The Study On Vibration Isolation Performance Of Periodic Row Piles In Subway Near Field Buildings

With the advantages of large capacity, high speed, safety and punctuality, urban rail transit has been developed rapidly, and the urban rail transit industry in China has entered a new stage of development by leaps and bounds. While the rapid development of urban rail transit eases traffic pressure, it also attracts more and more serious environmental vibration and secondary noise problems. The limitations of track vibration reduction measures and the negative effect on the wheel/rail relationship are more and more highlighted, together with the enhancement of people’s environmental protection awareness in recent years, the influence of vibration on the public is becoming more and more prominent, the subway environmental vibration problems will also set off a new round of public attention. Increasing the path vibration isolation measure is the new direction of the vibration control of urban rail transit.In addition, scholars all over the world have accumulated a wealth of theoretical research results in the propagation path isolation vibration measures, but have not carried out design, test and application yet on path vibration isolation measures. For this reason, influence of subway vibration sources is predicted and evaluated in this paper, which comes from the sensitive buildings of a metro depot in Beijing, using the combination of theoretical analysis, field test and numerical simulation. The main contents:(1) Through literature study and network inquiry, the in-depth research about the current development and application situation of the barrier isolation in China and abroad is conducted, pointing out that research on vibration isolation measures in metro vibration propagation path is few compared to the ground vibration.(2)According to the basic theory of vibration wave, the propagation and attenuation characteristics of the vibration in soil are researched, and the mechanism of vibration isolation is revealed, which provides a theoretical basis for the design of the subway periodic layered vibration isolation barrier.(3) For the planning building of a metro depot in Beijing, the rail vibration test, the natural frequency test of soil, the soil vibration test and the ground vibration test are carried out, It is concluded the acceleration of rail, the vibration of soil mass, and the vibration attenuation law with distance, which provides data support for the design of periodic row piles vibration isolation structure.(4) By using the ANSYS finite element software, the three-dimensional dynamic simulation model is established, and the accuracy of the model is verified by the measured data,then the periodic row piles structure for subway vibration reducing is designed.(5)The pile length, spacing, pile material and distance from building are simulated adopting controlling variable method. Combined with the actual situation in depot, an optimal parameter combination of the periodic row piles structure is proposed.The periodic row piles structure has very strong practical significance, it not only can as a kind of effective vibration reducing measure on Urban Rail Transit system for vibration sensitive buildings in the new subway line and pollution treatment of the existing line, but also as a vibration isolation facility between the vibration sensitive buildings and city vibration source, controlling the spread of urban harmful vibration.