Study On Influence Of Interface Connectiondamage And Mortar Disengaging Of The Longiyudinal Continuously Prefabricated Ballastless Track In Turnout Area

The successful construction of longitudinal continuously prefabricated ballastless track (LCPBT) on Wuhan-Guangzhou Passenger Dedicated Line (PDL) and Beijing-Shanghai High Speed Line shows that LCPBT is a new turnout area ballastless track structure which is suitable for the construction of our country’s high-speed railway. The LCPBT used in turnout area on bridge is composed by turnout components, prefabricated turnout slab, asphalt cement mortar, base plate and limit location structure. The asphalt cement mortar, which combines turnout slab and base plate together, is an important component in track structure which plays an important role of supporting, buffering and adjusting.The property of asphalt cement mortar under the turnout slab is complicated. It is sensitive to temperature change and train load, so mortar damage such as interface connection damage between mortar and slab or mortar disengaging is inevitable during turnout’s operation. It’s still not very clear that whether the interface connection damage or mortar disengaging would effect slab’s stability and mechanical behavior. This paper focuses on interface connection damage and mortar disengaging. The main research work is divided as follows:(1) Based on field investigation, the forms of mortar damage was summarized, and the interface damage was divided to interface connection damage and mortar disengaging. The cause and development mechanism of the interface connections damage was emphatically elaborated from the viewpoint of the performance of asphalt cement mortar and theory of interface damage of bi-material.(2) Simplified rational mechanics, finite element analysis statics model for the LCPBT used in turnout area on bridge was established. Using the finite element method to simulate the relationship between the mortar and track slab in normal state and damage state. Considering under the temperature load and temperature gradient alone or coupling, mechanical behavior and stability of turnout structure with different interface connection damage positions and different interface connection damage size was calculated and analysed.The study showed that, as one of the main damage forms of ballastless track, interface connection damage impacted relevantly great to turnout structure’s stability. Under temperature load or temperature gradient alone or coupling, interface connection damage had little impact to track structure’s mechanical behavior and deformation, but had more impact to the mortar’s limit location property. Damage at the edge of slab impacted most, damage at the corner of slab impacted relevantly small, and damage at the middle of slab impacted lowest.(3) Based on the statics model of LCPBT used in turnout area on bridge, interface relations under mortar disengaging was simulated. Considering the temperature load and temperature gradient alone or coupling, mechanical behavior of slab track structure with different interface connections damage forms and size was calculated and analysed.The study showed that, as one of the main damage forms in ballastless track, mortar disengaging impacted obviously to slab and mortar’s mechanical behavior and deformation.