Pull-Out Mechanism of Horizontal and Inclined Plate Anchors in Normally Consolidated Clay

Abstract

As most existing experimental studies on plate anchors were carried out in uniform clay, a centrifuge model study is presented in this paper to investigate the pull-out behaviour of plate anchors in normally consolidated clay, which is not uncommon in offshore seabed. Horizontal and inclined anchors with different embedment depths and aspect ratios (length to width) are considered. The soil movement pattern around the plate anchor is evaluated from high-resolution photographs taken during the tests employing the Particle Image Velocimetry technique. The separation mechanism at the plate-soil interface is hence identified. The significant contribution of suction towards the ultimate pull-out capacity of a plate anchor is quantified by monitoring the soil resistance and the pore pressure beneath the anchor base under undrained condition. By comparing the pull-out responses of horizontal and inclined anchors, the effect of anchor inclination on the anchor capacity and failure mechanism is evaluated.

Keywords

• plate anchor
• short-term pull-out
• suction
• non-separation
• shape factor