湿陷性黄土地区桩侧负摩阻力问题的试验研究

负摩阻力问题广泛存在于桩基工程中，在我国西北部自重湿陷性黄土地区尤为普遍，若处理不当，将导致严重的桩基功能失效。由于湿陷性黄土地区基桩负摩阻力受各种因素的影响，目前大面积现场浸水载荷试验仍是确定负摩阻力大小和发展规律最有效的方法。结合山西某电厂地基处理试验中大直径桩的大面积浸水静载荷试验，对自重湿陷性黄土浸水过程中桩侧负摩阻力的变化规律及湿陷变形对基桩竖向承载力性能的影响进行了分析，得到了桩侧负摩阻力的分布规律及对承载性状的影响，具有重要的工程指导意义。

Experimental study on negative skin friction resistance on piles in collapsible loess area

As it has long been recognized that negative skin friction resistance most possibly exists on piles when the soil around pile move downward relative to the pile, especially in collapsible loess in Northwest China. Once it is disposed improperly, the pile foundation will lose its efficacy. So to determine the distribution law of the negative skin friction is of important practical significance in engineering. Concerning the many factors, which always influence the distribution and numerical value of negative skin friction, the field immersion test under static load is still the most effective method in measuring the negative friction. Combined with the experiment of foundation disposal of a power plant in Shanxi Province, the distribution law of negative friction and the influence of collapsible deformation on the bearing capacity of piles are analyzed; and some beneficial results are obtained through these analysis, that will provide instruction for the engineering application.