Tbs, Non-ballasted Track Structure Design And Analysis Parameters

With the rapid development of passenger dedicated lines and city mass transit in China, ballastless track was developed rapidly for less maintenance or no maintenance. This paper focuses on the twin-blocks sleeper embedding ballastless track(be called TBS ballastless track for short)widely used in Wuhan-Guangzhou Passenger Dedicated Line, and applies the composite beam method and train-track coupling dynamics to analyze the coupling system.A composite beam method in statics is applied for the parameters analysis and optimum design of TBS' upper structural layer. The results show that the thickness and the elasticity modulus of track bed should not be too large, the reasonable thickness and the reasonable elasticity modulus is approximately 200mm and 32500N/mm~2. On the other hand, with the increase of the width of track bed, the thickness of supporting-layer and the elasticity modulus of the anti-freezing layer, the stress of upper structural layer decreases. Therefore we should take some measures to increase the stiffness of foundation to reduce the stress level of upper structural layer and maintain the stability of foundation engineering. As to the thickness of supporting-layer and the width of track bed, we could adopt 300mm and 2800mm respectively according to the experience of Germany.In the light of the characteristics of the system vertical vibration, a model with three-layer beam element is employed to simulate the track system. The vibration equation of the train-track coupling system are formulated by using the principle of total potential energy with stationary value in elastic system dynamics and the"set-in-right-position'rule for formulating matrixes. The model is applied for analyzing the parameters of the train-track coupling system, such as the number of vehicles, the length of track, the running speed of train, the type of rail, the stiffness of fastener, and the stiffness of foundation ect. The results indicate that the number of vehicles and the length of track have a little effects on the dynamic response of system. the heaver rail or increasing the stiffness of fastener and foundation is beneficial to decreasing the system response. In addition, with the increase of train running speed, the response of system will rise. To sum up, the reasonable stiffness of fastener is between 40kN/mm and 70kN/mm.With the random and deterministic irregularity as vertical vibrating resource, the dynamic response of train-track coupling system is studied, and several results were acquired as follows.Firstly, the eccentricity of wheel belongs to the periodical disturbance source, and leads to the periodically forced vibration of system. It has a slight impact on the vertical displacement of rail and track bed, while its influences on the acceleration of system and the force between the wheel and rail is very great.Secondly, the relationship between the dynamical response of vehicle and the wavelength of vertical profile irregularity is nonlinear, with a peak value, and the most unfavorable wavelength is 40m. Furthermore, with the increasement in the depth of wave, the response of system is linearly enlarged.And thirdly, the amplitude of random irregularity samples in Zhengzhou-Wuhan High-speed Test Section is about 4mm, it has slight influence on the dynamic of train-track coupling system, resulting in high ride comfort. Therefore, maintaining the good quality of track's ride comfort is vital important for train's safe and comfortable operation in the hign-speed railway.