Split type suction pile anchoring foundation and offshore construction method

Abstract

The invention discloses a split type suction pile anchoring foundation and an offshore construction method, and relates to the technical field of ocean engineering, and the split type suction pile anchoring foundation comprises a suction pile structure and a buoyancy tank structure; an apron board structure and a lug plate structure are arranged on the side wall of the suction pile structure; a drainage pipeline penetrates through the top of the suction pile structure and communicates with the interior of the suction pile structure and the water suction pump. A balance weight cabin and a ballast tank are arranged in the buoyancy tank structure, and a pressure discharging and loading system is arranged in the ballast tank; the supporting leg structures are arranged at the bottom of the buoyancy tank structure, and the buoyancy tank structure is pressed on the apron board structure through the supporting leg structures; a first eye plate connected with a mooring rope or a mooring chain is arranged on the outer side wall of the buoyancy tank structure. The technical problems that due to the fact that a traditional suction pile anchoring foundation is limited by the dead weight, the depth of penetrating into soil in the soil conditions such as sandy soil is insufficient, enough pressure difference cannot be generated in the closed space formed by the cylinder wall and soil in the space outside the cylinder wall, and the suction barrel reaches the preset installation depth and the designed tensile strength and the designed pulling strength are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of marine engineering technology, and in particular to a split suction pile anchor foundation and an offshore construction method. Background Art

[0002] Suction pile anchor foundation is widely used in marine engineering, providing anchor foundation for positioning of marine engineering structures. Its structure is a steel cylindrical structure with closed upper end and open lower end. Under the deadweight of the anchor foundation, the barrel wall penetrates into the seabed soil to form a closed space, and then the liquid in the closed space is pumped out by a pump, so that the closed space forms a pressure difference with the outside, so that the external pressure further penetrates the barrel wall deeper into the seabed soil.

[0003] For a given traditional suction pile, the depth to which it penetrates into the soil under the action of its own weight depends on the soil conditions. At the same time, the size of the internal and external pressure difference that the enclosed space formed by the pile wall and the soil can withstand depends on the penetration depth of the suction pile and the soil conditions. Therefore, the traditional suction piles and installation methods have the problem that the suction piles’ own weight does not penetrate deep enough into the soil, and a closed space cannot be formed, or the external pressure formed by the internal and external pressure difference that the formed enclosed space can withstand cannot make the pile wall penetrate to the designed penetration depth. The increase in the deadweight of traditional suction piles is limited by their own structural design and the capacity of the crane for offshore installation, which limits the soil conditions suitable for the application of traditional suction piles. Generally speaking, traditional suction piles and installation methods are more suitable for use in clay soils, but not in sandy soils, which limits the scope of application of suction piles. Summary of the invention

[0004] The purpose of the present invention is to provide a split suction pile anchor foundation and an offshore construction method in order to solve at least one of the above technical problems.

[0005] In the first aspect, an embodiment of the present invention provides a split suction pile anchor foundation, comprising: a suction pile structure and a pontoon structure; the pontoon structure is arranged on the top of the suction pile structure; wherein a skirt plate structure and an ear plate structure are arranged on the side wall of the suction pile structure; the ear plate structure is used to connect a mooring cable or a mooring chain; a drainage pipeline is arranged through the top of the suction pile structure, one end of the drainage pipeline is connected to the interior of the suction pile structure, and the other end of the drainage pipeline is connected to a water pump; a ballast tank and a ballast tank are arranged inside the pontoon structure, the ballast tank is filled with ballast objects, and a ballast discharge system is arranged in the ballast tank; a leg structure is arranged at the bottom of the pontoon structure, and the pontoon structure is pressed on the skirt plate structure through the leg structure; a first eye plate is arranged on the outer side wall of the pontoon structure, and the first eye plate is used to connect a mooring cable or a mooring chain.

[0006] Furthermore, the suction pile structure is a cylindrical structure with a closed upper end and an open lower end.

[0007] Furthermore, a second eye plate is arranged on the top of the suction pile structure, and the second eye plate is used for connecting a suspension cable.

[0008] Furthermore, the number of the skirt plate structures and the number of the leg structures are both multiple, and the multiple skirt plate structures are evenly or unevenly distributed along the circumference of the outer wall of the suction pile structure; the distribution of the multiple leg structures at the bottom of the pontoon structure is arranged correspondingly to the distribution of the multiple skirt plate structures.

