A multi-barrel combined foundation system for connecting offshore wind power box girders

Abstract

The present invention discloses a multi-barrel combined foundation system for connecting box girders of offshore wind turbines. The structure includes negative pressure suction barrels, a transition section central cylinder, and box-shaped connecting beams. A number of box-shaped connecting beams are circumferentially and equidistantly arranged on the outer side of the transition section central cylinder, and a negative pressure suction barrel is arranged below each box-shaped connecting beam. In view of different water depth conditions and seabed characteristics in complex sea areas of our country, the present invention takes the negative pressure suction barrel tripod foundation as the basic design type, connects the negative pressure suction barrels and large-diameter single pile foundations through box-shaped connecting beams, and improves the overall stiffness and bearing capacity of the foundation by adding a prestressed anchor system. On the premise of meeting the engineering design requirements, a foundation system with convenient construction and low cost is provided, which can be applied to various water depths and seabed conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field related to marine geotechnical engineering and the design of offshore wind turbine foundations, and relates to a multi-barrel combined foundation system for connecting offshore wind power box girders under complex sea area conditions. Aiming at the complex sea area conditions in the coastal waters of China, a set of offshore wind power composite foundation systems applicable to various water depths and seabed conditions is provided. Background Art

[0002] Under the background of increasingly prominent global environmental and energy issues, new renewable energy has been favored by countries around the world. Compared with expensive solar power generation and almost saturated hydropower resources, offshore wind power generation has the advantages of rich resource reserves, stable power generation, and convenient grid connection. Therefore, it has achieved rapid development in recent years. As of 2018, 18.5 GW of offshore wind power has been installed and grid-connected in Europe, including 4,543 wind turbines distributed in 11 countries. At present, offshore wind power in China has basically met the conditions for large-scale development. In the next stage, it is necessary to reduce the construction cost through technological innovation and large-scale development to achieve rapid development.

[0003] However, compared with the uniform dense sandy soil seabed in Europe, the sea area conditions for offshore wind power construction in the coastal waters of China are complex, with large variability in water depth and seabed conditions, posing more challenges to the foundation design of offshore wind power: In the coastal waters of Fujian and Liaoning in China, the buried depth of the submarine bedrock is shallow, and traditional wind power pile foundations require offshore rock socketing construction, with long construction periods, high risks, and high costs; In the coastal waters of Zhejiang, the thickness of the submarine silt layer is deep, the soil bearing capacity is low, and the applicability of large-diameter single pile foundations in the sea is poor; In the coastal waters of Guangdong, the water depth is relatively deep, the waves are large, the tidal current is rapid, and the deformation of the underwater section of the foundation under extreme loads is very significant. In addition, due to the harsh offshore construction conditions, the cost of offshore wind power foundations can account for about 30% of the total project investment. Therefore, providing a new, cheap, convenient, and reliable offshore wind turbine foundation system suitable for the complex sea areas in China has important engineering and economic significance for the construction of offshore wind turbines in China. Summary of the Invention

[0004] Aiming at different water depth conditions and seabed characteristics in the complex sea areas of China, the present invention aims to provide a multi-barrel combined foundation system for connecting offshore wind power box girders that adapts to various water depths and seabed conditions under complex sea area conditions.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A multi-barrel combined foundation system for connecting offshore wind power box girders of the present invention includes a negative pressure suction barrel, a transition section central barrel, and a box-shaped connecting beam. A plurality of box-shaped connecting beams are equidistantly arranged in a circumferential direction on the outer side of the transition section central barrel, and a negative pressure suction barrel is arranged below each box-shaped connecting beam.

[0007] Preferably, the box - shaped coupling beam is internally provided with internal longitudinal partition plates, internal transverse partition plates and internal reinforcing rib plates of the coupling beam. The internal longitudinal partition plates of the coupling beam are vertically arranged along the longitudinal direction of the box - shaped coupling beam. The internal transverse partition plates of the coupling beam are vertically arranged perpendicular to the internal longitudinal partition plates of the coupling beam. The internal reinforcing rib plates of the coupling beam are arranged at the upper and lower edges of the coupling beam.

