JP6105044B2 - Partially floating offshore platform for offshore wind power, bridges and offshore structures, and construction method - Google Patents

Description

  The present patent application relates generally to fixed foundation offshore platform technology, in particular for prestressed concrete platforms with or without wind turbines, bridges and piles supporting the building, This is a platform technology that uses a large-diameter hollow cylindrical column as a floater and uses a unique cone alignment technology that firmly secures the platform column to the seabed, and if necessary, a small-diameter pile can be installed inside the floater. It relates to the technology that can.

  The platform for offshore platforms can be classified into three types. Gravity type, pile support type, and floating type, which are used for shallow, medium depth, and deep areas, respectively. In the case of a structure including a wind turbine and a bridge, since the weight of the structure is light, horizontal forces of wind, waves, storm surges, and earthquakes tend to become control loads. However, this is not the case when constructing structures because the gravity load is relatively large. In the case of a horizontal force that controls the design, it is more effective to use tension piles than ballast to increase the weight of the foundation. However, when the base support layer is strong, that is, is a rock, the support layer can support the weight of the ballast structure. On the other hand, in the case of the vertical force that controls the design, if the foundation layer is close to the seabed surface, the use of a gravity foundation is effective and does not excavate a large amount of soft material. The gravity type is advantageous. In order to reduce the requirements for the strength of the foundation layer, the contact surface is enlarged or the load is reduced. In the case of pile-type foundations, pile driving work at sea and construction of pile caps in water are problems.

  The present patent application addresses these issues and eliminates the need for cone alignment technology that uses a hollow cylindrical floater to temporarily and / or permanently compensate for part of the gravity load and expensive pile driving at sea. Providing piles in the floater to accomplish the work.

  Important innovative technologies of the present invention include: By making a normal vertical pile or column into a hollow cylinder (referred to as a floater), the floater alone or the floater and platform unit is provided with a buoyancy that floats in water, and the floater provides a bearing pressure on the foundation layer. Due to the temporary or permanent reduction, the unique cone alignment technology that makes it easy to fix the floater to the seabed, and the large space in the floater, a small diameter pile is installed in the floater to secure the pipe cap. A foundation with piles can be realized by building, and all these can be done in a dry work environment.

  The present patent application is directed to offshore wind turbines, bridges and building partially floated offshore platforms, and construction methods.

  Offshore wind turbines, bridges and building partially floating offshore supported offshore platforms include a plurality of beams and a hollow cylindrical column called a floater, which form a platform. The floater is a hollow part whose both ends are closed with a plate. The bottom plate is composed of a single cone or a plurality of cones, and the apexes of the cones face downward. The floater provides buoyancy that allows the floater itself to float and compensates for some or all of the platform's own weight when the platform is underwater.

  The floaters and beams that form the platform structure are constructed by a segment matched cast construction method. This involves casting floaters, beams, and decks (if needed) in the form of a plurality of matching segments at a factory or a foundry. The segments are then joined near the harbor or dock to form a platform that can float in water.

  In a particular aspect where the number of floaters is one, the platform includes a hollow cylinder provided vertically and closed at both ends by plates. The bottom plate is composed of a single cone or a plurality of cones, and the apexes of the cones face downward.

  In another aspect, the floater may be tapered at the base and the bearing pressure on the foundation layer can be minimized to a small value for the gravity floater. A slant pile can be easily attached to the same tapered floater, and it becomes a floater with a pile.

