Seaborne booster station jacket anti-sinking structure and construction method

Abstract

The invention relates to an offshore booster station jacket anti-sinking structure and a construction method.The anti-sinking structure comprises an anti-sinking plate, an upper apron board and a lower apron board, an outer sleeve is fixed to the anti-sinking plate, a conical connecting section is fixedly arranged at the top end of the outer sleeve, and a plurality of pile clamping devices are evenly arranged on the upper portion of the outer sleeve in the circumferential direction; a shear plate is arranged between the outer sleeve and the jacket leg; and an upper yoke plate and a lower yoke plate are arranged between the outer sleeve and the jacket legs. The lower apron board is arranged at the bottom of the anti-settling plate, the mud entering depth of the structure is effectively increased, and therefore the vertical bearing capacity and the horizontal anti-sliding and anti-overturning capacity of the jacket are remarkably improved; an upper apron board is arranged at the top of the anti-settling plate, and the anti-settling plate and the upper apron board jointly form a box body structure with an upward opening. The ballasts filled in the box body not only can assist in entering mud when the jacket sinks by dead weight and does not reach the designed depth, but also can realize leveling and deviation correction of the jacket by adjusting the weights of the ballasts in the box body at different positions.

Description

Technical Field

[0001] The present invention relates to the field of offshore wind power infrastructure, and particularly to an anti-settlement structure and construction method for a jacket of an offshore substation. Background Art

[0002] An offshore substation is a substation set up in an offshore wind farm, where the electric energy generated by all wind turbines is collected again, stepped up in voltage, and then connected to the onshore power grid through submarine cables. As China enters the stage of large-scale development of offshore wind power, the development and construction of offshore wind farms with a long offshore distance and a large capacity all require the setting up of offshore substations. An offshore substation generally includes an upper module and a lower foundation. The upper module is an integration of power transmission and transformation equipment, and its core components are transformers and switches. The lower foundation has various structural forms such as monopile foundations, high-piled cap foundations, and jacket foundations. The jacket foundation is the most commonly used foundation form for large offshore substations, which is divided into foundation steel pipe piles and jacket modules. The steel pipe piles and the jacket are connected by grouting. According to the different construction sequences of the jacket and the steel pipe piles, the jacket foundation is divided into the pre-pile type jacket and the post-pile type jacket. The post-pile type jacket is the currently more commonly used foundation form, and its general construction process is to first sink the main structure of the jacket in place on the seabed mud surface, and then carry out construction operations such as pile insertion, pile driving, and grouting combination. After the concrete reaches the design strength, the upper module is hoisted.

[0003] As the core power transmission and transformation facility of an offshore wind farm, according to relevant code requirements, it should be ensured that the first-floor deck does not take in water under extreme wind and wave conditions once in a hundred years. Therefore, the elevation of the foundation top must meet the design requirements. The jacket foundation of an offshore substation is usually huge in size, with its bottom length and width usually exceeding 30 meters and its height exceeding 50 meters, and the total weight is generally between 1,000 and 3,000 tons. When the jacket is sunk to the seabed mud surface, if the bearing capacity of the mud surface is insufficient, the jacket foundation may sink or settle unevenly during the installation process, which will pose a major potential risk to the subsequent pile driving operation and the installation of the upper module.

[0004] In order to solve the above problems, the prior art usually sets an anti-sinking plate at the bottom of the jacket to increase its contact area with the mud surface, thereby reducing the pressure on the mud surface and reducing settlement. However, for deep sea areas, the seabed geology is relatively complex, and the seabed surface often has thick floating mud and silty soft soil layers with extremely limited bearing capacity. Under such geological conditions, if the traditional anti-sinking plate design is adopted, it is necessary to increase the plane size of the anti-sinking plate to ensure the safety requirements of the jacket before piling. However, this approach has the following disadvantages: (1) The difficulty of jacket leveling and deviation correction increases, and the construction quality risk increases; (2) The installation weight of the jacket increases, and the amount of steel engineering increases; (3) It puts forward higher requirements for the selection of construction equipment, such as the need for larger tonnage transport ships and crane ships, which directly leads to an increase in project costs; (4) The traditional anti-sinking plate is in plane contact with the seabed mud surface and cannot effectively constrain the lateral displacement of the soil. Therefore, even if the size is increased, its anti-slip and anti-overturning capabilities cannot be significantly improved. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an offshore booster station jacket anti-sinking structure and construction method. The anti-sinking structure has simple design, convenient construction and low cost, can effectively reduce the settlement of the jacket during construction, and significantly improve its anti-slip and anti-overturning capabilities, thereby ensuring the stability of the offshore booster station jacket after sinking into place.

