Study on vertical bearing capacity of solid and perforated mudmats in clay

As a kind of subsea shallow foundation, mudmats are widely employed to provide temporary support for jacket structures during installation and permanent support for deep-water subsea production infrastructures. Perforated mudmats are increasingly used to facilitate the installation and removal. An upper-bound solution was presented to evaluate the ultimate bearing capacity of solid and perforated mudmats. A series of model tests at 1 g and two centrifugal model tests at 100 g were conducted to examine the impact of loading rate, perforation ratio R, perforation number np and perforation shape. It was found that the bearing capacity factor Nc decreases with perforation ratio R, while the perforation number np and perforation shape only slightly affect Nc at the same R. Finally, the upper-bound method results and test results are in good agreement, which indicates the applicability of the proposed method. •An upper-bound method was presented to evaluate the ultimate bearing capacity of a solid or perforated mudmat.•The impacts of loading rate, perforation ratio, perforation number and perforation shape were investigated.•It was reasonable to simplify the perforation area of a mudmat as a single perforation.