静钻根植竹节桩抗压与抗拔对比研究

doi:10.16183/j.cnki.jsjtu.2018.11.008

摘要/Abstract

摘要： 静钻根植竹节桩是一种新型组合桩基础.大量试验研究表明，桩受到上拔荷载与压荷载时，桩侧极限摩阻力存在差异，并将抗拔桩与抗压桩极限侧摩阻力比值定义为抗拔侧摩阻力折减系数.为了研究静钻根植竹节桩在软土地基中抗拔与抗压条件下侧摩阻力大小的差异系数，通过一组现场试验得到了抗压桩与抗拔桩的荷载位移曲线，然后根据实测参数用有限元软件Abaqus对试桩进行模拟，并将现场试验与数值模拟的荷载位移曲线对比以验证模型的可靠性.研究结果表明：抗拔桩与抗压桩桩身轴力具有相似传递特性，静钻根植竹节桩在软土地基中的总侧摩阻力折减系数λ=0.5；桩端水泥土扩大头直径的增加对提高抗拔桩与抗压桩极限侧摩阻力作用不明显；静钻根植竹节桩的总侧摩阻力折减系数基本不随桩端扩大头直径的改变而改变.

关键词: 静钻根植竹节桩, 抗拔系数, Abaqus模拟, 极限侧摩阻力, 桩端扩大头

Abstract: The pre-bored grouting planted nodular (PGPN) pile is a new type of composite pile foundation. A large number of field test results have shown that the ultimate skin friction of piles under tension and compression has big differences. The total lateral friction reduction factor is defined as the ratio of shaft resistance between uplift pile and compressive pile. To investigate the differences of skin friction distribution of the PGPN piles under tension and compression in soft soils, a group of field tests were carried to obtain the load-displacement curves of piles under tension and compression, and then Abaqus was used to simulate test piles. The comparison between results of field tests and Abaqus simulation was used to validate finite element model. The results showed that the axial forces of piles under tension and compression have similar transfer characteristics; the uplift coefficient of the PGPN piles in soft soils is 0.5. The increase of diameter of enlarged pile tip has little effect on ultimate skin friction of piles under tension and compression. The total lateral friction reduction factor of the PGPN piles is a constant with the increase of the diameter of enlarged pile base.

Key words: pre-bored grouting planted nodular (PGPN) pile, uplift coefficient, Abaqus simulation, ultimate skin friction, enlarged pile base

中图分类号:

TU 47

龚晓南1，解才1，周佳锦1，邵佳函1，舒佳明2. 静钻根植竹节桩抗压与抗拔对比研究[J]. 上海交通大学学报（自然版）, 2018, 52(11): 1467-1476.

GONG Xiaonan，XIE Cai，ZHOU Jiajin，SHAO Jiahan，SHU Jiaming. A Comparative Study on the Static Drill Rooted Nodular Piles Under Tension and Compression[J]. Journal of Shanghai Jiaotong University, 2018, 52(11): 1467-1476.

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