不同埋深圆形隧道变形过程数值模拟与分析

Numerical Simulation and Analysis of Deformation Process of Circular Tunnels with Different Buried Depths

圆形隧道在不同埋深条件下会受到大小不同的应力,应力大小的区别作用在隧道上表现为隧道横截面形状的变化。不同埋深下隧道的变形问题对于隧道设计、地表沉降研究和施工都具有现实意义。早年的科技人员认识到隧道变形研究的重要性,做了大量的研究但没有达成明确、一致的方法,尤其是圆形隧道在不同埋深情况下的横截面变形仍有可完善研究的空间。将不同埋深的圆形隧道为研究对象,把隧道看作均质围岩,建立模型,结合数值模拟方法分别研究在自重应力下超浅埋、浅埋、深埋3种圆形隧道的变形过程。主要研究工作如下:①整理圆形隧道的相关理论知识,介绍当前圆形隧道埋深划分方法和划分区间,总结出超浅埋、浅埋、深埋和侧压力系数条件下的变形破坏分区;②根据圆形隧道相关理论,研究超浅埋、浅埋、深埋圆形隧道围岩变形区的分布情况,分析侧压力系数对变形区的影响规律,揭示三种埋深条件下圆形隧道的变形模式;③以超浅埋、浅埋、深埋的变形模式为基础通过不同埋深圆形隧道位移得出解析模型和附加位移;④研究不同侧压力系数并用数值模拟分析。

The circular tunnel will be subjected to diff erent stresses under different burial depth conditions,and the diff erence of the stress magnitude is reflected in the change of the tunnel cross-section shape.The deformation of tunnels with diff erent buried depths has practical significance for tunnel design,ground settlement research and construction.In the early years,scientific and technical personnel recognized the importance of tunnel deformation research,and did a lot of research,but did not reach an agreement and a clear method.Especially,there is still room for improving the research of cross section deformation of circular tunnels under diff erent burial depths.Therefore,this paper takes circular tunnels with diff erent burial depths as the research object,regards the tunnel as homogeneous surrounding rock,establishes a model,and studies the deformation process of ultra-shallow buried,shallow buried and deep buried circular tunnels under self-weight stress by combining numerical simulation methods.The main research work is as follows:(1)Sorting out the relevant theoretical knowledge of circular tunnels,introducing the current method for dividing the burial depth of circular tunnels and dividing the zones,and summarizing the deformation and failure zones under the conditions of ultra-shallow burial,shallow burial,deep burial and lateral pressure coeffi cient.(2)According to the relevant theory of circular tunnel,the distribution of surrounding rock deformation zone of super shallow buried,shallow buried and deep buried circular tunnel is studied,the infl uence of lateral pressure coeffi cient on the deformation zone is analyzed,and the deformation mode of circular tunnel under three burial depths is revealed.(3)Based on the deformation mode of super shallow buried,shallow buried and deep buried,the analytical model and additional displacement are obtained through the displacement of circular tunnels with diff erent burial depths.(4)Diff erent lateral pressure coeffi cients are studied and analyzed by numerical simulation.