Research On The Influence And Repairing Effect Of Hydraulically Bounded Layer Fracture Of CRTSⅡ Slab Track

CRTS II slab track is widely used in high-speed railway across China. Along with the operating of more and more high-speed rail lines, the damage of ballastless track gradually appears. Hydraulically bounded layer (HGT) or concrete base layer (BTS) and the filling layer are structrues where the damage are concentrated. Investigation on the damage of ballastless track is numerous, but research on the disease mechanism of ballastless track is less at home and abroad.This thesis mainly studied the fracture mechanism of HGT in CRTS II slab track, and the impact on ballastless track and vehicle was calculated. The main research contents are as follows:(1) Based on field investigation and research, the damage form of CRTS II slab track was summarized. The causes of diseases of HGT was analyzed. Furthermore, the fracture mechanism of HGT was studied from inner and outer aspects.(2) The static and dynamic mechanical properties of track structure after the fracture of HGT was studied. The results show that, under overall cooling load, vertical displacement of rail, longitudinal stress of slab track, vertical and longitudinal displacement of slab track and HGT will be influenced significantly, while under vehicle load, influence on longitudinal stress of slab track, vertical displacement of slab track and HGT will be tremendous.(3) Based on vehicle-track coupling dynamic, the wheel-rail dynamic response and influence of HGT fracture on track and vehicle was studied. The results shows:HGT fracture has little impact on vibration response of vehicle. As the speed of vehicle increases, the kinetic index increased significantly, but with the increase of the crack width, vertical displacement of track structures and acceleration of track slab and HGT changes greatly, while the vibration response of rail does not.(4) The repair effect of HGT was studies. The conclusion is drawn as follow:with the increasing of crack width under heating load while the elastic modulus of the material to repair remains the same, the stress of HGT and repairing material gradually increases, but under train load the stress decreases with slight change. With the increasing of elastic modulus of repairing material under heating load or train load while the crack width remains, the stress of HGT and raping material increases and gradually flattens. According to the result, a convenient repairing method was proposed.