A double-shell single pile foundation for offshore wind turbines and its installation method

Abstract

The present invention discloses a double-shell single pile foundation for an offshore wind turbine and an installation method thereof, the foundation comprising an outer shell, an inner shell, annular ribs, longitudinal ribs, a pile top flange and blade-type longitudinal ribs; the inner shell is arranged inside the outer shell, and a preset gap is maintained between the inner shell and the outer shell to form a pile body, the top of the inner shell is preset with a pile cap for placing a pile hammer, the pile top flange is arranged on the top of the pile body, a plurality of annular ribs and longitudinal ribs are arranged in the gap in sequence from top to bottom to form a plurality of watertight compartments for filling concrete or seawater, and the blade-type longitudinal ribs are arranged at the bottom of the pile body; the present invention breaks through the limitation of the ratio of the diameter to the wall thickness of a circular hollow cross-section, and for a single pile with an extra-large diameter, a plate with a smaller thickness can be used, which effectively reduces the weight of the single pile and improves the economy; the friendliness of the manufacturing process and the offshore construction process is taken into consideration, the dependence on construction resources is reduced, and it is conducive to mass implementation.

Description

Technical Field

[0001] The present invention relates to the technical field of offshore wind turbine monopile foundations, and in particular to an offshore wind turbine double-shell monopile foundation and an installation method thereof. Background Art

[0002] With the trend of large-scale offshore wind turbines and deeper waters in offshore wind farms, the diameter of single piles is getting bigger, their length is getting longer, and their weight is getting heavier. Therefore, in the design and construction process of single piles, more factors need to be considered and paid attention to, such as the ratio of the diameter to the wall thickness of the circular hollow section, the natural frequency of the single pile, the limitation of existing construction resources, the requirements of economical parity, and other factors.

[0003] The present invention aims to overcome the shortcomings of the existing design and construction of single pile foundations, and proposes a double-shell single pile foundation for offshore wind turbines suitable for deeper water depths and an installation method thereof. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies in the prior art and provide a double-shell single pile foundation for an offshore wind turbine and an installation method thereof. The pile body is formed by maintaining a preset gap between an inner and outer shell body, and the gap between the inner and outer shell body is provided with annular ribs and longitudinal ribs to form a plurality of watertight compartments for filling with concrete or seawater to resist external water pressure or soil pressure; the limitation of the ratio of the diameter to the wall thickness of the circular hollow cross-section is broken through, the weight of the single pile is effectively reduced, and the economy is improved.

[0005] To achieve the above-mentioned purpose, the technical solution provided by the present invention is: a double-shell single pile foundation for an offshore wind turbine, comprising an outer shell, an inner shell, annular ribs, longitudinal ribs, a pile top flange and blade-type longitudinal ribs; the inner shell is arranged inside the outer shell, and a preset gap is maintained between the inner shell and the outer shell to form a pile body, a pile cap for placing a pile hammer is preset at the top of the inner shell, the pile top flange is arranged on the top of the pile body, a plurality of annular ribs and longitudinal ribs are arranged in the gap in sequence from top to bottom to form a plurality of watertight compartments for filling concrete or seawater, and the blade-type longitudinal ribs are arranged at the bottom of the pile body.

[0006] Furthermore, it also includes a lifting lug; the lifting lug is installed on the outside of the pile body and is located in the middle part of the pile body.

[0007] Furthermore, it also includes a boat anchoring member; the boat anchoring member is installed on the outside of the pile body and close to the top of the pile body.

[0008] The installation method of the above-mentioned offshore wind turbine double-shell single pile foundation provided by the present invention comprises the following steps:

[0009] 1) Prefabricate the double-hull single pile foundation of offshore wind turbines in sections;

[0010] 2) All the sections of the double-hull single pile foundation of the offshore wind turbine are butt-jointed and assembled to form multiple watertight compartments inside the double-hull single pile foundation of the offshore wind turbine, and the watertight compartments are tested for airtightness;

[0011] 3) If the tightness of the watertight compartment is confirmed to be qualified, the assembled offshore wind turbine double-hull single pile foundation will be placed in the seawater to make the offshore wind turbine double-hull single pile foundation float on the sea; if the tightness of the watertight compartment is confirmed to be unqualified, the assembled offshore wind turbine double-hull single pile foundation will be repaired until the tightness test of the watertight compartment is qualified;

