Analysis Of Vibration Caused By Subway Train Operation And Secondary Noise Of Buildings Under Different Soil Conditions

In recent years,China's urban railway transit industry has flourished,bringing convenience,safety,speed,and punctuality to people's travel,and has greatly eased the pressure of urban traffic.However,the environmental vibrations and the secondary structure noise of buildings along the line caused by the operation of subway trains have become more prominent,and complaints from residents have also increased.These problems have become a part of urban construction that can not be ignored.Based on the extensive and in-depth research conducted by relevant scholars at home and abroad,this paper has established the numerical model and acoustic boundary element model of subway trains and structures for the different effects of different soils on the vibration transmission and attenuation caused by subway trains.The vibration response of the track,tunnel,soil and building under different soil conditions and the secondary structure noise response in the building are analyzed.The main research work of this paper is as follows:(1)The research status of environmental vibration and secondary structure noise of buildings caused by urban railway transit are combed and summarized,the basic theories and methods for studying such problems and the evaluation methods as well standards of environmental vibration and noise caused by subway railway transit are introduced.(2)Based on the theory of vehicle-track coupled dynamics,the simulation of subway vehicle-track vertical dynamic interaction is calculated by MATLAB,and the three-dimensional finite element model of track-tunnel-soil-building is established by using finite element software ANSYS.The calculated wheel-rail vertical force is applied as an external excitation to the rail in the finite element model,and the dynamic simulation calculation of the entire structure was performed.The reliability of the wheel-rail dynamics model and the finite element model is verified by comparing the results of the dynamic test results of the Bihai section of the Shenzhen Metro Line 11 with the simulation results.(3)The vibration responses of each structure under soft soil,hard soil and hard rock are analyzed by using finite element software.The effects of different soil conditions on the vibration of track,tunnel,building structure and the law of vibration propagation in the soil are studied.(4)The finite element model of the element plate track with vibration absorbing is established for the vibration exceeding standard of the building under the condition that the soil around the tunnel is hard rock.The stiffness of different damping cushions and the thickness,width and length of element plate track are analyzed for the influence of on the dynamics of the track structure,tunnel structure and building,and analysis of its vibration absorbing performance.(5)According to the finite element model and dynamics calculation results,the acoustic analysis software Virtual.Lab is used to establish the building acoustic boundary element model,and the calculated vibration response of the building structure is taken as the acoustic boundary condition,the direct boundary element method is used to analyze the indoor secondary structure noise response and spatial distribution characteristics the building,and the difference between the numerical calculation and formula prediction method for the indoor noise of the building floor are compared and analyzed.