山区偏压连拱隧道开挖方法适应性数值分析研究  

Numerical analysis and research on adaptability of excavation methods for biased strata tunnels in mountainous areas

作　　者：李坤 Li Kun(China Railway 12th Bureau Group Co.,Ltd.,Xi’an Shaanxi 710038,China)

机构地区：[1]中铁十二局集团有限公司,陕西西安710038

出　　处：《山西建筑》2025年第1期168-172,共5页Shanxi Architecture

摘　　要：山区常存在偏压或围岩破碎情况,隧道穿越该地层施工时,围岩变形控制困难,施工扰动容易致使隧道拱顶坍塌及支护结构破坏。依托银花隧道工程,开展了偏压地层隧道施工开挖方法的适应性数值仿真研究,对比分析了“三导洞法”和“中导洞法”两种开挖方式中不同开挖步对软弱围岩偏压隧道围岩变形、拱顶沉降、最大主应力分布的影响规律。结果表明:三导洞法随着偏压处侧导洞开挖,左洞拱顶沉降区与中导洞开挖扰动变形区会形成沉降叠加,最大工地沉降出现在正洞开挖后,为-12.35 mm,所占沉降比η达到55.23%。中导洞施工时,最大沉降值分布在偏压拱腰处且呈扇形分布,左右洞上台阶施工产生的沉降比最大达到73.57%,中、下台阶开挖对拱顶沉降影响较小,最大拱顶沉降值为-17.81 mm。两种方法的最大主应力并非严格对称,尽管中导洞法施工产生较大沉降,但考虑施工成本和效率,“中导洞法”更为合理。In mountainous areas,there are often situations of biased pressure or rock fragmentation.When tunnels pass through this stratum during construction,it is difficult to control the deformation of the surrounding rock,and construction disturbances can easily lead to the collapse of the tunnel arch and damage to the supporting structure.This article relies on the Silver Flower Tunnel project to conduct adaptive numerical simulation research on the excavation method of biased strata tunnel construction.It compares and analyzes the influence of different excavation steps on the deformation of weak surrounding rock,arch crown settlement,and maximum principal stress distribution in the“three guide tunnel method”and“middle guide tunnel method”.The results show that with the excavation of the side guide tunnel at the biased position,the settlement zone of the left tunnel arch and the disturbance deformation zone of the middle guide tunnel will form a settlement superposition.The maximum construction site settlement occurs after the excavation of the main tunnel,which is-12.35 mm,accounting for 55.23%of the settlement ratioη.During the construction of the central guide tunnel,the maximum settlement value is distributed in a fan-shaped manner at the biased arch waist.The settlement ratio generated by the construction of the upper steps on the left and right tunnels reaches a maximum of 73.57%.The excavation of the middle and lower steps has little impact on the settlement of the arch crown,with a maximum settlement value of-17.81 mm.The maximum principal stress of the two methods is not strictly symmetrical.Although the construction of the middle guide tunnel method generates significant settlement,considering construction costs and efficiency,the“middle guide tunnel method”is more reasonable.

关 键 词：偏压地层 连拱隧道 围岩变形 拱顶沉降 最大主应力分布 

分 类 号：TU997[建筑科学—市政工程] U455.4[建筑科学—桥梁与隧道工程]