The Vertical Dynamic Analysis Of Slab Ballastless Track In Different Loess Area

Owing to the rapid development of high-speed railway in recent years, departments have paid high attention to the technical problems about high-speed railway. The most important one in these questions is the environmental vibration that is caused by the train operation of high-speed railway. Scholars in each country have carried out a large amount of practical test and theoretical research. However the research of the environmental vibration that is caused by the high-speed railway whose ground is made up of loess in loess area is too rare. In China,a series of high-speed railway lines have opened to traffic, carrying out research on environmental vibration that is caused by high-speed railway in loess area has very significant theoretical value and practical significance in engineering. This paper research the environmental vibration that is caused by the railway in the loess areas of Xi'an and Tai yuan.This paper established a vertical vehicle-slab ballastless track coupled dynamics model on the theoretical basis of vehicle-track coupling dynamics, created corresponding equation by MATLAB programming. Using a new type of explicit numerical integral algorithm calculates wheel-rail force in stimulate of ballastless track spectrum of China Railway High-speed. The wheel-rail force is regarded as moving load and adds to the slab ballastless track-subgrade-loess foundation FEM model which is established by means of FEM method in ANSYS software. The model is used to analyze the regulation of the vibration which is influenced by the speed of vehicle and water content of loess in the slab ballastless track-subgrade-loess foundation model.According to the computing results and analyses of model dynamic response, it can come to the conclusion:Compared with other structure of track the displacement and the acceleration of rail are much higher than others due to the touching of wheel and rail directly. Fastener and CA mortar play an important role in the aspect of the immobilization between track plate and base plate and slows down the vibration. And then subgrade structure and loess foundation can obtain protection.The vibrant system of acceleration is sensible to the speed of vehicle. The speed of vehicle is in proportion to the acceleration and the velocity of attenuation in the direction of deep and transverse distance. Compared with acceleration, the vibrant system of displacement and vertical stress are not sensible to it. As for the water content of loess, the vibrant system of displacement is sensible to it and is in proportion to the water content of loess. The vibrant system of acceleration and vertical stress are sensible to it only in the direction of transverse distance. They are in proportion to the water content of loess.This paper finds that the vibration which is caused by vehicle in the direction of transverse distance mainly concentrates on the range whose distance is less than 18m from center to edge by means of calculation. The standard of rail track needs to satisfy corresponding requirement that the length is more than 20m between railway axis and residential area. It achieves the corresponding standard.Compared with the mechanical character of loess in Xi'an and Tai yuan, it can conclude that the loess in Xi'an is more stable than the one in Tai yuan in terms of loess structure. It accords with the feature of loess distribution in principle. The loess structure becomes more and more stable from west to east.