During working process

suction bucket foundation is not only subjected to the action of vertical load induced by the weights of fan and equipment

but also imposed by lateral loads caused by wind

wave

and current. In the case of high-latitude waters

the suction bucket foundation structures may also suffered by long-term ice pressure. To this end

by using three-dimensional finite element model

this paper researches on the horizontal ultimate bearing capacity and instability mode of suction bucket foundation under the saturated drainage sand conditions

analyzes the suction bucket foundation failure mechanism when horizontal loading slowly

discusses the bucket foundation bearing performance under different length-diameter ratios; and the earth pressure distribution and the rotation axis position of bucket inner and outer are studied. Furthermore

based on the limit equilibrium method

a formula of ultimate horizontal bearing capacity for the suction bucket under saturated drainage sand conditions is deduced. The study results can provide the reference and basis for the design of suction bucket foundation in sand ground.