Discussion on Negative Skin Friction of Piles in Collapsible Loess 

Chen PENG 

School of Traffic & Transportation, Chongqing Jiao Tong University, Chongqing400074, CHINA 

Abstract: The negative friction resistance of pie foundation is a neglected problem in the foundation engi-neering, especially in the loess subgrade area of northwest China. The article begins with an introduction to its formation mechanism and influential factors, then it analyzes theoretically and ensures the neutral point loca-tion of negative friction resistance. Next the paper combines the majority of researches to conclude the neutral point of self weight collapsible soil layer which ranges between 0.6 to 0.75 l0. What’s more, according to the theory of elastic force transfer model, it states the calculation of the negative skin friction by adopting effec-tive stress method. 

Keywords: Formation mechanism; Influencing factors; Neutral point location; Calculation