坑中坑开挖影响下的基坑变形特性有限元分析  

Finite Element Analysis of Deformation Characteristics of Pit-in-pit Influenced by Inner Pit Excavation

作　　者：熊中华[1] 

机构地区：[1]河海大学岩土工程研究所,江苏南京210098

出　　处：《土木工程与管理学报》2013年第2期57-61,共5页Journal of Civil Engineering and Management

摘　　要：基坑工程中的坑中坑式基坑问题是工程中常见但又未得到深入研究的问题。运用大型通用有限元软件ABAQUS对典型的坑中坑式基坑进行了有限元数值模拟分析,采用控制变量法的思路通过控制坑中坑坑趾系数、深度比、面积比三个参数的变化,探讨了内坑不同开挖位置、开挖深度及开挖面积等情况下外坑的变形特性。数值模拟结果表明:外坑围护结构最大水平位移及坑外地表最大沉降量随深度比、面积比的增大而加速增大,但随坑趾系数的增大而逐渐减小。坑趾系数存在一个与众多因素相关的分界值,内坑在小于该分界值的区域开挖对外坑变形的影响很小,而在大于该分界值的区域开挖对外坑变形的影响很大。较大的深度比和面积比将显著减小外坑围护结构有效插入深度,对外坑变形非常不利。The problem of pit in pit is a universal problem which has not been studied deeply. The numerical simulation is made of to analyse typical pit-in-pit by using finite element software ABAQUS. The deformation characteristics of the outer pit are studied in the cases of different inner pit＇s excavation positions, depths and areas by changing the three control parameters of pit toe coefficient, depth ratio and area ratio. The results show that the maximal horizontal displacement of the enclosure structure and the maximal ground settlement value increase rapidly with the increasing of depth ratio and area ratio. However, they performance completely opposite in terms to pit toe coefficient. It is found that there exist a cut off value of pit toe coefficient. When pit toe coefficient is larger than the value, the deformation characteristics of the outer pit is affected obviously, and when pit toe coefficient is smaller than the value, the deformation characteristics of the outer pit is not affected. Moreover, a larger depth ratio or area ratio which is adverse to the deformation will decrease the effective depth of the enclosure structure obviously.

关 键 词：坑中坑 坑趾系数 深度比 面积比 有限元 

分 类 号：TU47[建筑科学—结构工程]