Combined with swipe loading method and fixed displacement ratio method

the bearing capacity of suction caisson foundations subjected to horizontal and moment combined loading is explored through three dimensional finite element numerical studies. The effect of embedment to diameter ratio and soil strength nonhomogeneity on the H-M failure envelope of caisson foundations is investigated; and the soil deformation mechanism under various combinations of load components is shown. Through comparison with results under plane strain assumption

it is shown that the shape of failure envelopes of caisson foundations considering three dimensional effect varies from that under plane strain assumption; therefore to evaluate the stability of caisson foundation should account for the three dimensional effect. For nonhomogeneous soil

the failure envelope of caisson foundations with shallower embedment is negatively oblique. The equation of failure envelope available overestimates significantly the bearing capacity of caisson under this condition subjected to positive lateral and moment combined loading

and leads design of caisson foundation to unsafe side.