Aiming at the lack of recognition of the serious problem about column uplift in the excavation supporting design and construction,the steel support bearing capacity calculation method on the consideration of the influences of column uplift was con-structed based on theoretical analysis.Accordingly,the influence of column uplift of steel supporting system from three condi-tions was analyzed as the normal construction,overbreak and excavation placed for a long time by using the measured data.The influence of the supporting system after single support damage was then discussed.As is shown in the experiment,steel support decreases obviously along with the increase of column uplift bearing capacity.The greater design of the axial force is,the smaller axial displacement allows.The last layer of soil excavation is at highest risk nodes,while the penultimate layer is a relatively weak support.Overbreak causes significant increase of axial force of installed steel support which threatens the supporting stabili-ty.With the longer placement of excavation,the continuous column uplift threatens the safety of steel support;the length of placement of each layer of soil will affect the order of the support instability.Once the weakest steel support is damaged,it will cause dominoes effect of the supporting system and lead to the overall collapse or fracture of the retaining wall.The analyzing method in this paper is available for real-time decision of safe state of steel supporting system in the process of design and con-struction.%针对基坑支护设计和施工中对立柱隆起危害认识不足的问题，通过理论分析，提出考虑立柱隆起影响的钢支撑承载力计算方法。运用实测数据，从正常施工、超挖及基坑放置过长时间3个工况分析了立柱隆起对钢支撑体系的影响，并进一步分析了单根支撑破坏后支撑体系的响应。研究表明：钢支撑承载力随立柱隆起的增大而明显减小；设计轴力越大，允许的立柱竖向位移越小；最后一层土开挖是风险最高节点，倒数第二道是相对最薄弱的支撑；超挖会引起已安装钢支撑的轴力明显增加，危及支撑稳定；基坑长时间放置，立柱持续隆起将威胁到钢支撑的安全，每层土放置时间长短将影响各道支撑进入失稳状态的顺序；最薄弱钢支撑一旦失稳破坏将引发支撑体系“多米诺”骨牌效应，造成该处挡墙整体垮塌或断裂；所用的分析方法，可用于钢支撑体系设计和施工过程中实时判定钢支撑体系的安全性状。
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