Numerical Analysis of Pullout Bearing Capacity of End-Bearing Torpedo Anchors

Owing to the advantages of easy installation, low cost, and high bearing capacity (P), torpedo anchors (TAs) are suitable for anchoring the floating platforms used in deep-sea oil exploitation. This study investigated the P of conventional and end-bearing TAs in saturated, normally consolidated soils based on a numerical calculation using the ABAQUS software. According to numerical calculations with different parameter values, the effects of factors such as the location, area (S), embedment depth (h), and pullout angle (alpha) of the bearing plates on P were investigated. Based on the numerical calculation results, vertical (V)-horizontal (H) envelopes for the P of TAs were established. The results reveal that the P of a conventional TA under vertical pullout loading between numerical calculation and American Petroleum Institute (API) standard exist a difference of only 3%, which confirms the reliability of the numerical model. The P of the end-bearing TAs was significantly higher than that of conventional TAs, and the TA equipped with bearing plates at the bottom had a relatively high P, which increased significantly as S and h increased. When S exceeded a certain value, P increased with alpha. An increase in S resulted in an increase in the envelope coefficient A and a decrease in the envelope coefficient B, and caused the envelope to protrude outward. Establishing V-H envelopes has a certain reference value for estimating the P of TAs in actual engineering.