软弱围岩隧道洞口浅埋段变形特征及控制措施研究  

Study on deformation characteristics and control measures of shallow-buried section at portal of soft rock tunnel

作　　者：王伟[1,2] 李忠 沈学军 林玉刚 李赤谋[1,4] 毛永强 WANG Wei;LI Zhong;SHEN Xuejun;LIN Yugang;LI Chimou;MAO Yongqiang(CCCC Second Harbour Engineering Co.,Ltd.,Wuhan Hubei 430040,China;CCCC Highway Bridges National Engineering Research Centre Co.,Ltd.,Beijing 100088,China;China Communications 2nd Navigational Bureau 2nd Engineering Co.,Ltd.,Chongqing 400000, China;CCCC Wenshan Expressway Construction Development Co.,Ltd.,Wenshan Yunnan 663000,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430040 [2]中交公路长大桥建设国家工程研究中心有限公司,北京100088 [3]中交二航局第二工程有限公司,重庆400000 [4]中交文山高速公路建设发展有限公司,云南文山663000

出　　处：《中国安全生产科学技术》2020年第9期103-109,共7页Journal of Safety Science and Technology

基　　金：云南省交通运输厅科技创新示范项目(云交科教[2019]15号)。

摘　　要：为解决洞口浅埋段软弱围岩隧道大变形控制难、施工风险高的问题。依托在建隧道工程,对洞口浅埋段初支变形及破坏特征进行分析,提出适合该隧道的变形控制措施。结果表明:洞口浅埋段围岩松散破碎受开挖扰动和地表水影响显著,隧道破坏形式多样,围岩纵向变形不规律,随埋深增大,局部渗水严重段存在拱腰挤出现象;开挖初期围岩变形速率高,最高达到86.8 mm/d,累计变形量大,其中上、中台阶围岩变形量占比为80%~90%,变形主要分为“加速增长—缓慢增长—再次增长—趋于稳定”4个变化阶段,再增长阶段持续时间较短,约6~10 d。根据围岩预留变形量建立各施工阶段的变形控制基准及超限应对处置措施,并提出工法优化,通过数值模拟验证该优化工法有利于支护结构及时封闭,可控制前期围岩变形,保证施工安全和进度。To solve the problems of difficult control on large deformation and high construction risk in the shallow-buried section at the portal of soft surrounding rock tunnel,depending on the tunnel engineering under construction,the deformation and failure characteristics of the initial support in the shallow-buried section were analyzed,and the deformation control measures being suitable for the tunnel were proposed.The results showed that the surrounding rock in the shallow-buried section at the portal was loose and broken,which was significantly affected by the excavation disturbance and surface water.There were various failure form of the tunnel,and the longitudinal deformation of the surrounding rock was irregular,which increased with the buried depth,and there was an arch waist extrusion phenomenon in the section with serious local water seepage.The deformation rate of surrounding rock was generally large in the initial stage of excavation,with the maximum value of 86.8 mm/d,and the cumulative deformation amount was large.Among which,the deformation amount of the surrounding rock in the upper and middle steps accounted for 80%~90%.Moreover,the deformation was mainly divided into four change stages:accelerating growth,slow growth,growth again,and tending to stability,and the duration of growth again stage was short,as about 6~10 days.According to the reserved deformation amount of surrounding rock,the deformation control reference and over-limit treatment measures at each construction stage were established.Meanwhile,the optimization of the working methods was proposed.The numerical simulation was carried out to verify that the optimization method,which is conducive to the timely closure of the support structure,control the deformation of surrounding rock in the early stage,and ensure the construction safety and progress.

关 键 词：软弱围岩隧道 洞口浅埋 大变形特征 分级控制管理 控制措施 

分 类 号：X951[环境科学与工程—安全科学] U455[建筑科学—桥梁与隧道工程]