[0009] Furthermore, the counterweight includes iron ore.

[0010] Furthermore, the suction pile structure and the pontoon structure are both steel structures.

[0011] Further, the number of the first eye plates is at least three, and the first eye plates are evenly or unevenly distributed along the circumference of the outer side wall of the buoyancy structure.

[0012] Furthermore, the ballast discharge system includes a pipeline, a sea valve, a vent pipe and a one-way valve; wherein the vent pipe is arranged to pass through the top of the ballast tank, and a vent pipe valve is arranged on the top of the vent pipe; the vent pipe is used to connect the inside and outside of the ballast tank; the sea valve and the one-way valve are both arranged on the side wall of the ballast tank; the pipeline is arranged inside the ballast tank and connected to the sea valve.

[0013] In the second aspect, an embodiment of the present invention further provides an offshore construction method for a split-type suction pile anchor foundation, comprising: transporting the suction pile structure and the pontoon structure to the operating sea area respectively; lowering the suction pile structure from the water surface to the seabed anchoring point, and penetrating the cylinder wall of the suction pile structure into the seabed soil based on its own weight; connecting the pontoon structure and the tugboat with a tow cable to limit the position of the pontoon structure in the operating sea area; injecting ballast water into the ballast tank at a preset rate based on the ballast discharge system, controlling the pontoon structure to gradually sink to the suction pile The present invention relates to a method for preparing a floating pontoon structure and a floating pontoon structure, wherein the floating pontoon structure is positioned above the floating pontoon structure and the leg structure is pressed onto the skirt structure; ballast water is continuously added into the pontoon structure so that the cylinder wall of the suction pile structure continues to penetrate into the seabed soil to a preset depth and a closed space is suddenly formed between the interior of the suction pile structure and the seabed; the ballast water in the ballast tank is discharged based on the ballast discharge system so that the floating pontoon structure gradually floats to the sea surface and is recovered; the liquid in the closed space is pumped out based on the water pump and the drainage pipeline so that the suction pile structure continues to penetrate into the seabed soil to a target depth.

[0014] Furthermore, the suction pile structure and the pontoon structure are transported to the operating sea area respectively, including: dry-towing the suction pile structure to the operating sea area by a workboat; wet-towing or dry-towing the pontoon structure in a self-floating state to the operating sea area.

[0015] The present invention provides a split suction pile anchor foundation and an offshore construction method, in which a counterweight is arranged on the suction pile foundation to increase the deadweight of the suction pile anchor foundation, thereby improving the depth of the suction pile anchor foundation penetrating into the soil by its own weight and improving the applicability of the suction pile anchor foundation to the soil; a pontoon structure and a skirt structure are designed to realize the separable and recyclable functions of the counterweight and the suction pile anchor foundation, thereby avoiding the need to set a permanent structure for supporting the counterweight on the suction pile anchor foundation; during the installation process, the pontoon structure does not require the use of large marine engineering equipment such as floating cranes, and can be slowly lowered to the installation position through a tugboat limiting and pressure-discharging loading system, thereby improving the economy; the present invention alleviates the technical problem that the traditional suction pile anchor foundation is limited by the insufficient penetration depth of its own weight into the soil in soil conditions such as sand, resulting in the inability to generate a sufficient pressure difference in the closed space formed by the barrel wall and the soil in the space outside the barrel wall to enable the suction barrel to reach a preset installation depth and designed tensile and pull-out strengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic structural diagram of a split suction pile anchor foundation provided by an embodiment of the present invention;

[0018] Figure 2 A side view of a suction pile structure provided by an embodiment of the present invention;

[0019] Figure 3 A side view of a pontoon structure provided by an embodiment of the present invention;

[0020] Figure 4 A top view of a suction pile structure provided by an embodiment of the present invention;

[0021] Figure 5 A bottom plan view of a pontoon structure provided by an embodiment of the present invention;

[0022] Figure 6 A schematic diagram of a connection method for limiting the sea position of a buoyancy structure through a first eye plate provided in an embodiment of the present invention;

[0023] Figure 7 A flow chart of an offshore construction method for a split suction pile anchor foundation provided in an embodiment of the present invention.

