Analysis Of High-speed Train Induced Pressure On Track Adjacent Structure

High-speed train is fast, safe, comfortable, environmental protection, which has become an inevitable trend in the development of rail transport. When a high speed train is passing track adjacent structure, train-induced pressure will endanger the traffic safety, reduce the passenger comfort and deteriorate the surrounding environment. Recently, researchers have focused on the aerodynamic characteristics of high-speed train-induced pressure and its generation and propagation mechanism. However, the train-induced aerodynamic effects on track adjacent structure require further study. Study of train-induced pressure can help to better understand the aerodynamic effects of wind on track adjacent structure and provide theoretical basis for designers. It is theoretically significant and practically valuable in the engineering.In this paper, overhead bridge and canopy structure are mainly concerned. The pressure distribution and the influence of structure height, opening width and shape on train-induced pressure are reported through the field experiment and numerical simulation on the basis of the CFD software Fluent and wavelet transformation. The main content of this thesis has the following three parts:Firstly, based on the wavelet transformation, the collected pressure are decomposed and reconstructed. Analysis of the surface pressure fluctuation characteristics and identification of the pressure distribution in different frequency bands are conducted. Results show that train-induced pressure and its aerodynamic effects on track adjacent structure can not be ignored. Train-induced pressure is dominated by the time-varying low frequency(0-2.5Hz) component, while the pulsating component has little effect on the overhead bridge.Moreover, based on the computational fluid dynamics, sliding mesh technology combined with the Reynolds Averaged Navier-Stokes are adopted to simulate the three-dimensional unsteady flows around track adjacent structure. The numerical results are compared with the measured data to verify the accuracy of the numerical simulation. Results show that the method has better accuracy. Then, the aerodynamic effects of the flow around the train, the pressure distribution, the relationship between pressure and train speed, the relationship between pressure and train location are reported. The impact of overhead bridge parameters on train-induced pressure is studied by changing the height and width respectively. The influence of the opening width and shape of the canopy structure on train-induced pressure are conduced. Results show that as train head or tail passes, the maximum positive and negative pressure generate alternately, and the time interval between the occurrences of maximum pressure is0.13s. The maximum pressure decrease further away from the centre line with approximately a exponent attenuation, and the influencing scope of train-induced pressure is15m on both sides of the centre line. Many factors including the height of the structure, the middle opening width and the structural shape have influence on the train-induced pressure. Train-induced pressure decrease with the increment of height. Pressure decrease with larger opening width when the opening width range from0m to8m. The arched shape structure can reduce train-induced pressure significantly.Finally, taking the code as a reference, the train-induced pressure distribution of track adjacent structure with different height and the wind load calculation diagram are given on the basis of the above analysis. In order to eliminate the influence of train speed, train-induced pressure is transformed into pressure coefficient, which provides references and suggestions for the wind-resistant design of track adjacent structure.