Interlayer Performance Analysis Of CRTSⅡ Board Based On Quasi-distributed FBG Sensor

With the rapid development of the past ten years,the construction of high-speed railways in my country has also reached a climax.The proportion of high-speed railway bridges has exceeded 50%.With the long-term operation of high-speed railway ballastless tracks,the long-term impact load of trains and other factors Under the action,the cement asphalt mortar(CA mortar)layer in the ballastless track II type slab has various problems,such as: damage,separation,and void.The existence and development of these diseases will seriously affect the operation safety of trains and the personal safety of passengers.Therefore,it is urgent to analyze the interlayer performance of high-speed ballastless tracks on high-speed railways,especially on bridges.In view of the above problems,the interlayer performance of the CRTSⅡ plate on the bridge is studied,and a suitable quasi-distributed fiber grating sensing monitoring scheme is designed.The main work contents and conclusions are as follows:(1)Fully investigate the performance of ballastless track at home and abroad and the application of fiber grating sensors in railway engineering.On this basis,a quasi-distributed grating sensor monitoring network is designed,and a CRTSⅡ with shearing steel bar diameter as the parameter is designed.Pattern scale experiment.(2)The seismic performance test of high-speed railway CRTSⅡ slab was carried out,and its failure characteristics,hysteresis curve,skeleton curve and ductility properties were studied in depth.Experiments show that increasing the diameter of shear reinforcement improves the bonding force and ductility of the interface between the track slab and the CA mortar layer,thereby improving the seismic performance of the CRTSⅡ slab,but at the same time,it will also cause greater damage to the concrete around the track slab shear reinforcement.influence,revealing the failure mechanism of CRTSⅡ plate under the action of low cyclic reciprocating load and vertical pressure.(3)The interlayer performance test of quasi-distributed fiber Bragg grating sensor monitoring CRTSⅡ plate was completed.The variation characteristics of the strain of the track slab,CA mortar layer and base slab under the action of low-circumferential reciprocating load and vertical pressure are analyzed.The results show that the track slab,CA mortar layer and base slab undergo three stages of elasticity,elastoplasticity and failure under the action of low-cycle reciprocating load,but the regularity is not obvious under the vertical pressure.The performance change of the track slab after the separation of the CA mortar layer was analyzed.The results showed that after the track slab was separated from the CA mortar layer,under the action of horizontal force,the CA mortar layer and the base plate of the ballastless track embedded with shear steel bars increased with The strain decreases with the increase of displacement,while the strain of CA mortar layer and base plate of ballastless track without shear reinforcement is basically unchanged with the increase of displacement;under the action of vertical force,the strain of track plate is much larger than that of CA mortar layer.Provide the basis for the application of quasi-distributed fiber grating sensor to ballastless track.