[0008] Preferably, a top reinforcing plate is arranged between the box - shaped coupling beam and the suction bucket. The bottom surface of the top reinforcing plate is connected to the tops of the suction buckets, and the top surface of the top reinforcing plate is connected to the box - shaped coupling beams. A through - hole for fitting the transition section central cylinder is arranged in the middle of the top reinforcing plate.

[0009] Preferably, the number of the suction buckets and the box - shaped coupling beams is three.

[0010] Preferably, the edge shape of the top reinforcing plate between two adjacent box - shaped coupling beams is an arc - shaped concave inward.

[0011] Preferably, pumping holes are respectively arranged on both sides of the box - shaped cross - beam at the top of the suction bucket.

[0012] Preferably, a prestressed tension anchor is arranged at the end of the box - shaped coupling beam. One end of the prestressed tension anchor is connected to the end of the box - shaped coupling beam far from the transition section central cylinder, and the other end of the prestressed tension anchor is connected to the transition section central cylinder. The horizontal projection of the prestressed tension anchor coincides with the center line of the box - shaped coupling beam.

[0013] Preferably, at least two annular local transverse reinforcing plates are arranged on the inner wall of the transition section central cylinder. Local longitudinal reinforcing ribs are arranged between adjacent local transverse reinforcing plates. The local longitudinal reinforcing ribs are arranged equidistantly around the inner wall of the transition section central cylinder. The position where the prestressed tension anchor is connected to the transition section central cylinder corresponds to the local longitudinal reinforcing ribs.

[0014] Preferably, a lifting ring is arranged outside the transition section central cylinder. The height of the lifting ring is located between two adjacent local transverse reinforcing plates. Local longitudinal reinforcing ribs are arranged at the corresponding position on the inner side of the transition section central cylinder at the position of the lifting ring. A buckle is arranged at the top of the box - shaped coupling beam at the end far from the transition section central cylinder. One end of the prestressed tension anchor is connected to the lifting ring, and the other end is connected to the buckle. A tensiometer is arranged on the prestressed tension anchor.

[0015] Preferably, a single pile is sleeved inside the transition section central cylinder. A number of shear keys inside the cylinder are arranged along the axial direction of the inner wall of the transition section central cylinder. A grouting layer inside the cylinder is poured into the space between the transition section central cylinder and the single pile.

[0016] Combining the common advantages of the negative pressure suction bucket foundation, the prestressed anchor structure, and the large-diameter single-pile foundation, with the negative pressure suction bucket tripod foundation as the basic design form, the negative pressure suction bucket and the large-diameter single-pile foundation are connected through a box-shaped connecting beam, and the overall stiffness and bearing capacity of the foundation are improved by adding a prestressed anchor system. On the premise of meeting the engineering design requirements, a foundation system with convenient construction and low cost is provided, which can be applied to various water depths and seabed conditions. Compared with traditional gravity foundations and jacket foundations, etc., this new type of foundation uses suction installation, avoiding the cumbersome processes such as seabed leveling in gravity foundations and the design and welding of complex joints in jacket foundations, and avoiding pile foundation rock-socketing construction, greatly reducing the offshore construction time and lowering the construction cost.

