Large-diameter cylinder type combined foundation of negative pressure sinking skirt cabin and sinking method thereof

Abstract

The application discloses a negative pressure sinking skirt cabin large-diameter cylinder combined foundation and a sinking method thereof. The combined foundation comprises a large-diameter steel cylinder and a plurality of negative pressure sinking skirt cabins which are continuously or intermittently arranged along the ring direction outside the large-diameter steel cylinder. A top cover plate of each negative pressure sinking skirt cabin is provided with a skirt cabin one-way hole valve which is used as a channel for natural water discharge and negative pressure discharge in each negative pressure sinking skirt cabin. The skirt cabin one-way hole valve is connected with a negative pressure system through a negative pressure pipeline. During sinking, each negative pressure sinking skirt cabin is pumped by the negative pressure system to assist the sinking of the large-diameter steel cylinder, so that the large-diameter cylinder foundation is sunk without power. In addition, the skirt cabin array also significantly improves the bearing capacity of the combined foundation. The application breaks through the limitations that the traditional large-diameter cylinder foundation is easy to be failed due to soil liquefaction and damage in the cylinder under negative pressure or vibration impact sinking, and the sinking depth is insufficient due to the excessive height of the cylinder.

Description

Technical Field

[0001] This invention relates to marine foundation engineering, specifically to a large-diameter cylindrical composite foundation with a negative pressure sinking skirt and its sinking method. Background Technology

[0002] Various deep-water foundations derived from large-diameter cylindrical foundations are widely used in marine engineering. For example, ultra-large diameter steel cylinders are key retaining structures for artificial island walls, suction cylinder foundations are one of the important foundation types for offshore wind turbine jackets, and suction caisson foundations are one of the anchoring foundation types for floating oil and gas platforms and floating wind and solar power.

[0003] However, existing large-diameter cylindrical foundations have many limitations in application. Specifically, the ultra-large diameter steel cylinders used as retaining structures for artificial islands require the seabed soil to be liquefied through vibration using a linkage hammer before they can be successfully sunk. This makes the formed island wall structure system prone to instability and failure, making engineering treatment difficult. The dimensions of suction cylinder foundations for offshore wind turbine jackets and suction caissons for floating platforms are severely limited by the strength of the foundation soil and the negative pressure strength. Excessive negative pressure can easily damage the soil inside the cylinder, resulting in a significant reduction in the bearing capacity of the suction cylinder foundation. Therefore, the height-to-width ratio of cylindrical foundations has application limits, making it difficult to achieve higher bearing capacity through larger dimensions. Offshore large-diameter single-column suction cylinder foundations achieve the maximum diameter of the suction cylinder foundation through compartmentalization, but they also face the limitation of limited depth. In addition, the shallow foundation soil has insufficient strength, which means that the bearing capacity of this foundation cannot be fully utilized.

[0004] To maintain the stability of marine engineering platforms, the development of their supporting foundations into larger sizes has become an inevitable trend. Coupled with unfavorable factors such as long distances from the shore and deep waters, the success or failure of marine engineering projects is directly related to whether the large cylindrical foundations can be successfully constructed. Summary of the Invention

[0005] Purpose of the invention: The first purpose of this invention is to address the limitations of existing large-diameter cylindrical foundations, such as soil liquefaction and soil damage within the cylinder, which are prone to occur during the sinking construction process. This invention provides a negative pressure sinking-assisted skirted large-diameter cylindrical composite foundation that enables a passive, unpowered sinking process throughout the entire large-diameter cylindrical foundation construction, effectively avoiding soil damage or load-bearing failure. The second purpose of this invention is to provide a sinking penetration method for this negative pressure sinking-assisted skirted large-diameter cylindrical composite foundation.

[0006] Technical solution: The negative pressure sinking skirt chamber large-diameter cylindrical combined foundation of the present invention includes a large-diameter steel cylinder, and several negative pressure sinking skirt chambers are arranged continuously or at intervals along the outer side of the large-diameter steel cylinder in the circumferential direction. Each negative pressure sinking skirt chamber is provided with a one-way valve on its top cover plate, which serves as a channel for the natural discharge of water and the discharge of negative pressure in each negative pressure sinking skirt chamber; the one-way valve is connected to the negative pressure system through a negative pressure pipeline.

