The Vibration Isolation Performance Analysis About The Gravel Mattress Foundation Of The Building

In this paper the gravel layer what we study is one kind of new research of isolation mode. It is laid a layer of uniform thickness of certain medium materials (mainly with particle size distribution requirements of gravel or pebble) between the basic and the foundation, and composed a new kind of composite foundation with the original foundation. The upper structure can be as a whole when the earthquake happens. In the process of inputting earthquake energy into the buildings, gravel granular redistributes and dissipates the earthquake energy. It can reduce the earthquake energy inputting into the up of the building, and ensure the safety of the building in the earthquake.Because of inputting into the upper structure of attenuated seismic wave, the equivalent seismic force and vibration equation can be controlled. Due to gravel mattress is the intermediary dissipating energy layer and its shear stiffness is very small, so it can control the earthquake energy of transmitting to the upper structure (by adjusting the thickness and mechanical parameters of gravel mattress). At the same time as the adjustability of gravel and collaborative workability of foundation soil, the structural vibration periods appropriate grows and amplitude decreases. So it can achieve the purpose of vibration isolation. Firstly, the paper introduces the development of the damping control technology of the structure, the advantages and disadvantages of base-isolated rubber cushion structures, the advantages of vibration isolation of gravel mattress composite foundation, and determines the vibration isolation of the gravel mattress as this paper's research topic. Then, this paper quotes dynamic performance parameters of railway construction ballast, selects appropriate physical parameters and its applications in gravel mattress shock isolation research; and briefly introduces the explicit format of the finite element software ANSYS/LS-DYNA.Moreover, this paper studies the simplified calculation of all sorts of structure of gravel mattress composite foundation in horizontal earthquake; draws into the ballast dynamic performance parameters, establishes dynamic differential equations of motion of the gravel mattress, and carries on the detailed algorithm.Finally, the paper detailed analyses anti-seismic performance of specific cases engineering with large finite element software ANSYS/LS-DYNA using the mentioned research theory. Due to the rich resources of gravel, draw materials easily, low cost, simple construction process and quality control, and good anti-seismic performance, gravel mattress has a prospect as a kind of shock-isolation methods in seismic prone regions.