黄土地区路基地段高速铁路无砟轨道环境振动研究

Ballastless track of high speed railway on subgrade section in loess area will make the surrounding environment vibration under the action of the train, the impact is more prominent on nearby buildings, underground pipes, precision instruments and other equipment produced. The systematic research on the issue is lack at home and abroad. This project aims at research of environmental vibration propagation mechanism under the action of train load on high-speed railway ballastless track in loess area by the research method of theory and experiment. The wheel-rail coupling dynamics theory is applied to analyze the action characteristics of the high-speed dynamic train load including amplitude and frequency. With the theoretical parameters through laboratory tests and elastic plastic theory, dynamic constitutive model of undisturbed loess is established. The vibration propagation theory and dynamic constitutive model of loess is applied to analyze the calculated method on vibration propagation caused by the action of dynamic train load. Based on the finite element model including track, subgrade and loess, the vibration characteristic of loess and its influence of correlative factors is researched with the dynamic train load acting. The data support on the vibration propagation characteristics of loess is provided with field test of ballastless track of high-speed railway. Combined the theoretical analysis, laboratory and field test, the propagation mechanism of the Loess vibration is revealed caused by the dynamic loads of high speed trains. The research will be helpful to enrich the environmental vibration theory and to reduce the environmental vibration in loess area in ballastless track of high-speed railway.

黄土地区高速铁路无砟轨道在列车动荷载作用下将产生周边环境的振动，对临近建筑物及地下管道、精密仪器和设备等产生不利影响，目前国内外对该问题还缺乏系统研究。本项目拟针对黄土环境振动问题，对路基地段高速铁路无砟轨道列车动荷载作用条件下，黄土地区环境振动的传播机理进行理论与试验研究。采用车辆-轨道耦合动力学理论，研究高速列车动荷载的幅值和频率等振动特征；在弹塑性本构理论基础上，通过室内黄土特性参数试验，建立原状黄土的动本构模型，然后研究列车动荷载诱发的黄土振动传播计算方法；基于无砟轨道-路基-黄土地基有限元模型，研究列车荷载作用下黄土地基的振动特性和相关影响因素，并通过现场试验研究黄土振动传播特性。通过对计算结果和实测结果的对比分析，揭示路基地段高速铁路无砟轨道列车动荷载诱发黄土环境振动的传播机理。研究成果将为丰富和完善黄土地区高速铁路无砟轨道环境振动理论，降低黄土地区环境振动提供参考。

本项目对路基地段高速铁路无砟轨道列车动荷载作用条件下，黄土地区环境振动的传播机理进行理论与试验研究。采用车辆-轨道耦合动力学理论，研究了高速列车动荷载的幅值等振动特征；同时研究了列车动荷载诱发的黄土振动传播计算方法；基于无砟轨道-路基-黄土地基有限元模型，研究了高速列车荷载作用下黄土地基的振动特性和相关影响因素，在宝兰客专线路路基部分选取了路堤、路堑典型断面，开展了现场试验，对高速列车通过时诱发的黄土环境振动进行了现场测试。对仿真计算结果和实测结果的对比分析，揭示了路基地段高速铁路无砟轨道列车动荷载诱发黄土环境振动的传播特性和传播变化规律。主要研究结论如下。.（1）无论对于高速铁路路基的路堤地段还是路堑地段，数值模拟及现场实测结果均表明，线路两侧的环境振动响应衰减规律基本相同；环境振动强度随距线路中心线距离增加呈衰减趋势。.（2）数值模拟及现场实测结果的频谱分析均表明，高速列车振动频率分布规律相似，距轨道中心线较近处主要是高频起作用，距轨道中心线较远处主要是低频起作用。振动能量随距离衰减过程中高频成分衰减较快，低频成分衰减缓慢。.（3）高速铁路环境振动强度大小与黄土介质特性、行车速度、车辆轴重、线路结构形式等因素有关。黄土地基土含水率越大，环境振动的强度越大；列车运行速度越大，环境振动的振动强度越大；高路堤和深路堑对环境振动具有一定的抑制作用。.（4）数值模拟及现场试验均表明，高速铁路路堤段环境振动强度在随距离衰减的过程中会出现振动反弹现象，且路堤高度越大，振动反弹的位置越远。.（5）对黄土地区高速铁路环境振动的Z振级分析表明，现行的模式预测法不能较好地描述振级的衰减，而仿真预测法的衰减趋势与实测值更为接近，预测效果更好。.项目研究成果对黄土地区高速铁路路基地段环境振动预测、高速铁路结构设计、运营维护及城市规划等具有较强的指导意义，具有较好的应用前景。