[0024] In the figure: 1, suction pile structure, 2, pontoon structure, 3, skirt plate structure, 4, ear plate structure, 5, drainage pipeline, 6, water pump, 7, counterweight tank, 8, ballast tank, 81, first ballast tank, 82, second ballast tank, 9, outrigger structure, 10, first eye plate, 11, second eye plate, 12, pipeline, 13, sea valve, 14, vent pipe, 15, one-way valve, 16, tugboat, 17, external pipeline. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1

[0027] Figure 1 Schematic diagram of a split suction pile anchor foundation provided according to an embodiment of the present invention. Figure 1 As shown, it comprises: a suction pile structure 1 and a pontoon structure 2. The pontoon structure 2 is arranged on the top of the suction pile structure 1.

[0028] Figure 2 FIG. 1 is a side view of a suction pile structure provided according to an embodiment of the present invention. Figure 2 As shown, the side wall of the suction pile structure 1 is provided with a skirt plate structure 3 and a lug plate structure 4; the lug plate structure 4 is used for connecting a mooring cable or a mooring chain.

[0029] A drainage pipeline 5 is provided through the top of the suction pile structure 1 , one end of the drainage pipeline 5 is connected to the interior of the suction pile structure 1 , and the other end of the drainage pipeline 5 is connected to a water pump 6 .

[0030] Specifically, a flange is provided at the top port of the drainage pipeline 5 for connecting the water pump 6 via the external pipeline 17. One end of the external pipeline 17 is detachably connected to the drainage pipeline 5 via the flange, and the other end of the external pipeline 17 is connected to the water pump 6.

[0031] Specifically, the water pump 6 is used to pump out the seawater in the enclosed space formed between the suction pile structure 1 and the seabed soil through the external pipeline 17 and the drainage pipeline 5 to form an internal and external pressure difference, so that the suction pile structure 1 further increases the penetration depth into the seabed soil.

[0032] In the embodiment of the present invention, the suction pile structure 1 is a cylindrical structure with a closed upper end and an open lower end. For example, the suction pile structure 1 can be a square cylindrical structure, a cylindrical structure or a cylindrical structure of other shapes. Preferably, the suction pile structure 1 is a cylindrical structure.

[0033] Figure 3 FIG. 1 is a side view of a buoyancy structure provided according to an embodiment of the present invention. Figure 3 As shown, a ballast tank 7 and a ballast tank 8 are arranged inside the pontoon structure 2. The ballast tank 7 is filled with ballast objects, and the ballast tank 8 is provided with a pressure discharge system.

[0034] Preferably, in the embodiment of the present invention, the ballast comprises iron ore.

[0035] Optionally, the ballast also includes a ballast having a density close to or higher than that of the iron ore.

[0036] The embodiment of the present invention uses iron ore as the counterweight. Compared with other counterweight materials, iron ore has a high density, so that the volume is small under the same counterweight weight, thereby achieving volume control of the pontoon structure 2, so that the volume and cross-sectional area of ​​the pontoon structure 2 can match the suction pile structure 1.

[0037] Specifically, Figure 3 As shown, a leg structure 9 is provided at the bottom of the pontoon structure 2 , and the pontoon structure 2 is pressed onto the skirt structure 3 through the leg structure 9 .

[0038] Specifically, a first eye plate 10 is provided on the outer side wall of the buoyancy structure 2, and the first eye plate 10 is used to connect a mooring cable or a mooring chain.

[0039] like Figure 2 As shown, a second eye plate 11 is arranged on the top of the suction pile structure 1, and the second eye plate 11 is used for connecting the suspension cable.

[0040] Figure 4 is a top view of a suction pile structure provided according to an embodiment of the present invention, Figure 5 FIG. 1 is a bottom plan view of a buoyancy structure provided according to an embodiment of the present invention. Figure 4 and Figure 5 As shown, the number of skirt plate structures 3 and the number of leg structures 9 are both multiple, and the multiple skirt plate structures 3 are evenly or unevenly distributed along the circumference of the outer wall of the suction pile structure 1; the distribution of the multiple leg structures 9 at the bottom of the pontoon structure 2 is arranged correspondingly to the distribution of the multiple skirt plate structures 3.

