Method for improving bearing capacity of foundationin reclaimed areas of Dhaka city

Abstract

This research is intended to suggest a method for improving bearing capacity of shallow foundation system for reclaimed areas in Dhaka city. The study site was selected in Mirpur Defence Officers’ Housing Scheme (Mirpur DOHS) which was reclaimed in2004 by dredged fill material. Almost all the fills are basically silty sand. The SPT N- value of the filling varies from 1~11. A shallow foundation reinforced with geo-textile, sand and aggregate was constructed. Full scale load test was conducted to evaluate the bearing capacity of the improved foundation system. From load test, the ultimate bearing capacity was determined for allowable settlement. It was found that the ultimate bearing capacity of the improved system is 90% higher than the conventional shallow foundations. Field load test was simulated by FEM using tij-2D program. At first, analyses were conducted to simulate the field load test. Trials were made to find the most effective D/B ratio for the improved foundation design. From the analyses, it was revealed thata significant increase in bearing capacity can be achieved using shallow foundation system reinforced with geotextile. Maximum reinforcing effect was obtained with D/B=0.10. Finding of this study thus reveals a method for improving bearing capacity of shallow foundation in reclaimed areas of Dhaka city.