Abstract Bottom softening and voids in a railway tunnel often occur over long-term operation, which has a great impact on the service life of the tunnel structure. Based on the train vibration load represented by the superposition of sine functions with different frequencies, a numerical model is established of a tunnel rock mass with consideration given to the interactions between the tunnel bottom structure and foundation rock mass. The influence law is discussed based on the changing characteristics of the dynamic response of the tunnel bottom structure, and the influence of the basis condition on the service life of the heavy haul railway tunnel is analyzed based on the Miner linear cumulative damage law. The results show that in different softening and void conditions, the dynamic stress response regularities of the tunnel bottom structures are similar; average stress and stress amplification on each part of the tunnel bottom structure increases, and its fatigue life decreases; the maximum value of tensile stress occurs at the center of the invert at the tunnel bottom; and fatigue failure first occurs at the invert under the tunnel track.
Abstract：
Bottom softening and voids in a railway tunnel often occur over long-term operation, which has a great impact on the service life of the tunnel structure. Based on the train vibration load represented by the superposition of sine functions with different frequencies, a numerical model is established of a tunnel rock mass with consideration given to the interactions between the tunnel bottom structure and foundation rock mass. The influence law is discussed based on the changing characteristics of the dynamic response of the tunnel bottom structure, and the influence of the basis condition on the service life of the heavy haul railway tunnel is analyzed based on the Miner linear cumulative damage law. The results show that in different softening and void conditions, the dynamic stress response regularities of the tunnel bottom structures are similar; average stress and stress amplification on each part of the tunnel bottom structure increases, and its fatigue life decreases; the maximum value of tensile stress occurs at the center of the invert at the tunnel bottom; and fatigue failure first occurs at the invert under the tunnel track.
LIU Ning- Peng-Li-Min- Shi-Cheng-Hua- Yan-Wei-Guang
.Analysis of the Influence of Basis Conditions on the Dynamic Response of a Bottom Structure of a Heavy Haul Railway Tunnel and Its Service Life[J] MODERN TUNNELLING TECHNOLOGY, 2016,V53(5): 114-122
2016, Vol. 53 