NATM公路隧道围岩时间效应统计分析与变形稳定性评价指标

摘要

On the base of field monitoring dates about dozens of two-lane highway tunnels, the dates of convergence displacements and vault crown settlements were analyzed through statistical method, the deformation characteristic of the different surrounding rock grades from Ⅱ to Ⅴ with time were also studied, the stable time was proposed for surrounding rock from excavation to steady stabilization and the relation between grades and stable time of surrounding rock was defined. Meanwhile, this article gains the stable values analyzes of convergence displacement and vault crown settlement after lining completed, which are used as stability evaluation index of different surrounding rock levels. Research results provides basis for evaluation of surrounding rock and construction time of secondary lining.%基于几十座两车道NATM高速公路隧道的现场监测数据,通过对大量的围岩收敛变形和拱顶下沉数据的统计分析,探讨隧道Ⅱ、Ⅲ、Ⅳ、Ⅴ级围岩随时间的变形特性,分析不同级别围岩从开挖到变形稳定时的时间以及与围岩级别的关系;得到变形稳定时的收敛和拱顶下沉值,以此作为隧道不同级别围岩变形的稳定性评价指标;为隧道施工阶段围岩的稳定性评价以及二次衬砌的合理施作时机提供了依据.