ESTIMATION OF (Nγ) FOR STRIP AND CIRCULAR FOOTINGS USING THE METHOD OF CHARACTERISTICS

Abstract

By using the method of characteristics (commonly referred to as the slip line method), the values of the bearing capacity factor N_γ were computed for rigid surface strip and circular footings with smooth and rough bases. The analyses of bearing capacity for vertically loaded footings using the method of characteristics have been implemented in the publicly available computer program ABC, then N_γ –values were calculated theoretically. The supporting soil is modeled as a frictional Mohr – Coulomb material. For both footings, the value of the bearing capacity factor N_γ was found to increases significantly with an increase in the angle of internal frictionf. When friction angle of soil f  ≤25°, the computed values of N_γ for circular footing were found to smaller than those for strip footing and for larger values of f, the magnitude of N_γ for circular footing were greater than those for strip footing for both smooth and rough base of footings. On the other hand, the magnitude of N_γ for rough footings was seen be higher than for a footings with smooth base. The obtained results were compared with those available in the literature, and reasonable agreements were observed.