Experimental and numerical studies on footings supported on geocell reinforced sand and clay beds

Abstract

This paper presents the results of laboratory model tests and numerical studies conducted on a square footing resting on geocell reinforced sand and clay beds. Using suitable scaling considerations, a model footing size was arrived from the prototype raft foundation. Commercially available geocells made up of polyethylene having an equivalent pocket diameter of 0⋅25 m and aspect ratio of 0⋅6 were used in the experimental investigation. Clean sand was used to fill the geocell pockets in both sand and clay bed tests. Test results of unreinforced, geocell reinforced, and geocell reinforced with additional planar geogrid at the base of the geocell cases are compared separately for sand and clay beds. Results reveal that the use of geocell increases the ultimate bearing capacity of the sand bed by 2⋅4 times and clay bed by 3⋅2 times. Provision of the planar geogrid at the base of the cellular mattress arrests the surface heaving and prevents the rotational failure of the footing. Moduli of subgrade reaction values indicate that the contribution of the geocell reinforcement exists even at very low settlements. Using the concept of equivalent composite model, the three-dimensional nature of the geocell is numerically simulated in the fast Lagrangian analysis of continua in 2D (FLAC2D). Experimental and numerical results are in good agreement with each other.