[0007] Furthermore, the negative pressure sinking skirt compartment is fan-shaped and consists of a large-diameter steel cylinder, a first skirt compartment outer wall panel, a bulkhead panel, and a fan-shaped top cover plate. The first skirt compartment outer wall panel is arranged concentrically with the large-diameter steel cylinder, the bulkhead panel is arranged radially along the large-diameter steel cylinder, and the height of the bulkhead panel is the same as that of the first skirt compartment outer wall panel.

[0008] Furthermore, the dimensions of the fan-shaped columnar negative pressure sinking skirt chamber are determined by the following formula:

[0009]

[0010] in, The diameter of the outer wall panel of the first skirt compartment; The diameter of the large-diameter steel cylinder; The height of the large-diameter steel cylinder; The aspect ratio is [missing information]. The number of negative pressure sinking skirt compartments; The inner side length of the space between two adjacent negative pressure sinking skirt compartments; When the value is 0, the negative pressure sinking skirt chambers are continuously arranged circumferentially on the outside of the diameter steel cylinder; When the pressure is greater than 0, the negative pressure sinking skirt chambers are arranged at intervals along the circumference on the outside of the diameter steel cylinder.

[0011] Furthermore, the negative pressure sinking skirt chamber is crescent-shaped and consists of a large-diameter steel cylinder, a second skirt chamber outer wall panel, and a crescent-shaped top cover plate. The second skirt chamber outer wall panel is semi-circular, with the side length of the regular polygon inscribed in the large-diameter steel cylinder as its diameter.

[0012] Furthermore, the dimensions of the crescent-shaped columnar negative pressure sinking-aiding skirt chamber are determined by the following formula:

[0013]

[0014] in, The diameter of the large-diameter steel cylinder; The height of the large-diameter steel cylinder; The aspect ratio is [missing information]. The number of negative pressure sinking skirt compartments; The distance between the bases of two adjacent second skirt cabin outer wall panels on a large-diameter steel cylinder; when When =0, the negative pressure sinking-aiding skirt chambers are continuously arranged circumferentially on the outside of the diameter steel cylinder; when... When the pressure is greater than 0, the negative pressure sinking skirt chambers are arranged at intervals along the circumference on the outside of the diameter steel cylinder.

[0015] Furthermore, the bottom of the large-diameter steel cylinder is flush with the bottom of the negative pressure sinking skirt chamber; the top of the large-diameter steel cylinder is flush with or higher than the top of the negative pressure sinking skirt chamber, but the top of the negative pressure sinking skirt chamber must be flush with the mud surface.

[0016] Furthermore, the bottom burial depth of the large-diameter steel cylinder is greater than that of the bottom burial depth of the negative pressure sinking aid skirt chamber. The top of the large-diameter steel cylinder is level with or higher than the top of the negative pressure sinking aid skirt chamber, but the top of the negative pressure sinking aid skirt chamber must be level with the mud surface; the length of the large-diameter steel cylinder extending beyond the bottom of the negative pressure sinking aid skirt chamber. Determined by the following formula:

[0017]

[0018] in, The diameter of the large-diameter steel cylinder; The underwater self-weight of the large-diameter cylindrical composite foundation of the negative pressure sinking skirt chamber; and The measurements are the depth of each layer of foundation soil and the ultimate side friction resistance, respectively, when the top of the negative pressure sinking skirt chamber is flush with the mud surface, and the bottom of the large-diameter steel cylinder is embedded in the soil.