The cone alignment method is unique to this application and is used to secure the platform to the seabed.
At a position corresponding to the position of the cone at the bottom of the floater provided perpendicular to the seabed, a concrete bed having a shape corresponding to the cone at the bottom of the floater is formed on the concrete bed. A concrete bed is a large concrete deposit in a pothole made by removing the soft material from the seabed and exposing the foundation layer. Preferred steps for forming the inverted cone in the concrete bed include, but are not limited to:
At a location corresponding to the float bottom cone at the seabed, the soft material is drilled, drilled or sucked to expose a stiff layer of material that can withstand the expected load of the platform.
Float the platform and prepare a concrete bed at the same time. The concrete bed is prepared by using piles that have been lowered to the seabed using established underwater concrete technology, and filling the potholes created by excavating the seabed with concrete from the construction ship.
The amount of concrete used for the concrete bed is such that the platform is located at the design height and the cone of the bottom plate is completely contained within the concrete bed.
Before the concrete hardens in the concrete bed, the platform is lowered by taking in water and adjusting the buoyancy until the float's bottom plate cone is completely within the concrete bed.
Maintain the height and position of the platform until the concrete begins to set, i.e. harden, and use high pressure water to separate the two surfaces: the surface of the bottom plate of the floater and the surface of the concrete bed, and then the platform Lift up. This forms an inverted cone.
When the concrete reaches the design strength, the platform is lowered again to the inverted cone. This guides the platform to the already formed alignment position.
The platform is maintained in height and orientation, and if there is a gap between the two cone surfaces, the grout is injected through a grout pile pre-installed in the floater body. This completes the installation of the platform.

  In another aspect, a pressure pile driving system is installed in the floater and a high pressure water jet stream and a cement grout are flowed from the opening at the bottom of the floater. The pile driver may be in a floater or in an external construction ship.

According to a further embodiment, the concrete foundation layer for the conical end of the floater stakes the foundation when it cannot withstand further loads. Pile driving is then used in a preferred embodiment including:
Multiple small-diameter piles installed in the space of the floater,
Install slant piles as needed,
Cast the pile cap at the bottom end of the floater.

Although the preferable process of attaching a small diameter pile is as follows, it is not restricted to this.
A hole without a steel bar is formed in a position corresponding to the pile driving position in the bottom plate.
When water ingress can be addressed, piles are installed either by boring / drilling / driving using established pile driving techniques using a small pile driving plant mounted on the top or bottom of the floater. The pile penetrates the hole, concrete bed, and soil / sand layer and is finally pushed into the rock.
The concrete is ejected to the bottom of the floater to remove the water from the floater to form a concrete plug, stop the water from seeping in and make the working environment dry.
Cut the pile to the required height to form a good pile head and prepare to cast the pile cap by established process.
The pile cap reinforcement bar is connected and secured to a bar connector embedded in the floater wall.
Cast the pile cap to complete the installation.

  In a further aspect, to reduce the bearing stress in the soil layer, a rigid ring plate is joined to the bottom plate of the floater as necessary to expand the bearing area.

  In another aspect, round bottomless steel is dropped into a drilling pothole having a diameter that is larger than the outermost diameter of the floater or rigid ring plate. The concrete bed may be strengthened by confining the concrete by welding a reinforcing bar to the lower inner surface of the concrete bed.

  In another aspect, instead of using a bottomless steel can, stone and gravel may be dropped on the edge of the pothole to confine the concrete.

  In yet another embodiment, post drill holes may be formed in the bottom plate of the floater and the underlying concrete bed and joined together via a grouted steel rod to provide a shear key function.

  In another aspect, multiple platforms may be joined to form a large platform.

Another embodiment of the platform provides, but is not limited to, the following preferred steps for assembling a partially floated offshore platform.
Performs segment matching casting of floaters and beams in the factory.
Bring the floater segment to the assembly port and go to the assembly site.
At the position of the floater, at least three guide piles need to be driven into the seabed, and these guide piles can support the overhead frame that lifts the segment.
Place the segment at the floater position and make sure that the first of the segments floats on the water. At this time, the position is adjusted using the guide pile.
In the case of a segment connected to a beam, an overhead frame / truss is used to hang the floater so that the connection can be made above the sea level. However, if the floater section has adequate buoyancy, an overhead frame / truss is not necessary.
The connecting beam is floated or brought in by a cargo ship, and the connecting beam is lifted and temporarily fixed in place using temporary support by a guide pile. Thereafter, the gap between the floater and the beam is fixed, the floater and the beam are overlapped with the steel bars at both ends, the shutter form is set up, and the joint is cast with concrete.
The finished platform is designed to float on its own. Remove the guide stakes and free the platform. This allows the platform to run freely.

