LOWER BOUND LIMIT ANALYSIS OF PLANE STRAIN AND AXI-SYMMETRIC FOOTINGS
Lower bound solutions require choice of a statically admissible stress field. The present study is an attempt towards investigating the suitability of a new stress field for strip footings, which satisfies the conditions of element equilibrium, for obtaining lower bound optimal bearing capacity solutions. Surface and embedded strip footings have been considered. Sequential Unconstrained Minimisation Technique (SUMT) incorporating discrete elements in conjunction with non-linear programming has been used for the analysis. Obtained results have been compared with the ones available in the literature and it is observed that the proposed stress field predicts improved lower bound solutions.
A statically admissible stress field has been derived to obtain lower bounds on the bearing capacities of circular footings. Soil properties required for lower bound limit analysis have been obtained by conducting various laboratory tests on different soils. The obtained results have been compared with those available in the literature and by conducting FEM analysis. It has been observed that the proposed stress fields predict solutions, which are very close to the Limit Equilibrium, Slip line solutions and FEM solutions available in the literature.
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