2.5维有限/无限元法分析沟渠对列车引起振动的隔振研究

Research on train-induced ground vibrations by 2.5D finite/infinite element approach

近年来为了缓解城市的交通拥堵问题,城市建立了越来越多的轨道交通系统。列车行驶引起的周围环境的振动问题受到越来越多工程界和学术界的关注,本文首先研究了移动荷载引起的半空间稳态动力响应问题,并将2.5维数值解和理论解进行对比验证。通过假定土壤-结构系统属性沿着轨道方向保持不变,将列车荷载简化为移动点荷载,研究沟渠的隔振效果。研究表明,沟渠对高自振频率的隔振效果较低频率好;远处观测点隔振效果与沟渠位置关系不大;低振动频率移动荷载,需要较深的沟渠才能取得较好的隔振效果;增大沟渠宽度对隔振效果提升并不显著。

In recent years,more and more subways and high-speed railways have been built to alleviate traffic congestion in big cities.The problem of vibration induced by moving train has attracted the increasing attention from the domain of research and engineering.In this paper,the steady-state dynamic response of half-space due to the moving load is discussed,and the accuracy of the 2.5 D result is verified by comparing with the theoretical solution.Assuming the material and geometric properties of the soil-structure system to be identical along the railway direction,simplify the load of train into a moving point load and do the research on the vibration isolation alongside the railway by open or infilled trenches.The major conclusions drawn from the results include:Open trenches are good for reducing train-induced vibrations with higher self-oscillation frequencies.Effect of isolation on vibration in far field can little be influenced by the distance of trench,which is same to the width of trench.Deeper open trench is needed to isolate the vibrations with lower self-oscillation frequencies.