Experimental study on deformation characteristics of ballastless tracks under downward bending deformation of long-span cable-stayed bridge

Abstract

Laying ballastless tracks on long-span cable-stayed bridges is a new attempt. This has become an obstacle to the development of high-speed railway technology, which needs further research. The deformation characteristics of ballastless tracks are affected by the behaviors of long-span cable-stayed bridges. Meanwhile, the deformation conditions of long-span cable-stayed bridges also impose higher requirements for ballastless tracks. In this work, a segmental model was developed in laboratory, on which various types of ballastless tracks were paved. Based on this, the maximum downward bending deformation condition of a long-span cable-stayed bridge was obtained to investigate the deformation characteristics of ballastless tracks. The obtained experimental results indicated that interlayer deformation and pressure were linearly increased with the increase of test load. Moreover, the interlayers of ballastless tracks with EPDM isolation layer are always in a state of compression due to the pre-compressions of EPDM isolation layer produced in construction stage. However, interlayer defects are formed at the ballastless tracks with geotextile isolation layers, which can affect their durability and reliability. Therefore, reasonable arrangements of isolation layer highly coordinated deformations between long-span cable-stayed bridges and ballastless tracks. It should be noted that the feasibility of laying ballastless tracks on long-span cable-stayed bridges can be improved by using unit-plate ballastless tracks with elastic isolation layers.