注浆螺纹抗拔桩室内模型试验与承载机理分析

发布时间：2019-05-23 22:59

【摘要】：为探讨一种新型注浆螺纹桩的抗拔承载机理,进行了室内模型试验,用以研究等截面圆桩及不同螺纹间距的注浆成型螺纹桩的荷载-位移曲线和侧阻力的分布规律。采用三维有限元分析方法,探讨了桩周土的塑性行为。结果表明,与等截面圆桩相比,螺纹桩中螺纹与桩周土的相互咬合作用增大了桩侧摩阻力,其侧摩阻力的增幅自上而下近似为等值,使得螺纹桩抗拔承载力得以大幅度提高;抗拔承载力与桩体螺纹间距与桩径的比值(即距径比)密切相关;存在某一最优螺纹距径比,使得抗拔承载力最高。三维有限元分析结果表明,随距径比值增大,桩侧土体塑性区先不断增大后逐渐减小,距径比为1时塑性区范围最大,此时相邻螺纹间形成了贯通的破坏面。针对注浆螺纹抗拔桩提出了最优螺纹间距,可为该桩型的优化设计提供依据。
[Abstract]:In order to discuss the pullout bearing mechanism of a new type of grouting threaded pile, an indoor model test was carried out to study the load-displacement curve and lateral resistance distribution of round pile with equal cross section and grouting pile with different thread spacing. The plastic behavior of soil around pile is discussed by using three dimensional finite element analysis method. The results show that, compared with the circular pile with equal cross section, the interaction between thread and soil around the pile increases the lateral friction resistance of the pile, and the increase of the lateral friction resistance is approximately equivalent from top to bottom, which greatly improves the pullout bearing capacity of the threaded pile. The pullout bearing capacity is closely related to the ratio of thread spacing to pile diameter (that is, distance to diameter ratio), and there is an optimal thread spacing ratio, which makes the pullout bearing capacity the highest. The results of three-dimensional finite element analysis show that with the increase of the ratio of distance to diameter, the plastic zone of soil on pile side increases at first and then decreases gradually, and the range of plastic zone is the largest when the ratio of distance to diameter is 1. At this time, a through failure surface is formed between adjacent threads. The optimal thread spacing is put forward for grouting thread anti-pullout pile, which can provide the basis for the optimal design of the pile type.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;上海市政工程设计研究总院(集团)有限公司;华东建筑设计研究总院地基基础与地下工程设计研究中心;
【基金】：上海市重点科技项目(11231202002)
【分类号】：TU473.1

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