The advantage of a partially floated offshore platform for offshore wind turbines, bridges and buildings is that it can accommodate various depths and undersea conditions.
In the case of shallow areas near the seabed, bedrock or foundation layers, a single gravity floater can be used to secure the platform to the seabed using techniques that align the cones and inverted cones described above.
For intermediate depth regions, platforms with single or multiple floaters can be used with small diameter drill-in piles or drill-in steel H piles. A small pile driver will be placed on the platform and piled up above the sea level in a dry state. Therefore, a large and expensive offshore pile driver is unnecessary.

  Furthermore, the dangers associated with human work in the sea are eliminated.

In another embodiment, the platform installation itself is completed in the following preferred steps, but is not limited thereto.
Float in the platform, adjust its coordinates and orientation, maintain its position and sink to the sea floor by taking in water. When the platform is firmly located on the seabed, the soft material is removed by flowing a high pressure jet from the bottom plate nozzle until the rock surface is exposed or the designed foundation layer is exposed. Using the built-in tremy concrete lower pipe in the floater, pour wet concrete into the pothole emptied with water jet flow, and at the same time adjust the position and height of the platform to maintain its position. Fill the floater cone and flatten it with a rigid ring plate (if available). After the concrete hardens, lift the platform by reducing the water ballast. This allows the concrete bed to harden without being affected by waves and flows. If the platform remains in the concrete bed, the waves and current travel on the concrete bed by the platform. Subsequent steps are similar to those described above, and will not be repeated.

FIG. 1 is a view showing a platform with a three floater pile for wind turbines of the present patent application. FIG. 2A is a conceptual diagram showing the internal piping of the present patent application. FIG. 2B is a conceptual diagram showing holes previously formed in the bottom plate of the floater of the present patent application. FIG. 2C is a conceptual diagram showing holes previously formed in the upper plate of the floater of the present patent application. FIG. 3 is a plan view of the three floater platform of the present patent application. FIG. 4 is a side view of the three floater platform of the present patent application. FIG. 5 is a side view showing dredging work in the marine environment, and is a diagram illustrating a process of excavating the seabed. FIG. 6 is a side view showing a process of forming a concrete bed on the seabed in a marine environment. FIG. 7A is a conceptual diagram showing a construction method of the present patent application. FIG. 7B is a conceptual diagram showing a construction method of the present patent application. FIG. 8A is a conceptual diagram showing a construction method of the present patent application. FIG. 8B is a conceptual diagram showing a construction method of the present patent application. FIG. 9A is a conceptual diagram showing a construction method of the present patent application. FIG. 9B is a conceptual diagram showing a construction method of the present patent application. FIG. 10A is a conceptual diagram showing a construction method of the present patent application. FIG. 10B is a conceptual diagram showing a construction method of the present patent application. FIG. 11 is a conceptual diagram showing a construction method of the present patent application. FIG. 12 is a conceptual diagram showing attachment of the pier of this patent application. FIG. 13 is a conceptual diagram showing the structure of the offshore structure of the present patent application. FIG. 14 is a conceptual diagram showing a multiple platform scheme of the present patent application.

  A preferred embodiment of the partially floating body supported offshore platform 10 for offshore wind turbines, bridges and buildings disclosed in this patent application is described in detail and examples are described below. An exemplary embodiment of a partially floated offshore platform 10 for offshore wind turbines, bridges and buildings as disclosed in this patent application will be described in detail, but for clarity, the understanding of the partially floated offshore platform 10 is particularly important. It will be apparent to those skilled in the art that some insignificant features may not be shown.

