In the present study, blast furnace slag in granulated form has been used as a granular fill overlay on soft subgrade soil. The effectiveness of geogrid-reinforced granular fill overlay on soft subgrade soil has been assessed by small scale model tests in the laboratory by evaluating two parameters bearing capacity ratio (BCR) and reduction factor. The effect on BCR of strip footing for various lengths of geogird layers in the best performing thickness has been observed. Best performing thickness of the granular fill layer has been found by the parametric study which is not included in this paper. Parametric study has been performed to observe the effect of length of geogrid layers in granular fill overlay on soft subgrade soil. The test results indicate substantial improvement in terms of increase in bearing capacity and reduction in the footing settlement due to provision of geogrid in the granular fill overlay on soft subgrade soil. It has been found that b/B ratio of 4 gives substantial improvement in BCR and beyond b/B ratio of 4, there is no significant improvement in BCR. (C) 2013 The Authors. Published by Elsevier Ltd.