Study on Closely Spaced Asymmetric Footings Embedded in a Reinforced Soil Medium

Abstract

In practice, footings are rarely laid on the surface or at ground level; usually, they are embedded in the soil medium. Most studies focus on surface footings. This research examines the behavior of two interfering asymmetric footings while considering their widths to be dissimilar and the effect of embedment depth to enhance the ultimate bearing capacity and limit the settlement within the working range. This was evaluated through the finite element method of the ABAQUS software. The soil was assumed to have a Mohr-Coulomb failure, and the asymmetry corresponded to the footing widths. The results are presented in terms of interference factors, i.e., the ultimate bearing capacity (UBC) and the settlement, which are defined as the UBC/settlement ratio of the left/right footing in the presence of the other one placed on reinforced soil. This, in comparison with an identical isolated footing on unreinforced soil. Interference is more significant in small footings than in large ones. Due to behavioral variations, the bearing capacity and settlement are different. This effect increases with an increase in the width of large footings, and the interference factors decrease with an increase in the embedment depth of the footings. When the right footing width is twice that of the other and considering one layer of reinforcement and soil friction angles of 30º and 40º, the percent increments in the bearing capacity of interfering left footings, for a spacing of 0,5 times the left footing width, are 104 and 148%, respectively.

Keywords

• interference
• asymmetric footings
• ultimate bearing capacity
• settlement