层状地基中填充沟对不平顺列车动荷载的隔振效果研究

 建立列车–轨道–地基相互作用模型，将轨道简化为铺设在地基上的欧拉梁，推导轨道不平顺条件下列车荷载的半解析隐式表达式。将填充沟视为地基中的异质体，推导内含异质体弹性半空间的2.5维有限元法表达式。分析列车在低速和高速运行条件下填充沟对不平顺列车动荷载作用下地基振动的隔振效果，分析参数包括沟宽、沟深、沟距及填充料。研究结果表明：列车高速运行时，填充沟的隔振效果较好；增加沟深及沟宽均可增加填充沟的隔振效果；沟前地表出现一定范围的振动增强区，沟深越深，沟宽越宽，振动增强越明显；非刚性材料由于具有较大的材料阻尼作用，在沟前及沟后都有较好的隔振效果。相关成果可为列车产生环境振动的理论分析和工程应用提供参考。

VIBRATION SCREENING EFFECT OF IN-FILLED TRENCHES ON TRAIN DYNAMIC LOADS OF GEOMETRIC IRREGULAR TRACK IN LAYERED GROUNDS

A 2.5D finite element method(FEM) model of train-track-ground is built to analyze the train induced ground vibration with geometric irregular track. Then the expression of train loads is obtained implicitly by simplifying the track as an Euler beam resting on the layered ground. The 2.5D finite element formulas are derived by taking the in-filled trench as heteroplasmon. The screening of in-filled trench on ground under moving train load at high-speed and low-speed is analyzed. Then the parameters of in-filled trench are analyzed in detail. The parameters herein include the width，depth，distance and materials of the in-filled trench. The results show that，the screening as train runs at high-speed is better than that at low-speed train. In addition，increasing the depth and width of the in-filled trench can improve the screening under moving train load；vibration enhancement area appears in a certain range in front of the trench；the isolation effectiveness of nonrigid materials is better than that of concrete in front and back of the trench. The results will contribute to the theoretical and technical development of the screening of ground vibration induced by train load.