基坑底板施作后降水渗流对基坑变形影响规律  

Influence Law of Precipitation Seepage on the Deformation of Foundation Pit after the Foundation Plate Construction

作　　者：刘怀宇 Liu Huaiyu(China Railway Construction Group Co.,Ltd.,Beijing 100041,China)

机构地区：[1]中铁建设集团有限公司,北京100041

出　　处：《市政技术》2024年第5期123-128,共6页Journal of Municipal Technology

摘　　要：随着城市地下空间开发和建设需求的增加,基坑工程的开挖面积和开挖深度均越来越大,基坑降水对基坑变形和稳定性的影响越来越突出。为研究基坑在底板施作后不同降水深度条件下的变形特征,以北京城市副中心站综合交通枢纽基坑工程为例,运用有限元软件Midas GTS NX构建了详细的数值分析模型,系统性地探讨了底板施作后,不同降水条件下的基坑和地连墙变形特性。研究结果表明:降水深度对基坑顶部沉降变形影响显著,降水至基坑底部时导致的基坑沉降变形比不降水时的基坑沉降变形增加了55%;随着降水深度的增加,地表沉降也逐渐增大,且越靠近基坑侧,地表沉降越大;降水至基坑底部,距坑边0 m时的基坑沉降较距坑边100 m时的基坑沉降增加了57%;降水深度对地连墙竖向变形影响较大,降水至基坑底部时导致的地连墙总体竖向位移比水平位移增加了76%。With the increasing demands for urban underground space development and construction,both the exca-vation area and depth of foundation pit projects have been steadily rising.The impact of precipitation on the defor-mation and stability of foundation pits has become increasingly prominent.In order to investigate the deformation characteristics of foundation pits under different precipitation depths after the bottom slab construction,the founda-tion pit project of the comprehensive transportation hub at Beijing Municipal Administrative Center Station is taken as an example.A detailed numerical analysis model is conducted by the finite element software Midas GTS NX to systematically explore the deformation characteristics of the foundation pit and diaphragm wall under different pre-cipitation conditions.The study showed that the depth of precipitation had a significant effect on the settlement de-formation at the top of the foundation pit.The settlement deformation of the foundation pit caused by precipitation increased by 55%than the one without precipitation;With the increases of precipitation depth,the surface settle-ment gradually increased.And the closer to the side of the foundation pit,the larger the surface settlement;When precipitation reached the bttom of the foundation pit,the setlement of the foundation pit at O m from the pit edge increased by 57%than the one at 100 m;The depth of precipitation had a greater effect on the vertical deformation of the diaphragm wall.When precipitation reached the bottom of the foundation pit,the overall vertical displace-ment of the diaphragm wall increased by 76%than the horizontal displacement.

关 键 词：基坑 降水 渗流 地表沉降 地连墙变形 

分 类 号：TU473.3[建筑科学—结构工程]