This study deals with assessing the effect of stress level on bearing capacity
factor , distribution of shear stresses at soil-pile interface along pile shaft, and
presence of critical depth concept for bored piles axially loaded in compression and
embedded in dense sand. These investigations are made using finite element method
with the employment of a wide range of stresses by using piles with dimensions
starting from laboratory dimensions and goes towards field dimensions with
embedment ratio range from (15-40). The soil and the interface behavior is
modeled using Duncan-Chang hyperbolic soil model with empirical equations
account for reduction of angle of internal friction ø with increasing in stress level.
Bored pile is modeled as a linear elastic material. The results showed a dramatic
decrease in bearing capacity factor as length of pile increase. It was also found
that the embedment ratio has a significant effect in increasing bearing capacity
factor , and the distribution of shear stresses at soil-pile interface is not linear and
does not tend to take a constant value beyond a certain depth of pile nor decreases
after a certain depth along pile shaft. The fallacy of critical depth also noticed and
discussed in this paper.