滨海软土超长深基坑开挖时空效应监测分析  

Monitoring and analysis on time-space effect of ultra-long deep foundation pit excavation in coastal soft soil

作　　者：王小丁 秦善良 WANG Xiaoding;QIN Shanliang(Shenzhen Metro Group Co.,Ltd.,Shenzhen 518101,Guangdong,China;Sinohydro Bureau 7 Co.,Ltd.,Chengdu 610081,Sichuan,China)

机构地区：[1]深圳铁路投资建设集团有限公司,广东深圳518101 [2]中国水利水电第七工程局有限公司,四川成都610081

出　　处：《工程建设》2024年第1期51-56,共6页Engineering Construction

摘　　要：滨海软土基坑开挖中的空间效应和时间效应对基坑稳定性具有重要影响。为了控制软土地区基坑变形,本文以穗莞深城际铁路前海站超长深基坑工程为例,通过分析开挖过程中的围护结构水平位移、周边地表沉降、支撑内力等数据,研究超长基坑在开挖过程中的时空效应。结果表明:(1)基坑开挖中空间效应明显,基坑中部围护结构水平位移比端部大18.3%;(2)围护结构位移差异会导致坑边土体出现差异沉降现象,距离坑边相同距离时基坑纵向最大沉降差异达到17.5%;(3)施工间期,同一工况下的支护结构位移及受力均会随着时间的增长而增大;(4)软土地层中前四道混凝土内支撑养护期间,围护结构最大水平位移分别增长了31.2%,30.9%,23.2%,14.4%;(5)工程中应合理考虑基坑开挖的时空效应。The space-time effect on the excavation of coastal soft soil foundation pit has an important impact on the stability of the foundation pit.In order to control the deformation of foundation pit in soft soil area,the ultra-long deep foundation pit project of Qianhai Station of Guangzhou-Shenzhen Intercity Railway is taken as an example,and the space-time effect of the ultra-long foundation pit in the excavation process is researched by analyzing the horizontal displacement of the enclosure structure,the surrounding surface settlement,and the supporting internal force during the excavation process.The results show that:(1)the spatial effect is obvious in the excavation of the foundation pit,and the horizontal displacement of the enclosure structure in the middle of the foundation pit is 18.3%larger than that at the end;(2)the difference in displacement of the enclosure structure will lead to the differential settlement of the soil at the edge of the pit,and the maximum longitudinal settlement difference of the foundation pit reaches 17.5%when it is at the same distance from the edge of the pit;(3)during the construction interval,the displacement and stress of the supporting structure under the same working condition will increase with the growth of time;(4)during the curing period of the first four concrete internal supports in the soft soil layer,the maximum horizontal displacement of the enclosure structure increases by 31.2%,30.9%,23.2%and 14.4%,respectively;(5)the space-time effect of foundation pit excavation should be reasonably considered in the project.

关 键 词：深基坑 滨海软土 时空效应 受力状态 变形特性 现场监测 

分 类 号：TU941[建筑科学—建筑技术科学]