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为得到大跨度无衬砌蛋形黄土隧道围岩结构在重力和地震作用下的剪切破坏规律,借助于ANSYS软件,根据强度折减法,分别对蛋形无衬砌黄土隧道进行重力分析和地震作用下的动力稳定性分析;探讨跨度、覆土厚度和地震烈度对围岩抗剪强度安全系数的影响。数值算例结果表明:从抗剪强度的角度来看,大跨度无衬砌蛋形浅埋黄土隧道虽能达到初次衬砌的要求,但均不能达到正常使用的稳定性要求;安全系数随跨度、覆土厚度以及地震烈度的增大有所降低,但影响幅度不大。得出的结论可为大跨度蛋形无衬砌隧道的实际施工提供理论基础,并为定量分析大跨度有衬砌黄土隧道的地震反应提供参考。
In order to obtain the shear failure law of surrounding rock mass of long-span non-lined egg-shaped loess tunnel under the action of gravity and earthquake, with the aid of ANSYS software, according to the strength reduction method, The dynamic stability of surrounding rock is discussed. The influence of span, cover thickness and seismic intensity on the shear strength safety coefficient of surrounding rock is discussed. The numerical example shows that the long-span linerless shallow-lying loess tunnel can meet the requirement of initial lining from the point of view of shear strength, but can not meet the stability requirements of normal use. The safety factor varies with the span, The thickness and the increase of earthquake intensity have been reduced, but the impact is not large. The conclusion can provide a theoretical basis for the actual construction of long-span egg-shaped linerless tunnel and provide reference for quantitative analysis of seismic response of long-span lined tunnel.