超深圆形基坑顺-逆结合施工优化及变形性状分析  

Construction Optimization and Deformation Characteristics of the Ultra-deep Circular Foundation Pit with Top-down and Down-top Construction Method

作　　者：龚振宇 胡开富 徐前卫[3] 孙梓栗 贺翔 GONG Zhenyu;HU Kaifu;XU Qianwei;SUN Zili;HE Xiang(The Electricity Engineering Co.,Ltd.of CREC No.5 Group,Changsha,Hunan 410205,China;Kunming Branch of Central Yunnan Provincial Water Diversion Project Construction Administration Branch,Kunming,Yunnan 655600,China;Key Laboratory of Road and Traffic Engineering of Ministry of Education,Tongji University,Shanghai 201804,China)

机构地区：[1]中铁五局电务城通公司,湖南长沙410205 [2]云南省滇中引水工程建设管理局昆明分局,云南昆明655600 [3]同济大学道路与交通工程教育部重点实验室,上海201804

出　　处：《水利与建筑工程学报》2020年第3期104-111,共8页Journal of Water Resources and Architectural Engineering

基　　金：国家自然科学基金项目(41672360);住房和城乡建设部研究开发项目(2018-K9-076)。

摘　　要：结合滇中引水盾构接收井77.3m超深圆形基坑工程案例,通过数值模拟与现场实测相结合的方法,对超深圆形基坑施工方案进行优化。研究结果表明:在基坑开挖过程中,圆形地连墙变形很小,最大变形仅为3.39mm,且剪力弯矩均较小,表明圆形基坑施工安全性较高,可考虑采用顺作法施工代替逆作法施工;岩土交界处地连墙变形较大,且应力集中更容易发生塑性破坏,在开挖方案拟定时要偏安全考虑;对于类似小直径圆形基坑,其围护结构已具有足够支撑强度,改变开挖方式对基坑变形影响有限,建议采用“顺逆结合”的开挖方式,在上部采用顺作法,在下部采用逆作法,兼顾施工安全性的同时提高施工便利性。In this paper,Yunnan Dianzhongyinshui shield well which is a 77.3 m circular deep foundation excavation engineering case was taken as an example,based on the numerical simulation and measured analysis and the idea of"semi-top-down method",the construction plan of ultra-deep circular foundation pit is optimized,the results are as follows:During the excavation of the foundation pit,the deformation of the ground wall is very small,the maximum deformation is only 3.39 mm,and the shear bending moments are small,indicating that the safety grade of the circular foundation pit construction is higher,and the down-construction method can be considered instead of the up-construction method.the underground-wall at the junction of rock and soil has a relatively large deformation,and the stress concentration is more prone to plastic failure,so the safety should be considered when the excavation plan is drawn up.For similar small-diameter circular foundation pits,the retaining structure has sufficient support strength,and the impact of changing the excavation method on the deformation of the foundation pit is limited.It is suggested to adopt the"combination of forward and backward"method of excavation,and adopt the up-construction method in the upper part and the down-construction method in the lower part,while taking construction safety and construction convenience into consideration.

关 键 词：深基坑 圆形基坑 顺逆结合法 变形特征 

分 类 号：TU433[建筑科学—岩土工程]