[0017] The present invention has the following beneficial effects: (1) The structure is reasonably stressed, giving full play to the respective advantages of the negative pressure suction bucket, the steel strand anchor structure, and the single-pile foundation; (2) High economy, applicable to various water depths and seabed conditions; compared with traditional gravity foundations and jacket foundations, etc., the negative pressure suction bucket foundation uses suction installation, avoiding the cumbersome processes such as seabed leveling in gravity foundations and the design and welding of complex joints in jacket foundations, and avoiding pile foundation rock-socketing construction, greatly reducing the construction time and improving the economy of the foundation. At the same time, the negative pressure suction bucket involved in the present invention has an anti-scouring effect on the foundation, which can reduce the anti-scouring protection project quantity; (3) Convenient construction, the group bucket tripod foundation in this patent can use suction installation and serve as a pile-stabilizing device for pile foundation construction, without the need to set up a separate pile-stabilizing platform; (3) The composite foundation composed of the negative pressure suction bucket and the top reinforcement plate in this patent can be recovered by backpressure and reused, greatly reducing the project cost, and the construction quality is controllable, with great engineering significance; (5) The structural components are shared among various foundation forms in this patent, and the foundation can be modularly designed and processed, greatly reducing the foundation design cost and construction period. Description of the Drawings

[0018] Figure 1 It is a top view of Embodiment 1 of the present invention.

[0019] Figure 2 It is a side view of Embodiment 1 of the present invention.

[0020] Figure 3 It is a schematic diagram of the installation process of Embodiment 1 of the present invention.

[0021] Figure 4 It is an axonometric view of the box-shaped connecting beam component of the present invention.

[0022] Figure 5 It is a top view of the box-shaped connecting beam component of the present invention.

[0023] Figure 6Side view of the box-shaped continuous beam component of the present invention.

[0024] Figure 7 Top view of the second embodiment of the present invention.

[0025] Figure 8 Side view of the second embodiment of the present invention.

[0026] Figure 9 Schematic diagram of the installation process of the second embodiment of the present invention.

[0027] Figure 10 Structural diagram of the transition section central tube in the second embodiment of the present invention.

[0028] Figure 11 Top view of the transition section central tube in the second embodiment of the present invention.

[0029] Figure 12 Detail drawing of the connection position of the lifting ring and the transition section central tube in the second embodiment of the present invention.

[0030] Figure 13 Top view of the third embodiment of the present invention.

[0031] Figure 14 Side view of the third embodiment of the present invention.

[0032] Figure 15 Schematic diagram of the installation process of the third embodiment of the present invention.

[0033] In the figure:

[0034] 1. Negative pressure suction bucket; 2. Pumping hole; 3. Top reinforcement plate; 4. Box-shaped continuous beam; 41. Inner longitudinal partition of the continuous beam; 42. Inner transverse partition of the continuous beam; 43. Inner reinforcement rib plate of the continuous beam; 5. Transition section central tube; 6. Lifting ring; 7. Lock; 8. Prestressed anchor; 9. Tensile meter; 10. Local transverse reinforcement plate; 11. Local longitudinal reinforcement rib; 12. Shear key inside the tube; 13. Grouting layer inside the tube; 14. Single pile. Specific embodiments

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0036] Embodiment 1:

[0037] As Figure 1 , Figure 2 shown, a multi-barrel combined foundation system for connecting box-shaped beams of offshore wind power of the present invention includes a negative pressure suction bucket 1, a transition section central tube 5, and a box-shaped continuous beam 4. Three box-shaped continuous beams 4 are equidistantly arranged circumferentially outside the transition section central tube 5. A negative pressure suction bucket 1 is arranged below each box-shaped continuous beam 4.

[0038] A top reinforcement plate 3 is provided between the box-shaped coupling beam 4 and the suction bucket 1. The bottom surface of the top reinforcement plate 3 is connected to the top of each suction bucket 1, and the top surface of the top reinforcement plate 3 is connected to each box-shaped coupling beam 4. A through hole for fitting the transition section central cylinder 5 is provided in the middle of the top reinforcement plate 3. The edge shape of the top reinforcement plate 3 between two adjacent box-shaped coupling beams 4 is an arc-shaped concave inward. Pumping holes 2 are respectively provided on both sides of the box-shaped cross beam at the top of the suction bucket.