[0012] 4) Use an offshore tugboat to tow the double-hull single pile foundation of the offshore wind turbine to the offshore installation site;

[0013] 5) After the double-hull single pile foundation of the offshore wind turbine arrives at the offshore installation site, straighten the double-hull single pile foundation of the offshore wind turbine and mark the position;

[0014] 6) Place a pile hammer at the pile cap of the double-hull single pile foundation of the offshore wind turbine to carry out piling operations until the pile is driven to the preset elevation, completing the installation of the entire double-hull single pile foundation of the offshore wind turbine.

[0015] Further, in step 1), the following operations are specifically performed:

[0016] The double-hull single pile foundation of the offshore wind turbine is prefabricated in sections, and the pile top flange is pre-installed on the sections at the top part of the double-hull single pile foundation of the offshore wind turbine, and all sections are pre-protected.

[0017] Further, in step 2), the following operations are specifically performed:

[0018] All the sections of the double-hull single pile foundation of the offshore wind turbine are placed horizontally in the dock or on the pier and then butt-jointed and assembled to form multiple watertight compartments inside the double-hull single pile foundation of the offshore wind turbine, and the watertight compartments are subjected to a tightness test.

[0019] Further, in step 3), the following operations are specifically performed:

[0020] If the tightness of the watertight compartment is confirmed to be qualified, water will be injected into the dock to make the entire offshore wind turbine double-hull single pile foundation float; or a crane will be used on the dock to place the entire offshore wind turbine double-hull single pile foundation into the sea water to make the entire offshore wind turbine double-hull single pile foundation float; if the tightness of the watertight compartment is confirmed to be unqualified, the assembled offshore wind turbine double-hull single pile foundation will need to be repaired until the tightness test of the watertight compartment is qualified.

[0021] Further, in step 5), the following operations are specifically performed:

[0022] After the entire offshore wind turbine double-hull monopile foundation arrives at the offshore installation site, concrete or seawater is filled in the watertight compartment of the offshore wind turbine double-hull monopile foundation to make it automatically straighten, or a small crane is directly used to straighten the offshore wind turbine double-hull monopile foundation and position the offshore wind turbine double-hull monopile foundation.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1. The present invention breaks through the limitation of the ratio of diameter to wall thickness of the circular hollow cross section. For a single pile with an ultra-large diameter, a plate with a smaller thickness can be used, which effectively reduces the weight of the single pile and improves economic efficiency;

[0025] 2. Considering the friendliness of the manufacturing process and offshore construction process, when the foundation segments are placed horizontally during the manufacturing process, the deformation of the segments is smaller, which is conducive to docking. At the same time, the gap between the inner shell and the outer shell is used as a watertight compartment to provide buoyancy, that is, the foundation can float by itself and be towed to the installation sea area by a tugboat; reducing the dependence on construction resources, which is conducive to mass implementation;

[0026] 3. The present invention makes full use of seawater and concrete as fillers of the watertight compartment, changes the natural frequency of the single pile foundation, keeps away from the main frequency of the wind turbine, and avoids the occurrence of resonance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the structural longitudinal section of the double-hull single pile foundation of an offshore wind turbine.

[0028] Figure 2 This is one of the structural transverse sections of the double-hull single pile foundation of an offshore wind turbine.

[0029] Figure 3 This is the second structural transverse section view of the double-hull single pile foundation of an offshore wind turbine.

[0030] Figure 4 This is a structural cross-section diagram of the connection between the double-shell single pile foundation of an offshore wind turbine and the wind turbine tower.

[0031] Figure 5 This is a longitudinal cross-section of the floating structure of an offshore wind turbine with double hull and single pile foundation.

[0032] Figure 6 This is a transverse cross-sectional view of the floating structure of an offshore wind turbine with double hull and single pile foundation. DETAILED DESCRIPTION

[0033] The present invention will be further described below in conjunction with specific embodiments.

