摘要
软土深基坑开挖中的立柱隆起量通常较大而会威胁支护体系的安全。软土基坑立柱隆起分析涉及土体-立柱(立柱桩)-内支撑之间复杂的相互作用,尤其需要掌握不排水开挖过程中的土体隆起规律,目前还没有一个合适的简化计算方法。首先适当简化了地铁基坑土体-立柱(立柱桩)-内支撑的相互作用,给出一个可以应用于工程设计的立柱隆起分析模型,其中的关键点是确定立柱桩桩周土的隆起变形曲线。通过数值分析方法,给出深厚软土典型地铁车站基坑坑底土体隆起的归一化曲线,提出通过连续墙最大侧向变形预估坑底土体隆起变形的方法。最后以上海某地铁车站基坑为例,详细说明采用这一设计方法计算立柱隆起的过程,结合实测结果验证其合理性;并结合计算结果对地铁车站基坑立柱桩的受力、变形特征以及立柱隆起控制的设计原理进行更为深入的讨论。
Unloading in deep excavation in thick soft soil usually leads to large pillar uplift which may endanger the safety of the retaining system.In the pillar uplift analysis,complex interactions among soil,pillar(pillar pile)and struts are involved,and the soil heave behavior during undrained excavation shall be understood well,but there is no simplified calculation method available at present.Firstly,the interactions among soil,pillar(pillar pile)and strut are simplified,and a theoretical analysis model for pillar uplift estimation in practical design is proposed,in which the key point is the determination of the heave of the soil around the pillar.Based on the numerical analysis results,a normalized soil heave curve was proposed,and the soil heave could be estimated in terms of the maximum lateral displacement of the retaining wall.Finally,with the deep excavation of a subway station in Shanghai taken as an example,the design procedures with this new method were elaborated,and the rationality of the method was verified;the stress and deformation characteristics of the pillar and the design principles of uplift control of the pillar were also discussed in depth based on the calculation results.
作者
高彦斌
罗文康
李文勇
刘朝明
杨正园
杨洪杰
Gao Yanbin;Luo Wenkang;Li Wenyong;Liu Chaoming;Yang Zhengyuan;Yang Hongjie(Tongji University,Shanghai 200092,China;Shanghai Shentong Metro Group Co.,Ltd.,Shanghai 200092,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2023年第3期70-77,共8页
China Civil Engineering Journal
关键词
深基坑
坑底隆起
软土
立柱隆起
deep excavation
base heave
soft soil
pillar uplift