[0019] Furthermore, a sealing cap is provided at the top of the large-diameter steel cylinder, and the top of the large-diameter steel cylinder is flush with the top of the negative pressure sinking skirt chamber. The height of the large-diameter steel cylinder is greater than or equal to the height of the negative pressure sinking skirt chamber. Several one-way drainage holes are provided on the sealing cap, which serve as a natural drainage channel for water inside the large-diameter steel cylinder. Its total drainage capacity per unit time is higher than the negative pressure pumping and drainage capacity of all the negative pressure sinking skirt chambers. A one-way valve is provided at the center of the sealing cap, which serves as a negative pressure drainage channel for water inside the large-diameter steel cylinder. The one-way valve is connected to the negative pressure system through a negative pressure pipeline.

[0020] The sinking method for a large-diameter cylindrical composite foundation with a negative pressure-assisted sinking skirt chamber, as described in this invention, includes:

[0021] (1) Open all one-way valves of the skirt cabins, and slowly lower the large-diameter cylindrical composite foundation of the negative pressure-assisted sinking skirt cabins through the hoisting equipment until it can no longer sink naturally;

[0022] (2) Connect the one-way valve of each skirt compartment to the negative pressure system through the negative pressure pipeline, start the negative pressure system, and simultaneously extract the water in each negative pressure sinking skirt compartment to keep the negative pressure in each negative pressure sinking skirt compartment consistent, so as to realize the negative pressure sinking skirt compartment driving the large diameter steel cylinder to sink.

[0023] (3) After the large-diameter cylindrical combined foundation of the negative pressure sinking skirt cabin is sunk to the design depth, close all one-way valves of the skirt cabin and remove all negative pressure pipes.

[0024] Optionally, the sinking method for the large-diameter cylindrical combined foundation of the negative pressure sinking skirt chamber according to the present invention includes:

[0025] (1) Open all one-way valves of the skirt cabin, one-way drainage holes of the cylinder cover and one-way valve of the cylinder cover. The large-diameter cylindrical composite foundation of the negative pressure sinking skirt cabin is slowly lowered by the hoisting equipment until it can no longer sink naturally.

[0026] (2) Connect the one-way valve of each skirt compartment to the negative pressure system through the negative pressure pipeline, start the negative pressure system, and simultaneously extract the water in each negative pressure sinking skirt compartment to keep the negative pressure in each negative pressure sinking skirt compartment consistent, so as to realize the negative pressure sinking skirt compartment driving the large diameter steel cylinder to sink.

[0027] (3) After the large-diameter cylindrical composite foundation of the negative pressure-assisted sinking skirt chamber is sunk to the design depth, close all one-way valves of the skirt chamber and remove all negative pressure pipes connected to the one-way valves of the skirt chamber; close the one-way drainage hole of the cylinder cover, connect the one-way valve of the cylinder cover to the negative pressure system through the negative pressure pipe, start the negative pressure system, so that a negative pressure environment is formed inside the large-diameter steel cylinder, so that the large-diameter steel cylinder and the soil inside the cylinder are in close contact under the action of negative pressure, until the negative pressure value of the negative pressure system changes drastically and the operation is stopped.

[0028] (4) Close the one-way valve on the cylinder cover and remove the negative pressure pipe connected to the one-way valve on the cylinder cover.

[0029] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0030] (1) The present invention uses a negative pressure sinking skirt chamber to assist the sinking of large-diameter cylindrical foundations. During the sinking process, the large-diameter cylindrical foundation does not require any negative pressure operation, which breaks through the limitations of traditional large-diameter cylindrical foundations that are prone to liquefaction and damage of the soil inside the cylinder and failure due to negative pressure sinking, and insufficient sinking depth due to excessive cylinder height.

[0031] (2) The skirt array designed in this invention is distributed around the large-diameter cylindrical foundation, which significantly increases the contact area with the surrounding soil, thereby greatly improving the bearing capacity of the composite foundation.

[0032] (3) Traditional cylindrical foundations often use internal compartment design to improve the foundation bearing capacity and settlement performance. However, the interaction between the internal compartment and the surrounding soil involves complex soil mechanics behavior, which requires centrifuge testing to determine the bearing capacity design parameters, increasing the research and development cost. The large-diameter inner cylinder of this invention can adopt the mature single-cylinder design method, which greatly simplifies the design process and reduces the difficulty of research and development and construction.

