Influence Of Interface Connection Damage And Disengaging Of CA Mortar For The Longitudinal Continuously Slab Ballastless Track On The Bridge

CA mortar layer is the critical structural layer connecting track slab with base plate of the longitudinal continuously slab ballastless track structure,and plays the role of filling and adjusting track slab,bearing and transferring load,damping and isolating vibration.With the continuous development of high speed railway in China,the longitudinal continuously slab ballastless track has been widely applied.However,there are different degrees of interface connection damage and disengaging between track slab and CA mortar layer on the bridge due to the increase of service time.To study the influence of interface connection damage and disengaging of CA mortar layer for the longitudinal continuously slab ballastless track on the bridge.First,the current research situation on the mechanical influence of damage of the CA mortar layer for track structure both at home and abroad was summarized,and reasons of interface connection damage and disengaging of CA mortar layer was summarized,as well as current detection means of disengaging,and some repair suggestions were made in different degrees of interface connection damage.Then based on the finite element theory and simplified rational mechanics,3D solid finite element model of ballastless track-bridge was established,which tested and verified at the same time,then 3D solid model of ballastless track-bridge coupling of CA mortar layer with different conditions of interface connection damage and 3D solid model of ballastless track coupling of CA mortar layer with different conditions of disengaging was established by changing contact condition and applying the birth and death of element method,respectively static analysis and the influence of the model of track structure vibration was carried out.Finally,dynamic response analysis was made by the model which was established.Research result shows that:(1)According to the static analysis,interface connection damage changes the stress of track slab and CA mortar layer.As the height of interface connection damage increases,the stress of track slab increases in small range.As the length of interface connection damage increases,the stress of track slab increases as well,and especially after length of interface connection damage exceeds 0.9 m,the stress increases significantly.Under the same condition of interface connection damage,the stress of mid-span track slab on the bridge is bigger than any other positions.(2)Based on the result of dynamic response analysis,disengaging changes the natural frequency of vibration of track structure,and meanwhile,corresponding mode of vibration is also altered.Interface connection damage increases the vibration acceleration of both track slab and CA mortar layer,the increase of length makes the vibration acceleration of track slab nearly doubled.At the same time,the increase of width has little influence on the vibration acceleration of both the track slab and the CA mortar layer.