Laboratory model test results for the uplift capacity of a circular plate anchor embedded In saturated kaolinite and montmorillonite have been presented. The tests were conducted with and without venting the bottom of the anchor plate Based on the model test results, the variation of the ratio of mud suction force to the net ultimate uplift capacity With embedment ratio has been presented.
In many instances, earth anchors are used In ocean sediment to construct mooring systems during exploration and utilization of ocean resources. During the past two decades a number of papers have been published which relate to the ultimate and allowable uplift capacity of shallow and deep plate anchors embedded In sand and saturated clayey soils. A comprehensive summary of those studies was provided by Das (1990). However, several facts In the anchor uplift are not yet clearly understood and need further investigation. Consider an anchor plate resting In a soft saturated clay for a sufficiently long time. When an uplifting force is applied to the anchor, the soil above the anchor plate is compressed while the soil below is relieved from stress. Hence there will be an increase in the pore water pressure above the anchor while a decrease In the pore water pressure is encountered below It (Fig 1). The net result is a suction which is commonly referred to as the mud suction force. Very little is known about this force in a general sense (Veslc, 1971, Baba, GulhatI and Datta, 1989) The purpose of this paper is to present some recent laboratory model test results conducted to evaluate the nature of variation of the mud suction force for shallow Circular plate anchors With (a) type of clay mineral, (b) moisture content and thus liquidity index, and (c) depth of embedment.