[0006] The technical solution adopted by the present invention is: an offshore booster station jacket anti-sinking structure, characterized in that: it includes an anti-sinking plate, an upper skirt plate and a lower skirt plate, the lower skirt plate is arranged at the bottom of the anti-sinking plate, and each skirt plate is arranged in a one-to-one correspondence with the bottom edge of the anti-sinking plate; an upper skirt plate is arranged on the top of the anti-sinking plate, and each skirt plate is arranged in a one-to-one correspondence with the top edge of the anti-sinking plate;

[0007] An outer sleeve is fixed on the anti-sinking plate, a conical connecting section is fixedly arranged on the top of the outer sleeve, a plurality of pile clamps are evenly arranged along the circumferential direction on the upper part of the outer sleeve, a shear plate is arranged between the outer sleeve and the conductor frame leg; an upper yoke plate and a lower yoke plate are arranged between the outer sleeve and the conductor frame leg, the upper yoke plate and the lower yoke plate are penetrated by the outer sleeve and the conductor frame leg, and the penetration position is fixedly connected; the upper yoke plate and the lower yoke plate are fixedly connected to the shear plate.

[0008] Preferably, the anti-sinking plate is a regular polygon or a circle and is made of steel.

[0009] Preferably, a plurality of drainage holes are provided on the anti-sinking plate to effectively reduce the launching resistance during the sinking process and the buoyancy force after being in place; in order to ensure the vertical bearing capacity of the anti-sinking plate, the punching rate of the drainage holes is controlled to be less than 10%.

[0010] Preferably, the conductor frame legs, outer sleeve and shear plates are all welded and fixed to the anti-sinking plates.

[0011] Preferably, a plurality of drain holes are formed in the side wall of the upper skirt plate. The opening positions are located at the upper part and arranged in two rows, and the shape is a chamfered rectangle. The drain holes are formed at the upper part to achieve a wave dissipation effect, thereby reducing the wave force on the anti-settlement structure.

[0012] Preferably, the top edges of the upper skirt plate and the anti-settlement plate are connected by shear studs.

[0013] Preferably, the upper skirt plate and the anti-settlement plate form a box with an upward opening, and concrete counterweights are arranged inside the box.

[0014] Preferably, the outer sleeve is a steel pipe structure, and the height of the shear plate is the same as the height of the outer sleeve.

[0015] A construction method for the anti-settlement structure of the jacket of an offshore substation as described above, characterized in that it includes the following steps:

[0016] S1. First, conduct seabed sounding and leveling treatment; after the crane ship anchors and positions, place the jacket at the predetermined position and let it sink into the mud by its own weight.

[0017] S2. Use an underwater robot to observe the mud entry state of the steel lower skirt plate. If the steel lower skirt plate has completely entered the mud, it means that the sinking and positioning have been completed; if the design depth has not been reached, ballast needs to be applied in the box to assist its mud entry.

[0018] S3. If the elevations of the legs are inconsistent when the jacket sinks, the leveling and deviation correction can be carried out by adjusting the weight and distribution of the ballast to ensure the overall level and stability of the jacket.

[0019] S4. After the jacket sinks and is positioned, carry out the subsequent pile driving operation construction process.

[0020] S5. After pile driving, carry out underwater grouting operation for the connection section between the jacket and the pile foundation through a grouting ship to combine the steel pipe pile and the anti-settlement structure. The anti-settlement structure and the pile foundation form a synergistic effect. The pile foundation provides deep support for the jacket, and the anti-settlement structure transfers the load of the jacket to the pile foundation, further improving the vertical bearing capacity and horizontal anti-slip and anti-overturning capabilities of the jacket.

[0021] Preferably, the specific steps of S3 are as follows:

[0022] S31. Real-time monitor the elevation difference: During the sinking process, use an underwater robot or other monitoring equipment to accurately measure the sinking depth of each leg; if the elevations are inconsistent, it means that the jacket may be tilted or offset.

