武广高铁某涵路过渡段动力特征分析

以武广高铁密集涵洞过渡段为例,建立了列车-轨道耦合的三维动力学分析模型,分析了350km/h高速行车条件下过渡段路基的动力响应特性。分析表明:①过渡段路基基床表层、底层的竖向振动的位移、速度、加速度均在涵洞顶最小,在涵洞侧面出现较快速增长;动应力的变化趋势则与之相反,在涵洞顶最大,涵洞两侧逐渐降低。②动响应沿路基深度呈指数函数形式衰减,基床表层至基床底层衰减较快,路基面下1m左右动响应幅值衰减渐趋于平缓,路基面下3m动响应衰减基本趋于稳定。其中振动加速度衰减最为明显,动位移、振动速度、动应力衰减则相对较缓。现场实车试验测试值与仿真计算值较为接近,表明采用的仿真分析方法较为可靠。

Comparative Analysis of the Dynamic Characteristics of DK1252 Approach Culvert in Wuhan-Guangzhou High Speed Rail

This paper presents the three dimensional dynamic analysis of train-track system in a transition zone over culverts inthe Wuhan-Guangzhou high speed rail project. The dynamic response of the subgrade of the transition zone under an operationaltrain speed of 350 km/h is studied. The following results are observed 1） The dynamic displacement, vibration velocity andacceleration of the soils particles in the vertical direction at both the top and the bottom of the subgrade have minimum values atthe crown of culverts. A rapid increase of these values can be found at the culvert sides. The dynamic stress distributions are atthe opposite of the trend： It reaches the maximum value at the crown of culverts and creases towards the sides. 2） ： The degradation of the dynamic stress has an exponential relationship with depth and a plat pattern can be found at a depth of one meterbelow the ground. At a depth of three meters below the ground, the dynamic stress approaches a constant value. A rapid decease in the vibration acceleration can be found and the dynamic displacement, vibration velocity and dynamic stress have flatterreduction. The insitu monitoring results are similar to the numerical analysis results.