A prediction method for anchor penetration depth in clays

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Anchoring is one of the main causes of subsea pipeline damage, which makes anchor penetration depth one of the most important references for the design of subsea pipeline burial depth. The anchor penetration process is analysed experimentally, numerically and theoretically. First, a series of model tests of dropping anchors are conducted to study the influences of anchor weight, dropping height on the penetration depth. Second, taking the effects of strain and strain rate into account, a finite element method (FEM) model of anchor penetration is set up with Coupled Eulerian–Lagrangian (CEL) method. The soil deformation and effects of strain and strain rate are analysed with the CEL model, and the model is validated against the test results. Then the effects of touch-down velocity and soil properties on penetration depth are analysed with the numerical model. Third, the anchor penetration process is analysed with classical bearing capacity theory. The average bearing coefficient during anchor penetration is back-analysed with experimental and numerical results. And a prediction method for the average bearing coefficient, which takes into account the effect of touch-down velocity, is proposed. Finally, the prediction process for the penetration depth of dropped anchor is proposed. The proposed method is of great significance for predicting anchor penetration depth and subsea pipeline burial depth.