Study On The Dynamic Response And Vibration Isolation Of Layered Soil Under The Elevated High Speed Railway

With the development of economy and the progress of science and technology in China, more and more elevated high speed railway has been built.Although high speed trains are convenient for people to travel, the bad effect along the line caused by them can not be ignored at the same time. The vibration caused by high speed train will not only aggravate the damage speed of the building along the road, but also affect the use of precision instruments in the industrial equipment factories and laboratories. The noise caused by train will also affect the life, study and work of residents along the line. In order to reduce these adverse effects, it is important to study the propagation and attenuation law of vibration wave in layered soil caused by high speed railway, and set vibration isolation measures to reduce the vibration of soil.In this paper, the typical high speed railway is used as the research object,and the vibration of the surrounding soil caused by elevated high speed railway is studied by numerical simulation. Then different vibration isolation measures are set up, and the vibration isolation effect of different vibration isolation measures are discussed respectively. Elevated high-speed rail dynamics system is decomposed into two subsystems, which including train- bridge subsystem and base- layered foundation soil subsystem. At first, through the train- bridge subsystem to simulate the train driving on the bridge and get dynamic reaction force at the bottom of the pier by the transient analysis, Which will been applied in base- layered foundation soil subsystem. Based on this, the influence of the depth and distance of empty ditch, filling material of in-filled trench and the depth and thickness of WIB on the vibration isolation effect is studied.The results show that the depth of empty ditch has great influence on the vibration isolation effect, and which will be better with the increase of the depth.But for the pile foundation,the depth of empty ditch must be large enough to have an ideal vibration isolation effect. Empty ditch set at the near-field has better vibration isolation effect than set at the far-field. Filling material of in-filled trench has great influence on the vibration isolation effect, and flexible material such as rubber and foam has better vibration isolation effect than rigid material such as fine sand. The deeper the WIB is, the better vibration isolation effect they have, but the effect is not quite different. The thickness of WIB has greatinfluence on the vibration isolation effect, and WIB has better vibration isolation effect with the increase of thickness, but this effect is obvious only in the area of S < 28 m.