【摘要】 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。更多还原

【Abstract】 In order to obtain the shear failure laws of unlined egg-shaped loess tunnel under gravity action and earthquake action,using FEM software ANSYS and the shear strength reduction method,stability analysis is made about the soil mass surrounding tunnel of large-span unlined egg-shaped loess tunnel under the action of gravity and seismic.The important influences of shear strength safety factor are discussed on the span or coverage soil thickness of tunnel or seismic intensity.Result shows that: from the perspective of shear strength,the large-span unlined egg loess tunnel is able to achieve the requirements of initial lining,but can not reach the requirement of stability safety factor in normal use state.When the tunnel span or the coverage soil thickness of tunnel or seismic intensity increases,the shear strength safety factor will become low,but the magnitude of impact is not very obvious.And so a theoretical basis for the actual construction will be provided for the the large-span unlined egg-shaped loess tunnel,and a reference will be provided for the large-span lined structure design of loess tunnel under earthquake.更多还原