【摘要】 从断裂力学角度分析了高压水头作用下 ,裂隙的扩展机理 ,认为裂隙的扩展多属 型裂纹断裂扩展问题 ,由此推导了水力劈裂作用发生的临界水头压力值。在此基础上 ,探讨了高压水头作用下裂隙张开度的变化 ,提出了裂隙张开度变化的计算公式更多还原

【Abstract】 The mechanism of water gushing in jointed surrounding rocks of deep lying tunnels is studied. The results show that a hydro splitting course under high water pressure is involved just before water gushing out, which can be described by a fracture model with a joint and type II failure. According to the criterion of fracture instability, a formula of critical water pressure resulting in hydro splitting is derived. Also, the spacing variation of a joint under high pore water pressure during water gushing is especially regarded. An equation is put forward to describe the joint spacing variation ( Δ b) based on the deformation of joint walls. As an example, the case of Jinping deep lying tunnel is discussed. It gives a reasonable explanation to the high pressure water gushing encountered in this project.更多还原