直斜交替组合钢管桩支挡结构试验研究  

Experimental study on retaining structure of alternating combination of vertical and incline steel pipe piles

作　　者：干飞 郑刚[2] 曹腾 周海祚[2] 姜志恒 李美霖 毕靖 李亚林 GAN Fei;ZHENG Gang;CAO Teng;ZHOU Haizuo;JIANG Zhiheng;LI Meilin;BI Jing;LI Yalin(School of Civil Engineering,Guizhou University,Guiyang,Guizhou 550025,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China;Guizhou Zhongyan Technology Development Co.,Ltd.,Guiyang,Guizhou 550018,China)

机构地区：[1]贵州大学土木工程学院,贵州贵阳550025 [2]天津大学建筑工程学院,天津300072 [3]贵州中岩科技发展有限公司,贵州贵阳550018

出　　处：《岩石力学与工程学报》2023年第5期1175-1187,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(41630641);贵州省科技支撑计划基金资助项目(黔科合支撑[2021]–一般511)。

摘　　要：直斜交替组合钢管桩是一种新型的基坑支挡结构,具有施工方便、可循环利用、造价低等优点。已有工程实践证明其支护性能良好,但尚缺乏对其变形和受力机制的深入认识。开展悬臂桩和2种不同夹角(α=10°,20°)的直斜交替组合钢管桩模型试验研究,分析基坑开挖过程中,桩顶位移变化规律、桩身弯矩和变形及土压力分布特征,试验结果表明:相同的基坑开挖深度,直斜交替组合钢管桩的桩顶位移随着夹角增大而减小,悬臂桩桩顶位移最大。悬臂桩桩身弯矩图呈现“鱼腹式”分布特征,而直斜交替组合钢管则为“S”型分布,直斜交替组合钢管桩存在显著的反弯现象,其桩身最大弯矩值随着夹角α的增加而减小。直斜交替组合钢管桩在土压力作用下受力更加合理,斜桩受拉、直桩受压,其破坏模式从悬臂桩的弯剪破坏变化为斜桩与直桩的拉压破坏。此外,直斜交替组合钢管桩支护结构具有三大有益的效应:拉锚效应、重力效应和空间结构效应。拉锚效应和重力效应增加了结构的抗倾覆力矩,而空间结构效应提高了支挡结构的刚度。因此,该支挡结构具有很好的推广应用价值。As a new retaining structure for excavations,alternating combination of vertical and incline steel pipe piles has many advantages,such as convenient construction,recyclable and low cost.The previous engineering practices have proved the good supporting performance,but there is a lack of systematic and in-depth understanding of its deformation and stress mechanism.In this study,cantilever pile and two alternating steel pipe piles with anglesaof 10°and 20°,respectively,were investigated using model experiment.The pile top displacement change law,pile body bending moment and deformation,and soil pressure distribution characteristics were analyzed in the process of foundation pit excavation.The test results show that with the same excavation depth of foundation pit,the top displacement of straight inclined alternating combination steel pipe pile decreases with the increasing anglea,and the displacement of cantilever pile top is the largest.The bending moment diagram of cantilever pile shows the distribution characteristics of“fish belly”,while the alternating steel pipe is“S”type.The alternating combination of steel pipe has significant bending phenomenon,and the maximum bending moment of the pile body decreases with the increase of the anglea.Under the action of soil pressure,the force of straight inclined alternating combination steel pipe pile is more reasonable.The inclined pile is pulled and the straight pile is pressed.The damage mode changes from the curved shear failure of cantilever pile to the pull failure of inclined pile and straight pile.In addition,the alternating combination of steel pipe pile supporting structure has three beneficial effects:anchor pulling effect,gravity effect and space structure effect.The pulling anchor effect and the gravity effect increase the anti-overturning moment of the structure,while the space structure effect improves the stiffness of the support structure.Therefore,the support structure has a good promotion and application value.

关 键 词：桩基础 直斜交替组合钢管桩 试验研究 土压力 桩身变形 

分 类 号：TU473[建筑科学—结构工程]