高速铁路黄土隧道初期支护受力特性研究

支护结构的合理设计是大断面黄土隧道设计的关键环节。文章结合在建铁路黄土隧道,采用数值模拟,分析了大断面黄土隧道在不同初期支护时机情况下,支护结构、围岩受力状态和力学行为变化情况;基于控制围岩变形为核心,对大断面黄土隧道施工中初期支护施作时机的选择给出了合理的建议;根据现场监测结果,总结出了黄土隧道初期支护受力规律。黄土具有明显的流变特性,支护结构受力很大一部分承受围岩流变产生的附加荷载;另外,支护结构受力在空间上分布并不均匀对称,这些在设计中都应加以考虑。

Study of the Force Upon the Primary Support of a Loess Tunnel for a High-Speed Railway

The rational design of a supporting structure is key to the design of loess tunnels with large sections.Based on a specific loess tunnel,this paper analyzes the support structure,force upon the surrounding rock,and mechanical behavior variation at different stages of support of the loess tunnel.A rational suggestion for timing the selection of primary support is given with a focus on controlled rock deformation.This paper summarizes the law of force upon the primary support of loess tunnels and comes to the following conclusions:the loess features rheological properties and the additional load induced by the rock due to this is mainly born by the support structure;and the force acting upon the support structure is asymmetrical and should be taken into consideration in the design.