Structure Parameter Design And Evaluation Of Environmental Vibration For New Type Floating Slab Track With Rubber Vibration Isolator

An increasing number of urban rail transit construction were put into use in our country, which meets the city’s efficient travel demand, however, it also produces a new source of vibration and noise pollution. The new type rubber vibration isolator floating slab track, which has laid the test line and made a good test results in foreign country, has some good properties:such as high isolation efficiency, convenient lifting, and easy to repair. However, few applicability researches were conducted about the design of floating slab in our country, so further research on the properties and design about this kind of floating slab track is necessary.Based on the domestic and international data about the frequently-used vibration isolation in urban railway system, and the results from the studies about new type vibration isolation in test lines. In order to get the systemic dynamic parameters of the new type floating slab track with rubber vibration isolator, the finite element software ANASYS was used in this paper to analyze the natural frequency and to evaluate the structural strength of floating slab. Then the dynamic response with driving conditions of floating slab was analyzed through ANSYS/LS-DYNA. Finally ABAQUS and the theory of infinite boundary were integrated to establish a tunnel--soil 3D dynamic finite element model, this model can be used to study the vibration attenuation law and evaluate the damping effect of floating slab track with rubber vibration isolator. The results show that:1. Model frequency of floating slab system is in proportion to the vertical stiffness, but in converse proportion to the quality of floating slab; efficiency of floating slab track with rubber vibration isolator was improved by increasing the quality of floating slab, increasing distance between different isolators, reducing the stiffness. However, the abovementioned method might bring out some disadvantage about the safety and durability in the structure.2. Based on the consideration of floating plate strength calculation and economic factors,2.5m distance from contiguous rubber vibration isolator with vertical stiffness 12.5 kN/mm is recommended in the layout plan.3. Vibration energy produced while driving cannot transfer to the tunnel foundation as the effect of rubber vibration isolator. Damping of vibration isolator is not sufficient to completely consume the vibration energy at the same time. Therefore, the vibrations of carriage, rail and track structural in the area of using floating slab will be larger than the vibrations in normal monolithic track bed.4. From the perspective of time-domain and frequency-domain analysis, new floating slab can reach good vibration isolation effect. In the German high speed high disturbance line conditions, the amplitude of vibration isolation in this system reaches 28.91 dB. In Shortwave Irregularity conditions, the value reaches 17.53 dB.