This study is a laboratory investigation which compares the uplift behaviour with respect to the bearing behaviour of plate anchors embedded in soft clay. The effect of embedment depth of the anchor on the uplift as well as bearing behaviour has been studied for two different types of clays. It is observed that it is possible to relate the uplift behaviour of the anchor with the bearing behaviour especially at deep embedment depths.
The uplift behaviour of anchors has been a subject of study for the last few decades. As soft clays are very often encountered in offshore geotechnical engineering, a large number of studies on anchor behaviour have been on anchors embedded in soft clays. The more recent studies have reported the measurement of a suction force that develops beneath the anchor during uplift of anchors embedded in soft clays. It has been observed that the uplift behaviour of anchors embedded in soft clays wherein the suction force has been eliminated, has been extensively researched, whereas a clear understanding of the behaviour 6fthe suction force has yet to be developed. To determine the suction force developed beneath the anchor during uplift, Finn & Byrne (1972) proposed that a reversed end bearing capacity mechanism can be assumed and therefore the suction force in uplift will be equal to the bearing force. This theory was proposed and validated by laboratory model tests for shallow embedment of a suction caisson wherein soil is not present above the anchor. Extension of the above concept of similar failure mechanisms in uplift and in bearing to plate anchors where soil is also present above the anchor, under shallow and deep embedment conditions (fig. 1), indicates that uplift behaviour is probably similar to the bearing behaviour of the plate anchors.