[0039] As Figure 4 , Figure 5 , Figure 6 shown, the box-shaped coupling beam 4 is a precast member cast with concrete. There are inner longitudinal diaphragms 41, inner transverse diaphragms 42 and inner strengthening rib plates 43 inside it. The inner longitudinal diaphragms 41 are vertically arranged along the longitudinal direction of the box-shaped coupling beam 4. The inner transverse diaphragms 42 are vertically arranged perpendicular to the inner longitudinal diaphragms 41. Inner strengthening rib plates 43 are arranged at the upper and lower edges inside the coupling beam. In order to ensure the overall stiffness of the box-shaped coupling beam 4 and avoid the reduction of the foundation fatigue life caused by stress concentration, inner longitudinal diaphragms 41 and inner transverse diaphragms 42 are arranged inside the box-shaped coupling beam 4 in this invention patent to ensure the integrity of the coupling beam. Inner strengthening rib plates 43 are arranged at the welding or component connection corner points of the inner longitudinal diaphragms 41 and inner transverse diaphragms 42 and the box-shaped coupling beam 4, so as to avoid local stress concentration and improve the load transfer mechanism.

[0040] The technical solution of this embodiment is applicable to the working conditions with relatively shallow water depth or relatively shallow buried depth of the seabed bedrock and relatively small wave and current loads. The group bucket tripod foundation is composed of three suction buckets 1, which transfer the upper load to the seabed. The suction bucket forms negative pressure inside the bucket through the pumping hole 2, and relies on the pressure difference inside and outside the bucket to realize the penetration of the foundation. The three suction buckets 1 are welded and connected into a whole through the top reinforcement plate 3. On the one hand, it increases the integrity of the foundation and improves the mechanical properties. At the same time, it can also facilitate the positioning of the foundation components and ensure the subsequent processing accuracy.

[0041] Compared with the traditional jacket form, the box-shaped coupling beam 4 with a simpler structural form adopted in the embodiment of the present invention can simplify the foundation design and clarify the load transfer path of the foundation system. In this invention patent, the suction bucket 1, the top reinforcement plate 3 and the box-shaped coupling beam 4 are all connected by welding. The form is simple, and the components can be produced modularly, which can greatly reduce the design and manufacturing costs and shorten the construction period.

[0042] As Figure 3 is a schematic diagram of the installation process of this embodiment. The specific construction process is as follows:

[0043] Step 1, floating and positioning: First, the group bucket tripod structure composed of the negative pressure suction bucket 1, the transition section central cylinder 5, and the top reinforcement plate 3 is hoisted to the designated construction position and prepared for self-weight sinking.

[0044] Step 2, self-weight sinking: The above-mentioned group bucket tripod structure is sunk to the seabed surface, and the group bucket tripod structure completes the preliminary sinking under its own weight.

[0045] Step 3, suction sinking: After completing the self-weight sinking, the seawater inside the suction bucket is pumped out through the pumping hole 2 to form an internal and external pressure difference and seepage field, further completing the sinking process of the group bucket tripod structure. At the same time, during the installation process, the horizontalness of the foundation is further controlled by controlling the pumping speed of the three negative pressure suction buckets 1.

[0046] Embodiment 2:

[0047] This embodiment is a further optimized solution based on the above Embodiment 1. Considering the complex composition of China's offshore waters and the large spatial variability of water depth, the following technical solutions are proposed to resist the increase in wave and current loads caused by the increase in water depth and ensure the overall stiffness of the foundation:

[0048] As Figure 7 、 Figure 8 shown, a multi-bucket combined foundation system for connecting box girders of offshore wind turbines of the present invention includes a negative pressure suction bucket 1, a transition section central cylinder 5, and a box girder connection beam 4. Three box girder connection beams 4 are circumferentially and equidistantly arranged on the outer side of the transition section central cylinder 5. One negative pressure suction bucket 1 is arranged below each box girder connection beam 4.

