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土体抗剪、抗拉强度指标作为隧道稳定的主要控制参数,对某黄土隧道通过FLAC3D运用强度折减原理分析了随着地震作用的持续,隧道土体抗剪、抗拉强度指标和安全系数的动态变化过程。工程计算结果表明:黄土隧道在地震作用下土体的抗剪强度和抗拉强度都明显降低,破坏首先出现在侧墙部位,且随着地震作用的持续,其范围迅速扩大并向拱顶延伸,同时在拱顶也出现破坏区,当拱顶和两侧墙破坏区完全贯通时,隧洞就产生整体破坏;地震作用下黄土隧洞的剪应变增量随着地震作用时间而增大,但其增长速率随着地震的持续而减小。
Soil shear strength and tensile strength index are taken as the main control parameters of tunnel stability. Based on the strength reduction theory of FLAC3D applied to a loess tunnel, the relationship between shear strength, tensile strength index and safety factor The dynamic process of change. The results of engineering calculation show that the shear strength and tensile strength of the loess tunnel are obviously reduced under the action of earthquake, the damage first appears in the side wall, and the scope of the loess tunnel rapidly expands and extends to the vault , And at the same time there are also vandal areas in the vault. When the failure zone of the vault and the two side walls is completely penetrated, the tunnel will be destroyed completely. The increment of shear strain of the loess tunnel under earthquake will increase with the time of the earthquake, The rate of increase decreases as the earthquake continues.