隧道围岩失稳的突变理论分析

Mutation Theoretical Analysis of Tunnel Surrounding Rock Instability

通过探讨隧道围岩体发生塌方失稳破坏的机理,建立了隧道发生塌方失稳的突变模型,该模型可较好地解释隧道穿越软弱围岩时拱顶常发生大范围塌方的现象,具有较好的实用性。据所建立的突变模型,从刚度比、水致弱化系数比、几何-力学参数等参数进行了隧道围岩稳定性的突变分析,分析结果表明,水致弱化函数、几何参数、刚度比对软弱围岩体稳定性有很大的影响,分叉集上的点的是系统产生失稳的点,系统受外界环境和内部性质改变时,则系统将跨越分叉集,产生突变失稳。通过深埋隧道围岩稳定性的突变理论分析,从地下水防治、超前支护、控制爆破及监控量测方面提出了深埋隧道穿越软弱围岩体引起塌方的预防控制措施,对于隧道施工具有很好的指导意义。

Mechanism of tunnel surrounding rock collapse was studied and the mutation model built in this paper was proved to be a valid method to explain the phenomena of collapse in case of tunnel excavation through soft rock mass. Based on the model, the effect of the parameters such as stiffness, intenerating coefficient affected by water, and geometry-mechanic relationship was studied, the analysis showed that these parameters had great influence on the soft rock mass stability, the point at intersection collection could be considered as the point of system instability, when outer condition and inner property changed, the system could span the intersection collection and became instable. Then the measures for soft rock mass collapse control in deep-buried tunnel such as prevention and cure of groundwater, pre-supporting, control blasting and monitoring was put forward and a good guide to the tunnel construction could be provided.