[0049] A top reinforcement plate 3 is arranged between the box girder connection beam 4 and the negative pressure suction bucket 1. The bottom surface of the top reinforcement plate 3 is connected to the top of each negative pressure suction bucket 1, the top surface of the top reinforcement plate 3 is connected to each box girder connection beam 4, and a through hole for cooperating with the transition section central cylinder 5 is arranged in the middle of the top reinforcement plate 3. The edge shape of the top reinforcement plate 3 between two adjacent box girder connection beams 4 is an arc shape recessed inward. Pumping holes 2 are respectively arranged on both sides of the box cross beam at the top of the negative pressure bucket.

[0050] As Figure 4 、 Figure 5 、 Figure 6As shown in the figure, the box-shaped coupling beam 4 is a precast member made of concrete. Inside it, there are longitudinal partition plates 41, transverse partition plates 42 and reinforcing rib plates 43 inside the coupling beam. The longitudinal partition plates 41 inside the coupling beam are vertically arranged along the longitudinal direction of the box-shaped coupling beam 4. The transverse partition plates 42 inside the coupling beam are vertically arranged perpendicular to the longitudinal partition plates 41 inside the coupling beam. Reinforcing rib plates 43 are arranged at the upper and lower edges inside the coupling beam. In order to ensure the overall stiffness of the box-shaped coupling beam 4 and avoid the reduction of the foundation fatigue life caused by stress concentration, longitudinal partition plates 41 and transverse partition plates 42 inside the coupling beam are arranged inside the box-shaped coupling beam 4 of this invention patent to ensure the integrity of the coupling beam. At the welding or member connection corner points of the longitudinal partition plates 41 and transverse partition plates 42 inside the coupling beam and the box-shaped coupling beam 4, reinforcing rib plates 43 inside the coupling beam are arranged, so as to avoid local stress concentration and improve the load transfer mechanism.

[0051] As Figure 10 , Figure 11 , Figure 12 shown in the figure, there are two annular local transverse reinforcing plates 10 arranged on the inner wall of the transition section central tube 5. Local longitudinal reinforcing ribs 11 are arranged between adjacent local transverse reinforcing plates 10. The local longitudinal reinforcing ribs 11 are arranged equidistantly around the inner wall of the transition section central tube 5. The position where the prestressed tension anchor 8 is connected to the transition section central tube 5 corresponds to the local longitudinal reinforcing ribs 11.

[0052] There is a lifting ring 6 arranged around the outside of the transition section central tube 5. The height where the lifting ring 6 is located is between two adjacent local transverse reinforcing plates 10. Local longitudinal reinforcing ribs 11 are arranged at the corresponding position on the inner side of the transition section central tube 5 where the lifting ring 6 is located. A locking buckle 7 is arranged at the top of the box-shaped coupling beam 4 at one end far from the transition section central tube 5. One end of the prestressed tension anchor 8 is connected to the lifting ring 6, and the other end is connected to the locking buckle 7. One end of the prestressed tension anchor 8 is connected to the end of the box-shaped coupling beam 4 far from the transition section central tube 5, and the other end of the prestressed tension anchor 8 is connected to the transition section central tube 5. The horizontal projection of the prestressed tension anchor 8 coincides with the center line of the box-shaped coupling beam 4. A tensiometer 9 is arranged on the structure of the prestressed tension anchor 8. In this embodiment, the prestressed tension anchor 8 is made of steel strands.

[0053] Thus, the transition section central tube 5 is connected to the lower box-shaped coupling beam 4 and three suction buckets as a whole. Through this connection form, the cantilever length of the underwater foundation part is greatly reduced, and the overall stiffness of the foundation is increased. For the lifting ring 6 arranged on the upper part of the box-shaped coupling beam 4, in order to ensure the strength of the local connection, it is required that the lifting ring 6 be welded above the corresponding longitudinal partition plate 41 of the box-shaped coupling beam 4. For the lifting ring 6 welded above the transition section central tube 5, in order to avoid local damage of the transition section central tube 5 caused by stress concentration.

