Experimental and Numerical Investigations of Structural Performance of Slab Track under Hygrothermal Environment

Abstract

The coupled heat and moisture actions could easily cause deformation, cracking and corrosion problems in the slab ballastless track under operational conditions via China Railway Track System (CRTS) Ⅱ. In this paper, two one-quarter-scaled models of CRTS Ⅱ slab ballastless track under hygro-thermal environment were tested in a testing chamber, respectively. To study the effect of constrained conditions on the structural performance of track structure, temperature distribution, stress and displacement of two scaled models with constrained and free boundary conditions were also compared. Then, the temperature and stress field of the track structure was investigated by establishing a finite-element model. The results showed that the temperature transfer between layers has a temperature-lag effect. The positive and negative temperature gradients between the lower part of the track slab and the cement asphalt (CA) mortar layer of the constrained specimen are smaller than those of the free specimen. The longitudinal displacement of the track slab for the free specimen is significantly affected under the hygro-thermal environment and the longitudinal displacement of the concrete base and the track slab forms a displacement difference. Numerical-analysis results showed that the bottom of the concrete base is prone to produce a high-temperature core and that the temperature inside the track structure forms an agglomeration effect. KEYWORDS: Slab track, Hygro-thermal environment, Structural performance, Scale model, Finiteelement model.

Mechanical Properties of Slab Ballastless Track Subjected to Combined Effects of Loading and Temperature

“…The CRTS Ⅱ ballastless track-bridge has been widely used in China's high-speed railway construction because of its good stability and comfort. For example, Beijing-Shanghai high-speed railway bridge accounted for 80.47% of the line (Liu et al, 2019;Feng et al, 2019;Jiang et al, 2019;Song et al,2023). The CRTS Ⅱ ballastless track-bridge is a multi-layer heterogeneous structure which mainly consists of track slab, cement asphalt (CA) mortar layer, concrete base, wide-narrow joints and simply-support bridge, as shown in Fig.…”