Influence of Combined Vertical and Horizontal Reinforcement on Granular Piles in Soft Clays

Geosynthetic reinforced granular piles are commonly used in engineering practice to enhance the bearing capacity, reduce settlements and to increase the rate of consolidation of very soft clays. In the present paper, laboratory model tests have been carried out on vertical–horizontal combined reinforced floating granular piles installed in soft clay. A 75 mm diameter and 375 mm length single granular pile was formed by simulating unit cell concept. Geotextile and geogrid were used over the full length of granular piles as vertical encasement and horizontal strips respectively. Geogrid strips of 65 mm diameters were placed at three different centre to centre spacing of 25, 50, and 70 mm. Vertical load–settlement relationship of untreated clay bed, unreinforced and reinforced granular pile treated ground were obtained under short-term loading. The influence of reinforcement was examined in term of ultimate load intensity of granular piles compared to untreated ground. Model tests indicated significant improvement in the load carrying capacity of granular piles due to the incorporation of geosynthetic.