关键词: 桩基础, 螺钉桩, 竖向承载特性, 模型实验, 有限元

Abstract: In order to study the effect of pile thread structure parameters on the bearing characteristics of screw piles under vertical load. Laboratory model test and finite element analysis were carried out to compare and analyze the load settlement curve and axial force distribution curve under different thread length, thread spacing, thread inner diameter, thread width and thickness. The results show that with the increase of the length of thread section, the ultimate bearing capacity of screw pile increases, and the sudden change of axial strain at the variable section increases. It is recommended to take the length of pile 1/2—2/3. The bearing capacity of screw pile increases first and then decreases with the increase of thread spacing. There is a suitable pitch which can maximize the interaction between pile and soil. Changing the diameter reduction ratio of screw pile will affect the end-bearing action of soil at the variable section and the end of pile and will easily cause stress concentration in the section of thread section. The recommended value is between 0.7—0.8. The change of thread width and thickness will change the constraint degree of thread and soil, and then affect its ultimate bearing capacity. The influence of thread width on ultimate bearing- DOI:10.3969/j.issn.1000-1565.2024.06.002竖向荷载下螺钉桩承载特性的影响因素邓友生^1,2,庄子颖^1,2,董晨辉^1,2,陈茁^1,2,吴阿龙^1,2(1.西安科技大学 建筑与土木工程学院,陕西 西安 710054;2.西安科技大学 桩承结构研究中心,陕西 西安 710054)摘 要:为了研究桩身螺纹结构参数对竖向荷载下螺钉桩承载特性的影响,开展室内模型试验与有限元分析,对比分析不同螺纹段长度、螺纹间距、螺纹内径、螺纹宽度与螺牙深度下的荷载沉降曲线与轴力分布曲线.结果表明:随着螺纹段长度的增加,螺钉桩极限承载力提升,变截面处轴向应力突变程度增加,建议长度取桩长的1/2~2/3;螺钉桩承载能力随螺纹间距增加呈先增后减的趋势,存在一个合适螺距可以最大程度发挥桩土间相互作用;改变螺钉桩变径比,将影响变截面处与桩端处土体端承作用,同时易引起螺纹段截面应力集中,建议取值0.7~0.8;螺纹宽度与螺牙深度的变化改变螺纹与土体的约束程度,进而影响其极限承载能力.螺纹宽度的变化对极限承载力的影响要大于螺牙深度变化的影响.关键词:桩基础;螺钉桩;竖向承载特性;模型实验;有限元中图分类号:TU473 文献标志码:A 文章编号:1000-1565(2024)06-0571-10Influencing factors for bearing characteristics of screw pile under vertical load DENG Yousheng^1,2,ZHUANG Ziying^1,2,DONG Chenhui^1,2,CHEN Zhuo^1,2,WU Along^1,2(1. School of Architecture and Civil Engineering, Xi’an University of Science and Technology, Xi’an 710054, China;2. Pile-supported Structures Research & Test Center, Xi’an University of Science and Technology, Xi’an 710054, China)Abstract: In order to study the effect of pile thread structure parameters on the bearing characteristics of screw piles under vertical load. Laboratory model test and finite element analysis were carried out to compare and analyze the load settlement curve and axial force distribution curve under different thread length, thread spacing, thread inner diameter, thread width and thickness. The results show that with the increase of the length of thread section, the ultimate bearing capacity of screw pile increases, and the sudden change of axial strain at the variable section increases. It is recommended to take the length of pile 1/2—2/3. The bearing capacity of screw pile increases first and then decreases with the increase of thread spacing. There is a suitable pitch which can maximize the interaction between pile and soil. Changing the diameter reduction ratio of screw pile will affect the end-bearing action of soil at the variable section and the end of pile and will easily cause stress concentration in the section of thread section. The recommended value is between 0.7—0.8. The change of thread width and thickness will change the constraint degree of thread and soil, and then affect its ultimate bearing capacity. The influence of thread width on ultimate bearing- 收稿日期:2024-07-07;修回日期:2024-08-24 基金项目:国家自然科学基金资助项目(51878554);陕西省自然科学基础研究计划重点项目(2018JZ5012) 第一作者:邓友生(1969—),男,西安科技大学教授,博士生导师,博士,主要从事基础工程与防灾减灾结构研究.E-mail:dengys2009@126.com 第6期邓友生等:竖向荷载下螺钉桩承载特性的影响因素河北大学学报(自然科学版) 第44卷capacity is greater than that of thread thickness.

Key words: pile foundation, screw pile, vertical bearing characteristic, model test, finite element