隧道下穿松散高填土路堤的沉降规律及其影响范围研究  

Settlement Law and Its Influence Range of Tunnel Crossing Underneath Loose High Filling Embankment

作　　者：郭瑞 郑波[1] 黎晨[2] GUO Rui;ZHENG Bo;LI Chen(China Railway Southwest Research Institute Co., Ltd., Chengdu 611731, Sichuan, China;China Railway 15 Bureau Group Co., Ltd., Shanghai 200040, China)

机构地区：[1]中铁西南科学研究院有限公司,四川成都611731 [2]中铁十五局集团有限公司,上海200040

出　　处：《隧道建设（中英文）》2019年第4期601-608,共8页Tunnel Construction

基　　金：中国中铁股份有限公司科技开发计划项目(2017-重点-19-02);中铁十五局集团科技研发计划项目(B10)

摘　　要：为解决下穿隧道施工对既有高填土路堤的影响问题,依托成贵铁路大方隧道下穿杭瑞高速工程建立三维有限元模型,研究隧道施工对上覆地层位移影响、地表纵向变形特征以及下穿施工对地表各特征位置的主要影响范围。研究结果表明:1)隧道下穿施工造成高填土路堤层发生显著沉降变形,上覆地层向隧道正中方向产生明显横向位移; 2)大方隧道下穿施工产生的地表纵向变形可划分为微变形区(洞口浅埋沉降区)、强变形区(高填土路堤沉降区)和弱变形区(地表沉降区)3个区域; 3)大方隧道施工分别开挖至洞口、挡墙和公路路面等特征位置时的地表纵向影响范围分别为开挖前方的75、52、65 m,在此影响范围内地层位移变化强烈; 4)拱顶动态沉降曲线均呈反"S"形特征。结合现场监测数据进行对比分析,得出模拟计算值与监测值变化趋势基本吻合,并最后给出相关施工建议措施。In order to solve the influence problem of underpass tunnel construction on existing high filling embankment, a three-dimensional finite element model is established based on Dafang Tunnel of Chengdu-Guiyang Railway crossing underneath Hangzhou-Ruili Expressway project. The influence of tunnel construction on overlying strata displacement, surface longitudinal deformation characteristics and the main influence range of underpass construction on various surface feature positions are studied. The results show that:( 1) The significant settlement deformation of the high filling embankment layer is caused by the underpass construction, and the overlying strata produce obvious lateral displacement towards the middle of the tunnel.(2)The surface longitudinal deformation caused by the underpass construction can be divided into three zones: the micro-deformation zone (the shallow buried settlement area at tunnel portal), the strong deformation zone (the settlement zone of high filling embankment) and the weak deformation zone (the settlement zone of surface).( 3) When the tunnel construction is carried out to the characteristic positions such as tunnel portal, retaining wall and road surface, the longitudinal influence range of the surface is 75, 52 and 65 m in front of the excavation respectively, and the displacement of strata within this influence range changes strongly.(4) The dynamic settlement curves of vaults are all of the inverse " S" shape. Combined with the field monitoring data for comparative analysis, the variation trend of the simulated value and the monitored data is basically consistent, and finally relevant construction suggestions and measures are put forward.

关 键 词：松散高填土路堤层 隧道 下穿施工 数值模拟 沉降规律 影响范围 

分 类 号：U455[建筑科学—桥梁与隧道工程]