[0034] See also Figures 1 to 3As shown, the double-shell single pile foundation of the offshore wind turbine provided in this embodiment includes an outer shell 1, an inner shell 2, a ring rib 3, a longitudinal rib 4, a pile top flange 5, a blade-type longitudinal rib 7, a lifting lug 9 and a ship-mooring member 10;

[0035] The inner shell 2 is arranged inside the outer shell 1, and a preset gap is maintained between the inner shell 2 and the outer shell 1 to form a pile body. A pile cap 6 for placing a pile hammer 11 is preset at the top of the inner shell 2. The pile top flange 5 is arranged on the top of the pile body. A plurality of the annular ribs 3 and the longitudinal ribs 4 are arranged in the gap in sequence from top to bottom to form a plurality of watertight compartments 8 for filling concrete or seawater. The blade-type longitudinal ribs 7 are arranged at the bottom end of the pile body. The lifting lugs 9 are installed on the outside of the pile body and are located in the middle part of the pile body. The ship-supporting member 10 is installed on the outside of the pile body and close to the top of the pile body.

[0036] See also Figure 4 As shown, the pile top flange 5 of the double-shell single pile foundation of the offshore wind turbine can be connected to the foundation flange 13 at the bottom end of the tower 12 .

[0037] See also Figure 5 to Figure 6 As shown, the following is a method for installing a double-hull single pile foundation of an offshore wind turbine provided in this embodiment, comprising the following steps:

[0038] 1) Prefabricate the double-hull single pile foundation of the offshore wind turbine in sections, and perform the following operations:

[0039] The double-hull single pile foundation of the offshore wind turbine is prefabricated in sections, and the pile top flange is pre-installed on the sections at the top part of the double-hull single pile foundation of the offshore wind turbine, and all sections are pre-protected.

[0040] 2) All the sections of the double-hull single pile foundation of the offshore wind turbine are butt-jointed and assembled to form multiple watertight compartments inside the double-hull single pile foundation of the offshore wind turbine. The watertight compartments are tested for tightness. The specific operations are as follows:

[0041] All the sections of the double-hull monopile foundation of the offshore wind turbine are placed horizontally in the dock or on the pier, and then docked and assembled to form multiple watertight compartments inside the double-hull monopile foundation of the offshore wind turbine, and the watertight compartments are tested for tightness;

[0042] 3) If the tightness of the watertight compartment is confirmed to be qualified, the assembled offshore wind turbine double-hull single pile foundation will be placed in the seawater to make the offshore wind turbine double-hull single pile foundation float on the sea; if the tightness of the watertight compartment is confirmed to be unqualified, the assembled offshore wind turbine double-hull single pile foundation needs to be repaired until the tightness test of the watertight compartment is qualified. The specific operations are as follows:

[0043] If the tightness of the watertight compartment is confirmed to be qualified, water is injected into the dock to make the entire offshore wind turbine double-hull single pile foundation float; or a crane is used on the dock to put the entire offshore wind turbine double-hull single pile foundation into the seawater to make the entire offshore wind turbine double-hull single pile foundation float; if the tightness of the watertight compartment is confirmed to be unqualified, the assembled offshore wind turbine double-hull single pile foundation needs to be repaired until the tightness test of the watertight compartment is qualified; in addition, if it has been put into use at sea, if one of the watertight compartments is damaged and water is infiltrated, it can still meet the requirements of foundation floating and stability;

[0044] 4) Use an offshore tugboat to tow the double-hull single pile foundation of the offshore wind turbine to the offshore installation site;

[0045] 5) After the double-hull single pile foundation of the offshore wind turbine arrives at the offshore installation site, the double-hull single pile foundation of the offshore wind turbine is straightened and the position is marked. The specific operations are as follows:

[0046] After the entire offshore wind turbine double-hull monopile foundation arrives at the offshore installation site, fill the watertight compartment of the offshore wind turbine double-hull monopile foundation with concrete or seawater to make it automatically straighten, or directly use a small crane to straighten the offshore wind turbine double-hull monopile foundation and position the offshore wind turbine double-hull monopile foundation;

[0047] 6) Place a pile hammer at the pile cap of the double-hull single pile foundation of the offshore wind turbine to carry out piling operations until the pile is driven to the preset elevation, completing the installation of the entire double-hull single pile foundation of the offshore wind turbine.