[0041] Specifically, Figure 5 As shown, the number of the first eye plates 10 is at least three, and the plurality of first eye plates 10 are evenly or unevenly distributed along the circumference of the outer side wall of the pontoon structure 2 .

[0042] Figure 6FIG. 1 is a schematic diagram of a connection method for limiting the sea position of a buoyancy structure through a first eye plate according to an embodiment of the present invention. Figure 6 As shown, the first eye plate 10 and the tugboat 16 are connected by a tow cable, and then the pontoon structure 2 is limited to the operating sea area at sea by three tugboats 16 arranged in a triangle.

[0043] In the embodiment of the present invention, the skirt plate structure 3 and the lug plate structure 4 are arranged to avoid interference between each other and between the mooring cable or mooring chain and the skirt plate structure 3 and the lug plate structure 4 .

[0044] Specifically, Figure 4 As shown, the skirt plate structure 3 is a skirt plate-like structure composed of steel brackets and steel plates, which is used to support the bottom structure of the pontoon structure 2 and transfer the deadweight of the pontoon structure 2 to the side wall of the suction pile structure 1.

[0045] Specifically, in the embodiment of the present invention, the diameter of the pontoon structure 2 is greater than the outer diameter of the suction pile structure 1. When the pontoon structure 2 is disposed above the skirt structure 3 through the leg structure 9, the bottom of the pontoon structure 2 does not contact the second eye plate 11 on the top of the suction pile structure 1.

[0046] In an optional implementation provided by the embodiment of the present invention, the suction pile structure 1 and the pontoon structure 2 are both steel structures, and the leg structure 9 is a steel structure.

[0047] Specifically, Figure 3 As shown, the pressure relief system includes a pipeline 12, a sea valve 13, a vent pipe 14 and a one-way valve 15; wherein,

[0048] The vent pipe 14 is arranged to pass through the top of the ballast tank 8, and a vent pipe valve is arranged on the top of the vent pipe 14; the vent pipe 14 is used to connect the inside and outside of the ballast tank 8;

[0049] The sea valve 13 and the one-way valve 15 are both arranged on the side wall of the ballast tank 8;

[0050] The pipeline 12 is disposed inside the ballast tank 8 and connected to the sea valve 13 .

[0051] In the embodiment of the present invention, a flange is provided at the top of the vent pipe 14, and the flange is used to connect with an external pipeline. During the ballasting process, the vent pipe valve of the vent pipe 14 is in an open state. At this time, after the sea valve 13 is opened in the water, seawater enters the ballast tank 8 through the pipeline 12. During the unloading process, the top port of the vent pipe 14 is connected to the external pipeline and connected to the air pump. At this time, the sea valve 13 is closed, and air is pumped into the ballast tank 8 through the air pump, so that the seawater is discharged through the one-way valve 15. The present invention adjusts the ballast water and buoyancy of the pontoon structure 2 through the above-mentioned settings, and then realizes the installation and recovery process of the pontoon structure 2.

[0052] Preferably, there are multiple ballast tanks 8 , and each ballast tank 8 is provided with a corresponding pipeline 12 , a sea valve 13 , a vent pipe 14 and a one-way valve 15 .

[0053] In an optional implementation provided by the embodiment of the present invention, Figure 3 As shown, the ballast tank 8 includes a first ballast tank 81 and a second ballast tank 82. When the pontoon structure 2 floats on the water surface, the vent valve of the vent pipe 14 of the first ballast tank 81 is opened, the vent valve of the vent pipe 14 of the second ballast tank 82 is closed, and the sea valve 13 of the first ballast tank 81 is opened to allow seawater to enter the first ballast tank 81 through the pipeline 12 shown by the dotted line, so that the pontoon structure 2 presents a state where the deadweight is greater than the buoyancy, and can be as shown in FIG. Figure 6 As shown, it is slowly lowered to the installation position with the assistance of the tugboat 16 and the towline.

[0054] When Figure 1 As shown, after the pontoon structure 2 is located on the suction pile structure 1, the vent valve 14 of the second ballast tank 82 and the sea valve 13 are opened, so that seawater can enter the second ballast tank 82 through the pipeline 12 shown by the dotted line, thereby increasing the deadweight of the pontoon structure 2 and transferring the increased deadweight to the suction pile structure 1 through the skirt structure 3.