[0033] (4) This invention provides a new reference for offshore wind power jacket suction cylinder foundation, photovoltaic wind power and oil and gas floating platform suction anchor foundation, artificial island wall structure, and other marine engineering structure foundation. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of an embodiment of the present invention showing a continuous arrangement of equal-length fan-shaped columnar skirts along the circumferential direction on the outer side of a large-diameter steel cylinder without a cover.

[0035] Figure 2 yes Figure 1 Perspective view;

[0036] Figure 3 This is a schematic diagram of an embodiment of the present invention showing an equally long fan-shaped columnar skirt compartment arranged circumferentially on the outer side of a large-diameter steel cylinder without a cover.

[0037] Figure 4 yes Figure 3 Perspective view;

[0038] Figure 5 This is a top view of a fan-shaped columnar skirt arranged circumferentially on the outer side of a large-diameter steel cylinder without a cover, according to an embodiment of the present invention.

[0039] Figure 6 This is a schematic diagram of a crescent-shaped columnar skirt continuously arranged along the circumferential direction on the outer side of a large-diameter steel cylinder without a cover, according to an embodiment of the present invention.

[0040] Figure 7 This is a top view of a crescent-shaped columnar skirt arranged circumferentially on the outer side of a large-diameter steel cylinder without a cover, according to an embodiment of the present invention.

[0041] Figure 8 This is a schematic diagram of a large-diameter steel cylinder without a cover, with unequal (top flush) fan-shaped columnar skirts arranged continuously along the circumference on the outside.

[0042] Figure 9 yes Figure 8 Schematic diagram of the mating structure between the medium and large diameter steel cylinder, the outer wall panel of the first skirt compartment, and the bulkhead;

[0043] Figure 10 This is a schematic diagram of a continuously arranged, circumferentially circumferentially circumferentially fan-shaped columnar skirt cabin on the outer side of a large-diameter steel cylinder with a cover, according to an embodiment of the present invention.

[0044] Figure 11 yes Figure 10 Perspective view. Detailed Implementation

[0045] The invention will now be further described with reference to the accompanying drawings.

[0046] Appendix Figures 1 to 11 The accompanying figure labels are as follows:

[0047] 1. Large-diameter steel cylinder; 11. Sealed cylinder cover; 21. Bulkhead plate; 22. Fan-shaped top cover plate; 23. Crescent-shaped top cover plate; 3. First skirt compartment outer wall panel; 4. Second skirt compartment outer wall panel; 51. Skirt compartment one-way valve; 53. Cylinder cover one-way drain hole; 54. Cylinder cover one-way valve.

[0048] like Figures 1 to 11 As shown, the negative pressure sinking-aid skirt chamber large-diameter cylindrical composite foundation includes a large-diameter steel cylinder 1 that bears the main load-bearing function. Several negative pressure sinking-aid skirt chambers are arranged continuously or at intervals along the outer side of the large-diameter steel cylinder 1 in a circumferential direction. Each negative pressure sinking-aid skirt chamber has a one-way valve 51 at the centroid of its top cover plate, serving as a channel for natural water drainage and negative pressure discharge within each skirt chamber. The one-way valve 51 is connected to the negative pressure system via a negative pressure pipeline. Driven by the negative pressure sinking-aid skirt chambers, the large-diameter steel cylinder 1 can achieve unpowered sinking, ensuring the smooth sinking of the composite foundation. Simultaneously, the bearing capacity of the composite foundation is significantly enhanced by the synergistic bearing effect of the negative pressure sinking-aid skirt chambers and the large-diameter steel cylinder 1.

[0049] As one implementation method, such as Figures 1 to 5 As shown, the negative pressure sinking skirt compartment is fan-shaped and consists of a large-diameter steel cylinder 1, a first skirt compartment outer wall panel 3, a bulkhead 21, and a fan-shaped top cover 22. The first skirt compartment outer wall panel 3 is arranged concentrically with the large-diameter steel cylinder 1, and the bulkhead 21 is arranged radially along the large-diameter steel cylinder 1. The height of the bulkhead 21 is the same as that of the first skirt compartment outer wall panel 3.

