An Experimental Study of the Behavior of a Strip Footing Adjacent to Reinforced Sand Slope Above a Soft Pocket

Abstract

Underground soft pockets, located in a footing's failure zone, may result in foundation instability and severe super structural damage. Throughout this paper, an experimental study is presented showing the behavior of a model strip footing on both geogrid-reinforced as well as un-reinforced sand slope above a soft pocket. Affecting factors, including the depth of a soft pocket below the strip footing, the setback distance between the crest of a sand slope and the strip footing, the relative density and the various number of reinforcement layers below the footing were all examined. The stress-settlement of the model footing supported on a medium and dense sandy slope with and without a soft pocket were obtained and compared at different studied parameters. Test results indicated that the existence of such a soft pocket within the subgrade layer under the footing has a great effect on the stress and settlement of footing. Furthermore, it has been found that the inclusion of the reinforcement layers in the sand not only significantly increases the stability of the sandy slope itself, but also lessens the settlement. Moreover, two main factors upon which the efficiency of sand-geogrid systems depends are the location of the footing relative to the slope crest, and the depth of the soft pocket below the footing. Variations of the stresssettlement with different parameters are given and discussed, based on the test results.