桩顶荷载对桩基负摩阻力特性的影响

比较了在桩顶荷载作用下的负摩阻力特性与无桩顶荷载时的差异,指出不考虑桩顶荷载的中性点位置最低,下拽力最大。分析结果表明,当有桩顶荷载作用时,中性点的位置明显高于无桩顶荷载时,下拽力也明显小于无桩顶荷载时,而且随着桩顶荷载的增加,中性点上移和下拽力减小的趋势也很明显;桩顶荷载较小时,负摩阻力对于桩基沉降的影响基本上是线性的;在桩顶荷载作用下,长桩比短桩的中性点位置和下拽力的变化都小些,这对桩基负摩阻力特性的研究是有益的。

Influences of Working Load on Negative Skin Friction Characters of Pile

The differences of negative skin friction(NSF) character between pile with working load and without working load are compared.It is pointed out that neutral point of pile is the lowermost,and downdrag caused by NSF is maximal taking no account of working load on pile.Analysis shows that neutral point of pile with working load is much higher than that of pile without working load,downdrag with working load is smaller than that without working load evidently.Furthermore,neutral point moves upwards obviously as working load increasing,the downdrag decreases obviously as working load increasing.The influence of NSF on pile settlement is almost linear while working load is small.Shift of neutral point and change of downdrag are smaller in longer pile than that in shorter pile while working loads act.It may be useful to the research of negative skin friction characters of pile.