Numerical Simulation Method And Application Of Metro Vehicle-tunel Dynamic Nonlinear Coupled System

With the development of Chinese urban subway traffic towards the stage of rapid expansion, different kinds of tunnel become very important parts in the subway traffic construction and development, it is necessary having intensive research of the impact on tunnel subjected to nonstop crossing of opposite metro vehicles and multi-operating mode of a metro vehicle respectively.Numerical simulation is an effective research method and can be used to obtain relatively satisfactory answers for those complex theory and practical engineering problems,which were restricted by some factors and could not be efficiently settled by theory and experimental verification.In this article,a three-dimensional dynamic nonlinear coupled model of the metro vehicle-tunnel system is established using LS-DYNA based on the virtual-reality modeling and an in-depth numerical simulation study of the system is carried out based on high performance computer.Taking three-dimensional simulation for river-crossing tunnel project of Nanjing metro line 10 as the engineering application background, a three-dimensional dynamic nonlinear coupled numerical modeling method has been put forward for the metro vehicle and tunnel, and the whole three-dimensional vehicle-tunnel-soil dynamic nonlinear coupled finite element model is established according to the design drawings and geological survey data, in which the metro vehicle is a firm-soft coupled multi-body dynamics finite element model, the soil is a elastic-plastic hierarchical model, and the semi-infinite field of the system is simulated by the viscous-elastic artificial boundary. Different kinds of coupled methods are used to simulate the interaction between tunnel and soil and between wheel and rail.The whole model is approximative to the true situation.Based on the three-dimensional vehicle-tunnel-soil dynamic nonlinear coupled finite element model an in-depth numerical simulation study of the system is carried out. Numerical simulation for initial static stress field of the system is conducted. When tunnel lining, track bed, baffle-plate, platform, flue sheet and bracket are constructed, the initial static stress field of the coupled system makes an important effect on the dynamic analysis of the whole coupled model. For the purpose of simulating real situation and obtaining correct results, the initial static stress field of the system under water pressure and gravity is simulated, which also provides prerequisite for subsequent dynamics calculation. Numerical simulation of the metro vehicle-tunnel dynamic coupled system subjected to nonstop crossing of opposite metro vehicles is studied with the consideration of initial stress. Based on the initial stress, nonstop crossing of opposite metro vehicles in a single bore tunnel is simulated. After comparative study of one metro vehicle moving in the tunnel, comprehensive dynamic response property is obtained. Numerical simulation of the metro vehicle-tunnel dynamic coupled system subjected to multi-operating mode of a metro vehicle is studied with the consideration of initial stress. Operational conditions of metro vehicle,such as traction,idle running and braking are simplified as uniformly accelerated motion, uniform motion and uniformly retarded motion in tunnel respectively, based on the initial stress, multi-operating mode of a vehicle running in the tunnel is simulated. After competing the numerical analysis, relevant dynamic response property is acquired. The whole simulation processes are practical, and the results indicate that the stress and displacement resulted from the nonstop crossing of opposite metro vehicles in a single bore tunnel and multi-operating mode of a vehicle running in the tunnel are small magnitude response, and that the tunnel in such conditions is stable.