高铁桩网复合路基环境振动影响因素分析

Factors affecting environment vibration of high speed railway's pile-net composite subgrade

为了研究高速列车动荷载引起的桩网复合路基环境振动的影响因素,运用ABAQUS有限元软件,建立了包含垫层、桩帽、桩体的轨道-路堤-桩网复合地基三维有限元模型。首先以京沪高铁苏州站东侧某段桩网复合路基为背景建立模型,将模拟结果与实测结果对比,验证了该数值模型方法的可靠性。在此基础上,分析了车速、路堤高度及土体阻尼比对高铁复合路基地面环境振动的影响。研究表明,近轨道中心处,车速与路基土体的共振条件决定地面振动大小;距轨道中心远处,地面振动主要由车速决定;路堤高度越高,复合路基中加固范围越大,对列车动荷载引起的地面振动减小越大,原因是垫层和桩体将振动波向路基深部传播;土体的材料阻尼比决定路基远处地面振动,材料阻尼越大,地面振动随距离衰减越快,因此预测路基远处地面振动需要合理的获取确定土体的阻尼比。

To study environmental vibration of pile-net composite subgrade under high speed train dynamic load,a3D track-embankment-pile-net composite subgrade model containing cushions,pile caps and pile bodies was established based on the finite element software ABAQUS.Firstly,a certain segment of pile-net composite subgrade on the east side of Suzhou station in Beijing-Shanghai high-speed railway was taken as the background to build the model,and the simulated ground vibration results were compared with the actual measured results to verify the reliability of the proposed numerical model method.Then,the influences of train speed,embankment height and soil damping ratio on ground environment vibrations of high-speed railway composite subgrade were analyzed.The results showed that at the place near track center,the resonance condition between train speed and roadbed soil determines the intensity of ground vibration;at the place far from track center,train speed mainly determines ground vibration;the higher the embankment height,the larger the reinforcement range in the composite subgrade,the larger the vibration reduction caused by the dynamic load of the train,it is due to cushions and piles transmitting vibration waves into the bottom of subgrade;soil damping ratio determines ground vibration at the place far from subgrade,the larger the soil damping ratio,the faster the attenuation of ground vibration with distance,so it is necessary to reasonably determine soil damping ratio.