A foundation for a subsea assembly is provided. The foundation comprises connection points. The connection points permit other components to be connected to the suction anchor and permit loads to transfer from the component connected to the connection points into the foundation. The foundation may be a suction anchor. A method of converting an exploration well using such a foundation to a production well is provided.

A construction method of a rectangular working well includes steps of: (I) designing functional requirements for the rectangular working well; (II) constructing a caisson of an enclosing structure of the rectangular working well; (III) constructing an edge protector; (IV) excavating earthwork of the rectangular working well; (V) forming a back cover for the rectangular working well, and pre-embedding a sliding track, a pull ring and a back wall anchor; (VI) installing a ladder for entering the rectangular working well; (VII) preventing joint leakage; (VIII) installing a water-proof pressure plate at an entrance of the preset pipe jacking hole; (IX) constructing the sliding back wall; (X) lifting the sandwich concrete slab wall at a top of the preset pipe jacking hole; and (XI) performing pipe jacking. The structure system constructed by the present invention has many advantages such as clear function, safety, quickness, and flexible design.

A suction anchor for a subsea well is provided. The suction anchor comprises: a wellhead support structure, wherein the wellhead support structure is at least in part external of the internal volume.

A caisson block construction method, including: manufacturing a plurality of bottom caisson blocks having a plurality of first unit compartments disposed consecutively in a horizontal direction; manufacturing a plurality of upper caisson blocks having a plurality of second unit compartments; forming a bottom caisson block structure by installing the plurality of bottom caisson blocks side by side in the horizontal direction; installing the plurality of upper caisson blocks above the installed bottom caisson blocks; filling with rubble the second unit compartment of the upper caisson block positioned above the first unit compartment for rubble and exposed upward; inserting a vertical reinforcing bar module after the upper caisson blocks are installed; and forming a vertical concrete column for joining by casting concrete into the upper part of the second unit compartment in which the vertical reinforcing bar module is inserted.

A caisson block construction method, including: manufacturing a plurality of bottom caisson blocks having a plurality of first unit compartments disposed consecutively in a horizontal direction; manufacturing a plurality of upper caisson blocks having a plurality of second unit compartments; forming a bottom caisson block structure by installing the plurality of bottom caisson blocks side by side in the horizontal direction; installing the plurality of upper caisson blocks above the installed bottom caisson blocks; filling with rubble the second unit compartment of the upper caisson block positioned above the first unit compartment for rubble and exposed upward; inserting a vertical reinforcing bar module after the upper caisson blocks are installed; and forming a vertical concrete column for joining by casting concrete into the upper part of the second unit compartment in which the vertical reinforcing bar module is inserted.

Disclosed are a foundation having a chain cutter at the base during construction and a construction method of the same. A rock and soil conveying apparatus is provided inside or beside a foundation (1) having a chain cutter (3) at the base during construction, the base of the foundation (1) has a track (1-1), the chain cutter (3) is mounted on the track (1-1) during construction, and the chain cutter (3) is composed of a chain (3-1) and a rock and soil excavating cutter (3-2) fixed on the chain (3-1). A chain excavating apparatus mainly consists of the chain cutter (3) and a transmission apparatus, the transmission apparatus mainly being composed of a driving apparatus (4) and a sprocket (6). During construction, the driving apparatus (4) drives the chain cutter (3), the chain cutter (3) runs along the track (1-1), the cutter (3-2) at the base of the foundation (1) excavates rock and soil, which are removed by the rock and soil conveying apparatus, and the chain cutter (3) at the base of the foundation (1) and the foundation (1) descend together. The defects of the prior art are overcome, and since the foundation (1) itself has an excavating apparatus, the foundation (1) can be pre-formed in blocks at the factory, or can be constructed by pouring while descending in on-site fixed formwork, construction is simple, in particular waterproofing is especially good as descending is done as a whole, the construction period is short, and costs are low.

Disclosed are a foundation having a chain cutter at the base during construction and a construction method of the same. A rock and soil conveying apparatus is provided inside or beside a foundation (1) having a chain cutter (3) at the base during construction, the base of the foundation (1) has a track (1-1), the chain cutter (3) is mounted on the track (1-1) during construction, and the chain cutter (3) is composed of a chain (3-1) and a rock and soil excavating cutter (3-2) fixed on the chain (3-1). A chain excavating apparatus mainly consists of the chain cutter (3) and a transmission apparatus, the transmission apparatus mainly being composed of a driving apparatus (4) and a sprocket (6). During construction, the driving apparatus (4) drives the chain cutter (3), the chain cutter (3) runs along the track (1-1), the cutter (3-2) at the base of the foundation (1) excavates rock and soil, which are removed by the rock and soil conveying apparatus, and the chain cutter (3) at the base of the foundation (1) and the foundation (1) descend together. The defects of the prior art are overcome, and since the foundation (1) itself has an excavating apparatus, the foundation (1) can be pre-formed in blocks at the factory, or can be constructed by pouring while descending in on-site fixed formwork, construction is simple, in particular waterproofing is especially good as descending is done as a whole, the construction period is short, and costs are low.

A subsea assembly comprising; a foundation, a support device; and a subsea equipment adapter frame is provided. The foundation, support device and subsea equipment adapter frame are separate modular components that can be installed separately. The foundation may be a suction anchor. A method of installing and uninstalling the subsea assembly is also provided.

A self-sinking-type deep foundation pit retaining wall structure, comprising a cylindrical retaining wall body (1); a ground breaking structure (2) is formed at the bottom of the cylindrical retaining wall body (1), and the cylindrical retaining wall body (1) is suitable for achieving downward ground breaking and sinking by means of the cooperation of the ground breaking structure (2) and the gravity of the cylindrical retaining wall body; and a water pipe (20) running through the cylindrical retaining wall body is cast in the cylindrical retaining wall body (1), and the water pipe (20) is provided with a water outlet (80) located at the lower end face of the cylindrical retaining wall body (1) and a water inlet (81) located at the upper end face of the cylindrical retaining wall body (1). The self-sinking-type deep foundation pit retaining wall structure further comprises resistance increasing devices (4) provided on an outer side wall (3) of the cylindrical retaining wall body (1), and the resistance increasing devices (4) are used for cooperating with a foundation (5), so as to adjust upward resistance applied by the foundation (5) to the cylindrical retaining wall body (1). In addition, further provided is a construction method for an underground space.

A self-sinking-type deep foundation pit retaining wall structure, comprising a cylindrical retaining wall body (1); a ground breaking structure (2) is formed at the bottom of the cylindrical retaining wall body (1), and the cylindrical retaining wall body (1) is suitable for achieving downward ground breaking and sinking by means of the cooperation of the ground breaking structure (2) and the gravity of the cylindrical retaining wall body; and a water pipe (20) running through the cylindrical retaining wall body is cast in the cylindrical retaining wall body (1), and the water pipe (20) is provided with a water outlet (80) located at the lower end face of the cylindrical retaining wall body (1) and a water inlet (81) located at the upper end face of the cylindrical retaining wall body (1). The self-sinking-type deep foundation pit retaining wall structure further comprises resistance increasing devices (4) provided on an outer side wall (3) of the cylindrical retaining wall body (1), and the resistance increasing devices (4) are used for cooperating with a foundation (5), so as to adjust upward resistance applied by the foundation (5) to the cylindrical retaining wall body (1). In addition, further provided is a construction method for an underground space.