are adopt to simulation the different dynamic interaction between maglev train and guideway, wheel-rail train and track, inner and outer lining, tunnel and soil in the model. The semi-infinite foundation in the dynamic analysis of underground structures is simulated by PML artificial boundary.High performance computing method of train-tunnel coupling system is studied. Huge computing resources are required for the large-scale nonlinear vehicle-tunnel system model. The initial static stress field computation and subsequent dynamics calculation are considered as a whole process, the explicit integration algorithm is used to solve this problem, which has advantages in convergence and environment adaptability. The difficulty of model transformation between implicit and explicit algorithm can also be avoided. On Dawning 5000A of the Shanghai Supercomputer Center, a vehicle-tunnel dynamic balanced algorithm for domain decomposition is designed and implemented. Two engineering application example of rail train-tunnel and maglev train-tunnel confirmed that the partition method has a better parallel efficiency.Numerical simulation for maglev train-tunnel dynamic coupling system is carried out in the application of the cross-river tunnel in Shanghai Airport maglev connection line. A 3D refined finite element of the maglev train-guideway-tunnel-soil system is established. Using the same modeling and computation method, the Shanghai elevated maglev line is established, and the numerical results and experimental results of the acceleration vibration level with distance shows the reasonable agreement, which confirmed the feasibility of the model and method. The initial static stress field, the cases of one maglev train travelling and two maglev train meeting are computed using this model. The results show that: the maglev dynamic load has little effect on the inner and outer lining, but has significant effect on guideway; the deflections of guideway mid-span in the two maglev travelling cases are less than the design safety; the maximum coupling stress between inner and outer lining lies in the four pillars locations of the guideway support platform; the dynamic coupling stress has the same level compared to the initial static stress, and therefore, bolts should be added in these locations to enhance the connection strength between inner and outer lining.Numerical simulation for rail train-tunnel dynamic coupling system is carried out in the application of the Shanghai Chongming cross Yangtze tunnel. A 3D refined finite element of the rail train-track-bed-tunnel-soil system is established. The initial static stress field and the train travelling through the tunnel are computed. The results show that: the road and train load have relatively small influence to the lining deformation and stress compared to the soil and self-gravity static load; the stress at the connectional location between tunnel and connectional passage is about three times that of the ordinary tunnel cross-section, which should be reinforced to avoid fatigue damage; the deformation joints of the connectional passages has small relative displacements, which will not affect the structure security.