Environmental Vibration And Mitigation Measures Caused By Elevated Rail Traffic

With the rapid development of urban elevated rail transit system in our country,the running speed of the train is getting faster and faster.The environmental vibration caused by the train passing the viaduct not only affects the neighboring buildings,but also greatly disturbs people's life.Therefore,in order to eliminate these adverse vibration effects,we must take the appropriate vibration isolation and vibration isolation measures.This article briefly introduces the research background,purpose and significance of environmental vibration caused by elevated rail transit,summarizes the current research status at home and abroad,systematically expounds the research results of the environmental vibration and vibration isolation and vibration isolation measures caused by elevated rail transit and the current research situation.Based on the above research,taking the viaduct section of Shanghai Metro Line 2 as a starting point,the dynamic response of the vehicles with different speeds passing through the elevated structure and the law of vibration propagation caused by the elevated structure are studied.In addition,under the action of ele-vated rail transit loads,the influences of various barrier isolation measures on the vibration isolation effect are discussed in detail.The indexes of vibration response before and after vibration isolation are compared.The obtained results and conclusions provide some references for the application of vibration isolation and vibration isolation measures in practical engineering.Based on the above analysis,the main research content and results of this dissertation can be divided into the following aspects.(1)Firstly,the calculation and comparison between the three-dimensional large-size model and the small-size model of the viaduct-bridge-soil layer have little effect on the calculation results.Therefore,the application of the small-size model can meet the demand and save time Improve calculation efficiency;Secondly,compared with the two-dimensional model,the small-size three-dimensional model is calculated and compared.The calculated vibration caused by elevated rail transit in the two-dimensional model is much larger than that calculated by the three-dimensional model.(2)Establishing the dynamic response of the structure caused by the vehicle passing through the high speed structure under different speeds,and obtaining the propagation law of environmental vibration caused by the vehicle on the elevated structure.Under the condition of no barrier vibration,the law of vibration attenuation is obtained by finite element analysis at the bottom of the bridge pier,bridge span,and 23m away from the viaduct,and the decrease of vertical acceleration is obvious.Comparing with the national standard "Urban Rail Transit Caused by Building Vibration and Secondary Radiation Noise Limits and Measurement Methods Standard"(JGJ/T170-2009)environmental assessment,when the distance is greater than 10m compliance.(3)Based on the design theory of vibration isolation barrier,and combined with the real situation of environmental vibration in the elevated section of Shanghai Metro Line 2,the reaction force of the abutment at the piers is applied to soil submodel.By using finite element software ANSYS,Under the condition of barrier vibration isolation calculation,a variety of barrier isolation before and after the data information.In this paper,the generation of vibration and the acceleration and vibration level in the process of propagation are analyzed.The vibration isolation method proposed in this paper can be used when the environment vibration is too large and people or buildings need special protection.Finally,on the basis of a comprehensive summary of the thesis work,several issues to be further studied are proposed.