中文摘要：

由于隧道施工扰动及重载列车长期循环荷载作用下,隧道底部围岩出现局部基岩脱空现象。基岩脱空引起拱底围压的差异性分布,进而关系到隧道仰拱结构的疲劳寿命。通过引入重载列车隧道结构振动理论和Miner线性累积损伤理论,建立考虑基岩脱空条件下仰拱结构疲劳寿命的预测方法,研究基岩脱空条件下列车荷载对铁路隧道底部结构疲劳寿命的影响。计算结果表明:在隧道底部基岩脱空条件下,隧底结构仰拱中心处出现拉应力最大值,仰拱与边墙连接处出现压应力最大值,仰拱结构动应力响应分布规律相似。随着脱空变量的增大,隧底结构各部位动拉应力和动压应力增幅较大,仰拱结构疲劳寿命明显减小。

英文摘要：

Due to tunneling construction disturbance and long-term cyclic heavy haul train loading,the void of surrounding rock may appear at the bottom of tunnel.The conditions of bedrock void affect the fatigue life of tun-nel base structure.In the paper,the softening of surrounding rock at the bottom of heavy-haul tunnel was intro-duced into the fatigue life analysis and dynamic response of the base structure.The analyses were carried out by using the finite element method.Based on the vertical load induced by train vibration and the linear cumulative damage theory,the fatigue life prediction of tunnel base structure was established to study the influence of the bed situation on the force status of railway tunnel base structure.The results show that the maximum value of ten-sile stress emerges at the center of the invert,so does the compressive stress at the junction of the sidewall and invert.The distribution of dynamic response of the base structure is similar under different conditions of bedrock void.As the void extent increases,the tensile stress and pressure stress amplitude of the base structure increase, and the fatigue life of the base structure is also reduced greatly.