中文摘要：

通过模型试验与数值分析方法将隧洞破裂面与稳定性引入到定量分析，采用有限元强度折减法，求得围岩破裂面的位置及围岩的稳定安全系数．研究表明，浅埋拱形隧洞破坏来自拱顶，深埋隧洞来自侧壁．通过从浅埋到深埋的数值分析，研究隧洞从浅埋到深埋的破坏过程．结果表明：对于矩形隧洞，当埋深小时逐渐形成浅埋压力拱，当到达某一埋深时，浅埋压力拱消失，同时深埋压力拱（普氏压力拱）出现，可以确定深、浅埋的分界线，当埋深增大至某一深度时，破坏从拱顶转向侧壁；对于拱形隧洞，当埋深小时出现浅埋压力拱，但不出现深埋压力拱，当达到一定埋深后，破坏从拱顶转向侧壁，可以确定深、浅埋的分界线．深、浅埋的分界线主要取决于洞跨与洞形，与围岩强度关系不大，浅埋时围岩可以是稳定的．

英文摘要：

The stability of tunnel was induced to the quantitative analysis through model test and numerical analysis. The location of fracture surface and the stability safety factor of surrounding rock were analyzed by adopting the strength reduction finite element method （FEM）. Results show that the failure of shallow-buried arch tunnel is from the vault and the failure of deep-buried tunnel is from the sidewall. The failure process of tunnel from shallow-buried to deep-buried was analyzed. For the rectangle tunnel, the shallow-buried pressure arch gradually forms when the buried depth is small, and it disappears at a certain depth and meanwhile the deep-buried pressure arch （Protodyakonov＇s arch） appears. Then the dividing line between deep-bury and shallow-bury can be identified. The failure moves from the vault to the sidewall if increasing the bury depth to a certain depth. For the arch tunnel, the shallow-buried pressure arch appears and there is no deep-buried pressure arch when the bury depth is small. Failure moves from the vault to the sidewall at a certain bury depth, so the dividing line between deep-bury and shallow-bury can be identified. The dividing line is mainly decided by the span and the shape of the tunnel and has little relationship with the strength of the surrounding rock, and shallow-buried tunnel can be stable.