Granular anchors under vertical loading/axial pull

Abstract

Granular anchors are a relatively new concept in ground engineering with relatively little known of their applications, failure modes and ultimate pullout capacities. A granular anchor consists of three main components: a base plate; tendon and compacted granular backfill. The tendon is used to transmit the applied load to the base plate which compresses the granular material to form the anchor. A study of the load?displacement response and ultimate pullout capacity of granular anchors constructed in intact lodgement till and made ground deposits is reported in this paper. Parallel tests were also performed on cast-in situ concrete anchors that are traditionally used for anchoring purposes. A new method of analysis for the determination of the ultimate pullout capacity of granular anchors is presented and verified experimentally, with the dominant mode of failure controlled by the column aspect ratio. Granular anchors with L/D > 7 failed principally on bulging whereas short granular anchors failed on shaft friction, with the latter mobilising similar pullout capacities as conventional concrete anchors.