The diving and keying capacities of OMNI-Max anchors in clay

Abstract

Different to the conventional gravity installed anchors (GIAs), the OMNI-Max anchor is capable of deriving higher capacity through the diving behavior (obtaining deeper embedment depth) after the keying process (usually accompanied by the loss of embedment depth) subjected to excessive loading, due to its three-dimensional structure and the various way to bear applied loading. The capacity properties of the anchor during keying and diving not only determine the keying and diving behaviors of the anchor, but also influence the other anchor behaviors, such as the embedment loss, pulling out and kinematic trajectory. Existing knowledge of the diving and keying behaviors is rather rare, stimulating further exploration of diving and keying capacities for OMNI-Max anchors. A systematic and quantitative study is performed on the complex capacities of OMNI-Max anchors during diving and keying in clay under multiple factors, including the anchor embedment depth, the anchor orientation, the interface friction, the loading direction, the bearing area of the anchor, the rotational center of the anchor, and the property of soil. Numerous cases of large deformation finite element (LDFE) analyses are conducted by employing the technique of coupled Eulerian-Lagrangian (CEL), through which the impacts of different factors can be analyzed. The position of the rotational center affects most the moment capacity factor among all the factors, while the anchor orientation has only a tiny influence on the moment capacity factor. The minimum value of the moment capacity factor results from the rotational center located at approximately one-third to half of the shaft length away from the anchor rear. The end bearing during diving when the movement is parallel to the shaft, is about one-quarter to one-third of that during pulling out when the movement is perpendicular to the shaft. Explicit expressions of bearing capacity factors composed of multiple factors are eventually formulated, which are validated by orthogonal tests and published data, and can be used conveniently not only to quantify the effects of different factors but also to evaluate the diving and keying capacities of OMNI-Max anchors.