Experimental Study On Vibration Isolation Table Of Geo-reinforced Rubber Sand Composite Cushion

In many earthquakes such as Wenchuan earthquake,Yushu earthquake and Ya'an earthquake,the low-multistory houses are destroyed seriously,it is important to study the low-cost isolation method.The automobile industry is booming and the waste tire is increasing,causing many environmental problems.Mixing waste tires into rubber particles and sand can improve the isolation performance of foundation.The shear modulus and compression modulus of pure rubber sand cushion(RSM)are small,which results in large shaking under horizontal earthquake.In order to improve the overall stability,three kinds of reinforcement methods,Soilbag,Geocell and Geogrid,are proposed in this paper.In this paper,a simple device test is carried out around SBRSMC,GGRSMC and GCRSMC,and a supplementary test of the shaking table in the later stage.The main contents of the research are as follows:(1)A simple device test is carried out for SBRSMC with three thickness in four layout.The acceleration time history and FFT curve under different conditions are compared and analyzed.The results are as follows: the isolation coefficient is the smallest when the thickness of 14cm(21cm/30cm)is staggered(horizontal/Vertical),and the optimum isolation layer is the three layers when the horizontal and longitudinal are laid,and the isolation coefficient is little affected by the thickness when the thickness is staggered.(2)The shaking table test of SBRSMC shows that: the isolation effect of SBRSMC is mainly influenced by the thickness of the cushion,soilbag filling ratio and the quality of the upper structure weight,while is less influenced by the laying pattern of soilbag.The isolation effect of SBRSMC increases with both the thickness of the cushion and the quality of the upper structure weight,while decreases with the filling ratio of soilbag.However,the rate of damping coefficient decreases with the increase of cushion thickness and the decrease of soil bag filling ratio.SBRSMC with thickness 21 cm and soilbag filling ratio 60% is the reasonable suggestion of this study,as both the isolation effect and economic cost are taken into considered.(3)The simple device test of GCRSMC and GGRSMC is carried out from the two factors of cushion reinforcement and non-reinforcement and cushion thickness.The results show that the isolation effect of reinforced rubber sand composite cushion is obviously better than that of non-reinforced cushion.The isolation effect of SBRSMC increases with both the thickness of the cushion and stiffened layers in the range of test.(4)The comparison of SBRSMC GCRSMCG GGRSMC with other simple methods shows that :The isolation effect of geo-reinforced rubber sand composite cushion is demonstrated better than both pure sand cushion and rubber sand cushion,and its isolation coefficient is nonlinear attenuation with the increase of input acceleration amplitude.(5)The isolation effect of geo-reinforced rubber sand composite cushion(GRRSMC)excited by both sine loading and El centro earthquake loading is good,which shows that the isolation effect of GRRSMC is not related to the input waveform.The effect of isolation is universal and can be used as a low-cost isolation method to mitigate earthquake induced disasters of low-rise buildings,in which the rural houses are typical representatives.