A construction method of reclaiming land from the sea based on the basement utilization, which implementation steps are as follows: a. installing a dike along the coastline, enclosing a central reclamation area by the dike and the coastline; b. installing crisscross enclosures in the central reclamation area, dividing the central reclamation area into a mesh area by the enclosure and the dike; c, pumping drainage of seawater in a block area in the mesh area, forming land in the block area; d. constructing the enclosure in the mesh reclamation area, using the enclosure and subsidiary roads to form road arteriality; the block area being lower than the height of the enclosure, constituting a grid-like high-road/low-land land supply mode; e. developing the block area into an underground space area.

A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.

A method of installing an upright elongate hollow subsea foundation that is higher than it is wide, such as a suction pile. The foundation is at least partially embedded in seabed soil. A partition layer is placed within the foundation, for example by injecting a grout, supported by a plug of soil that is surrounded by the foundation. The partition layer is placed on the plug of soil at a level that is spaced from the top of the foundation by at least 20% of the height of the foundation. Above the partition layer, the interior of the foundation may be filled with water and/or a rigid body, such as a solid mass or a hollow liquid-filled tank.

A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.

A ring-wing floating platform is disclosed. The ring-wing floating platform includes a floating hull, a top of the floating hull being above a sea surface and its geometry at a water plane is centrally symmetric, a ring-wing surrounding a perimeter of a bottom of the floating hull with a horizontal projection of concentric annular geometries, a positioning system located at the bottom of the floating hull, and a topsides located above the floating hull and connected to the floating hull by deck legs or installed directly on the top of the floating hull. The axes of the ring-wing and the floating hull are collinear, and their bottoms are in a same horizontal plane. The ring-wing and the floating hull are connected together as a unitary structure by multiple connecting components with an annular gap in-between.

A modular HVDC platform and a method for constructing the same are disclosed herein. The modular HVDC platform has a topside disposed on a structural jacket. The topside includes a first rectifier module, a second rectifier module, and a utility module. The first and second rectifier modules have equipment for converting AC power to DC power disposed therein. The utility module contains equipment for supporting the operations of the rectifier modules. Each of the rectifier modules and the utility modules can be fabricated and commissioned onshore prior to installation on the structural jacket at an offshore location.

An autonomous deployment system for deploying systems and a method of deploying a seafloor device. The autonomous deployment system includes a release unit, a support frame, a plurality of mats, a hose, a plurality of weighted bands, a gas supply, a waterproof housing, and a timer. The method of deploying a seafloor device includes spooling a plurality of mats in a rolled-up position, each of said plurality of mats comprising a hose, wherein each mat is adjacent to a support frame, submerging the seafloor device in a body of water, releasing the seafloor device from a vessel via a release unit, supplying gas to each hose of the plurality of mats, unfurling each of the plurality of mats from the support frame, sinking the seafloor device to lay on the seafloor. The invention may also include a microbial fuel cell and support weights.

A cofferdam is disclosed that includes an open frame structure having double walls defining a hollow space within each double wall, with each double wall having an open bottom end and a closed top end. Each of the double walls are configured to act as suction piles allowing liquid to be removed from the space within each double wall to thereby induce negative pressure when the cofferdam is installed in a sub-sea configuration. Each of the double walls may include a plurality of partitions respectively defining a plurality of suction piles, the suction piles fluidically coupled by a manifold that may allow liquid to be removed from the suction pile to thereby drive the cofferdam structure into the subsea surface due to the induced negative pressure. A further embodiment cofferdam structure includes an open frame structure and one or more suction piles attached to the open frame structure.

A corrosion-resistant cover system, having a corrosion-resistant cover structured and configured to be arrangeable around an object having one or more metallic surfaces that are susceptible to corrosion. The corrosion-resistant cover is operable to provide increased corrosion resistance to the object by preventing contact between the one or more metallic surfaces and ambient conditions exterior to the corrosion-resistant cover.

A subsea tank element comprises at least one tank section (1), the tank section(s) forming a cylindrical concrete-tank (2) closed at its opposite ends by two end caps (12). The tank element further comprises a rectangular structure (3, 4, 5) surrounding the cylindrical tank (2), and a connection (150, 160) between the rectangular structure (3, 4, 5) and the cylindrical tank (2) permitting a motion of the wall of the cylindrical tank (2) within predetermined limits for deflection of the rectangular structure (3, 4, 5). Permanent ballast (6, 7) and a ballast tank (8) control buoyancy and ensure static stability. Post tensioning cables through channels 9 tie the parts into a tank element, and the tank elements into a system. Several applications, including a subsea barge, a subsea hydro-electric plant and a hovering storage tank assembly are disclosed.