Research On Damping Performance Of Steel Spring Floating Slab And Metro Vibration Propagation Track Strueture

As a kind of green energy conservation city transportation, the metro is developing rapidly at home and abroad. At the same time, people are becoming more and more demanding to living environment. The vibration problem caused by metro operation is becoming a growing concern.After summarizing the research status of metro train vibration load, vibration propagation and vibration reduction measures, on the base of Qingdao metro first period engineering (line3), the vibration characters of vehicle-track system, wheel-rail contact force and foundation reaction force and vibration propagation have been researched roundly by the way of theoretical analysis and numerical calculation, using software of ANSYS and MATLAB. The main works are as follows:(1) The vehicle-track dynamics analysis model was established according to analytic dynamics theory. Then modal and harmonic response analyses were carried out. The system nature frequency and the mode of vibration were obtained. The amplitude spectrum curves of foundation reaction and the force transmission rate were presented according to vibration theory. The results show that the lower the excitation frequency, the larger the foundation reaction force and force transmission rate.(2) The riding comfort was studied using the Sperling index. The variation of the riding comfort and foundation reaction were profiled with different steel spring stiffness and damping. The results reveal that the greater the steel spring stiffness and damping, the better the riding comfort; the smaller the steel spring stiffness and the greater the damping, the smaller the foundation reaction.(3) According to the American grade6track vertical irregularity power spectrum, wheel-rail contact forces and foundation reaction forces of steel spring floating slab track structure were obtained by the method of Newmark and Matlab.(4) A2-dimention finite element model was established. Then the vibrations and its spread rule were described. After that, the steel spring floating slab track structure vibration damping performance was analyzed. The results show that the horizontal vibration velocity at surface and the vibration acceleration above the tunnel center are both periodic variation. If the elastic modulus is smaller, the horizontal vibration velocity at surface and the vibration acceleration above the tunnel center are both greater. The horizontal speed of steel spring floating slab track structure is about a third of monolithic roadbed track structure. The vibration reductions of the steel spring floating slab track structure are around9dB.(5) Considering various factors, the Z vibration grade of some point distancing tunnel center L was forecasted.