Effects of temperature changes on the thermomechanical behavior and interface stress of longitudinal connected slab track

In the context of modern railway systems, ensuring the structural integrity and longevity of longitudinal connected slab tracks under variable environmental conditions is paramount. This study aims to address the critical gap in understanding how diurnal temperature variations affect the deformation and interface integrity of such tracks, specifically within the framework of the China Railway Track System II (CRTS II). Employing a sophisticated three-dimensional model and leveraging the cohesive zone model (CZM) for simulating interface bonding behaviors, the research meticulously evaluates the temperature profiles, thermal deformations, and interface stresses of the slab track under daily thermal fluctuations. Notable findings include the observation of significantly higher temperature gradients in summer, with peak positive gradients approximately twice those of negative gradients. The analysis reveals pronounced deformation near the slab edges—arching due to positive gradients and warping under negative gradients, with arching deformation magnitudes substantially exceeding those of warping. Interface stress distribution proved to be non-uniform, with the highest stress concentrations near the slab edges reaching up to 0.094 MPa at 13:00. Seasonally, summer presents the greatest challenge regarding thermal deformation, interface stress, and damage, underscoring the necessity for enhanced monitoring and maintenance strategies during high daytime temperatures. The investigation concludes with the finding that minor interlayer bonding damage predominantly occurs at the track edges, yet does not escalate to full bonding failure or extensive cracking, thus preserving the structural integrity overall.