Hydraulic damage characteristics of cracks adjacent to sleepers of concrete slab

In order to investigate the hydraulic damage characteristics of cracks adjacent to twinblock sleepers and estimate its fatigue life, an analytical expression of the hydrodynamic pressure in cracks under the external load was derived, and a hydraulic fracturing model of twinblock sleeper has been established based on the vehicle-track coupling dynamics theory and fracture mechanics theory. In addition, a laboratory test was conducted to verify the hydrodynamic pressure expression. It was observed that the computed results are in good consistent with the experimental results. The value of the hydrodynamic pressure in the crack peaks when the wheelset is close to the cracking area, while the hydrodynamic pressure is zero when the wheelset or the bogie reaches the damaged area. Numerous factors affect the hydrodynamic pressure and the effective stress intensity factor, including the train speed, crack opening, and crack length. In comparison, the hydrodynamic pressure and the effective stress intensity is more sensitive to the crack opening. The initial crack length is the main factor affecting the fatigue life of the crack. If the initial crack length is long enough, the critical fracture length can be easily reached under the coupling effect of the train load and water. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

By establishing a hydraulic fracturing model of twinblock sleeper and conducting laboratory tests, it was found that the hydrodynamic pressure in cracks varies under different conditions, with crack opening being a sensitive factor affecting both hydrodynamic pressure and effective stress intensity. The initial crack length is identified as the main factor influencing the fatigue life of cracks.