隧道施工对围岩应力变形的分析

发布时间：2018-08-18 18:38

【摘要】：以某高速公路隧道开挖和支护为工程背景,通过数值模拟方法分析上下台阶法、交叉中隔壁法和三台阶法3种施工方法情况下,隧道围岩的变形情况以及对支护时机的影响。设置不同的应力释放率方案,得到上台阶开挖、初衬施工步、核心土开挖和仰拱施工的应力释放率分别为50%,30%,5%和5%。采用上下台阶留核心土法施工最多允许释放90%的原岩应力,而采用三台阶法和交叉中隔壁法施工时分别为90.5%和91%。隧道的施工方法对掌子面和二次衬砌之间的允许距离具有较为显著的影响,交叉中隔壁施工方法允许掌子面和二次衬砌之间的距离最大,从而延缓二衬衬砌的支护时间。选取V级围岩中的上下台阶留核心土法的掌子面和二次衬砌之间的距离作为参考值,则需对其他开挖方法的掌子面和二次衬砌之间的距离进行修正,分别为:交叉中隔壁法1.53,三台阶法1.14。
[Abstract]:Taking the excavation and support of a highway tunnel as the engineering background, this paper analyzes the deformation of surrounding rock and the influence on the supporting opportunity of the tunnel surrounding rock under the three construction methods of the upper and lower step method, the cross middle adjoining method and the three step method through numerical simulation method. The stress release rate of different stress release rate schemes is 50% and 5% respectively for the excavation of upper steps, initial lining construction, core soil excavation and inverted arch construction, respectively. At most, 90% of the original rock stress can be released by using the method of retaining the core soil in the upper and lower steps, but 90.5% and 91% respectively in the construction of the three-step method and the intersection-middle adjoining method. The tunnel construction method has a significant effect on the allowable distance between the face of the palm and the secondary lining, and the construction method next door in the crossing allows the maximum distance between the face of the palm and the secondary lining, thus delaying the supporting time of the second lining. The distance between the face of the face and the secondary lining of the upper and lower steps in the V class surrounding rock is chosen as the reference value, and the distance between the face of the face and the secondary lining of the other excavation methods should be corrected. The results are as follows: 1.53 in the cross middle, 1.14 in the three classes.
【作者单位】：湖南省交通科学研究院;
【分类号】：U456.31

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