This work presents an experimental study using centrifuge modelling on mudmat shallow foundations which are mainly used to support offshore subsea equipment. An optimized design of these foundations requires the maximizing of the ratio between the installation and the pull-out resistance of the foundation. International standards, based on classical theories, are often limited and do not meet the complexity of the projects. The bibliography is not yet conclusive about the load capacity factors for this particular problem. In this work, physical modelling has been performed on both perforated and solid mudmats subjected to vertical load and simulating both installation and extraction scenarios.
The soil used in this study is a marine clay taken from the Roncador field at Campos basin located offshore of the state of Rio de Janeiro, Brazil. The physical modelling experiments have been carried out on the mini-drum geotechnical centrifuge at COPPE/UFRJ. The technique of lumps was adopted for the preparation of the soil models and a temporary surcharge using a sand layer has been applied to develop a soil strength profile similar to the one found in the field. The results obtained in this study provided a better understanding of the soil-structure interaction problem with regard to the installation and pull-out resistance of the studied type of foundation focusing on their bearing capacity factors.