Investigation of the seismic performance of CRTS III slab ballastless track of high-speed railway under low-cycle reciprocating load

Abstract

In the China Railway Track System (CRTS) III slab ballastless track (SBT) system, the self-compacting concrete filling layer (SCCFL) and the base slab are connected via a rubber pad, geotextile, convex platform, and groove. This is a complex interaction between the SCCFL and base slab. As a buffer member between SCCFL and base slab, the rubber pad significantly impacts the seismic performance of CRTS III SBT. To explore the failure mode and seismic performance of CRTS III SBT, four CRTS III SBT specimens with different rubber pad thicknesses were designed and subjected to low-cycle reciprocating load tests in this study. The characteristics of the load-displacement hysteresis curve and load-displacement skeleton curve of CRTS III SBT specimens were then analysed. The failure mode, energy-dissipation capacity, ductility, stiffness degradation of CRTS III SBT specimens, and the influence of rubber pad thickness on the seismic performance of CRTS III SBT specimens were studied. It was found that when the low-cycle reciprocating loading was applied on the CRTS III SBT specimens, the interlayer bonding between the SCCFL and the base slab was the first to fail, followed by compressive deformation of the rubber pad. The concrete at the convex platform-SCCFL interface cracked, and the concrete in the four corners of the groove cracked until failure. When the rubber pad thickness was increased, the ultimate bearing capacity of the CRTS III SBT specimens under low-cycle reciprocating loads remained constant. However, the corresponding energy-dissipating capacity, ductility, and seismic performance all improved.