Experimental behavior of piggy-backed anchors in cohesionless soils

Abstract

As the offshore wind platform ventured into deep water, improving anchor efficiency has become the main focus of foundation design. Plate anchors are attractive options due to factors such as high anchor efficiency and low cost. Appropriately attaching two plate anchors improves the total capacity of the piggy-backed anchors configuration, and generally, this capacity is greater than twice the capacity of an individual anchor. This paper presents the centrifuge drag embedment tests of an individual drag embedment anchor (DEA) and the piggy-backed DEAs in cohesionless soil. The piggy-backed configuration with the spacing between the two anchors at three fluke lengths and an attachment point at the back of the fluke can improve the anchor total capacity. The main reason is that a deeper penetration of the back anchor and the steeper pitch of the front anchor facilitate both anchors to dive deeper.