Back calculated a and b coefficients from case histories of negative skin friction piles

摘要

This paper presents the back calculated a and b coefficients from case histories in negative skinnfriction piles and provides an engineering reference for engineers to design a negative skinnfriction pile. Negative skin friction or dragload is a common problem for a pile in a highlyncompressible soil. There are mainly two methods to calculate negative skin friction: a and bnmethods. In this paper, a and b coefficients are back calculated based on several known casenhistories. It is found that both a and b coefficients vary in a wide range. The average values of 0?62nfor a and 0?21 for b are recommended for uncoated piles compared to 0?17 and 0?07 for a and bnfor coated piles..