2013年1月上 施工技术 第42卷第1期 CONSTRUCTION TECHNOLOGY 35 软弱土中大面积深基坑工程快速支护施工技术* 任望东",李春光',田建平",郑刚²,刁钰² (1.中铁房地产集团(天津)置业有限公司,天津300000;2.天津大学土木工程系,天津300072) [摘要]对于天津软弱土地基中大面积基坑,应用与发展了多种无大面积水平支撑的基坑快速支护施工方法,包括 单排桩(墙)+反压土支护、双排桩+反压土支护、双排桩+单排桩联合支护、重力式挡土墙+反压土联合支护等方 法。
可靠的变形预测手段、止水幢幕、良好的反压土区降水效果、利用时空效应分块开挖基坑并分块施工地下结构 是本方法控制变形关键。
与传统方法相比,这些方法可显著缩短大面积基坑中高层建筑的施工工期,显著减小基 坑支护造价并减少支撑拆除形成的固体废弃物等。
[关键调】地下工程;深基坑;软土;支护;快速施工;变形;时空效应 [中图分类号]TU447 [文献标识码]A[文章编号]1002-8498(2013)01-0035-05 Rapid ConstructionMethodof Large AreaDeepFoundationExcavationinSoftSoil Ren Wangdong',Li Chunguang',Tian Jianping',Zheng Gang²,Diao Yu² (1.China Railway Construction Real Estate Group(Tianjin)Co.,Lad.,Tianjin 300000,China; 2.Department of Civil Engineering,Tianjin University,Tianjin 300072,China) Abstract:The rapid construction methods of large area deep foundation excavation in soft soil are applied and developed in Tianjin.These methods include bined retaining pile(wall) and earth berm, bined double-row retaining pile and earth berm, bined double-row retaining pile and single row retaining pile,bined gravity retaining and single row retaining pile.The key respects of these methods include accurate deformation prediction,waterproof curtain,dewatering of earth berm,time- space effect of staged excavation and underground structure construction. Compared with the conventional retaining methods,the rapid retaining methods of large area deep foundation excavation have the advantages of short construction period of underground structure of high-rise building, low cost and less discharge of solid waste produced by the demolish of concrete struts. Key words:underground; deep foundation excavation; soft soil; supports; rapid construction; deformation;time-space effect 在天津、上海等沿海土质较为软弱的地区,一难以根据实际工程需要进行分区开挖,特别是大面 般而言,在基坑周边存在建筑物、道路、地下管线等积基坑中分布有多幢高层建筑时,往往高层建筑的 情况下,由于环境保护的需要,当基坑深度>5~6m施工工期是最重要的。
时,需要采用围护桩(墙)+水平支撑的支护形式。
因此,对大面积深基坑,条件适当时,应在现有 但是,对基坑开挖达4万~19万㎡²的大面积基坑基坑支护技术与经验的基础上,采用与发展能够取 来说,设置一道或多道水平支撑,虽可较好地控制消大面积水平支撑、满足快...