Unsaturated bearing capacity of strip foundations by using the upper bound rigid block method

Shallow strip foundations are ubiquitous in the field of geotechnical engineering. However, most of the analyses regarding the strip foundations were performed without considering the unsaturated state of the soil. The present article aims to evaluate the upper bound collapse load of the strip footing by duly considering the matric suction developed above the water table. The effect of the vadose zone is considered by employing the suction-stress-based effective stress approach. The suction stress is modelled by employing van-Genuchten’s soil water characteristics curve and Gardner’s one-parameter hydraulic conductivity function. The kinematic admissibility of the problem is ensured by considering a Hill-type mechanism. A new bearing capacity factor is introduced into the formulation which takes care of the unsaturated soil properties and the climate changes. The obtained results are in good agreement with the available solutions.