无碴轨道路基基床动力特性的研究

以遂渝线无碴轨道路基为背景，通过室内模型试验研究，分析了在循环加载条件下路基基床的动态力学特性。试验结果表明，动应力响应在基床表层横断面方向上呈“W”形分布，混凝土基础板轨下位置响应最大，中线处和端部响应较小，但随着深度的增加，逐渐变为盆形分布特征；在基床表层范围内，动态响应最为强烈，且随深度的增加，衰减速率较快；加载频率对动应力影响较小，对动位移及加速度影响较大。另外，在遂渝线无碴轨道综合试验段现场实车试验中，分别进行了CRH2型动车组和货物列车不同运行速度下路基基床的动力学响应测试研究，验证并评价了遂渝线无碴轨道路基基床工程适应性。

Study of dynamic characteristics of soil subgrade bed for ballastless track

Based on Suining-Chongqing high speed railway, the dynamic characteristics of ballastless track soil subgrade are analyzed through an indoor large-scale model test under dynamic loading. The result indicates that along the subgrade surface cross section, dynamic responses have the W-shaped distribution. But gradually become the basin-shaped distribution with the increase of depth. The largest dynamic response measured are under the concrete track position base, while the responses under the centre-line and the two ends of the concrete slab are smaller. The most intense dynamic responses are measured on the surface and graded gravel area; it reduces sharply with the increase of depth. Dynamic stress is slightly affected by loading frequency, while acceleration and dynamic deformation are fairly affected by it. In addition, a comprehensive field test has been conducted on the test course in Suining-Chongqing line by using CRH2-EMUs and freight train. The dynamic response of ballastless track subgrade under diffident speeds have been collected and the dynamic characteristics are analyzed. The results verify the suitability and adaptability of subgrade construction on Suining-Chongqing line.