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结合软土地区某地铁深基坑工程,通过对半逆作深基坑的横纵剖面支撑轴力值随土体开挖变化数据规律的分析,阐明了在软弱地层条件下,半逆作法深基坑支撑轴力的变化特征。结果表明:支撑轴力大小及其变化形式与支撑空间位置、施工工况、支撑形式、挖土时机及开挖速度等因素密切相关;缩短第二道钢支撑及基坑垫层浇筑时的无支撑暴露时间可有效减小最大支撑轴力值;逆作下二层板框架下土体开挖引起基坑某一剖面整体支撑轴力重分布;因第一道钢筋混凝土支撑刚度较大,其对深基坑稳定具有重要作用。
Combined with the deep foundation pit project of a subway in soft soil area, by analyzing the regularity of the supporting axial force value of the semi-inverted deep foundation pit with the change of excavation data, it is clarified that in the weak formation condition, Variations of foundation pit supporting axial force. The results show that the magnitude of axial force and its variation are closely related to the location of supporting space, construction condition, supporting form, excavation timing and excavation speed. The shortening of the second steel support and foundation pit cushioning Supporting exposure time can effectively reduce the maximum support axial force; under the action of under-two-story plate under the excavation of soil caused by a section of the overall support shaft load distribution; the first reinforced concrete support stiffness is greater, the The stability of deep foundation pit has an important role.