Study On Influence Of Vibration Induced By Subway Train On Ground And Ground Structures

Subway transporting system, one of main city traffic methods, has many obvious advantages. In resent years, subway transportation systems have been developed rapidly in China. However, with the development of subway construction, some negative effects also appear. One of the serious problems is the impact of vibration induced by subway train to environment. Owing to that subway circuit in a city generally passes through downtown area, the vibration effects of the subway to the buildings and circumstance around can not be neglected.The huge structure (huge platform with storied buildings on it) of Bawangfen vehicle depot of Beijing subway and its soil-foundation system are studied in this thesis. Based on interpretation of relevant geotechnical data, a 2D numerical model is built with FLAC (Fast Lagrangian Analysis of Continua). With the input of a vibration acceleration history of subway train, a full dynamic analysis of soil-pile-structure is carried out. The propagation of vibration wave on the ground and vibration responses of the huge platform and the storied buildings are analyzed. Some conclusions are drawn as follows:(1) With the increase of the distance to the vibration source, vibration intensity of the ground decreases;(2) The vibration intensity of the ground in vertical direction is slightly larger than that in horizontal direction;(3) With the increase of the distance to the vibration source, the situation that the vibration intensity of each building in horizontal direction is maximum at highest and lowest story whereas minimum at the middle story changes gradually to that decreasing with the height of building;(4) In vertical direction, the vibration velocities and accelerations at the end points of each story of a building are the nominal identical, which indicates that the vertical vibration of them is unanimous;(5) The vibration intensity in vertical direction of a building is larger than that in horizontal direction;(6) Increasing of the elasticity of track is an effective way to abate vibration of ground and buildings.The conclusions mentioned above can provide references for subway track design and vibration control of buildings around the subway line.