Experimental Investigations on Uplift Capacities of Single and Group of Granular Anchor Piles

Among a variety of ground improvement techniques, granular piles or stone columns find use in a variety of ground problems. Although Granular piles are economical and versatile in application, they are unable to provide safeguard the foundation against uplift or pull-out loads. In such situations, a modification over granular pile known as granular anchor piles is used. In the present study, a series of pull-out tests has been conducted on granular anchor piles by varying its diameter and length to diameter ratio. Pull-out tests have also been conducted on group of two granular anchor pile by varying the spacing between them. It was observed that, with increase in diameter and length to diameter ratio of granular anchor piles, pull-out capacity increases. The pull-out resistance of the group of two pile was found to be greater than that for a single pile having same diameter and length to diameter ratio. But it was lesser than twice the capacity of single pile. The value further increased when the spacing between piles was increased from three times diameter to four times diameter .