分析了在桩顶荷载作用下的负摩阻力特性。
The characteristics of negative skin friction (NSF) with working load on pile top were analyzed.
采用有限元方法模拟了基桩负摩阻力随着固结时间的变化。
Change of negative friction in pile with consolidation time is simulated by finite element method.
负摩阻力分布曲线大致呈抛物线型，与桩基现场浸水试验结果相似。
Distribution curves of negative skin friction were similar to parabola, as was also found in some field test studies.
并根据打桩引起的桩负摩阻力概念对两类桩基沉降差异的机制作了分析。
And the mechanism causing the difference is also analyzed based on the concept of negative frictional resistance.
基于荷载传递函数的概念，提出了一种用双折线模型来计算桩负摩阻力的方法。
Based on load transferring concept, this paper puts up a new method which USES double broken line model to calculate the negative friction of pile.
同时，该修正方法可应用到钻孔灌注桩及桩侧负摩阻力引起的基桩沉降计算中。
At the same time, the revised method can be used to calculate the settlement of a bored pile and that of a foundation pile caused by negative frictional resistance around the pile.
本文基于荷载传递函数的概念，提出了一种用双折线模型来计算负摩阻力的新方法。
Based on load transferring concept, the author puts up with a new method which USES double broken line model to calculate negative friction.
有限元分析结果表明，影响桩基负摩阻力特性的桩体材料弹性模量存在一个临界值。
Finite element analysis shows that a critical value exists for Young's module of pile that affects NSF character.
湿陷性黄土地区地基土浸水湿陷后，桩侧表面可能产生负摩阻力，将导致桩基承载力降低。
The negative skin friction resistance caused by collapsible deformation after water soaking into collapsible loess will reduce the vertical bearing capacity of piles.
工程中，因负摩阻力问题造成工程事故屡有发生，负摩阻力问题相关研究现在越来越受到重视。
Engineering accidents often occur due to negative skin friction in pile foundation engineering. The research on problems of negative skin friction has been paid more and more attention.
工程中由于负摩阻力产生的下拉荷载不仅使桩竖向承载力减小，还会导致结构物的不均匀沉降。
In the engineering project, negative skin friction is the drag force that will reduce the vertical bearing capacity and cause differential settlement of the structure.
由于负摩阻力的作用，桩身轴力随着深度的增加先增大后减小，桩侧摩阻力沿深度呈非线性变化。
The axial force of piles first increases with the depth and then decreases. The variation of negative skin friction with the depth of piles is nonlinear.
试验的观测结果表明，地震诱发黄土震陷时的桩基负摩阻力不容忽视，应当在桩基设计时加以考虑。
It was shown by these test data that the NSF along piles induced by seismic settlement of loess was significant and should not be ignored in the design of pile foundation.
实例分析表明，由于桩侧负摩阻力的影响，单桩承载力大为降低。产生负摩阻力的土层，不宜采用端承型桩基。
The greatly reduced capacity of a single pile resulting from the negative friction leaves the end-bearing pile unsuitable in the backfilling soil.
结合以往研究实心桩的成果和PC C桩自身的特点，基于太沙基固结理论，探讨了PCC桩负摩阻力作用机理。
Combined with the previous results and the property of PCC pile, based on Terzaghi consolidation theory, mechanism of negative skin friction of PCC pile has been studied.
基桩负摩阻力是桩基础设计中必须考虑的重要问题之一，但是针对考虑土体固结时间效应的群桩负摩阻力研究却相对较少。
Negative skin friction is one of important problems in design of pile foundation, but the negative skin friction of pile groups considering time effect is less studied.
主要论述群桩负摩阻力的特点及群桩负摩阻力的计算，并结合国内外几种常用的近似估算法进行比较，对各种计算方法加以评价。
The characters and the calculation of negative friction of a pile group are given. Several approximately estimating methods are compared with the others and commented on as well in this paper.
阐述了桥梁桩基负摩阻力产生的原因，分析了桩基中性点位置确定、负摩阻力计算等问题，并提出了十条有效减少负摩阻力的措施。
This paper expatiates on the causes of negative frictional resistance which may appear on bridge piles, analyses the calculation methods and gives ten methods reducing it.
阐述了桥梁桩基负摩阻力产生的原因，分析了桩基中性点位置确定、负摩阻力计算等问题，并提出了十条有效减少负摩阻力的措施。
This paper expatiates on the causes of negative frictional resistance which may appear on bridge piles, analyses the calculation methods and gives ten methods reducing it.
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