粉土-圆砾复合地层中异形深基坑开挖变形规律研究  

Research on the Deformation Law of Irregular Deep Foundation Pit Excavation in Silt-Round Gravel Composite Stratum

作　　者：布强 周颖 周洋 王亮 李金梅 杨明杰 BU Qiang;ZHOU Ying;ZHOU Yang;WANG Liang;LI Jinmei;YANG Mingjie(The Third Engineering Branch of China Railway First Bureau Group Co.,Ltd.,Baoji Shaanxi 721016,China;Nanning Rail Transit Co.,Ltd.,Nanning Guangxi 530029,China;School of Civil Engineering and Architecture,Guangxi University,Nanning Guangxi 530004,China)

机构地区：[1]中铁一局集团有限公司第三工程分公司,陕西宝鸡721016 [2]南宁轨道交通集团有限责任公司,广西南宁530029 [3]广西大学土木建筑工程学院,广西南宁530004

出　　处：《工程质量》2024年第5期25-30,共6页Construction Quality

基　　金：国家自然科学基金(51678166)。

摘　　要：为研究粉土-圆砾复合地层中开挖深度有高差的异形深基坑的坑内外土体和围护结构的变形规律,以南宁地铁5号线广西大学站2号风亭(2号基坑)及M出入口(1号基坑)异形深基坑工程为依托,利用有限元软件Plaxis 3D模拟基坑开挖过程,建立了隔离桩、地下连续墙、坑内围护桩等围护结构,地层采用能较为准确模拟土体变形特性的小应变本构模型。研究结果表明:基坑开挖引起的地表沉降值在距基坑边缘0.4He(He为基坑开挖深度)处达最大值,为0.33%He;异形基坑中2号基坑开挖深度为1号基坑的1.6倍,但1号基坑坑底最大隆起值却为2号基坑的2.5倍,原因为2号基坑坑底为圆砾层,而1号基坑坑底为粉土层,圆砾层的回弹模量比粉土层的大。In order to study the deformation law of soil mass and retaining structure of irregular deep foundation pit with different height in excavation depth in silt-round gravel composite stratum,relying on the irregular deep foundation pit project of No.2 Wind Pavilion(No.2 foundation pit)and M entrance and exit(No.1 foundation pit)of Guangxi University Station of Nanning Metro Line 5,using the finite element software Plaxis 3D to simulate the excavation process of the foundation pit,and the retaining structures such as isolation piles,underground continuous walls,and the retaining piles inside the foundation pit have been established,and the strata adopts a small strain constitutive model which can accurately simulate the deformation characteristics of soil mass.The results show that the surface settlement value caused by excavation of the foundation pit reaches a maximum value of 0.33%He at 0.4 He from the edge of the foundation pit(He is the excavation depth of the foundation pit);The excavation depth of No.2 foundation pit in the irregular foundation pit is 1.6 times that of No.1 foundation pit,but the maximum uplift value of the bottom of No.1 foundation pit is 2.5 times that of No.2 foundation pit,the reason is that the bottom of the No.2 foundation pit is a round gravel layer,while the bottom of the No.1 foundation pit is a silty soil layer,and the rebound modulus of the round gravel layer is larger than that of the silty soil layer.

关 键 词：地铁 异形深基坑 数值模拟 地表沉降 坑底隆起 

分 类 号：TU47[建筑科学—结构工程]