Site Soil Response From Moving Loads And Research Of Barrier Isolation

With the continuous development of modern industry in our country, the vibration problem caused by production, transportation, construction and other activities for people’s normal life and work is increasingly outstanding. So, the study is of great significance to vibration isolation measures. Vibration isolation is set a barrier which between the vibration source and the protected object that perpendicular to the surface, when the shock wave encounters barriers in the communication process, due to the different wave impedance of the two media,shock wave will appear the phenomenon of reflection and refraction, thereby forming a surface shield region of the vibration reduction, reducing the shock wave energy input, achieve the purpose of protecting structures. Such measures have good isolation effect, wide range of applications, has been widely used in practice.In the paper, according to the environment vibration problem caused by moving load, make a series of research of the barrier isolation measures and the factors which influence the vibration isolation effect. Based on the investigation of the domestic and foreign literature, the research content of this paper are put forward. Firstly, analyzes the soil vibration wave properties, and establishes a moving load-foundation soil numerical model, studies propagation and attenuation characteristics of the vibration wave; then analyzes the method of barrier isolation, simulates the three isolation of isolation trenches, sheet pile-open trench combination barrier and WIB, and analyzes the isolation effect of the impact of depth, position and width of isolation trenches, and the isolation effect of the impact of the sheet pile material of sheet pile-open trench combination wave barrier, and the isolation effect of the WIB’s depth, thickness and width.Summarizes the parameters of each the barrier’s appropriate choice,and provides reference for the isolation barrier engineering applications that apply to the environmental vibration problems that caused by moving loads.Main results:(1) environment vibrations generated by train moving loads,for the vibration more than 40 Hz, the isolation trench can reduce the amplitude of the vibration energy more than 80%, and the isolation has a good effect; but for the low-frequency vibration, there is little vibration isolation effect. Depth isthe primary factor affecting its isolation effect, the deeper the better vibration isolation effect; position followed by, and the vibration isolation in the near field effect is superior to the far field; the influence of width is the weakest.(2) sheet pile-open trench combination wave barrier can improve the small amplitude of the effect in comparison with the open trench alone, but it still can’t change to the defects of that low frequency vibration isolation effect is not good; sheet pile material impact on its isolation effect is more obvious, in the three different materials of sheet pile, metal foam sheet pile vibration isolation effect is best.(3)WIB isolation effect is better than isolation trench and sheet piles-open trench combination’s around 20 Hz vibration, and the buried depth, thickness and width of WIB has certain influence on the vibration isolation effect.