围岩空洞对重载铁路隧道动力稳定性的影响

Influence of Surrounding Rock Voids on the Dynamic Stability of Heavy-haul Railway Tunnels

以浩吉铁路万荣隧道为研究对象,基于围岩拱部空洞的各类参数(长度、高度、分布范围),对隧道动力响应特性、隧道衬砌应力等进行研究。在分析列车动力荷载的施加机理与施加方法的基础上,建立车辆-轨道-隧道动力有限元模型,计算在列车荷载的作用下,不同的空洞参数对隧道位移、加速度、衬砌主应力等方面的影响。研究表明,空洞加剧了隧道各部位的振动响应,其中拱顶的动力响应变化最大,空洞高度从0增大到20 cm时,拱顶的位移峰值增大了近3倍,而仰拱部位位移最小;空洞也改变了衬砌混凝土的受力状态(由受压变为受拉),这对于混凝土材料极为不利;随着空洞范围的不断增大,动力荷载对拱顶的影响加剧,拱顶的加速度峰值由无空洞状态的1.62 m/s^(-2)增加到3.49 m/s^(-2),此时结构已处于不稳定状态。

This paper took Wanrong Tunnel of Haolebaoji-Ji'nan Railway as the research object,based on various parameters such as length,height and distribution range of the surrounding rock arch cavity,the dynamic response characteristics of the tunnel and the tunnel lining stress were studied.On the basis of analyzing the mechanism and the method of applying train dynamic loads,a vehicle track tunnel dynamic finite element model was established to calculate the effects of different cavity parameters on tunnel displacement,acceleration,and lining principal stress under the action of train loads.Research shows that cavities exacerbate the vibration response of various parts of the tunnel,with the dynamic response of the arch changing the most.When the height of the cavity increases from 0 to 20 cm,the peak displacement of the arch increases by nearly three times,while the displacement of the inverted arch is the smallest.The cavity also changes the stress state of the lining concrete(from compression to tension),which is extremely unfavorable for the concrete material.As the range of voids continues to increase,the impact of dynamic loads on the arch increases.The peak acceleration of the arch increases from 1.62 m/s^(-2) without voids to 3.49 m/s^(-2),indicating that the structure is already in an unstable state.