Bearing capacity factor Nc under ϕ=0 condition for piles in clays

Abstract

AbstractBearing capacity factor Nc for axially loaded piles in clays whose cohesion increases linearly with depth has been estimated numerically under undrained (ϕ=0) condition. The study follows the lower bound limit analysis in conjunction with finite elements and linear programming. A new formulation is proposed for solving an axisymmetric geotechnical stability problem. The variation of Nc with embedment ratio is obtained for several rates of the increase of soil cohesion with depth; a special case is also examined when the pile base was placed on the stiff clay stratum overlaid by a soft clay layer. It was noticed that the magnitude of Nc reaches almost a constant value for embedment ratio greater than unity. The roughness of the pile base and shaft affects marginally the magnitudes of Nc. The results obtained from the present study are found to compare quite well with the different numerical solutions reported in the literature. Copyright © 2008 John Wiley & Sons, Ltd.