基于围岩浸水的黄土公路隧道衬砌开裂分析  

Analysis of Lining Cracking of Loess Highway Tunnel Under Flooded Surrounding Rock Conditions

作　　者：宋维龙 来弘鹏[2] 刘禹阳 杨文辉 朱志铎[1] SONG Wei-long;LAI Hong-peng;LIU Yu-yang;YANG Wen-hui;ZHU Zhi-duo(Institute of Geotechnical Engineering, Southeast University, Nanjing 210096, Jiangsu, China;Shaanxi Provincial Major Laboratory for Highway Bridge ＆ Tunnel, Chang＇an University, Xi＇an 710064, Shaanxi, China)

机构地区：[1]东南大学岩土工程研究所,江苏南京210096 [2]长安大学陕西省公路桥梁与隧道重点实验室,陕西西安710064

出　　处：《中国公路学报》2018年第5期117-126,150,共11页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51378071);国家重点基础研究发展计划("九七三"计划)项目(2015CB057803);陕西省自然科学基金项目(2014KJXX-53;2014SZS19-Z01);中央高校基本科研业务费专项资金项目(2014G3213006;310821163302)

摘　　要：针对甘肃省境内某黄土公路隧道的衬砌开裂现状,采用统计分析的方法对隧道衬砌裂缝的分布特征进行了系统研究;通过有限元数值模拟,详细分析了多种围岩浸水工况下隧道结构的变形规律和应力特征,并将数值模拟结果与隧道现场裂缝分布特征进行对比,给出了围岩浸水恶化条件下衬砌结构开裂的原因、规律和特征。研究结果表明:地表水通过土体裂缝入渗是衬砌开裂的主要原因,衬砌裂缝主要分布于拱部和边墙;围岩发生浸水后,浸水范围内的土体强度降低,失去承载力,隧道上部围岩下沉,挤压衬砌结构;随着围岩浸水范围的扩大,隧道结构的受力与变形状态逐渐恶化,结构呈压扁趋势且产生偏压,引起拱部内表面被拉裂,边墙内表面由于局部压应力过大产生开裂;拱部开裂先于边墙且开裂情况最为严重,隧道上下行线相邻两边墙衬砌开裂情况较另外两边墙严重,数值模拟结果与现场衬砌裂缝特征基本吻合;在相似工程条件的黄土隧道设计时,应加强隧道拱部结构的抗拉性能和边墙结构的抗压性能。Based on the current state of lining cracking of an existing loess highway tunnel in Gansu province,the distribution characteristics of lining cracks were studied systematically through a statistical analysis.Based on a finite-element numerical simulation,the deformation rules and stress characteristics of the tunnel structure under various flooding cases of the surrounding rock were investigated in detail.Through a comparison between the numerical simulation results and the distribution characteristics of the in-situ cracks,the underlying causes,rules,and characteristics of the lining cracking were determined.The research results show that surface water infiltration through ground cracks may be the main cause of lining cracking.The lining cracks are mainly distributed in the parts of the vault and sidewall.After the surrounding rock is flooded,the strength of the soil mass within the flooding scope is decreased,and the surrounding rock gradually loses its bearing capacity.The sinking of the surrounding rock presses the lining struc-ture.With the increasing flooding scope of the surrounding rock,the stress and deformation behaviors of the tunnel structure gradually deteriorate.The structure is under unsymmetrical pressure conditions and shows a squashed deformation.The internal surface of the vault undergoes cracking from excessive tension,and the internal surface of the sidewall cracks from high localized compression.The vault experiences cracking prior to the sidewall and more seriously than the same;in addition,the two adjacent sidewalls of the uplink and downlink crack more severely.The simulation results are basically consistent with the characteristics of the in-situ lining cracks.In the design of loess tunnels under similar engineering conditions,the tensile resistance of the vault and the compressive resistance of the sidewall should be strengthened.

关 键 词：隧道工程 衬砌开裂 数值模拟 开裂机理 围岩浸水 

分 类 号：U451.2[建筑科学—桥梁与隧道工程]