Abstract: Mudmat is commonly used as the foundation of subsea wellhead, pipeline manifold and umbilical cable. In practice, it suffers severe V-H strong coupling nonlinear loads. A new type of slope-skirted mudmat foundation is developed, which can not only reduce the current scour to empty and erode the bottom soil of foundation, but also adjust envelops in V-H loading space by changing the angle ? to match different engineering design requirements. The bearing capacity of the new type of mudmat foundation is studied in combination with the engineering design examples. The results show that the ultimate bearing capacity of the new type of mudmat foundation increases linearly with the increase of soil strength heterogeneity index ?. Effect of the contact properties between mudmat and soil on the horizontal bearing capacity is more significant than that on the vertical direction. The normalized envelope of V-H load space of mudmat foundation can generally applies to the case that the index ? varies from 0 to 10, and the Hanson equation overestimates the bearing capacity of mudmat foundation when the normalized vertical load ranges from 0.5 to 0.8.

Key words: subsea production system, mudmat foundation, slope-skirt, bearing capacity