钢支撑滞后架设对深基坑内支撑轴力的影响

Effect of Delaying Installation of Steel Bracing on Strut Axial Forces of Deep Excavation

为探究钢支撑滞后架设对基坑内支撑轴力的影响,以某地铁车站深基坑为研究对象,基于有限元计算结果,系统分析了钢支撑滞后架设对基坑各内支撑轴力的影响规律。结果表明:钢支撑滞后架设对与其相邻的上道支撑轴力影响较大,对与其相隔的上道支撑轴力影响较小,对在其之后架设的支撑轴力影响很小;支撑滞后架设会使其自身少承担坑后主动土压力,第1道支撑主要分担了第2道支撑由于滞后架设而少承担的主动土压力,第2道支撑主要分担了第3道支撑由于滞后架设而少承担的主动土压力,第1道支撑和坑底被动区土体共同分担了2、3道支撑均出现滞后架设而少承担的主动土压力;第3道支撑滞后架设会导致第1道钢筋混凝土支撑出现拉力,说明了深基坑第1道支撑普遍采用钢筋混凝土支撑而不选择钢支撑的优越性。相关研究成果可为类似工程设计及施工提供参考。

In order to study the influence on strut axial forces of deep excavation when the steel bracing occurring delayed installation,a deep excavation of subway station was taking as the research object.And the influence of delaying installation of steel bracing on strut axial forces was analyzed based on the numerical simulation results.The results show that lag of erection for steel bracing has a great influence on the axial force of the adjacent upper support,and has less influence on the axial force of non-adjacent upper support,and little influence on the force of the support axial that erected later.Delaying Installation for steel bracing can make it less responsible for the active earth pressure.The first inner support mainly shares the active earth pressure due to that the second support occurs delayed installation.The second support mainly shares the active earth pressure due to that the third support occurs delayed installation.And the first inner support and the soil in passive area at the bottom share the active earth pressure due to that both the second and third steel bracing occur lag erection.Lag of erection for the third inner support may lead to tension in first reinforced concrete support.It indicates that the superiority of selecting the reinforced concrete support for the first inner support of the deep excavation without selecting the steel bracing generally.The research results can provide necessary reference for the design and construction of similar projects.