[0048] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are covered by the protection scope of the present invention.

Claims

1. A method for installing a double-hull single pile foundation of an offshore wind turbine, characterized in that: The double-shell single pile foundation of an offshore wind turbine comprises an outer shell, an inner shell, annular ribs, longitudinal ribs, a pile top flange, a blade-type longitudinal rib, a lifting lug and a ship-mooring member; the inner shell is arranged inside the outer shell, and a preset gap is maintained between the inner shell and the outer shell to form a pile body; a pile cap for placing a pile hammer is preset at the top of the inner shell, and the pile top flange is arranged at the top of the pile body; a plurality of annular ribs and longitudinal ribs are arranged in the gap in sequence from top to bottom to form a plurality of watertight compartments for filling concrete or seawater; the blade-type longitudinal rib is arranged at the bottom end of the pile body; the lifting lug is installed on the outside of the pile body and is located in the middle part of the pile body; the ship-mooring member is installed on the outside of the pile body and close to the top of the pile body; the method comprises the following steps: 1) Prefabricate the double-hull single pile foundation of offshore wind turbines in sections; 2) All the sections of the double-hull single pile foundation of the offshore wind turbine are butt-jointed and assembled to form multiple watertight compartments inside the double-hull single pile foundation of the offshore wind turbine, and the watertight compartments are tested for airtightness; 3) If the tightness of the watertight compartment is confirmed to be qualified, the assembled offshore wind turbine double-hull single pile foundation will be placed in the seawater to make the offshore wind turbine double-hull single pile foundation float on the sea; if the tightness of the watertight compartment is confirmed to be unqualified, the assembled offshore wind turbine double-hull single pile foundation will be repaired until the tightness test of the watertight compartment is qualified; 4) Use an offshore tugboat to tow the double-hull single pile foundation of the offshore wind turbine to the offshore installation site; 5) After the double-hull single pile foundation of the offshore wind turbine arrives at the offshore installation site, straighten the double-hull single pile foundation of the offshore wind turbine and mark the position; 6) Place a pile hammer at the pile cap of the double-hull single pile foundation of the offshore wind turbine to carry out piling operations until the pile is driven to the preset elevation, completing the installation of the entire double-hull single pile foundation of the offshore wind turbine.

2. The installation method of a double-hull single pile foundation of an offshore wind turbine according to claim 1, characterized in that: In step 1), specifically perform the following operations: The double-hull single pile foundation of the offshore wind turbine is prefabricated in sections, and the pile top flange is pre-installed on the sections at the top part of the double-hull single pile foundation of the offshore wind turbine, and all sections are pre-protected.

3. The installation method of a double-hull single pile foundation of an offshore wind turbine according to claim 1, characterized in that: In step 2), specifically perform the following operations: All the sections of the double-hull single pile foundation of the offshore wind turbine are placed horizontally in the dock or on the pier and then butt-jointed and assembled to form multiple watertight compartments inside the double-hull single pile foundation of the offshore wind turbine, and the watertight compartments are subjected to a tightness test.

4. The installation method of a double-hull single pile foundation of an offshore wind turbine according to claim 1, characterized in that: In step 3), specifically perform the following operations: If the tightness of the watertight compartment is confirmed to be qualified, water will be injected into the dock to make the entire offshore wind turbine double-hull single pile foundation float; or a crane will be used on the dock to place the entire offshore wind turbine double-hull single pile foundation into the sea water to make the entire offshore wind turbine double-hull single pile foundation float; if the tightness of the watertight compartment is confirmed to be unqualified, the assembled offshore wind turbine double-hull single pile foundation will need to be repaired until the tightness test of the watertight compartment is qualified.

5. The installation method of a double-hull single pile foundation of an offshore wind turbine according to claim 1, characterized in that: In step 5), specifically perform the following operations: After the entire offshore wind turbine double-hull monopile foundation arrives at the offshore installation site, concrete or seawater is filled in the watertight compartment of the offshore wind turbine double-hull monopile foundation to make it automatically straighten, or a small crane is directly used to straighten the offshore wind turbine double-hull monopile foundation and position the offshore wind turbine double-hull monopile foundation.

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