The Study On The Environmental Vibration Of High-speed Railway Embankment Area In Lanzhou Loess Area

In recent years, with the rapid development of China’s railway especially high-speed railway, the government and scientific research departments have paid high attention to the environmental vibration caused by high-speed railway. Scholars at home and abroad have carried out a lot of site test and theoretical research on the environmental vibration caused by high-speed railway in soft soil region. But the Study of environmental vibration caused by high-speed railway in loess area is less. Many high-speed and intercity railway will pass through the Lanzhou area included Lanzhou-Xinjiang high-speed railway which is the world’s longest mileage of one-time construction, Lanzhou-Zhongchuan intercity railway which is the first intercity railway in the west region of China, Baoji-Lanzhou PDL being constructed, as well as other planned high-speed and intercity railway. Lanzhou region is the largest area of loess sedimentary thickness in the world.So carring out research on environmental vibration caused by high-speed railway in the loess region of Lanzhou has very important theoretical and practical significance. This paper primary research the environmental vibration in the embankment area of the high-speed railway for Lanzhou loess area.First of all, the paper review the research status of environmental vibration and introduce or summarize the problem of environmental vibration caused by high-speed railway, these problems include the generation and propagation of the environmental vibration of high-speed railway, the evaluation and control standards of the environmental vibration at home and abroad. Then the basic properties and physico-mechanical properties of loess in china are introduced and explained. Including physical and mechanical properties of typical loess in Lanzhou. On the basis of the above problems, a vertical train-track coupled dynamics model is established according to the vehicle-track coupling dynamics and a double block ballastless track-embankment-loess foundation FEM model is established by means of FEM method in ANSYS software.The first model is used to calculate the vertical forces between train and track on the condition of the track random irregularity.The second model is used to calculate and analyse the vibration’s propagation and attenuation laws in double block ballastless track-embankment-loess foundation system, the loess ground vibration is influenced by the embankment height, speed of trains and water content of loess. By combining two models above, the calculation is carried out.The results of analysis and calculation show that embankment structure can weaken the vibration intensity and filter the high frequency contents of vibration. The influence of the embankment height on the ground vibration is mainly reflected in the distance of 30 m from the toe of embankment, with the increase of the height of embankment, the strength of the ground vibration will decrease, the changes of embankment height has no effect on the main frequency distribution of ground vibration acceleration. the influence of the train speed on the ground vibration is mainly reflected in the distance of 30 m from the centerline of the track, with the increase of the train speed, the strength of the ground vibration will increase, with the increase of the train speed, the main frequency range of ground vibration acceleration will increase, but the main frequency range and vibration strength change within a small range. The different water content of loess has little influence to the vibration of loess ground.There is a slight effect on the vibration acceleration of the ground in the distance of 20 m from the centerline of the track, when the water content of loess is different, there has no effect on the main frequency range of the ground vibration acceleration.