Study on the hydraulic characteristics of interlayer crack of CRTS Ⅲ slab track under train loads

In areas with abundant rainfall or poor drainage, standing water significantly accelerates the expansion of interlayer cracks in slab tracks. To solve the hydraulic characteristics problem of CRTS Ⅲ slab track with interlayer cracks, a two-way transient fluid-solid coupling calculation model was established. The model considered the coupling effect of train load and water accumulation in the crack. The distribution of dynamic water pressure and water velocity and the change of peak value in the gap between layers of ballastless track were revealed. The effects of train axle weight, train speed, crack morphology, and depth of water accumulation on dynamic water pressure and water velocity were analyzed. The results show that the dynamic water pressure and water velocity at the fixed points in the interlayer crack exhibit alternating positive and negative periodic changes as the train approaches and moves away. The dynamic water pressure decreases gradually along the exit direction of the seam, with its peak occurring at the tip of the crack, while the water velocity increases gradually along the exit direction of the seam, with its peak occurring at the seam outlet. The peak values of dynamic water pressure and water velocity increase linearly with the increase of axle weight. When the axle load increases by 1 t, the peak values of dynamic water pressure and water velocity increase by 2.850 kPa and 0.085 m/s, respectively. The peak dynamic water pressure has a quadratic increasing relationship with the vehicle speed, while the peak water velocity is linearly related to the vehicle speed at speeds less than 300 km/h, and the trend of flow velocity growth is more rapid after exceeding this speed than before. The peak values of dynamic water pressure and water velocity are inversely proportional to the opening volume. They both increase significantly with the increase of the crack depth and crack water depth. The relationship between them follows a cubic polynomial function with crack depth and a quadratic function with crack water depth. These findings provide a basis and reference for analyzing the expansion of interlayer cracks in CRTS III slab tracks under the coupling effect of train load and water, as well as for curing and repair work. © 2024 Central South University of Technology. All rights reserved.