砂质页岩隧道洞口浅埋段变形特征与控制措施研究  

Study on Deformation Characteristics and Control Measure of Shallow-buried Section at Portal of Sandy Shale Tunnel

作　　者：张永辉 胡志平[1] 李芳涛 安学旭 李华明 ZHANG Yong-hui;HU Zhi-ping;LI Fang-tao;AN Xue-xu;LI Hua-ming(School of Civil Engineering,Chang’an University,Xi’an Shaanxi 710061,China;Sichuan Leshan-Hanyuan Expressway Co.,Ltd.,Leshan Sichuan 614299,China)

机构地区：[1]长安大学建筑工程学院,陕西西安710061 [2]四川乐汉高速公路有限责任公司,四川乐山614299

出　　处：《公路交通科技》2023年第6期155-163,202,共10页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(41941019);峨汉高速工程科研专项(LH-HT-45);引汉济渭联合基金项目(2021JLM-49)。

摘　　要：为解决砂质页岩类软弱围岩隧道大变形问题,以峨汉高速双桥1#隧道作为研究背景,对隧道的病害、地表沉降、拱顶下沉、拱腰收敛进行调研和监测,分析洞口浅埋段初支变形特征及变形原因,并提出相应的变形控制措施,通过监测数据分析控制措施的效果。结果表明:隧道施工造成的病害以地表建筑和洞内拱腰及拱顶开裂为主。隧道随埋深的增加,隧道拱顶下沉量逐渐增加,隧道的变形由拱腰收敛向以拱顶下沉为主转变;围岩变形具有不对称性、变形量大、变形速率快、持续时间长、差异性显著、纵向范围大等特征;拱顶沉降与拱腰收敛规律一致,均经历“急剧增长—缓慢增长—快速增长—趋于稳定”4个阶段,其中急剧增长段围岩变形量大,占最终变形值的55%~75%;地表各断面沉降均经历“快速下沉—平台—缓慢下沉—2次平台—2次快速下沉—趋于稳定”6个阶段,横向分布呈不对称“V”字型,最大沉降位置位于隧道中线及右侧;洞内大变形主要是由于隧道仰拱施工滞后导致,水、地质围岩、外荷载等因素加剧大变形的发展;采取双层支护、注浆小导管、排水措施、快速封闭仰拱等措施后,隧道最大沉降值仅为大变形段的23.4%,最大下沉速率由39.0 mm/d降为12.0 mm/d。隧道变形得到控制,研究结果可为类似环境的软弱围岩隧道提供参考。In order to solve the large deformation problem of soft surrounding rock tunnel with sandy shale,on the study background of Shuangqiao Tunnel No.1 of Emeishan-Hanyuan Expressway,the disease,surface settlement,vault subsidence and haunch convergence of the tunnel are investigated and monitored.The deformation characteristics and causes of the initial support in the shallow-buried section at portal are analyzed,and the corresponding deformation control measures are put forward.The effect of the control measures is analyzed by monitoring data.The result shows that(1)The diseases caused by tunnel construction are mainly the crackings of surface buildings,haunch and vault in the tunnel.With the increase of buried depth,the subsidence of tunnel vault increases gradually,and the tunnel deformation changes mainly from haunch convergence to vault subsidence.(2)The deformation of surrounding rock has the characteristics of asymmetry,large deformation,fast deformation rate,long duration,significant difference and large longitudinal range,etc.(3)The rule of vault subsidence is consistent with that of haunch convergence,both of which experience the stages of sharp growth,slow growth,rapid growth and stability.The surrounding rock deformation is large in the sharp growth stage,which accounting for 55%-75%of the final deformation value.(4)The surface settlement of each section experiences the stages of rapid subsidence,platform,slow subsidence,secondary platform,secondary rapid subsidence and stability.The lateral distribution is asymmetric“V”shape,and the maximum settlement position is located at the middle line and right side of tunnel.(5)The large deformation in the tunnel is mainly due to the lag of tunnel invert construction,and the large deformation development is aggravated by water,geological surrounding rock,external load and other factors.(6)After adopting double-layer support,grouting small pipe,drainage measure,rapid closure of inverted arch and other measures,the maximum settlement value of the tunnel is only 2

关 键 词：隧道工程 变形特征 现场监测 砂质页岩隧道 洞口浅埋段 控制措施 

分 类 号：U25[交通运输工程—道路与铁道工程]