Study On Source Reduction Of Vibration Of Chengdu Museum Induced By Metro Running

With the rapid development of our country’s urban subway, the problem of the vibration induced by subway is becoming prominent increasingly. Moreover, vibration control is also a key technical problem to be solved for the development of subway. Due to the trains of Chengdu subway line2running through the underneath of Chengdu Museum, vibration caused by trains spreading through the surrounding strata will be transmitted to the museum floor through the foundation, which will have an adverse effect on the museum building.Based on the background of chengdu museum, the environment vibration caused by subway and the key parameters of source vibration attenuation are studied, the main research contents include:1. Based on the basic theory, the principles of vibration induced by subway were studied, including the generation of vibration, propagation characteristics of vibration wave in the soil medium and vibration of the building caused by the wave.2. In this article, data was analyzed according to environmental vibration test caused by subway, combined with the existing vibration standard, a clear evaluation of environmental vibration was presented. Then the propagation laws of vibration near the field were obtained by the analysis of the measured data using the way of one-third octave.3. According to the measured data, a three-dimensional finite element model of floating slab-tunnel-soil was established in MIDAS/GTS, and the load was vertified through the measured results and the empirical formula.4. With the verified finite element model, the vertical vibration of the tunnel wall and the ground at the top of tunnel were selected as the control parameters, to studythe attenuation effect of the floating slab, steel spring stiffness, the train speed, the tunnel wall thickness and tunnel buried depth.Analysis shows that:floating slab could decrease the vibration in high frequency band and amplity the vibration in low frequency band. When the stiffness of steel spring is6900kN/m, the comprehensive vibration attenuation effect is12.1dB; almost all the source vibration attenuation measures have little effect on low frequency vibration reduction, and have obvious effect on high frequency vibration reduction. Reducing the stiffness of the steel spring can effectively reduce the Z direction vibration of tunnel wall and the ground. Increasing the thickness of the tunnel wall can reduce the Z direction vibration of tunnel wall and the ground, however, the effect is not obvious. Reducing the train speed can effectively reduce the tunnels and the ground of Z direction vibration. Increasing the tunnel buried depth can reduce the Z direction vibration of tunnel wall and the ground, however the effect is not obvious for tunnel wall, while the effect is obvious for the ground.