  Further, the partially floating body-supported offshore platform 10 for offshore wind turbines, bridges and buildings disclosed in the present patent application is not limited to the following detailed embodiments, and those skilled in the art will claim protection. It should be understood that various changes and modifications can be made without departing from the scope. For example, within the scope of the disclosure, the requirements and / or features in the various exemplary embodiments can be combined and / or substituted for each other.

  In order to clearly illustrate the intent of this patent application, the following detailed description is provided.

(Embodiment 1)
The purpose of the first embodiment is to mount the platform 10 described in this patent application in an open sea having a depth of 25 m in order to support the 3 MW horizontal axis wind turbine 5.

  The platform 10 constructed according to the present patent application has the advantage of the floater 1 that it can offset up to half of its own weight by buoyancy. The water ballast in the floater 1 can change the base frequency of the structure to avoid the maximum wind energy spectrum seismic energy.

  FIG. 1 shows a platform 10 of the present patent application. The platform 10 includes three floaters 1 provided vertically, and the floaters 1 are partially supported by buoyancy. A small-diameter pile 27 is attached to the bottom of the floater 1.

  The pile is fixed to the bedrock 40 or the foundation layer 14. The bottom plate of the floater 1 is provided with a cone 2 whose apex faces downward.

  As shown in FIGS. 1, 2, and 4, the inner surface of the bottom plate of the floater 1 has a circular hole 39. The pile 27 is guided by the hole and inserted into the concrete bed 9 and the soil / sand layer 13 of the seabed 6 and finally pushed into the bedrock 40 or the foundation layer 14. As shown in FIG. 3, the three floaters 1 are connected to each other to form a platform 10. A horizontal axis wind turbine 5 is attached to one of the floaters 1. As shown in FIG. 9B, the platform 10 can be formed by using one floater 1. A platform including a single floater 1 includes a floater 1 provided vertically and a rigid ring-like plate 4 at the bottom of the floater 1, and may include a small-diameter pile 27. In a platform including a plurality of floaters, a spatial structure is formed by connecting vertically disposed floaters 1 by beams. A group of small diameter piles 27 may or may not be fixed to the bottom of the floater 1. FIG. 1 shows a platform 10 that is triangular in plan view. This platform is triangular, but may have other shapes on the same principle, for example, square, rectangular, pentagonal, etc. The cross section of the floater 1 may also be a polygon other than a circle.

  In the present embodiment, the dimensions and sizes of the configuration requirements are as follows. The height of the floater 30 is 30 m, the wall thickness of the floater 1 is 0.35 m, the top plate thickness is 0.35 m to 0.5 m, and the thickness of the bottom conical plate 2 is 0.35 m to 0.6 m.

  In FIG. 2, the floater 1 of the platform 10 has a hollow cylindrical shape. Alternatively, the floater 1 may have a taper shape whose bottom is larger than the top, in which case the stability increases and the bearing pressure on the support layer decreases. In addition, in order to further reduce the bearing pressure, a rigid ring-shaped plate 4 may be added to the bottom of the floater 1 to further increase the area.

  As shown in FIG. 1, the platform further includes a regulation tower portion 3 that supports the wind turbine above the floater 1. The height of the regulation tower part 3 should be above the design maximum wave height.

  In the example of the present embodiment, for example, the example shown in FIGS. 2A, 2 </ b> B, and 2 </ b> C, the pressure pipe 37 is already attached inside the floater 1. The pressure pipe 37 has an inlet connected to a water pump or a concrete / cement grout plant, thereby ejecting high-pressure water and cement grout toward the water side at the bottom of the floater 1. The outlet of the pressure tube is on the water side of the bottom plate. Water pipes are used to remove excess material from the seabed and to remove material between the bottom cone plate 2 of the floater 1 and the concrete bed 9 to create a gap.

  In order to stabilize the floater 1, if necessary, the floater 1 can be filled with water or sand to increase its own weight.

  For a 3 MW horizontal axis wind turbine, the steel tower 5 has a height of 65 m. A nacelle is placed on the tower and its weight is 400 t.