[0050] The dimensions of the fan-shaped columnar negative pressure sinking skirt chamber are determined by the following formula:

[0051]

[0052] in, The diameter of the outer wall panel 3 of the first skirt compartment; The diameter of the large-diameter steel cylinder 1; Height of the large-diameter steel cylinder 1; height-to-width ratio ,in When the coverage area of ​​all negative pressure sinking skirt chambers is equivalent to a steel cylinder, the diameter of this equivalent steel cylinder is... Generally, 1.5~6 is used; The number of negative pressure sinking skirt compartments is generally no less than 4; The inner length of the space between two adjacent negative pressure sinking skirt compartments (e.g.) Figure 5 The space between the lines can be considered as consisting of two straight lines and two arcs, and the length of the inner side is the length of the arc closest to the steel cylinder. When =0, the negative pressure sinking skirt chamber is continuously arranged circumferentially on the outside of the diameter steel cylinder 1; when When the pressure is greater than 0, the negative pressure sinking skirt chambers are arranged circumferentially on the outside of the diameter steel cylinder 1, which can play a better role in resisting torsion.

[0053] As another implementation method, such as Figure 6 and Figure 7 As shown, the negative pressure sinking-aid skirt compartment is a crescent-shaped column, consisting of a large-diameter steel cylinder 1, a second skirt compartment outer wall panel 4, and a crescent-shaped top cover plate 23. The second skirt compartment outer wall panel 4 is semi-circular, with its diameter being the side length of the regular polygon inscribed in the large-diameter steel cylinder 1. The height of the second skirt compartment outer wall panel 4 is less than or equal to the height of the large-diameter steel cylinder 1.

[0054] The dimensions of the crescent-shaped columnar negative pressure sinking aid skirt chamber are determined by the following formula:

[0055]

[0056] in, The diameter of the large-diameter steel cylinder 1; Height of the large-diameter steel cylinder 1; height-to-width ratio ,in When the coverage area of ​​all negative pressure sinking skirt chambers is equivalent to a steel cylinder, the diameter of this equivalent steel cylinder is... Generally, 1.5~6 is used; The number of negative pressure sinking skirt compartments is generally no less than 4; The distance between the bases of two adjacent second skirt compartment outer wall panels 4 on the large-diameter steel cylinder 1 (i.e., the distance between two adjacent negative pressure sinking skirt compartments); when When =0, the negative pressure sinking skirt chamber is continuously arranged circumferentially on the outside of the diameter steel cylinder 1; when When the value is greater than 0, the negative pressure sinking skirt chambers are arranged circumferentially at intervals on the outside of the diameter steel cylinder 1.

[0057] The relative height of the negative pressure sinking skirt chamber and the large-diameter steel cylinder 1 can be combined in the following ways:

[0058] 1) The bottom of the large-diameter steel cylinder 1 is flush with the bottom of the negative pressure sinking skirt chamber; the top of the large-diameter steel cylinder 1 is flush with or higher than the top of the negative pressure sinking skirt chamber, but the top of the negative pressure sinking skirt chamber must be flush with the mud surface. When the top of the large-diameter steel cylinder 1 is higher than the top of the negative pressure sinking skirt chamber, it can be used as an ultra-large diameter steel cylinder island wall structure for artificial islands, avoiding the instability of the island wall structure caused by the vibration of the linkage hammer liquefying the foundation soil. It can also be used as a seabed support structure in other marine engineering projects.

[0059] 2) The bottom burial depth of the large-diameter steel cylinder 1 is greater than the bottom burial depth of the negative pressure sinking aid skirt chamber. The top of the large-diameter steel cylinder 1 is flush with or higher than the top of the negative pressure sinking aid skirt chamber, but the top of the negative pressure sinking aid skirt chamber must be flush with the mud surface; the bottom of the large-diameter steel cylinder 1 extends beyond the bottom of the negative pressure sinking aid skirt chamber by a certain length. Determined by the following formula:

[0060]

[0061] in, The diameter of the large-diameter steel cylinder 1; The underwater self-weight of the large-diameter cylindrical composite foundation for the negative pressure sinking skirt compartment; and The values ​​are the depth of each layer of foundation soil embedded in the bottom of the large-diameter steel cylinder 1 when the top of the negative pressure sinking skirt chamber is flush with the mud surface, and the ultimate side friction resistance.