[0023] S32. Adjust the weight and distribution of ballast: By adding or reducing ballast at specific positions inside the jacket box body, the area with increased weight will sink further, thereby adjusting the tilt angle of the jacket to achieve leveling; precisely control the sinking speed in each direction.

[0024] S33. Repeat measurement and fine-tuning: After adjusting the ballast, continue to monitor the elevation difference of the pile legs and perform multiple fine-tunings until the heights of all pile legs meet the design requirements to ensure that the jacket is in a horizontal state.

[0025] The beneficial effects achieved by the present invention are as follows:

[0026] (1) A steel lower skirt plate is provided at the bottom of the anti-settlement plate, effectively increasing the penetration depth of the structure into the mud, thereby significantly enhancing the vertical bearing capacity of the jacket and its horizontal anti-slip and anti-overturning capabilities;

[0027] (2) A reinforced concrete upper skirt plate is provided at the top of the anti-settlement plate. The anti-settlement plate and the upper skirt plate together form a box structure with an upward opening. The ballast filled inside the box can not only assist in mud penetration when the self-weight settlement of the jacket does not reach the design depth, but also achieve leveling and deviation correction of the jacket by adjusting the weight of the ballast in different positions of the box;

[0028] (3) The ballast in this box can further enhance the anti-overturning and anti-scouring capabilities of the jacket after it is in place; the ballast can be selected from block materials such as concrete blocks, or bulk materials such as sand, stones, and iron ore. The material cost is low and it has high economic efficiency. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the embodiment of the present invention in the jacket structure;

[0030] Figure 2 It is a schematic diagram of the outer sleeve of the embodiment of the present invention;

[0031] Figure 3 It is a top view of the anti-settlement structure of the embodiment of the present invention;

[0032] Figure 4 It is a bottom view of the anti-settlement structure of the embodiment of the present invention;

[0033] Figure 5 It is a front view of the anti-settlement structure of the embodiment of the present invention;

[0034] Among them: 1. Jacket main structure; 11. Jacket leg; 2. Outer sleeve; 21. Conical connection section; 22. Pile gripper; 23. Shear plate; 24. Upper (lower) yoke plate; 3. Anti-settlement structure; 31. Anti-settlement plate; 311. Drainage hole; 312. Outer sleeve interface; 32. Lower skirt plate; 33. Upper skirt plate; 331. Drainage hole; 34. Counterweight. Detailed implementation mode

[0035] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0036] As Figures 1-5 shown, an anti-settlement structure for the jacket of an offshore booster station applicable to a silty soft soil foundation includes an anti-settlement plate 31, an upper skirt plate 33 (reinforced concrete), and a lower skirt plate 32 (steel). In this embodiment, a four-leg jacket is taken as an example, and the number of anti-settlement structures is 4, which are respectively arranged at the lower part of the jacket pile legs 11, and each anti-settlement structure is arranged corresponding to the corresponding leg one by one.

[0037] An outer sleeve 2 is fixed on the anti-settlement plate 31, which is a steel pipe structure. A conical connection section 21 is arranged at the top of the outer sleeve, and the outer sleeve 2 and the conical connection section 21 are connected by welding. Eight pile grippers (22) are arranged along the circumferential direction on the upper part of the outer sleeve 2 to fix the internal pile body. A shear plate 23 is arranged between the outer sleeve 2 and the jacket leg 11, and the height of the shear plate 23 is the same as that of the outer sleeve 2. The shear plate 23 is connected to the outer sleeve 2 and the jacket leg 11 by welding. In addition, upper and lower yoke plates 24 are arranged between the outer sleeve 2 and the jacket leg 11, and the upper and lower yoke plates 24 are penetrated by the outer sleeve 2 and the jacket leg 11, and the penetrated positions are connected by welding. The upper and lower yoke plates 24 are also connected to the shear plate 23 by welding to ensure the safe and reliable force of the structure.

[0038] In this embodiment, the anti-settlement plate 31 is square and made of high-strength steel. A number of drainage holes 311 are opened on the anti-settlement plate 31 to reduce the water resistance during the sinking process of the jacket. The jacket leg 11, the outer sleeve 2, and the shear plate 23 are all connected to the anti-settlement plate 31 by welding.

