Document Type : Research Article
Department of Civil Engineering, Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
Department of Civil Engineering, K.N. Toosi University of Technology, Tehran, Iran
Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
The rigid base proximity (such as stiff rock) under a relatively thin sand stratum and employing a 3D reinforcement (e.g. geocell) can tend to significant improvement in the bearing capacity of shallow footings. In this study, the behavior of circular footings located on unreinforced and geocell-reinforced thin sand layers was investigated. The simultaneous or individual effects of footing dimensions, sand layer thickness, and geocell reinforcement on the bearing capacity and settlement of footing were studied by conducting large-scale model tests. The influence of soil layer thickness on footing behavior was elucidated by considering optimum dimensions and location for geocell reinforcement. Based on the results, improvement in the bearing capacity and settlement reduction for both unreinforced and reinforced footing beds were observed when the sand layer thickness is lower than two times the footing width. Additionally, the effective depth of the rigid base for both cases was obtained two times of footing width. The combination of geocell-reinforcement and rigid base as lateral and vertical confinement factors led to an increase in the bearing capacity and settlement reduction at the failure point up to 45% and 53%, respectively. The test’s results were served to define new factors extending classical bearing capacity equations for footings located on thin soil at reinforced and unreinforced cases. The comparison of results with the previous investigations confirmed their good agreement.