螺纹桩的抗拔承载特性模型试验与螺距优化  

Model Test on the Uplift Bearing Characteristics and Pitch Optimization of Screw Piles

作　　者：马宏伟[1] 胡志涛 袁松 陈鑫 MA Hongwei;HU Zhitao;YUAN Song;CHEN Xin(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan Anhui 232001,China)

机构地区：[1]安徽理工大学土木建筑学院,安徽淮南232001

出　　处：《安徽理工大学学报（自然科学版）》2023年第2期44-50,共7页Journal of Anhui University of Science and Technology:Natural Science

基　　金：国家自然科学基金资助项目(51408006);安徽省博士后基金资助项目(2016B01)。

摘　　要：螺纹桩特殊的螺纹结构改善了桩-土间相互作用形式,使其抗拔承载特性显著优于等直径直孔桩,但目前对其抗拔承载机理的认识尚不够深入。文章采用模型试验方法进行了上拔力作用下的螺纹桩承载性能研究,根据试验结果进行了螺纹桩荷载位移关系、螺距对桩承载特性的影响、桩体轴力与侧阻力分布特征以及最优螺距的分析。研究表明,上拔力引起的螺纹桩荷载位移曲线由近似弹性承载段、非线性承载段和位移快速增长段构成;桩周土随上拔力的增大自上而下逐步失效,螺纹桩被拔出时侧阻力不能充分发挥,其拔出破坏具有突发性;螺纹桩的极限抗拔承载力随螺距的增大先增大后减小,试验工况下的最优螺距内径比为1.26。螺距能够显著影响螺纹桩的抗拔承载性能,桩基设计中应合理选择螺距以提升桩的抗拔承载力。Screw piles have better uplift bearing characteristics than straight piles as their special screw structure improves the interaction between the pile and soil.However,the uplift bearing mechanism of the screw pile has not been fully revealed.The model tests were carried out to study the bearing performance of screw piles under hte uplift force,and the test data was used to analyze the load-displacement relationship of the pile,the influence of screw pitch on the pile bearing performance,the distribution characteristics of the axial force and lateral resistance and the screw pitch optimization.It was shown that the load-displacement curve of the screw pile caused by uplift loading consisted of an approximately elastic bearing section,a nonlinear bearing section and a rapidly increasing displacement section.As the uplift load increased,the soil around the screw pile gradually failed from shallow to deep.Since the deep lateral resistance did not play its full role,the screw pile was pulled off abruptly.With the increase of the screw pitch,the ultimate uplift bearing capacity of the screw pile first increased and then decreased.The optimal ratio of the screw pitch to internal diameter was found to be 1.26 in the test conditions.In the pile foundation design,the screw pitch should be determined rationally to improve the piles uplift capacity caused by its special influence to the uplift bearing characteristics of screw piles.

关 键 词：桩基础 螺纹桩 抗拔承载力 模型试验 

分 类 号：TU473.1[建筑科学—结构工程]