[0039] In this embodiment, three steel lower skirt plates 32 are arranged at the bottom of the anti-settlement plate 31, and each skirt plate is arranged corresponding to the four sides of the bottom of the anti-settlement plate 31 one by one. The length of the steel lower skirt plate 32 is comprehensively determined by the thickness of the silty soft soil layer in the construction sea area and the size of the anti-settlement plate, and at the same time, the buckling resistance requirement needs to be met. The steel lower skirt plate 32 and the bottom edge of the anti-settlement plate 31 are connected by welding.

[0040] In this embodiment, four reinforced concrete upper skirt plates 33 are provided on the top of the anti-settlement plate 31, and each skirt plate is arranged corresponding to the four sides of the top of the anti-settlement plate 31 one by one. A number of drain holes 331 are opened on the side wall of the reinforced concrete upper skirt plate 33, and the opening positions are located at the upper part and arranged in two rows. The shape is a chamfered rectangle. This design helps to reduce the lateral water resistance during the sinking process of the jacket, improves the controllability and stability of the jacket sinking, and at the same time achieves a wave-dissipating effect after the jacket sinks, reducing the wave force on the foundation. The reinforced concrete upper skirt plate 33 and the top edge of the anti-settlement plate 31 are connected by shear studs.

[0041] In this embodiment, the reinforced concrete upper skirt plate 33 and the anti-settlement plate 31 form a box with an upward opening, and a concrete counterweight 34 is provided inside the box.

[0042] The construction method of the anti-settlement structure of the offshore substation jacket applicable to the silty soft soil foundation provided by the present invention includes the following steps:

[0043] (1) First, conduct seabed sounding and leveling. After the crane ship anchors and positions, place the jacket at the predetermined position and let it sink into the mud by its own weight.

[0044] (2) Use an underwater robot to observe the mud entry state of the steel lower skirt plate. If the steel lower skirt plate has completely entered the mud, it means that the sinking in place has been completed; if it has not reached the design depth, ballast needs to be applied inside the box to assist its entry into the mud.

[0045] (3) If the elevations of the legs are inconsistent when the jacket sinks, leveling and deviation correction can be carried out by adjusting the weight and distribution of the ballast to ensure the overall level and stability of the jacket. The specific steps are as follows.

[0046] a) Real-time monitor the elevation difference: During the sinking process, use an underwater robot or other monitoring equipment to accurately measure the sinking depth of each leg. If the elevations are inconsistent, it indicates that the jacket may be tilted or offset.

[0047] b) Adjust the weight and distribution of the ballast: By adding or reducing ballast at specific positions inside the jacket box, the area with increased weight will sink further, thereby adjusting the tilt angle of the jacket to achieve leveling. This method can accurately control the sinking speed in all directions.

[0048] c) Repeat measurement and fine-tuning: After adjusting the ballast, continue to monitor the elevation difference of the legs and perform multiple fine-tunings until the heights of all legs meet the design requirements to ensure that the jacket is in a horizontal state.

[0049] (4) After the jacket sinks in place, carry out the subsequent piling operation construction process.

[0050] After pile driving is completed, underwater grouting operations for the connection section between the jacket and the pile foundation are carried out by a grouting vessel to combine the steel pipe piles and the anti-settlement structure. The anti-settlement structure and the pile foundation form a synergistic effect. The pile foundation provides deep support for the jacket, and the anti-settlement structure transfers the load of the jacket to the pile foundation, further enhancing the vertical bearing capacity of the jacket and its horizontal anti-slip and anti-overturning capabilities.

[0051] This anti-settlement structure has fewer construction processes, a simple process flow, is easy to operate, and has low construction risks.

[0052] Here, it should be noted that the description of the above technical solution is exemplary. This specification can be embodied in different forms and should not be construed as limited to the technical solution described herein. On the contrary, providing these descriptions will make the disclosure of the present invention thorough and complete, and will fully convey the scope disclosed in this specification to those skilled in the art. In addition, the technical solution of the present invention is only limited by the scope of the claims.

[0053] Finally, it should be pointed out that the above embodiments are only relatively representative examples of the present invention. Obviously, the present invention is not limited to the above embodiments and there can be many variations. Any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention should be considered to fall within the protection scope of the present invention.

