富水软岩隧洞变形特征及变形机制分析

 基于库尉引水隧洞现场监测资料，对富水软岩隧道的变形特性及变形机制进行分析。研究表明：侧墙收敛变形是拱顶沉降变形的2～3倍，且前者稳定时间长。土质软岩隧道的变形受时空效应综合作用的影响，即使在开挖面影响范围之内，时间效应也能产生很大比例的变形。侧墙变形受空间效应影响范围为4D～5D，与拱部变形相比，其时间效应更为显著。围岩–支护结构的变形在不同部位的特性主要是由各部位的围岩变形方式和应力释放规律所决定的，侧墙处围岩应力释放时间效应明显，塑性区不断增长发展，形变压力也随时间增长难于稳定。拱顶处存在一定深度范围内的围岩整体下沉现象，围岩压力稳定时间短。该研究对软岩隧道施工、监测具有一定指导意义和参考价值。

ANALYSES OF DEFORMATION CHARACTERISTICS AND MECHANISM OF WATER-RICH SOFT ROCK TUNNEL

Based on the monitoring data of the Kuyu diversion tunnel，the deformation characteristics and mechanisms of the water-rich soft rock tunnel are analyzed. The results indicate that the convergence deformation of sidewalls and the subsidence of the vault develop towards constant values，the former takes much more days，and the value of the sidewalls deformation is 2–3 times as much as that of the vault. The deformation of soil tunnel is influenced by the combined tempo-spatial effects. And the ratio of deformation produced by the time-effect is quite large even in the range impacted by excavation. The effect distance of space-effect on sidewalls deformation is in range of 4D–5D. And comparing with the deformation of vault，the time-effect of the sidewalls deformation is more remarkable. The differences between the sidewalls and vault deformation characteristics are mainly determined by the types of rock deformation and the way of stress release. The time-effect of stress release of surrounding rock around the sidewall is obvious. The plastic area and deformation pressure increase with time and take a long time to reach stability. In a certain depth，the rock mass at the vault has an integral settlement deformation together；and the rock pressure can reach stability quickly. The research results can provide some scientific guidelines and valuable references for construction and monitoring of soft rock tunnel projects.