拉桩支护结构变形及工作机制试验研究  

Experiment on deformation and working mechanism of the pull-pile supporting structure

作　　者：兰斌鹏 王延平[1] 王卫国[1] 王义军[2] 赵跃[2] LAN Bin-peng;WANG Yan-ping;WANG Wei-guo;WANG Yi-jun;ZHAO Yue(School of Civil Engineering and Geomatics,Shandong University of Technology,Zibo,Shandong 255049,China;Chengdu Institute of Survey and Investigation,Chengdu,Sichuan 610084,China)

机构地区：[1]山东理工大学建筑工程与空间信息学院,山东淄博255049 [2]成都市勘察测绘研究院,四川成都610084

出　　处：《岩土力学》2025年第2期551-562,共12页Rock and Soil Mechanics

基　　金：山东省自然科学基金(No.ZR2021MD011)。

摘　　要：深基坑拉桩支护结构是由前排桩、后拉桩、冠梁以及连系梁构成的三维空间结构体系。既有工程案例已经表明拉桩支护结构具有较好的抗倾覆、控制水平侧向变形的服役性能,但相应的理论支撑及成体系性研究较少。为深入探究拉桩支护结构体系变形性状、内力演化特征以及工作机制,进行了拉桩支护结构室内缩尺试验。结果表明:前排桩桩身水平侧向位移分布曲线呈上凸状,桩身弯矩分布曲线呈反S状,桩身轴力分布曲线呈梭子状,桩身轴力为压力;后拉桩弯矩分布曲线呈弓状,桩身轴力分布曲线呈勺子状,上部为轴向拉力,下部为轴向压力;冠梁水平侧向位移分布曲线呈短冠梁的正弦函数状,轴力分布曲线呈明显M状,M状曲线的双峰处对应的区域为不带后拉桩的前排桩桩顶冠梁,亦是冠梁薄弱点。拉桩支护结构的空间特点可形成较为稳定的拉压结合的大三角内嵌两个小三角式、三向门式框架结构,随之产生的后拉桩效应与空间变形协调效应分别具有锚拉前排桩、遮蔽土压力的能力和控制支护桩桩顶倾角差异过大与冠梁水平侧向变形差异过大的能力。The pull-pile support structure in a deep foundation pit is a three-dimensional spatial structure system composed of front-row piles,back-pull piles,a crown beam,and tie beams.Existing engineering cases demonstrate that the pull-pile support structure effectively resists overturning and controls horizontal deformation,yet lacks comprehensive theoretical support and systematic research.To thoroughly investigate the deformation behavior,internal force evolution,and working mechanism of the pull-pile support system during foundation pit excavation,an indoor scale test was conducted.Results indicate that the horizontal displacement curve of the front-row pile is convex,the bending moment curve is anti-S shaped,the axial force curve is shuttle-shaped,and the axial force on the pile body is compressive force.The bending moment curve of the back-pull pile is bow-shaped,and the axial force curve is spoon-shaped.The upper section of the back-pull pile experiences axial tension,while the lower section experiences axial compression.The horizontal lateral displacement curve of the crown beam presents sine function shape of the short crown beam,and the axial force curve presents an obvious M shape.The double peaks of the M shape correspond to the crown beam atop the front-row pile without back-pull support,marking a weak point for potential failure of the crown beam.The spatial characteristics of the pull-pile support structure allow for a stable tension-compression combined structure,forming a large triangle with two smaller triangles and a three-way door frame.The resulting back-pull pile effect and spatial deformation coordination can anchor the front-row pile and shield against earth pressure,as well as suppress differences in the top inclination angle of the supporting pile and excessive deformation of crown beam.

关 键 词：拉桩支护结构 变形特征 工作机制 试验研究 

分 类 号：TU473[建筑科学—结构工程]