Abstract: Umbrella suction anchor foundation (USAF) shows great potential in marine geotechnical applications for its unique structure improved by traditional suction anchors. The control standard of displacement for horizontal load bearing capacity of USAF has been determined by small-scale model tests. The bearing capacity of USAF and deformation characteristics of the soil around USAF at different loading heights in soft clay were evaluated by the finite element analysis method. Meanwhile, stress reduction effects of seabed under cyclic wave loading were described. The results show that the rotation center of USAF moves up, and the stress diffusion depth of seabed goes deeper, with the increase of horizontal loading height. The soil resistance around the sidewall of master cylinder leads to stress redistribution for the “anchor branch” and “skirt” structure. The core control area of the bearing capacity for USAF is the soil around the upper front and the bottom back part of anchor. In addition, accumulation of excess pore water pressure in the clay seabed around USAF exerts influence on soil resistance significantly. Thereby the horizontal bearing capacity of the entire structure reduces. The above research results are necessary and significant for the improvement of USAF in marine geotechnical engineering.

Key words: umbrella suction anchor foundation, finite elements, horizontal bearing, soil resistance, excess pore water pressure