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.