[0062] Figure 8 and Figure 9 The diagram shows the top of the large-diameter steel cylinder 1 being flush with the top of the negative pressure sinking skirt chamber, with the former having a greater bottom burial depth than the latter.

[0063] like Figure 10 and Figure 11 As shown, a sealing cap 11 is provided at the top of the large-diameter steel cylinder 1. In this case, the top of the large-diameter steel cylinder 1 is flush with the top of the negative pressure sinking skirt chamber, and the height of the large-diameter steel cylinder 1 is greater than or equal to the height of the negative pressure sinking skirt chamber. When the former height is greater than the latter height, the excess length is handled as described above. The length is determined by a method.

[0064] A series of one-way drainage holes 53 are arranged in a ring on the sealing cylinder cover 11, which serve as a natural drainage channel for water inside the large-diameter steel cylinder 1. Its total drainage capacity per unit time is higher than the negative pressure pumping and drainage capacity of all negative pressure sinking skirt chambers. A one-way valve 54 is provided at the center of the sealing cylinder cover 11, which serves as a negative pressure drainage channel for water inside the large-diameter steel cylinder 1. The one-way valve 54 is connected to the negative pressure system through a negative pressure pipeline.

[0065] The present invention also provides a sinking method for a large-diameter cylindrical composite foundation of a negative pressure sinking skirt chamber. This sinking method is divided into two types according to whether the top of the large-diameter steel cylinder 1 has a cylinder cover.

[0066] When the top of the large-diameter steel cylinder 1 is not covered, the sinking method for the large-diameter cylindrical composite foundation with negative pressure-assisted sinking skirt includes the following steps:

[0067] (1) Open all one-way valves 51 of the skirt cabins, and slowly lower the large-diameter cylindrical composite foundation of the negative pressure-assisted sinking skirt cabin through the hoisting equipment until it can no longer sink naturally;

[0068] (2) Connect the one-way valve 51 of each skirt compartment to the negative pressure system through the negative pressure pipeline, start the negative pressure system, and simultaneously extract the water in each negative pressure sinking skirt compartment to keep the negative pressure in each negative pressure sinking skirt compartment consistent, so as to realize the negative pressure sinking skirt compartment driving the large diameter steel cylinder 1 to sink.

[0069] (3) After the negative pressure sinking skirt cabin large-diameter cylindrical combined foundation sinks to the design depth, close all skirt cabin one-way valves 51 and remove all negative pressure pipes.

[0070] When a cylinder cover is installed on the top of the large-diameter steel cylinder 1, the sinking method of the large-diameter cylindrical combined foundation with negative pressure sinking skirt includes the following steps:

[0071] (1) Open all one-way valves 51, one-way drainage holes 53 and one-way valves 54 of the sleeve cabin, and slowly lower the large-diameter cylindrical composite foundation of the negative pressure-assisted sinking skirt cabin through the hoisting equipment until it can no longer sink naturally.

[0072] (2) Connect the one-way valve 51 of each skirt compartment to the negative pressure system through the negative pressure pipeline, start the negative pressure system, and simultaneously extract the water in each negative pressure sinking skirt compartment to keep the negative pressure in each negative pressure sinking skirt compartment consistent, so as to realize the negative pressure sinking skirt compartment driving the large diameter steel cylinder 1 to sink.

