Research On The Effect Of Repairing Methods Of Interlayer Gap In Ballastless Track On The Characteristics Of Interlayer Force Transmission

The interlayer gap between the track slab and the CA mortar layer is a common disease of the CRTS Ⅱ slab ballastless track structure,and it is one of the important factors that cause the premature deterioration of the mortar adjustment layer.The quality of the connection between the track slab and the mortar layer is related to the integrity and stability of the entire track structure.In this paper,aiming at the three repair methods of the track slab and the mortar delamination,a meso-level finite element analysis of the ballastless track composite structure based on the cohesion zone model is carried out.the cracking mechanism of interlayer interface and glue-concrete interface of composite structure based on the size of the model in this paper and the influence of three repairing methods on the interlayer force transfer characteristics are studied.Research indicates:(1)When the composite structure repaired by grouting is split and pulled,the damage of the interlayer interface develops from the middle to the two sides,while the damage during shearing develops from the two sides to the middle.The maximum normal stress of the interlayer bonding interface is 2.538 MPa,and the maximum tangential stress is 0.950 MPa.The tensile force of the interlayer connection is greater than the Shear Force.(2)During the splitting and shearing of the composite structure repaired by anchoring by planting bars,the damage of the glue-mixed interface will develop from the seam position to the anchor end of the board.When the composite structure is under tension,the maximum shear stress at the tangential interface between the planted bar glue and the concrete is 3.268 MPa.When under shear,the maximum shear stress in the anchoring bar is 623.55 MPa.The determined interlayer tensile strength is 10.061 kN,the shear strength is 95.988 kN,and the interlayer shear strength is greater than the interlayer tensile strength.(3)When the composite structure repaired by "grouting+planting bar anchorage" is under tension and shear,the interlayer bonding interface will be destroyed before the anchoring interface.During tension,the crack bonding interface expands from the inside to the outside.Extend from outside to inside.During the failure process of the interlayer bonding interface,the glue-mixed interface will accumulate stress at the interlayer bonding interface and crack from the interlayer interface to the anchor end.The tensile strength of the interlayer connection under this repair method is 67.963 kN,and the shear strength is 117.349 kN.The shear resistance of the interlayer connection is greater than the tensile strength.(4)When the composite concrete structure bears the tensile force,the bearing capacity of "grouting+planting bar anchorage" repair is greater than the bearing capacity of grouting repair,and the bearing capacity of both is greater than the bearing capacity of the planting bar anchorage repair of the composite concrete structure;The composite concrete structure bears shear force,the bearing capacity of "grouting+planting bar anchorage”is greater than the bearing capacity of planting bar anchorage restoration,and the bearing capacity of the two is greater than the bearing capacity of grouting restoration.