Interference of Two Nearby Footings Resting on Clay Medium

The study pertains the behaviour of two closely spaced strip footings resting on the surface of the semi-infinite clay soil medium. The effect of interference on characteristic behaviour like bearing pressure, settlement and tilt are observed using two dimensional plane strain finite element analysis. The foundation soil medium is modelled using Mohr–Coulomb soil model that follows linear-elastic perfectly plastic behaviour using finite element analysis software PLAXIS. The soil domain is discretized into 15-noded triangular elements with fine meshing in vicinity of the footings and coarser meshing towards boundary of the domain. Parametric study is performed by varying the clear spacing between the footings and depth of the footings; their effect on the load-settlement characteristic, variation of settlement and bearing pressure with clear spacing are studied. The results are presented in terms of non-dimensional efficiency factors defined as the ratio of settlement/bearing pressure of interfering footings to that of the isolated footing. It is found the interference affect the performance of isolated footing. The bearing pressure is found to decrease with decrease in clear spacing between the footings and in contrast, the settlement is found to increase compared to that of the isolated footing. The results may help in finding the minimum spacing between the footings for better performance.