Correction Factor for Pile Compressibility Ck
The values of the factor Ck are generally presented as a function of the pile-stiffness factor K for various pile length to pile diameter ratios (l/d). These graphs are implemented in the program in a digital format.
Compressibility correction factor for base load Ck
Poulos, H. G. et. Davis, E. H.: Pile Foundations Analysis and Design. New York: John Wiley and Sons, 1980, chapter 5.3.3, pp. 86 (figure 5.12).