The Bearing Capacity of Torpedo Anchor in Clay Under Inclined Loading of Mooring Chain

Abstract Torpedo anchors represent a promisingly innovative anchorage foundation for deep water applications due to their efficient and economical installation. During installation, a significant length of mooring chain was embedded into the seabed alongside the torpedo anchor. This interaction between the chain and the soil alters the strength characteristics of the clay, and also affect the loading angle at the padeye during pullout. As a result, the bearing capacity of the torpedo anchor is influenced by the movement of the chain. However, existing numerical studies lack a comprehensive understanding of the pullout performance of torpedo anchors, particularly in considering the presence of mooring chains. This study endeavors to investigate the pullout capacity of torpedo anchors in clay, accounting for the effect of the mooring chain attached to the padeye, utilizing the large deformation finite element method (LDFE). The elastic-perfectly plastic material model, adhering to the modified Tresca yield criterion, was employed. Verification of the model’s accuracy and effectiveness was conducted through centrifuge test results. The influence of the mooring chain and loading angle on the pullout capacity were investigated. The findings indicate that the discrepancy in the bearing capacity of torpedo anchors, with and without considering the mooring chain, increases from 3% to 38.4% as the loading angle rises from 0° to 75°. Conversely, for vertical loading, the difference decreases to 7%. Based on the numerical analysis, normalized V-H envelopes were provided. This work contributes valuable insights into the capacity of torpedo anchors.