[0055] When recovering the buoyancy structure 2, the sea valve 14 of the first ballast tank 81 can be closed first, an air pump and an external pipeline can be set on the tugboat 16, and the external pipeline of the air pump can be connected to the vent pipe 14 of the first ballast tank 81 through a flange, and the air pump can be used to pump air into the first ballast tank 81, and the water in the first ballast tank 81 can be discharged from the buoyancy structure 2 through the one-way valve 15, and then the vent pipe valve of the vent pipe 14 of the first ballast tank 81 can be closed. The external pipeline of the air pump can be moved to the vent pipe 14 of the second ballast tank 82, and connected through a flange, and the sea valve 13 of the second ballast tank 82 can be closed, and the air pump can be used to pump air into the second ballast tank 82, and the water in the second ballast tank 82 can be discharged from the buoyancy structure 2 through the one-way valve 15, so that the buoyancy of the buoyancy structure 2 is greater than the gravity, and the buoyancy structure 2 can slowly float to the water surface for recovery and reuse.

[0056] Embodiment 2

[0057] Figure 7 1 is a flow chart of an offshore construction method of a split suction pile anchor foundation provided according to an embodiment of the present invention. Figure 7 As shown, the method specifically comprises the following steps:

[0058] Step S702, transporting the suction pile structure and the pontoon structure to the operating sea area respectively.

[0059] Step S704, lowering the suction pile structure from the water surface to the seabed anchoring point, and penetrating the cylinder wall of the suction pile structure into the seabed soil based on its own weight.

[0060] Specifically, the second eye plate on the top of the suction pile structure or the ear plate structure on the side wall is connected to the crane of the workboat through a lifting cable, and the suction pile structure is slowly lowered from the water surface to the anchoring point on the seabed through the crane.

[0061] Step S706: Use a tow cable to connect the pontoon structure and the tugboat to position the pontoon structure in the operating sea area.

[0062] In an optional implementation provided by an embodiment of the present invention, three tugboats are used to Figure 6 The connection method shown uses a towline to connect the first eye plate of the pontoon structure and the tugboat, and uses three tugboats to limit the position of the pontoon structure at sea.

[0063] Step S708, based on the ballast water discharging system, ballast water is pumped into the ballast tank at a preset rate, the pontoon structure is controlled to gradually sink to a position above the suction pile structure, and the leg structure is pressed onto the skirt structure.

[0064] Specifically, the pontoon structure, with the assistance of the tugboat and the tow cable, gradually sinks from the water surface to a position above the suction pile structure.

[0065] Step S710, ballast water is continuously added into the buoyancy structure, so that the cylinder wall of the suction pile structure continues to penetrate into the seabed soil to a preset depth, and a closed space is suddenly formed between the interior of the suction pile structure and the seabed.

[0066] Step S712: discharge the ballast water in the ballast tank based on the ballast discharge system, so that the pontoon structure gradually floats to the sea surface and is recovered.

[0067] Step S714: pump out the liquid in the enclosed space based on the water pump and the drainage pipeline, so that the suction pile structure continues to penetrate the seabed soil to the target depth.

[0068] Specifically, step S702 also includes the following steps:

[0069] Step S7021, dry-tow the suction pile structure to the operating sea area by a workboat;

[0070] Step S7022, wet-tow or dry-tow the pontoon structure in a self-floating state to the operating sea area.

[0071] From the above description, it can be seen that the embodiments of the present invention provide a split suction pile anchor foundation and an offshore construction method, in which a counterweight is set on the suction pile foundation to increase the deadweight of the suction pile anchor foundation, thereby improving the depth of the suction pile anchor foundation penetrating into the soil by its own weight, and improving the applicability of the suction pile anchor foundation to the soil; the design of a pontoon structure and a skirt structure is adopted to realize the separable and recyclable functions of the counterweight and the suction pile anchor foundation, thereby avoiding the need to set a permanent structure for supporting the counterweight on the suction pile anchor foundation; during the installation of the pontoon structure, there is no need to use large marine engineering equipment such as floating cranes, and the pontoon structure can be slowly lowered to the installation position through the tugboat limit and pressure discharge loading system, thereby improving the economy.