[0073] (3) After the negative pressure-assisted sinking skirt cabin large-diameter cylindrical combined foundation sinks to the design depth, close all skirt cabin one-way valves 51 and remove all negative pressure pipes connected to the skirt cabin one-way valves 51; close the cylinder cover one-way drainage hole 53, connect the cylinder cover one-way valve 54 to the negative pressure system through the negative pressure pipe, start the negative pressure system, so that a negative pressure environment is formed inside the large-diameter steel cylinder 1, so that the large-diameter steel cylinder 1 and the soil inside the cylinder are in close contact under the action of negative pressure, until the negative pressure value of the negative pressure system changes drastically and the operation is stopped.

[0074] (4) Close the one-way valve 54 of the cylinder cover and remove the negative pressure pipe connected to the one-way valve 54 of the cylinder cover.

Claims

1. A large-diameter cylindrical composite foundation for a negative pressure sinking skirt chamber, comprising a large-diameter steel cylinder (1), characterized in that, A number of negative pressure sinking skirt chambers are arranged continuously or at intervals along the outer side of the large diameter steel cylinder (1). Each negative pressure sinking skirt chamber is equipped with a one-way valve (51) on its top cover plate, which serves as a channel for natural water discharge and negative pressure discharge in each negative pressure sinking skirt chamber. The one-way valve (51) is connected to the negative pressure system through a negative pressure pipeline. The negative pressure sinking skirt is fan-shaped and consists of a large-diameter steel cylinder (1), a first skirt outer wall panel (3), a bulkhead (21), and a fan-shaped top cover (22). The first skirt outer wall panel (3) is arranged concentrically with the large-diameter steel cylinder (1), and the bulkhead (21) is arranged radially along the large-diameter steel cylinder (1). The height of the bulkhead (21) is the same as that of the first skirt outer wall panel (3). The dimensions of the fan-shaped columnar negative pressure sinking skirt chamber are determined by the following formula: in, The diameter of the outer wall panel (3) of the first skirt compartment; The diameter of the large-diameter steel cylinder (1); The height of the large-diameter steel cylinder (1); The aspect ratio is [missing information]. The number of negative pressure sinking skirt compartments; The inner side length of the space between two adjacent negative pressure sinking skirt compartments; When =0, the negative pressure sinking skirt chamber is continuously arranged in the circumferential direction on the outside of the diameter steel cylinder (1); When >0, the negative pressure sinking skirt chambers are arranged circumferentially on the outside of the diameter steel cylinder (1); Alternatively, the negative pressure sinking skirt chamber is crescent-shaped and consists of a large-diameter steel cylinder (1), a second skirt chamber outer wall panel (4), and a crescent-shaped top cover plate (23). The second skirt chamber outer wall panel (4) is semi-circular, with the side length of the regular polygon inscribed in the large-diameter steel cylinder (1) as its diameter. The dimensions of the crescent-shaped columnar negative pressure sinking aid skirt chamber are determined by the following formula: in, The diameter of the large-diameter steel cylinder (1); The height of the large-diameter steel cylinder (1); The aspect ratio is [missing information]. The number of negative pressure sinking skirt compartments; The distance between the bases of two adjacent second skirt cabin outer wall panels (4) on the large-diameter steel cylinder (1); when When =0, the negative pressure sinking skirt chamber is continuously arranged circumferentially on the outside of the diameter steel cylinder (1); when When the pressure is >0, the negative pressure sinking skirt compartments are arranged circumferentially on the outside of the diameter steel cylinder (1).

2. The large-diameter cylindrical combined foundation for the negative pressure sinking skirt chamber according to claim 1, characterized in that, The bottom of the large-diameter steel cylinder (1) is flush with the bottom of the negative pressure sinking skirt chamber; the top of the large-diameter steel cylinder (1) is flush with or higher than the top of the negative pressure sinking skirt chamber, but the top of the negative pressure sinking skirt chamber must be flush with the mud surface.

