This paper presents an equivalent continuum method for simulating the behaviour of geocell reinforced sand foundation beds, using finite element technique. An equivalent composite model is used for numerically simulating the improvement in the strength and stiffness of sand confined with geocells. Shear strength of geocell encased sand is derived from the additional confining pressure due to geocell using hoop tension theory. The stiffness of geocell encased sand is represented by an empirical equation in terms of the stiffness of the unreinforced sand and the tensile modulus of the geocell material. Numerical simulations of strip footings resting on sand bed are carried out with and without geocell layer, varying parameters like, the dimensions of geocell layer, pocket size, depth of placement of geocell layer and the tensile modulus of the geocell material. The results of numerical analyses are validated with the corresponding experimental results. The comparison between the numerical results and the experimental results is found to be reasonably good. Some significant observations on the mechanism of geocell reinforcement have been presented in this paper. © Springer Science+Business Media B.V. 2008.