Critical Load and Shape Factors of Circular Foundations

Abstract:

According to Mohr Coulumb Criterion and the elastic theory for circular distribution pressure, the critical bearing capacity can be determined, which is the pressure when the maximums depth in plastic zone is upto one fourth of the diameter. Based on a comparison with strip foundation, the critical bearing capacity factors and shape factors are presented. The shape factors of the critical bearing capacity for circular foundation are compared with those of several ultimate bearing capacity. Similarity is found for the shape factors in relation with cohesion and embedded depth of foundation, but inconsistency is found for the shape factor in relation with width of foundation, which is advised to adopt Meyerhof’s shape factor for safety. The safety factor of the ultimate capacity divided by the critical one for circular foundation is consistent with that for strip foundation.

Key words:circular foundation; critical load; ultimate bearing capacity; shape factors