3. The large-diameter cylindrical combined foundation for the negative pressure sinking skirt chamber according to claim 1, characterized in that, The bottom burial depth of the large-diameter steel cylinder (1) is greater than the bottom burial depth of the negative pressure sinking skirt chamber. The top of the large-diameter steel cylinder (1) is flush with or higher than the top of the negative pressure sinking skirt chamber, but the top of the negative pressure sinking skirt chamber must be flush with the mud surface. The bottom of the large-diameter steel cylinder (1) extends beyond the bottom of the negative pressure sinking skirt chamber by a certain length. Determined by the following formula: in, The diameter of the large-diameter steel cylinder (1); The underwater self-weight of the large-diameter cylindrical composite foundation of the negative pressure sinking skirt chamber; and The depth of each layer of foundation soil and the ultimate side friction resistance are respectively determined when the top of the negative pressure sinking skirt chamber is flush with the mud surface, and the bottom of the large diameter steel cylinder (1) is embedded in the soil.

4. The large-diameter cylindrical combined foundation for the negative pressure sinking skirt chamber according to claim 3, characterized in that, A sealing cylinder cover (11) is provided on the top of the large-diameter steel cylinder (1). The top of the large-diameter steel cylinder (1) is flush with the top of the negative pressure sinking skirt chamber. The height of the large-diameter steel cylinder (1) is greater than or equal to the height of the negative pressure sinking skirt chamber. Several one-way drainage holes (53) are provided on the sealing cylinder cover (11) as a natural drainage channel for the water inside the large-diameter steel cylinder (1). Its total drainage capacity per unit time is higher than the negative pressure drainage capacity of all negative pressure sinking skirt chambers. A one-way valve (54) is provided at the center of the sealing cylinder cover (11) as a negative pressure drainage channel for the water inside the large-diameter steel cylinder (1). The one-way valve (54) is connected to the negative pressure system through a negative pressure pipeline.

5. A sinking method for a large-diameter cylindrical composite foundation with a negative pressure sinking skirt chamber as described in any one of claims 1 to 3, characterized in that, include: (1) Open all one-way valves (51) of the skirt cabins, and slowly lower the large-diameter cylindrical composite foundation of the negative pressure-assisted sinking skirt cabins through the hoisting equipment until it can no longer sink naturally; (2) Connect the one-way valve (51) of each skirt compartment to the negative pressure system through the negative pressure pipeline, start the negative pressure system, and simultaneously extract the water in each negative pressure sinking skirt compartment to keep the negative pressure in each negative pressure sinking skirt compartment consistent, so as to realize the negative pressure sinking skirt compartment driving the large diameter steel cylinder (1) to sink. (3) After the large-diameter cylindrical combined foundation of the negative pressure sinking skirt cabin is sunk to the design depth, close all one-way valves (51) of the skirt cabin and remove all negative pressure pipes.

6. A sinking method for a large-diameter cylindrical composite foundation with a negative pressure sinking skirt chamber as described in claim 4, characterized in that, include: (1) Open all one-way valves (51), one-way drainage holes (53) and one-way valves (54) of the sleeve cabin, and slowly lower the large-diameter cylindrical composite foundation of the negative pressure-assisted sinking skirt cabin through the hoisting equipment until it can no longer sink naturally; (2) Connect the one-way valve (51) of each skirt compartment to the negative pressure system through the negative pressure pipeline, start the negative pressure system, and simultaneously extract the water in each negative pressure sinking skirt compartment to keep the negative pressure in each negative pressure sinking skirt compartment consistent, so as to realize the negative pressure sinking skirt compartment driving the large diameter steel cylinder (1) to sink. (3) After the large-diameter cylindrical composite foundation of the negative pressure sinking skirt chamber is sunk to the design depth, close all one-way valves (51) of the skirt chamber and remove all negative pressure pipes connected to the one-way valves (51) of the skirt chamber; close the one-way drainage hole (53) of the cylinder cover, connect the one-way valve (54) of the cylinder cover to the negative pressure system through the negative pressure pipe, start the negative pressure system, so that a negative pressure environment is formed inside the large-diameter steel cylinder (1), so that the large-diameter steel cylinder (1) and the soil inside the cylinder are in close contact under the action of negative pressure until the negative pressure value of the negative pressure system changes drastically and the operation is stopped. (4) Close the one-way valve (54) of the cylinder cover and remove the negative pressure pipe connected to the one-way valve (54) of the cylinder cover.

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