Claims

1. An anti-settlement structure for the jacket of an offshore booster station, characterized in that: It includes a sinker plate (31), an upper skirt plate (33) and a lower skirt plate (32). The lower skirt plate (32) is arranged at the bottom of the sinker plate (31), and each skirt plate is arranged corresponding to the bottom edge of the sinker plate (31) one by one; the upper skirt plate (33) is arranged at the top of the sinker plate (31), and each skirt plate is arranged corresponding to the top edge of the sinker plate (31) one by one. An outer sleeve (2) is fixed on the sinker plate. A conical connection section (21) is fixedly arranged at the top end of the outer sleeve. A plurality of pile grippers (22) are uniformly arranged along the circumferential direction on the upper part of the outer sleeve (2). A shear plate (23) is arranged between the outer sleeve (2) and the jacket leg (11); an upper yoke plate and a lower yoke plate are arranged between the outer sleeve (2) and the jacket leg (11). The upper yoke plate and the lower yoke plate are penetrated by the outer sleeve (2) and the jacket leg (11), and the penetrated positions are fixedly connected; the upper yoke plate and the lower yoke plate are fixedly connected with the shear plate (23).

2. The anti-settlement structure of the jacket of the offshore booster station according to claim 1, characterized in that: The sinker plate (31) is a regular polygon or a circle and is made of profiled steel.

3. The anti-settlement structure of the jacket of the offshore booster station according to claim 2, wherein: Drainage holes (311) are opened on the sinker plate (31).

4. The anti-settlement structure of the jacket of the offshore booster station according to claim 1, wherein: The jacket leg (11), the outer sleeve (2) and the shear plate (23) are all fixedly welded to the sinker plate (31).

5. The anti-settlement structure of the offshore substation jacket according to claim 1, characterized in that: Drainage holes (331) are opened on the side wall of the upper skirt plate (33), and the opening positions are located at the upper part, arranged in two rows, and the shape is a chamfered rectangle.

6. The anti-settlement structure of the offshore substation jacket according to claim 1, characterized in that: The upper skirt plate (33) and the top edge of the sinker plate (31) are connected by shear studs.

7. The anti-settlement structure of the jacket of the offshore booster station according to claim 1, characterized in that: The upper skirt plate (33) and the sinker plate (31) form a box with an upward opening, and a concrete counterweight block (34) is arranged inside the box.

8. The anti-settlement structure of the offshore substation jacket according to claim 1, wherein: The outer sleeve is a steel pipe structure, and the height of the shear plate (23) is the same as the height of the outer sleeve (2).

9. A construction method for the anti-settlement structure of the jacket of an offshore booster station as described in any one of claims 1 to 8, characterized in that: It includes the following steps: S1. First, conduct seabed sounding and leveling treatment; after the crane barge anchors and positions, place the jacket at the predetermined position and let it sink into the mud by its own weight. S2. Use an underwater robot to observe the mud entry state of the steel lower skirt plate. If the steel lower skirt plate has completely entered the mud, it means that the sinking and positioning have been completed; if the designed depth is not reached, ballast needs to be applied in the box to assist it in entering the mud. S3. If the elevations of each pile leg are inconsistent when the jacket sinks, leveling and deviation correction can be carried out by adjusting the weight and distribution of the ballast to ensure the overall level and stability of the jacket. S4. After the jacket sinks and is in place, carry out the subsequent pile driving operation construction process. S5. After pile driving is completed, carry out the underwater grouting operation of the connection section between the jacket and the pile foundation by a grouting barge to combine the steel pipe pile and the anti-settlement structure. The anti-settlement structure and the pile foundation form a synergistic effect. The pile foundation provides deep support for the jacket, and the anti-settlement structure transfers the load of the jacket to the pile foundation, further improving the vertical bearing capacity and horizontal anti-slip and anti-overturning capabilities of the jacket.

10. The construction method of the anti-settlement structure of the offshore substation jacket according to claim 9, characterized in that: The specific steps of S3 are: S31. Real-time monitor the elevation difference: During the sinking process, use an underwater robot or other monitoring equipment to accurately measure the sinking depth of each pile leg; if the elevations are found to be inconsistent, it means that the jacket may be tilted or deviated. S32. Adjust the weight and distribution of ballast: By adding or reducing ballast at specific positions inside the jacket box, the area with increased weight will sink further, thereby adjusting the tilt angle of the jacket to achieve leveling; precisely control the sinking speed in all directions. S33. Repeat measurement and fine-tuning: After adjusting the ballast, continue to monitor the elevation difference of the legs, and perform multiple fine-tuning operations until the height of each leg meets the design requirements to ensure that the jacket is in a horizontal state.

Images