  In the first embodiment, an important point in designing the platform 10 for supporting the wind turbine is to provide a resistance against the lifting force induced in the floater 1 by a very large tipping moment. In the calculation, the small-diameter pile 27 is a mini-pile in which grout is injected at a high pressure, 0.3 m, an embedding length in the rock mass is 3 m, and a reinforcing bar is 3 × 50 mm. The horizontal load is resisted by the rigid bottom conical plate 2. The bottom conical plate 2 transfers the force to the concrete bed 9 which transfers the force to the support layer 13.

(Embodiment 2)
FIG. 12 shows the piers 35, 36 supported on the platform 10. The platform 10 is supported by a system including two floaters 1 and a small diameter pile 27. The floater 1 has a diameter of 8 m, a height of 30 m, a wall thickness at a water depth of 30 m is 0.4 m, a soil / sand layer is 25 m, and the small-diameter pile 27 is pushed into the bedrock 40. .

(Embodiment 3)
FIG. 13 shows a grid platform 10 in which a floater 1 is provided at a node. The frame which is the main structure is formed by connecting the floaters 1. At this time, the main beam 32 is used in the upper part, and the main beam 34 is used in the lower part as necessary. The second beam 33 is branched so as to match the layout of the building.

The basic module of the offshore building platform includes four cylindrical floaters 1. These cylindrical floaters 1 support a grid beam of 30 m × 30 m in total. The size of the platform can be increased by combining a plurality of basic modules. In the present embodiment, the dimensions and sizes of the structural requirements of the structure are as follows.
Water depth: 30 m, soil / sand layer: 20 m, floater 1 diameter: 8 m, height: 30 m, wall thickness: 0.4 to 0.5 m, upper and lower plates: 0.4 to 0.6 m.

(Embodiment 4)
FIGS. 5-11 show the mounting of a platform including one tapered floater secured to the seabed.

  FIG. 5 shows a state in which the seabed 6 is excavated using the dredger 23 and the foundation layer 14 is exposed in the excavation pothole 15 in the seabed 6.

FIG. 6 shows a state where the work boat 26 injects concrete into the pothole 15 using the tremy concrete pipe 31 to form the concrete bed 9 confined by the rough stone mount 7 and at the same time the platform 10 floats. .

  FIG. 7A shows the platform 10 being lowered onto the concrete bed 9 on the seabed 6 before the concrete hardens.

  FIG. 7B shows the platform 10 at the design height and the bottom conical plate fully contained within the concrete bed 9 that is still wet.

  FIG. 8A shows how the platform 10 is lifted after the concrete is set (hardened) in the concrete bed, and as a result, the concrete bed 9 has an inverted cone 11 with a recess corresponding to the bottom conical plate 2 of the platform 10. Show the state.

  FIG. 8B shows how the bottom cone plate fits well with the inverted cone 11 of the concrete bed 9 when the platform 10 is lowered again and placed on the concrete bed 9. Thereafter, the gap between both surfaces is filled with grout 12.

  FIG. 9A shows how the small boring plant 24 is attached to the small-diameter pile 21. At this time, the small-diameter pile 21 is placed on the bottom of the floater 1 to penetrate the bottom conical plate 2, the concrete bed 9 and the soil / sand layer 13, and finally pushed into the rock 40.

  FIG. 9B shows how the pile 21 is cut to an appropriate height and the pile cap 17 is cast at the bottom of the floater 1.

  FIG. 10A shows a state in which the boring plant 24 opens a hole for a pile from the upper end of the platform 10 using a protective tube 25.

  FIG. 10B shows the pile driving plant driving the pile 27 from the upper part of the platform 10.

  FIG. 11 shows how a group of small-diameter piles 27 are attached and a short pile protection tube is secured in the pile cap 17 by the grout 12.

(Embodiment 5)
The casting of the concrete bed 9 on the seabed 6 can be performed without using a digging boat as described above as long as the geological state of the seabed 6 is preferable.

