大直径超长钻孔灌注桩桩端后压浆机理探讨

在分析大直径超长灌注桩实时应力监测资料的基础上,从力学机理入手分析桩端后压浆对基桩承载特性的影响.分析结果表明:桩端后压浆主要通过渗透固结、挤密充填等作用,改善桩端及桩周地层土的物理力学性质,消除桩端虚土对承载力的影响效果明显;由于扩底和劈裂泥皮作用,基桩桩端承载面积及桩体的有效长度与侧摩阻力均得到明显的提高.

Discussion on post-grouting mechanism at end of super-long large-diameter bored piles

Based on real-time stress monitoring data for super-long large-diameter bored piles,the influences of post-grouting at the end of piles on bearing characteristics of foundation piles were analyzed.The result shows that post-grouting improves the physical-mechanical properties of pile-surrounding soil and soil stratum at the end of piles by seepage-induced consolidation and compaction filling,and it greatly enhances the bearing capacity of loose soil at the end of piles.Moreover, the loading area at the end of foundation piles,the effective length and lateral friction of piles are also greatly improved by base enlargement and mud-cake fracturing.