The present invention relates to a free-sliding seabed mudmat foundation, which belongs to the fields of offshore and ocean engineering. The mudmat comprises a base foundation, an upper foundation, and a cover plate. The base foundation sits on the seabed to support dead weights of the mudmat itself and the subsea production system fixed on the mudmat. The upper foundation, with a plurality of universal rolling ball bearing being attached to the bottom, can slide on the base foundation when it is subjected to a horizontal push force generated by the pipeline during operation. Therefore, the axial load on the pipeline during operation due to heating and pressurization is released and the buckling failure risk is then reduced. The mudmat disclosed has smaller size and lighter weight, which is beneficial in reducing fabrication costs and reducing requirements for cranes on the pipeline laying vessel.

Disclosed is a method for preventing sudden subsidence of an open caisson in a soft foundation, which includes the following steps: a position of the open caisson is determined; grouting is carried out to reinforce a foundation of the open caisson; an open caisson manufacturing site is leveled; sections of the open caisson are manufactured and installed; the step of sections of the open caisson are manufactured and installed is repeated until all the sections are manufactured and the open caisson subsides in place as a whole. The application is suitable for construction on soft soil, loss caused by the phenomenon of sudden subsidence may be avoided, and personal safety of constructors may be guaranteed.

Disclosed is a method for preventing sudden subsidence of an open caisson in a soft foundation, which includes the following steps: a position of the open caisson is determined; grouting is carried out to reinforce a foundation of the open caisson; an open caisson manufacturing site is leveled; sections of the open caisson are manufactured and installed; the step of sections of the open caisson are manufactured and installed is repeated until all the sections are manufactured and the open caisson subsides in place as a whole. The application is suitable for construction on soft soil, loss caused by the phenomenon of sudden subsidence may be avoided, and personal safety of constructors may be guaranteed.

The present invention relates to a free-sliding seabed mudmat foundation, which belongs to the fields of offshore and ocean engineering. The mudmat comprises a base foundation, an upper foundation, and a cover plate. The base foundation sits on the seabed to support dead weights of the mudmat itself and the subsea production system fixed on the mudmat. The upper foundation, with a plurality of universal rolling ball bearing being attached to the bottom, can slide on the base foundation when it is subjected to a horizontal push force generated by the pipeline during operation. Therefore, the axial load on the pipeline during operation due to heating and pressurization is released and the buckling failure risk is then reduced. The mudmat disclosed has smaller size and lighter weight, which is beneficial in reducing fabrication costs and reducing requirements for cranes on the pipeline laying vessel.

This publication relates to a shallow water terminal, preferably for storing and loading or unloading hydrocarbons, such as LNG, oil or gas. The base structure comprises a floatable, and removable seabed substructure (10) intended to be supported by a seabed (30), the seabed substructure (10) comprising a base structure (11) provided preferably with an upwards extending wall structure (22), arranged along at least a part of the periphery of the base structure (11), the base structure (10) preferably also being provided with an opening (23) in the wall structure (22) for allowing the floatable module to be berthed in and supported by the seabed substructure (10). The base structure (10) is provided with strong points (24) configured to receive the ends of preinstalled vertical piles (14) for at least temporary support of the base structure (11) during a piling operation for permanent piling of the base structure (10) to the sea bed (30). The publication also relates to a method for piling a base structure on or above a seabed (30).

This publication relates to a shallow water terminal, preferably for storing and loading or unloading hydrocarbons, such as LNG, oil or gas. The base structure comprises a floatable, and removable seabed substructure (10) intended to be supported by a seabed (30), the seabed substructure (10) comprising a base structure (11) provided preferably with an upwards extending wall structure (22), arranged along at least a part of the periphery of the base structure (11), the base structure (10) preferably also being provided with an opening (23) in the wall structure (22) for allowing the floatable module to be berthed in and supported by the seabed substructure (10). The base structure (10) is provided with strong points (24) configured to receive the ends of preinstalled vertical piles (14) for at least temporary support of the base structure (11) during a piling operation for permanent piling of the base structure (10) to the sea bed (30). The publication also relates to a method for piling a base structure on or above a seabed (30).

A subsea foundation for supporting a pipeline or a pipeline accessory has a mudmat and at least one pile arranged to anchor the mudmat by extending from the mudmat into seabed soil. A coupling that couples the pile to the mudmat has at least one interface member supported for angular displacement relative to the mudmat, such as a pivoting beam or a wedge-shaped adaptor ring, to accommodate the orientation of the mudmat relative to the pile.

A subsea foundation for supporting a pipeline or a pipeline accessory has a mudmat and at least one pile arranged to anchor the mudmat by extending from the mudmat into seabed soil. A coupling that couples the pile to the mudmat has at least one interface member supported for angular displacement relative to the mudmat, such as a pivoting beam or a wedge-shaped adaptor ring, to accommodate the orientation of the mudmat relative to the pile.

This publication relates to a shallow water terminal, preferably for storing and loading or unloading hydrocarbons, such as LNG, oil or gas. The base structure comprises a floatable, and removable seabed substructure (10) intended to be supported by a seabed (30), the seabed substructure (10) comprising a base structure (11) provided preferably with an upwards extending wall structure (22), arranged along at least a part of the periphery of the base structure (11), the base structure (10) preferably also being provided with an opening (23) in the wall structure (22) for allowing the floatable module to be berthed in and supported by the seabed substructure (10). The base structure (10) is provided with strong points (24) configured to receive the ends of preinstalled vertical piles (14) for at least temporary support of the base structure (11) during a piling operation for permanent piling of the base structure (10) to the sea bed (30). The publication also relates to a method for piling a base structure on or above a seabed (30).

This publication relates to a shallow water terminal, preferably for storing and loading or unloading hydrocarbons, such as LNG, oil or gas. The base structure comprises a floatable, and removable seabed substructure (10) intended to be supported by a seabed (30), the seabed substructure (10) comprising a base structure (11) provided preferably with an upwards extending wall structure (22), arranged along at least a part of the periphery of the base structure (11), the base structure (10) preferably also being provided with an opening (23) in the wall structure (22) for allowing the floatable module to be berthed in and supported by the seabed substructure (10). The base structure (10) is provided with strong points (24) configured to receive the ends of preinstalled vertical piles (14) for at least temporary support of the base structure (11) during a piling operation for permanent piling of the base structure (10) to the sea bed (30). The publication also relates to a method for piling a base structure on or above a seabed (30).