Fatigue Test on Heavy Haul Railway Tunnel Bottom Structure With Base Cavity

The presence of a base cavity will degrade the bearing capacity tunnel bottom structures, and also have noteworthy impact on its fatigue performance. In order to study performance cumulative damage structure, series bending tests are conducted by reference heavy haul railway with cavity. Through tests, evolution characteristics structure obtained, then based expression S - N curves, non-linear model is therefore proposed, deflection can be divided into three stages, characterized an “s-shaped” curve. results reveal that develops rapidly when exists in rock, occurs more easily, life specimens decreases increase stress level width.