摘要
过大的基底隆起严重影响深基坑工程的稳定性与安全性,为研究基底变形特性及其发展规律,规避底部隆起引发的深基坑失稳破坏,以北京某超深大基坑项目为例,通过分析深基坑隆起诱发机理,建立基坑开挖数值模型,系统研究整体开挖引起的土压力差、支挡结构向坑内变位、地下水渗透及深层承压水水头变动等导致的基底隆起变形特性及变形规律。结果表明,整体开挖是坑底隆起的主要原因;支挡结构变位对坑底隆起影响范围集中在距侧壁约1倍开挖深度区域;地下水渗透及深层承压水水头变动引起周边地层的整体上浮,但对基底隆起影响较小;基底实测变形前期以稳定回弹为主,后在某时段内发生明显的突变隆起,然后又缓慢上浮达到峰值,并以日变形量亚毫米级缓慢上浮、下沉波动。
Excessive basement uplift seriously affects the stability and safety of the deep foundation excavation project.In order to study the deformation characteristics of the basement and it’s development laws,and avoid the instability and damage of the deep foundation excavation caused by the basement uplift,a super-deep and large foundation excavation project in Beijing is taken as an example,by analyzing the inducing mechanism of deep foundation excavation uplift,a numerical model of excavation is established to systematically study the deformation characteristics and deformation laws of the basement uplift caused by the earth pressure difference caused by the overall excavation,the displacement of the retaining structure into the foundation excavation,the groundwater infiltration and changes of the deep confined water head.The results show that the overall excavation is the main reason for the basement uplift.The influence of the displacement of the retaining structure on the basement uplift is concentrated in the area about 1 times the excavation depth from the side wall.Groundwater infiltration and changes in deep confined water head cause the overall uplift of the surrounding strata,but have little effect on the uplift of the basement.The measured deformation of the basement is dominated by stable rebound in the early stage,and then there is an obvious sudden uplift in a certain period of time,and then it slowly rises to a peak,and the daily deformation is sub-millimeter-level slowly rising and sinking.
作者
高莉
吕连勋
钱明
张衍林
GAO Li;LüLianxun;QIAN Ming;ZHANG Yanlin(PetroChina Company Limited Guangxi Petrochemical Co.,Ltd.,Qinzhou,Guangxi 535008,China;Qingdao China Petroleum Geotechnical Engineering Co.,Ltd.,Qingdao,Shandong 266071,China;BGI Engineering Consultants Co.,Ltd..,Beijing 100038,China;Research Institute of Mine Big Data,China Coal Research Institute,Beijing 100013,China)
出处
《施工技术（中英文）》
CAS
2022年第10期60-64,111,共6页
Construction Technology
基金
国家自然科学基金(51409154)。
关键词
基坑
基底隆起
变形特性
监测规律
支护
foundation excavation
basement uplift
deformation characteristics
monitoring laws
supports
