Research On The Seismic Performance Of Rubber Particles-crushed Stones Cushion

By mixing crushed stones and rubber particles made from waste tires in a certain proportion,the cushion obtained has a good seismic performance and economic benefits,and its seismic insulation characteristic applies to the basic seismic isolation of electrical facilities such as transformers.The main transformer equipment is composed of a heavy box body with large volume and a "high,flexible and thin" porcelain blushing on the top of the box bottom.Compared with architectural structures,it has the characteristics of long natural vibration period,low damping ratio and concentrated rigidity.Based on this transformer-bushing equipment,this study conducts a shaking table test to explore the seismic performance of the rubber particles-crushed stones cushion.The main research contents are as below:(1)To discuss the principle of basic seismic isolation and the isolation principle of the rubber particles-crushed stones isolation cushion,to expound the seismic isolation principle of the cushion and to derive its calculation formula.(2)To deduce similar theories of the relevant parameters of shaking table test,and to design a transformer model with a scale ratio of 1:5 according to the theory;to design the shaking table test plan according to the vulnerable step of the seismic action model obtained from the analysis of investigation and test,and to provide relevant reference for future similar tests.(3)To carry out free-field shaking table tests on three kinds of cushions with different mixture ratios of rubber content;through the analysis of the dynamic characteristics,acceleration amplification coefficient and response spectrum curves of the model system,to explore the seismic response of the rubber particles-crushed stones cushion.The results show that the increase in rubber content can reduce the natural frequency of the model system,increase the damping ratio,and extend the characteristic cycle.(4)To conduct a comparative study of three seismic isolation cushion systems with different mix proportions of rubber content and those without seismic isolation cushions under the unidirectional seismic excitation and the bidirectional seismic excitation of different seismic waves and different ground motion intensities respectively;to analyze the seismic isolation and reduction performance of the transformer-bushing model based on the analysis of acceleration time history,peak acceleration,Fourier amplitude spectrum and displacement response,and therefore to explore the seismic performance of rubber particles-crushed stones isolation cushion.The conclusions are that the mixture cushion with a rubber mix ratio of 30% has the best seismic performance;the seismic isolation and reduction effect on the body part of the box is better than that in the bushing part,and the overall isolation effect increases with the increase of the input PGA;in addition,the seismic responses of the other two cushions with different rubber mix ratios are significantly amplified at the bushing part.The research introduces the seismic response rules of the rubber particles-crushed stones isolation cushion under different mixture ratios of rubber content in the transformer model,and also explores the impact of mixture ratios of rubber content on the seismic performance of the isolation cushion.This study aims to develop an economical and safe idea of seismic isolation for transformers and other power facilities,and to provide theories and methods for the seismic resistance research of basic isolation cushions of power facilities such as main transformers under earthquake action.