基底脱空条件下仰拱振动特性及寿命预测分析

针对重载铁路基底不同脱空情况下隧道结构的振动特性和疲劳寿命预测问题，建立双线30T轴重列车荷载 隧道 围岩的三维模型。通过二次开发将拟合的列车振动荷载直接作用在轨道上模拟列车的行驶过程，实现了运行过程中重载列车对基底结构的振动响应特性分析。得到了30T轴重列车通过基底不同脱空条件隧道时，仰拱结构竖向位移、加速度和最大拉、压应力变化规律。进而结合混凝土寿命预测理论，计算出基底不同脱空条件下仰拱结构疲劳寿命预测值。并依据预测寿命将仰拱可靠度分为安全、警戒、危险和非常危险四个等级。研究结论对重载铁路基底脱空病害的评价与治理和仰拱结构的寿命预测分析具有一定的参考价值。

Vibration characteristics and life prediction analysis of tunnel arch with base void

In view of the vibration response and fatigue life of the heavy haul railway tunnel with base voids, a three-dimensional model of train-tunnel-rock is established. Through the secondary development, the fitted train vibration load is directly applied to the track to simulate the driving process of the train, and the analysis of the vibration response characteristics of the heavy haul train to the base structure during the operation process is realized. The vertical displacement, acceleration and maximum tensile and compressive stress of the inverted arch when the 30T axle-loaded train passes through the tunnel with different base voids are obtained. Combined with the life prediction theory of concrete, the fatigue life prediction value of the inverted arch under different base voids is calculated. And according to the predicted life, the reliability of the arch is divided into four levels: safety, vigilance, danger and very dangerous. The conclusion has certain value for the evaluation, treatment and fatigue life analysis for the basement of heavy haul railway with base voids.