Model tests on tilt adjustment techniques for a mooring dolphin platform with three suction caisson foundations in clay

Abstract

A series of installation model tests have been performed in order to investigate the influence of the inclination angle on caisson installation penetration behavior during the suction-assisted penetration process and to explore the feasibility of the caisson tilt adjusting technique by applying suction/positive pressure and intermittent pumping among the caissons. The specially designed experimental model was a mooring dolphin platform with three suction caisson foundations. The test results indicate that the tilt angle could be adjusted to 0.5° by applying different suction pressures inside the caissons in soft clay during the suction-assisted penetration process, even with an initial tilt angle of up to 6.28°. Moreover, in stiff clay, it was still possible to adjust the tilt from 6.6° to 1.29°. Aside from applying the suction in the caissons, positive pressures were also applied to the caissons during the tilt adjustment at larger tilt angles. The reciprocating tilt adjustment process resulted in a larger soil heave, especially at larger tilt angles. This side effect would make the final insertion depth of the suction caisson less than the designed depth.