Review on Seabed Trenches Induced by Mooring Lines and Analyses of Anchor Bearing Capacity

Mooring systems are usually adopted to position floating structures, including mooring lines and anchors, and directly determine the safety of floating structures. Seabed inspection reported that seabed trenches induced by mooring line-soil interaction appear in front of the anchor and reduce the anchor bearing capacity. This work first introduces the research progress of mooring line-soil interaction and seabed trenching simulation. Research about the suction anchor capacity in clay and sand is presented, and the seabed trench influence on anchor capacity is analyzed. For anchor analysis, this study gives a new perspective to analyze anchor installation and bearing capacity, i. e., structure-soil interface characteristic. Some common anchor types are analyzed. Results showed that seabed trench simulation is still needed to acquire trench 3D profiles, in which the mooring line-soil dynamic interaction cannot be ignored. At present, the trench influence is not considered in suction anchor design, making the design dangerous. For the anchor, the interface shear characteristics control the most unfavorable loading conditions. Thus, accurate interface parameters should be obtained for anchor analysis.