Interaction of adjacent strip footings on reinforced soil using upper-bound limit analysis

This paper explores the ultimate bearing capacity of two closely spaced interfering strip footings resting on a reinforced cohesionless soil bed using upper-bound limit analysis. The soil is assumed to follow the Mohr-Coulomb failure criteria along with the associated flow rule. A kinematically admissible multi-block failure mechanism is adopted in the analysis. The effect of interaction is studied with respect to angle of internal friction of soil (phi), clear spacing between the footings (s) and the number of reinforcement layers (p). The interference effect in terms of efficiency and influence factor is found to increase with the increase in s and becomes maximum at a critical spacing (s(cr)) followed by a reduction with further increase in s. However, the interference effect is seen to decrease with increase in the number of reinforcement layers. The present theoretical observations are generally found to be in good agreement with the results reported in literature for the same class of problem.