  The platform 10 applied to this comprises a high-pressure water jet and a concrete pipe that opens towards the water side of the bottom plate. In the case of shallow bedrock 40 on the seabed with a relatively thin layer of soft material, the concrete bed 9 on the seabed can be formed by the platform itself.

  Float in the platform, adjust its coordinates and orientation, maintain its position and sink to the sea floor by taking in water. If the platform is firmly located on the seabed, the soft material is removed using a high pressure jet stream from the nozzle on the bottom plate until the bedrock 40 is exposed or the designed foundation layer is exposed. Using the built-in tremy concrete lower pipe in the floater 1, wet concrete is poured into the pothole 15 emptied with a water jet flow, and at the same time the position and height are adjusted to maintain that position. Fill the conical plate of the floater 1 and flatten it with a rigid ring plate 4 (if available). After the concrete hardens, lift the platform by reducing the water ballast. As a result, the concrete bed 9 can be cured without being affected by waves and flows. If the platform remains in the concrete bed 9, the platform will receive waves and flows.

  After the concrete bed 9 (having a recess corresponding to the shape of the bottom cone plate) reaches the design strength, the platform is lowered and placed on the concrete bed 9, and the bottom cone plate of k is the inverted cone of the concrete bed 9 To slide. Thereafter, cement grout is injected using a pressure pipe attached in advance, and the gap 12 between the floater 1 and the concrete bed 9 is filled. This fixes the floater 1 on the seabed 6.

The partially floating body supported offshore platform 10 can be assembled as follows, but is not limited thereto.
Segment matching casting of the floater 1 is performed at a factory or a foundry.
Perform segment matching casting of connecting members in factories or ingot mills.
At least three guide piles are installed per floater at the location of the floater 1 at the port. The guide pile is used to confine the floater 1 segment in place and support the weight of the floater 1 segment by an overhand frame / truss.
Bring the floater 1 segment to the port site.
Using a levitating crane or other means, lift the bottom segment to the proper position while guiding with the guide pile. The guide pile should be able to levitate against its own weight and the segment just above it.
The next segment is lifted to the completed part and the next segment is joined using the original stress. Repeat this process until the last segment.
If the length of the finished floater 1 includes a joint connecting the beams, the length is suspended from the overhead frame / truss and is regulated by the guide pile.
Carry the beam segments to the site and connect them to form the beam.
The beam is lifted and temporarily supported on a guide pile or by an overhead frame / truss.
The floater 1 and the steel bar from the beam are fixed and stacked.
Cast joints with on-site concrete.
When all segments are secured, all the confinement mechanisms are removed and the platform is floated on its own.
Remove overhead frames / truss and guide piles. Float out the platform. This completes the assembly of the platform.
Install wind turbines as needed.

DESCRIPTION OF SYMBOLS 1 Floater 2 Bottom conical plate 3 Control tower part 4 Hard ring-shaped board 5 Wind turbine tower 6 Seabed 7 Coarse stone wall / mount 8 Sea surface 9 Concrete bed 10 Partial floating body supported offshore platform 11 Reverse cone 12 Cement grout or just grout 13 Soil / Sand layer 14 Base layer 15 Pot hole 17 Pile cap 21 Small-diameter pile 22 Dredging arm 23 Dredging vessel 24 Boring plant 25 Protective pipe 26 Work boat 27 Small-diameter pile 28 Piling plant 31 Tremy concrete pipe 37 Pressure pipe 38 Valve 39 Hole 40 Rock

Claims (12)

