ANALYSIS OF DYNAMIC RESPONSE BY TRANSITION ZONE OF SPEED-RAISE RAILWAY

In order to evaluate the improvement level of track structure dynamic response by the transition zone between railraod and bridge of speed-raise railway, the research is made on the design and test of track dynamic response of transition zone of Beijing-Kowloon Line in this paper. The transition zone was filled by 20m gradation crushed stones and the test parameters to track dynamic response were rail vertical force, rail acceleration and tie acceleration. The test shows if there is a transition zone at junction location between railroad and bridge, when train runs from the rail of low rigidity to the rail of high rigidity, the rail vertical force, rail acceleration and tie acceleration gradually change from small to large without sudden change. When train runs from the rail of high rigidity to the rail of low rigidity, the rail vertical force, rail acceleration and tie acceleration gradually change from large to small. If there is no transition zone at junction location between railroad and bridge, when train runs from the rail of high rigidity to the rail of low rigidity, the dynamic response becomes small suddenly with sudden change. It is known from the analysis of the tests to the junction location with transition zone and without transition zone, when the train's speed is less than 200km/h, the transition zone filled by 20m graduation crushed stones can assist reducing track dynamic response of transition zone.