Effect of Submergence on Settlement and Bearing Capacity of Surface Strip Footing on Geotextile-Reinforced Sand Bed

This paper presents the effects of submergence on the settlement and the bearing capacity of a surface strip footing resting on the reinforced sand bed at a relative density of 90 % by conducting the laboratory model tests. The reinforcement layers used were woven geotextile layers, without and with wraparound ends. The number of reinforcement layers was varied from 1 to 4. The test tank had an arrangement for the water table rise, from the bottom of the sand bed constructed in the tank. The model strip footing was placed at the surface of the sand bed, and measurement of the settlement occurring with the rise of the water table, was taken to observe the effect of water table rise. When the water table reached the top surface of the sand bed, that is, the sand bed was fully submerged under water; the measurement of settlement of the footing was continued, by applying the load incrementally through the hydraulic jack. The results show that the rise of the water table causes a significant settlement of the footing for both unreinforced and reinforced cases. However, the beneficial effect of reinforcement layers was observed in terms of increased load-bearing capacity. An increase in the number of reinforcement layers, from 1 to 4 as well as providing the wraparound ends to the reinforcement, brought a significant increase in load-bearing capacity. When compared to the dry situation, there is a significant decrease in the load-bearing capacity as well as in the modulus of subgrade reaction of the unreinforced and reinforced sand beds with the rise of water table and full submergence.