Abstract: This paper presents the three dimensional dynamic analysis of traintrack system in a transition zone over culverts in the WuhanGuangzhou high speed rail project. The dynamic response of the subgrade of the transition zone under an operational train speed of 350 km/h is studied. The following results are observed: 1) The dynamic displacement, vibration velocity and acceleration of the soils particles in the vertical direction at both the top and the bottom of the subgrade have minimum values at the crown of culverts. A rapid increase of these values can be found at the culvert sides. The dynamic stress distributions are at the 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 meter below 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 flatter reduction. The insitu monitoring results are similar to the numerical analysis results.

Key words: WuhanGuangzhou High Speed Rail, Transition Zone, Subgrade, Culverts, Dynamic Simulations