Study On Train Runnabilities During Earthquake On High-Speed Railway Bridge

High-speed railway has the advantage of high-speed,safety and comfort,and has developed rapidly in many countries.The construction of high-speed railway drops behinds relatively in our country,but it now developing rapidly with the economic development and social progress,for example,Qinhuangdao-Shenyang passenger railway has been built,Wuhan-Guangzhou passenger railway and Shijiazhuang-Taiyuan passenger railwaya are under construction,and Beijing-Shanghai high-speed railway will be built recently.Earthquakes often occur in our country.So studying coupling vibration of vehicle and bridge under high-speed train during earthquake become more and more important.In this dissertation,the coupling vibration equations of vehicle and bridge system are derived by three-dimension coupling dynamic model.Dynamical responses of vehicle and bridge system are analyzed using two different wheel-rail contact models.In the model, rail irregularities are regared as external excitation of vehicle bridge system.One of the wheel-rail models is elastic contact model,considering 31 degrees of freedom for a vehicle. The other is tight contact model,considering 23 degrees of freedom for a vehicle.The vehicle is modeled consisting of a body,two trucks and four wheel-sets.The body and each truck are considered to have 5 DOFs of transverse and vertical displacements,rolling, pitching and yawing respectively.In elastic contact model,a wheel-set is considered four DOFs of transverse,rolling,yawing,and pitching,but in tight contact model,a wheel-set is considered to have only two DOFs of transverse and rolling.The program to analyze the vehicle and bridge system is established in FORTRAN, which can be used to simple-supported beam,continuous beam and cable-stayed bridge. Vertical wheel-rail force is solved with Hertz nonlinear theory,wheel-rail creep with Kalker theory,in which the wheel-rail short-term deviation is considered.The calculation results approach experiment values.It proves the program is reliable.By comparing the calculation results of elastic contact model and tight contact model,the application of two models is dear.When bridge dynamical responses are computed,the values of two models are both correct.But when vertical train acceleration,load decrement rate of wheel weight and derailment coefficient of vehicle are computed,the results of two models have great difference,the ones of elastic contact model approach reality more. Train security and comfort on bridges excited by rail irregularities,including irregular wavelength and wave amplitude under the different train velocity,are studied,whose management criterions are lateral acceleration,wheel-rail force,derailment coefficient. The conclusion is that short wavelength irregularity influences security evidently,but long wavelength irregularity effects comfort prominently.The vehicle-bridge coupling vibration model during earthquake is established,which considers the system responses under earthquake and vehicle simultaneously.The research, analyzing three different geology earthquake waves and no earthquake wave,indicates that the responses of vehicle and bridge are evidently amplifier under earthquake wave,and running security is greatly lowered.The dynamical responses of the vehicle-bridge system by earthquake strength, earthquake frequency,train velocity and pier height,are analyzed.The results are different for different earthquake wave,so the earthquake wave should be selected by factual geology condition.The dynamical responses are greater with higher earthquake wave strength,and lower with higher earthquake frequency for the same earthquake wave.At last running security circumscription map of high-speed railway during earthquake in different geology condition is discussed according to running evaluation, which can provide a reference to practice engineering design.