Abstract:Research purposes : The interface bond damage ( IBD) between the slab and self - compaction concrete (SCC) is one of the most common damages of CRTS Ⅱ slab track. Based on the theory of vehicle - track coupling dynamics and the structural characteristics of CRTS Ⅱ slab track, a spatial vibration model for train - CRTS Ⅱ slab track interaction was established,and the influence law of IBD between the slab and SCC on the vibrations of CRTS Ⅱ slab track was revealed,by comparing the conditions without IBD and those with IBD. Research conclusions :( 1 ) The dynamic responses of CRTS Ⅱ slab track generally increase with the rising of train speed and the depth of IBD,especially for the vertical tension of the fastener,the dynamic responses of the slab,SCC and foundation, as well as the interaction of the interface. Compared with conditions without IBD, the increase amplitude of the vertical tension of the fastener may reach 5 % and 25 % respectively,the increase amplitude of the slab acceleration may reach 30% and 70% respectively,and the increase amplitude of the foundation acceleration may reach 35% and 60% respectively,when the depths of IBD are equal to 0. 25 m and 0. 50 m respectively. (2) When the bond under the entire edge of the slab is damaged,the relative vertical acceleration between the slab and SCC may exceed 2 times larger than the slab acceleration,and the patting between the slab,SCC,and foundation may increase greatly,which may lead to a faster damage of each part and the corresponding interface of CRTS Ⅱ slab track. (3) The depth and length of IBD should be strictly controlled during the maintenance of CRTS Ⅱ slab track. (4) The research results can provide useful references for the maintenance of CRTS Ⅱ slab track.