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隧道围岩大变形是目前公路、铁路隧道建设中遇到的重要科学问题。工程实践中,隧道围岩大变形主要是由于围岩遭受剪切破坏而产生了流变而导致的,部分隧道的围岩大变形是由于围岩成分中的亲水矿物遇水发生水化学反应而发生体积膨胀产生的,故隧道围岩大变形可以分为应力型、材料性和结构型3类。通过全面分析前人的研究成果,可以将隧道围岩相对变形3%作为划分隧道内是否发生大变形的定量评价指标。而对于应力型围岩大变形,Hoek提出的隧道围岩径向变形和掌子面变形预测公式较好地预测了施工现场的围岩变形量,其现实意义较为明显,但需要针对不同的工程条件调整原地应力的估算公式或者考虑围岩二次应力场的赋存状态。对于材料型和结构型围岩大变形的变形量预测,目前仍然是一块研究的空白区,需要进一步开展相关工作。
Large deformation of the tunnel surrounding rock is an important scientific problem encountered in the current highway and railway tunnel construction. In engineering practice, the large deformation of the tunnel surrounding rock is mainly caused by the shear deformation of the surrounding rock, and the large deformation of the surrounding rock of some tunnels is caused by the hydration reaction of the hydrophilic minerals in the surrounding rock with water While the volume expansion occurs, the large deformation of the tunnel surrounding rock can be divided into three types: stress type, material type and structure type. Through comprehensive analysis of previous research results, the relative deformation of tunnel surrounding rock can be used as a quantitative evaluation indicator for whether there is any large deformation in the tunnel. However, for the large deformation of stress surrounding rock, Hoek’s prediction formula of surrounding rock radial deformation and facet deformation predicts the deformation of surrounding rock in the construction site well, but the practical significance is obvious. However, Conditions to adjust the in situ stress estimation formula or consider the occurrence of secondary rock stress state. Prediction of the deformation of large deformation of material type and structural type of surrounding rock is still a blank area of research, and further work needs to be done.