Experimental Study On The Desert Sand Isolation Cushion Modified By Village And Town Buildings In Northwest China

In the implementation of the country’s rural revitalization strategy,ensuring the seismic safety of rural houses is the connotation of beautiful and livable rural construction.In the past major earthquakes,the seismic safety of village and town buildings is not optimistic.According to the characteristics of northwest rural buildings,the use of desert sand in the base isolation cushion can mitigate the effect of earthquakes and solve the problem of earthquake resistance of houses at low cost.In particular,the surrounding desert resources in Ningxia are rich,and there are broad prospects for promoting desert sand-isolated buildings.In this paper,the key research and development project of Ningxia Hui Autonomous Region(2016KJHM38),according to the architectural characteristics of northwest villages and towns,using small-scale shaking table test and finite element numerical analysis to study the working mechanism and seismic reduction effect of modified desert sand base isolation cushion The main research work and conclusions are as follows:(1)Introduces the background and development of the isolation structure,shows the significance of the proposed isolation layer of the desert sand foundation,briefly describes the isolation principle of the isolation layer of the desert sand foundation,and establishes the friction-slip model of the isolation structure To explain the equation of motion of the desert sand isolation cushion and its deformation and motion principles,and to elaborate the judgment conditions of slippage.(2)The isolation performance of the desert sand base isolation cushion is restricted by two factors.One is the earthquake intensity,and the other is the friction of the cushion against the superstructure.In order to reduce the friction between the superstructure and the cushion,and make the cushion exert the effect of seismic isolation as soon as possible,the cushion structure is used to protect the building structure more efficiently,and the seismic performance of the pure desert sand isolation cushion is further improved.A modified small-scale shaking table test was conducted on the desert sand isolation cushion to study its isolation performance under the action of earthquake and the optimal modification plan.(3)According to the results of the simple shaking table test,using the damping coefficient β as an index to quantitatively evaluate the damping performance of the modified desert sand base isolation system,and discusses the damping of the modified desert sand cushion under different seismic waves The coefficients are gradually decreasing with the increase of the peak value of seismic wave acceleration.The performance of graphite incorporation is slightly better than that of rubber particles.The 30%graphite incorporation is the optimal ratio.The desert sand base isolation cushion The isolation effect is the best.(4)Use finite element software to establish the seismic and isolation model of the desert sand base isolation cushion,verify the reliability of the model based on the previous simple shaking table test results,and take the three-layer frame structure as an example to analyze the use of modified desert sand Seismic response of simple frame structure after isolation cushion.The finite element simulation results are in good agreement with the overall law of the shaking table test results.It reflects that the desert sand isolation cushion can effectively reduce the transmission of seismic energy to the upper building,extend the natural vibration period of the structure,increase the damping of the structure,and achieve the effect of isolation.