Pullout Bearing Capacity of End-Bearing Torpedo Anchors in Cohesive Soil Seabed

Abstract

As a new type of deep-sea anchoring foundation, thetorpedo anchor has the characteristics of simple installation, low cost, and high bearing capacity. Compared with the torpedo anchor without an anchor wing, the end-bearing torpedo anchor forms pile end resistance using a bearing plate, thus further improving its uplift bearing capacity. By conducting the pullout model test of torpedo anchors, we have compared and analyzed the effects of the pullout angle and bearing-plate radius on the bearing characteristics of T, EN3, EN4, and EC types of torpedo anchors. Based on the model test results, we established the V-H envelope of torpedo-anchor bearing capacity using the regression analysis method. The results show that when the displacement is small, the load-displacement curve of the torpedo anchor increases in an approximately linear mode, and the curve fluctuates and gradually entersa stable state with the gradual increase of the displacement. With the increasing pullout angle, the bearing capacity of the torpedo anchor increases first and then decreases. When the pullout angle is 45°, the torpedo anchor has the maximum bearing capacity. When the pullout angle is constant, the order of bearing capacity generated by different types of torpedo anchors is as follows: EC > EN4 > EN3 > T, and the bearing capacity rises with the increasing bearing-plate area. Through regression analysis, it is concluded that for the torpedo anchors of T, EN3, EN4, and EC types, the V-H envelope of bearing capacity shows an outward convex trend, and the determination coefficient reaches 0.930, indicating that the established V-H envelope is suitable for predicting the bearing capacity of torpedo anchors.