软土地区布袋注浆桩复合地基承载性状分析

Analysis of bearing properties of bag-grouting-pile composite foundation in soft soil area

通过研究土体、桩体及桩-土接触面的摩擦,并对这三者之间的联系及传力模式进行分析;研究桩长、桩间距对单桩复合地基的承载性状的影响。本文基于有限元程序ABAQUS,采用有限单元法对布袋注浆桩复合地基进行研究分析,通过控制单一变量分析随桩长、桩间距变化的单桩复合地基的承载性状的变化。研究发现复合地基桩顶处存在较明显应力集中现象,在桩身上部逐渐衰减且在下部速度加快。随着荷载增加,桩身上部侧摩阻力增加且分布趋势随桩长变化而产生的差别不大,发挥程度随桩间距的增大而减小。结果表明:布袋注浆桩能够将荷载传递到深部土层,侧摩阻力在桩身上部得到稳定发挥,下部侧摩阻力发挥程度大,复合地基承载力设计时应考虑桩土相互作用和桩间土固结作用的影响。

By studying the friction of soil,pile and pile-soil contact surface,and analyzing the connection and force transfer mode between these three.The bearing properties of monopile composite foundation with the variation of pile length and pile spacing is analyzed.The finite element program ABAQUS is used to study and analyze the composite foundation of bag-grouting-pile by finite element method.The bearing properties of the composite foundation of single pile with the variation of pile length and pile spacing are studied by controlling a single variable.The stress concentration phenomenon at the top of the composite foundation pile is obvious,which decays gradually at the top of the pile and accelerates at the bottom.With the increase of load,the lateral frictional resistance of the upper part of the pile increases and the distribution trend with the change of pile length is not much different,and the degree of play decreases with the increase of pile spacing.The results show that the bag grouting pile can transfer the load to the deep soil layer,and the lateral friction resistance in the upper part of the pile is stabilized,and the lower part of the lateral friction resistance is played to a large extent.The influence of pile-soil interaction and soil consolidation between piles should be considered when designing the bearing capacity of composite foundation.