摘要
研究目的:螺纹桩是一种新型异型桩,具有高效、环保、经济的优点。但目前对螺纹桩承载机理尚无准确的认识,因此本文通过模型试验和数值模拟,对比分析螺纹桩和直桩竖向承载性状的不同,研究螺纹桩桩身轴力及桩侧摩阻力分布规律,分析桩顶荷载作用下桩身与桩周土体的变形规律,揭示螺纹桩竖向承载机理,并讨论螺纹结构参数对螺纹桩承载力的影响。研究结论:(1)竖向荷载作用下长径比为12的直桩和螺纹桩分别表现为摩擦端承桩和端承摩擦桩的承载特性;(2)螺纹桩极限承载力和桩身材料利用率都明显优于直桩;(3)螺纹结构参数中,螺距和螺纹宽度是影响螺纹桩承载力的主要因素,螺纹厚度对承载力影响很小;(4)螺纹桩桩侧承载力主要由桩周土体的剪切力提供,存在最优螺距使螺纹桩桩周土体抗剪强度发挥程度最大,极限承载力最大;(5)实际工程中,过大的螺纹宽度或过小的螺纹厚度会引起螺纹强度不足,并加大施工难度,因此,设计时要兼顾承载力、螺纹强度、施工难度及工程成本;(6)本研究成果可为螺纹桩地基或路基处理工程提供有用参考。
Research purposes: Screw pile is a new type of special-shaped pile,which has the advantages of efficiency,environmental protection and economy. But at present,there is no accurate understanding of the bearing mechanism of screw pile. In this paper,the vertical bearing characteristics of straight and screw piles are compared by method of model test and numerical simulation,and the distribution law of axial force and side friction of screw pile are studied. The deformation of the pile and the soil around the pile under the load of the pile top is analyzed,and the vertical bearing mechanism of the screw pile is revealed. And the influence of screw structural parameters on the bearing capacity of screw pile is analyzed.Research conclusions:(1) The straight and screw piles with length-diameter ratio of 12 under vertical load show the bearing characteristics of friction end bearing pile and end bearing friction pile respectively.(2) The ultimate bearing capacity and the pile material utilization of screw piles are obviously better than those of straight piles.(3) Among the structural parameters of screw pile,the spacing and width of the screw are the main factors affecting the bearing capacity of the screw pile,and the thickness of the screw has little effect on the bearing capacity.(4) The bearing capacity of the side of the screw pile is mainly provided by the shear force of the soil around the pile. The existence of optimal screw spacing allows the shear strength of the soil around the screw pile to be maximized,and the ultimate bearing capacity to be maximized.(5) In actual engineering,an excessively large screw width or an excessively small screw thickness will cause insufficient screw strength and increase the difficulty of construction. To take full advantage of the screw pile,the bearing capacity,screw strength,construction difficulty,and engineering cost must be taken into consideration.(6) The research results can provide useful reference for the engineering of screw pile foundation or subgrade.
作者
冷伍明
魏广帅
聂如松
魏丽敏
董俊利
LENG Wuming;WEI Guangshuai;NIE Rusong;WEI Limin;DONG Junli(Central South University,Changsha,Hunan 4010075,China)
出处
《铁道工程学报》
EI
北大核心
2020年第5期1-6,35,共7页
Journal of Railway Engineering Society
基金
国家自然科学基金资助项目(51878671,51878666)
中南大学中央高校基本科研业务费专项资金资助(2019zzts622)。
关键词
螺纹桩
模型试验
数值模拟
极限承载力
螺纹结构参数
screw pile
model test
numerical simulation
ultimate bearing capacity
structural parameters of screw pile
