隧道仰拱底鼓机理及列车振动荷载影响研究

为研究列车振动荷载下隧道仰拱结构既有底鼓病害的扩展特性,探究列车动载对仰拱底鼓的放大效应,从围岩静载作用下仰拱底鼓的破坏模式出发,基于现场实测数据,利用动态扩展有限元模型,研究列车动载下各底鼓破坏模式的扩展规律及特性。结果表明:影响仰拱底鼓的主要原因有围岩静载、仰拱结构自身特征以及列车动载,仰拱底鼓模式主要有W型底鼓、LJ型底鼓以及H型底鼓。列车动载的加入改变了仰拱底鼓裂缝的扩展规律,缩短了裂缝贯通的时间,列车动载循环100次后裂缝贯通时间仅为围岩静载时的50%左右,循环10000次后裂缝贯通时间仅为围岩静载时的25%左右。围岩与仰拱间的接触压力斜率随着动载的加入而提高,提高的幅度与动载的循环次数正相关。

Study on mechanism of tunnel invert floor heave and the effect under vibration load of train

To study the propagation characteristics and inquiry into the amplification effect of tunnel invert floor heave under vibration load of train,this article starts from the failure mode of floor heave under pressure of surrounding rock,based on the data from field measurement,used dynamically extended finite element model,study on the propagation law and characteristic of failure mode caused by the pressure of surrounding rock under train vibration load.The results show that the three main reasons affecting the floor heave are pressure of surrounding rock,structure features of tunnel invert,train vibration load.Failure modes of floor heave mainly include W type,LJ type,H type.Propagation law of tunnel invert floor heave is changed when the train vibration load is added,0x09reduces the time of cracks through by 50%compared only the pressure of surrounding rock play a role with both train vibration load after 100 cycles and 25%after 10000 cycles.The gradient of contact pressure between surrounding rock and tunnel invert increased with the addition of train dynamic loads,the magnitude of increase is positively correlated with the number of dynamic load cycles.The research results can be a reference for the system design and vibration prevention of tunnel invert.