大断面强烈湿陷性黄土隧道变形特征与支护技术研究

Study on Deformation Characteristics and Supporting Technology of Large⁃section Strongly Wet⁃submerged Loess Tunnel

大断面强烈湿陷性黄土隧道在施工过程中易发生大变形、初期支护失效及坍塌等事故,存在较大的困难和风险。以宝兰客运专线兰山隧道为工程背景,通过现场勘察,分析隧道坍塌情况及原因,并提出帷幕注浆+超前支护+填充砂浆的支护技术。研究结果表明,兰山隧道工程采用的支护技术能够有效控制围岩变形,使隧道拱顶沉降和拱腰收敛最大值分别为58.6,25.4mm,围岩应力基本稳定,钢拱架最大应力为53.7MPa,未达到屈服强度,可知隧道围岩受力和变形满足要求,支护技术合理有效。

Large⁃section strongly wet⁃submerged loess tunnel is prone to large deformation,failure of initial support and collapse during the construction process,and there are great difficulties and risks.This paper takes Lanshan Tunnel of Baolan Passenger Dedicated Line as the engineering background,through on⁃site investigation,researches and analyses the tunnel collapse condition and the reasons,and puts forward the curtain grouting,advanced support and filling mortar support technology.The research results show that the curtain grouting,advanced support and filling mortar support technology can effectively control the deformation of surrounding rock.After the support technology is adopted,the maximum values of tunnel settlement and hance convergence are 58.6mm and 25.4mm respectively.The stress of surrounding rock is basically stable.The maximum stress of steel arch is 53.7MPa,which does not reach the yield strength.It can be seen that the stress and deformation of tunnel surrounding rock meet the requirements,and the support technology is reasonable and effective.