A partially floating body supported offshore offshore platform for offshore wind turbines, bridges and offshore structures, adapted to underwater deeper than 5 m of the marine environment,
Including at least one hollow cylindrical buoyancy tube having a tapered lower end and disposed vertically in the marine environment;
The tapered lower end is embodied as a conical bottom plate whose apex faces the lower seabed direction;
Wherein at least one of the conical bottom plate of the buoyancy tubes, the marine platform of one of the seabed is secured to the concrete bed cast in wind turbines in the marine environment, bridges and marine structures It is supported by the upper, marine platform.   A plurality of elongate piles attached to the conical bottom plate and extending in the direction of the seabed; and a lower end attached to the bedrock under the seabed, wherein the pile attached to the conical bottom plate is the at least one The offshore platform of claim 1, further comprising a plurality of elongate piles that provide a counter force that balances the lifting force of two buoyancy tubes.   A plurality of buoyancy tubes interconnected by a plurality of horizontal beams to form a triangular marine platform, wherein one of the buoyancy tubes supports a wind turbine disposed vertically thereon. The offshore platform according to 1.   The offshore platform of claim 1, further comprising a rigid ring-like plate extending outwardly from the conical bottom plate at the lower end of the buoyancy tube to increase surface area and thereby further reduce bearing pressure.   A vertically arranged regulation tower attached to the upper end of the at least one buoyancy tube, the regulation tower supporting a wind turbine provided on its own, the height of the regulation tower being The marine platform of claim 1, further comprising a regulation tower portion configured such that at least a portion of the regulation tower portion extends above a predetermined maximum wave height in the marine environment. A pressure pile driving system mounted in the hollow interior of the at least one buoyancy tube;
One or more valves provided at an upper end of the at least one buoyancy tube, connected to the pressurized pile driving system, and ejecting a high-pressure water jet through the pressurized pile driving system, To remove a material between the surface of the conical bottom plate and the surface of the concrete bed to leave a gap, and press grout into the gap between the conical bottom plate and the concrete bed. One or more valves connectable to a high pressure water source;
The marine platform of claim 1, further comprising:   The ocean of claim 1, wherein the at least one buoyancy tube is filled with one of sand and water to increase the weight of the ocean platform and counter the lifting force imparted to the platform by wind loads. platform. A construction method for installing the offshore platform according to claim 1 in a marine environment to support offshore wind turbines, bridges and offshore structures,
Excavating the soft material of the seabed using one of dredging, suction, and flushing at a position of the platform where the at least one buoyancy tube is raised to form a pothole in the seabed;
Injecting wet concrete into the pothole to form the concrete bed using one of a gravity method and a concrete jetting method;
Prior to the initial hardening of the wet concrete forming the concrete bed, the platform is lowered until the conical bottom plate of the at least one buoyancy tube fits within the concrete bed, whereby the conical bottom plate is Forming a mirror-image inverted conical recess in the wet concrete of the concrete bed;
Maintaining the platform position until the wet concrete forming the concrete bed is in an initial hardened state that begins to harden;
The material between the conical bottom plate and the inverted conical recess formed in the concrete bed is removed by fluid to separate the conical bottom plate and the inverted conical recess, and between them Forming a gap;
Lifting the platform when the removing step is completed;
Lowering the platform again so that the conical bottom plate and the inverted conical recess formed in the concrete bed of the seabed are in contact with each other with the gap;
A grout is press-fitted into a gap between opposing surfaces of the conical bottom plate of the at least one buoyancy tube and the inverted conical recess formed in the concrete bed, and finally the marine platform is attached to the concrete bed. Fixing, and
Including methods. A construction method for mounting an offshore platform according to claim 1 in an offshore environment to support offshore wind turbines, bridges and offshore structures, wherein the offshore platform is a hollow interior of the at least one buoyancy tube. And a pressure pile driving system attached to the at least one buoyancy tube, and the one or more valves are connected to the pressure pile driving system. A construction method that is connectable to a high-pressure water source that ejects a high-pressure water jet through the pressurized pile driving system, and that can be connected to a cement grout source that ejects cement grout through the pressurized pile driving system,
