THE LEAST UPPER-BOUND SOLUTIONS FOR BEARING CAPACITY FACTOR N_g

 DAYONG ZHU

ABSTRACT The correct solution to bearing capacity factor N_g due to soil self-weight is not available by the classical theory of plasticity, so numerical approximation based on limit equilibrium method or limit analysis is required. Limit analysis using upper-bound theorem can give an upper-bound solution for the bearing capacity problem. If the critical failure mechanism is found, such an upper-bound solution is a good approximation for the correct one. By employing the equivalence of limit analysis and limit equilibrium method a straightforward procedure is proposed in this paper to determine the critical failure mechanism in solving the least upper-bound solution of bearing capacity N_g.. This procedure proves to be efficient in accommodating various loading or geometrical conditions. The least upper-bound values of N_g in a variety of cases are presented and comparisons with other accepted methods are made in the paper.

Key words: bearing capacity, failure, footing, granular material, limit analysis, limit equilibrium, self-weight (IGC: E3)