摘要
通过室内K0试验和数值分析以及工程实测,并结合近年来上海软土地区深大基坑的工程实践,对深大基坑卸荷变形的影响因素和影响区域特性以及坑周的地表沉降机理进行了研究,对基坑卸荷变形的影响范围按变形特性进行分析和归纳.结果表明：上海软土深大基坑卸荷变形的影响深度范围为坑底以下2.5倍开挖深度;当基坑开挖宽度达到5倍开挖深度以上时,在围护结构底与影响深度范围内存在深层土体滑移带,坑外地表沉降影响范围扩大到3.5倍开挖深度以上,且地表最大沉降值是基坑侧向变形最大值的1-2倍;深大基坑与窄条基坑的变形特征有明显区别.针对深大基坑卸荷变形的特点,提出了减少和控制其卸荷变形的设计对策和工程措施,以保护周边设施和环境,为软土地区的深大基坑工程设计、施工提供借鉴和参考.
By K0 laboratory test, numerical analysis, in-situ measurement and engineering practice, this paper presented the investigation on the influencing factors, the characteristic of influenced area and the settlement mechanism of ground surrounding deep and large excavations in Shanghai soft clay area. The results show that the scope affected by pit unloading can be characterized by 5 sub-areas based on deformation behavior around the excavation. The maximum depth of soil influenced by pit unloading is about 2.5 times of the excavation depth. When the excavation width exceeds 5 times of cutting depth, deep slip band of soil will occur between the retaining structure bottom and the maximum influenced depth. As a result, the affected area of out-pit ground exceeds 3.5 times of excavation depth and its maximum settlement is 1 2 times of the maximum lateral deformation of the retaining wall. In addition, there exists significant deformation characteristic difference between the deep-large excavation and the narrow excavation. Finally, some measures on the design and construction were proposed to reduce the deformation of deep-large excavation, and to protect the facilities surrounding the excavation in Shanghai soft clay area.
出处
《上海交通大学学报》
EI
CAS
CSCD
北大核心
2009年第6期1005-1010,共6页
Journal of Shanghai Jiaotong University
关键词
深大基坑
卸荷
变形分区
机理
控制
deep-large excavation
unloading
deformation sub-area
mechanism
control measures