Levitating the marine platform to an appropriate location within the marine environment, such that the at least one buoyancy tube of the platform floats in a desired position above the soft material of the seabed;
Using the high pressure water jet flow through the piles in the pressure pile driving system, the soft material in a desired position is removed until reaching the foundation layer, thereby exposing the pothole to expose the foundation layer. Forming the step,
Further lowering the marine platform within the marine environment so that it is positioned directly above the pothole formed in the seabed;
Injecting wet concrete into the pothole to form the concrete bed using one of a gravity method and a concrete jetting method;
Prior to the initial hardening of the wet concrete forming the concrete bed, the platform continues to be lowered until the conical bottom plate of the at least one buoyancy tube is within the concrete bed, whereby the conical bottom plate is Forming a mirror image inverted conical recess in the wet concrete of the concrete bed;
Maintaining the platform position until the wet concrete forming the concrete bed is in an initial hardened state that begins to harden;
Using the high pressure water jet flow through the pile in the pressurized pile driving system to remove material between the conical bottom plate and the inverted conical recess formed in the concrete bed Separating the conical bottom plate and the inverted conical recess and forming a gap therebetween;
Lifting the platform when the removing step is completed;
Lowering the platform again so that the conical bottom plate and the inverted conical recess formed in the concrete bed of the seabed are in contact with each other with the gap;
Grouting into the gap between the conical bottom plate of the at least one buoyancy tube and the inverted conical recess formed in the concrete bed using the pile in the pressurized pile driving system. Press-fitting and finally fixing the marine platform to the concrete bed;
Including methods.   And further comprising stabilizing the at least one buoyancy tube by filling the hollow interior of the at least one buoyancy tube with water or sand after securing the at least one buoyancy tube of the offshore platform to the concrete bed. The construction method according to claim 8 or 9.   The method further comprises forming a coarse stone wall by dropping stones around the pothole after forming the pothole on the seabed, and including injected concrete to form the concrete bed. The construction method according to 8 or 9. A method of assembling an offshore platform used at a port site to support offshore wind turbines, bridges, and offshore structures in an offshore environment,
Performing a segment matching casting of a plurality of first segments assembled in a hollow cylindrical buoyancy tube vertically provided in the marine environment at a factory or a foundry, wherein the assembled marine platform includes a plurality of the buoyancy forces. A process comprising a tube;
Performing a segment alignment casting of a plurality of second segments assembled in an elongated horizontal beam connecting the buoyancy tubes adjacent to each other at a factory or a foundry, wherein the assembled offshore platform includes a plurality of the horizontal platforms. Including beam, process,
At a harbor site, as a confinement mechanism for attaching at least three guide piles for one buoyancy tube at the position where the buoyancy tube is assembled, and confining the first segment in an appropriate position and supporting its weight by an overhead frame / truss A process in which the guide pile is used;
Carrying the plurality of first segments to the port site;
Using a levitating crane to lift the first segment, which is the bottom segment of the buoyancy tube to be assembled, to the appropriate position while being guided by the guide pile, wherein the bottom first segment has its own weight and a first just above it. A process capable of levitating against the weight of the segment;
Lifting the next first segment over the bottom first segment and joining the next first segment to the bottom first segment using original stress;
Completing the assembly of the buoyancy tube by repeating the subsequent process of lifting and joining the first segment, wherein each of the assembled buoyancy tubes is connected to one or more of the horizontal beams; A process including a joint;
Hanging the completed buoyancy tube so that it extends vertically from the overhead frame / truss and is regulated by the guide pile;
Carrying the plurality of second segments to the port site;
Assembling and joining the second segment using the original stress to form a horizontal beam;
Using a levitation crane to lift each of the formed horizontal beams onto a temporary support on the guide pile;
Fixing the steel bar in the buoyancy tube and the horizontal beam, and then stacking the steel bar;
Casting the joint at a position where the end of the horizontal beam and the end of the buoyancy tube face each other with concrete on-site so that all the beams are fixed to the buoyancy tube;
Removing the overhead frame / truss and the guide piles;
A step of float out the said marine platform assembly to the marine environment,
Optionally installing a wind turbine on one of the buoyancy tubes of the platform;
Including the method.

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