[0072] An embodiment of the present invention provides a split suction pile anchor foundation and an offshore construction method. In a scenario where horizontal bearing capacity is provided for a catenary mooring system, the suction pile anchor foundation provided by the present invention has comparable steel usage, volume, force-bearing area, and system complexity to a traditional suction pile anchor foundation, but has better adaptability to soil conditions.

[0073] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0074] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A split suction pile anchor foundation, characterized in that: include: A suction pile structure and a pontoon structure; the pontoon structure is arranged on the top of the suction pile structure; wherein, The side wall of the suction pile structure is provided with a skirt plate structure and a lug plate structure; the lug plate structure is used to connect a mooring cable or a mooring chain; A drainage pipeline is arranged through the top of the suction pile structure, one end of the drainage pipeline is connected to the interior of the suction pile structure, and the other end of the drainage pipeline is connected to a water pump; A ballast tank and a ballast tank are arranged inside the pontoon structure, the ballast tank is filled with ballast objects, and a ballast discharge system is arranged in the ballast tank; A leg structure is arranged at the bottom of the pontoon structure, and the pontoon structure is pressed onto the skirt structure through the leg structure; A first eye plate is arranged on the outer side wall of the buoyancy structure, and the first eye plate is used for connecting a mooring cable or a mooring chain.

2. The split suction pile anchor foundation according to claim 1 is characterized in that: The suction pile structure is a cylindrical structure with a closed upper end and an open lower end.

3. The split suction pile anchor foundation according to claim 1 is characterized in that: A second eye plate is arranged on the top of the suction pile structure, and the second eye plate is used for connecting a suspension cable.

4. The split suction pile anchor foundation according to claim 1 is characterized in that: The number of the skirt plate structures and the number of the leg structures are both multiple, and the multiple skirt plate structures are evenly or unevenly distributed along the circumference of the outer wall of the suction pile structure; the distribution of the multiple leg structures at the bottom of the pontoon structure is arranged correspondingly to the distribution of the multiple skirt plate structures.

5. The split suction pile anchor foundation according to claim 1 is characterized in that: The ballast material includes iron ore.

6. The split suction pile anchor foundation according to claim 1, characterized in that: The suction pile structure and the pontoon structure are both steel structures.

7. The split suction pile anchor foundation according to claim 1 is characterized in that: The number of the first eye plates is at least three, and the first eye plates are evenly or unevenly distributed along the circumference of the outer side wall of the buoyancy structure.

8. The split suction pile anchor foundation according to claim 1 is characterized in that: The pressure relief system includes pipelines, sea valves, vent pipes and one-way valves; wherein, The vent pipe is arranged through the top of the ballast tank, and a vent pipe valve is arranged on the top of the vent pipe; the vent pipe is used to connect the inside and outside of the ballast tank; The sea valve and the one-way valve are both arranged on the side wall of the ballast tank; The pipeline is arranged inside the ballast tank and connected to the sea valve.

9. An offshore construction method for a split suction pile anchor foundation according to claim 1, characterized in that: include: transporting the suction pile structure and the pontoon structure to the operating sea area respectively; Lowering the suction pile structure from the water surface to a seabed anchoring point, and penetrating the cylinder wall of the suction pile structure into the seabed soil based on its own weight; Connecting the pontoon structure and the tugboat using a tow cable to position the pontoon structure on the operating sea area; Based on the ballast water being pumped into the ballast tank by the ballast system at a preset rate, the pontoon structure is controlled to gradually sink to a position above the suction pile structure, and the leg structure is pressed onto the skirt structure; Continue to add ballast water into the buoy structure so that the cylinder wall of the suction pile structure continues to penetrate into the seabed soil to a preset depth and a closed space is suddenly formed between the interior of the suction pile structure and the seabed; Based on the ballast discharge system, the ballast water in the ballast tank is discharged, so that the buoyancy structure gradually floats to the sea surface and is recovered; The liquid in the closed space is pumped out based on the water pump and the drainage pipeline, so that the suction pile structure continues to penetrate the seabed soil to the target depth.

10. The method according to claim 9, characterized in that: The suction pile structure and the pontoon structure are transported to the operating sea area respectively, including: The suction pile structure is dry-towed to the operating sea area by a workboat; The pontoon structure is wet-towed or dry-towed in a self-floating state to the operating sea area.

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