[0054] In the present invention, a partial transverse reinforcing plate 10 and a partial longitudinal reinforcing rib plate 11 are provided inside the transition section central barrel 5 at corresponding positions to ensure the strength and stiffness of the transition section central barrel 5 at the connection position of the lifting ring 6 in the circumferential and radial directions. Considering that in the foundation design, in order to meet different stiffness requirements, it is necessary to adjust the pre-tension of the steel strand. In the present invention, a tensiometer 9 is provided on the prestressed tension anchor 8, which can ensure the accuracy of the pre-tension in the prestressed tension anchor 8. At the same time, during the subsequent use of the foundation, the change of the tension inside the prestressed tension anchor 8 can be monitored for a long time, which can reflect the long-term bearing performance of the foundation as side monitoring data.

[0055] As Figure 9 is a schematic diagram of the installation process of this embodiment, and the specific construction process is as follows:

[0056] Step 1, floating and positioning: First, the group bucket tripod structure composed of the suction bucket 1, the transition section central barrel 5, the top reinforcing plate 3 and the prestressed cable is hoisted to the designated construction position and prepared for self-weight penetration.

[0057] Step 2, self-weight penetration: The above-mentioned group bucket tripod structure is sunk to the seabed surface, and the group bucket tripod structure completes the preliminary penetration under its own weight.

[0058] Step 3, suction penetration: After completing the self-weight penetration, the seawater inside the suction bucket is pumped out through the pumping hole 2 to form an internal and external pressure difference and a seepage field, and further complete the penetration process of the group bucket tripod structure. At the same time, during the installation process, the levelness of the foundation is further controlled by controlling the pumping speed of the three suction buckets 1.

[0059] Embodiment 3:

[0060] This embodiment is a further optimized solution based on the above Embodiment 1. Considering that the strength of the shallow soil layer of the seabed in some areas of the southeast sea area of our country is relatively low, relying solely on the three suction buckets 1 in Embodiment 1 cannot provide sufficient foundation bearing capacity. For this working condition, based on Embodiment 1, the following technical solutions are proposed in this embodiment.

[0061] As Figure 13 、 Figure 14 shown, a multi-barrel combined foundation system for connecting a box girder of an offshore wind turbine of the present invention includes a suction bucket 1, a monopile 14, a transition section central barrel 5 and a box girder connection beam 4. The transition section central barrel 5 is sleeved outside the monopile 14. Three box girder connection beams 4 are equidistantly arranged in the circumferential direction outside the transition section central barrel 5. A suction bucket 1 is arranged below each box girder connection beam 4.

[0062] A top reinforcement plate 3 is provided between the box-shaped coupling beam 4 and the suction bucket foundation 1. The bottom surface of the top reinforcement plate 3 is connected to the top of each suction bucket foundation 1, and the top surface of the top reinforcement plate 3 is connected to each box-shaped coupling beam 4. A through hole for mating with the transition section central cylinder 5 is provided in the middle of the top reinforcement plate 3. The edge shape of the top reinforcement plate 3 between two adjacent box-shaped coupling beams 4 is an arc shape that is concave inward. Pumping holes 2 are respectively provided on both sides of the box-shaped cross beam at the top of the suction bucket foundation.

[0063] As Figure 4 , Figure 5 , Figure 6 shown, the box-shaped coupling beam 4 is a precast member cast with concrete, and a longitudinal inner partition 41, a transverse inner partition 42 and an inner stiffening rib plate 43 are arranged inside it. The longitudinal inner partition 41 is vertically arranged along the longitudinal direction of the box-shaped coupling beam 4, the transverse inner partition 42 is vertically arranged perpendicular to the longitudinal inner partition 41, and inner stiffening rib plates 43 are arranged at the upper and lower edges inside the coupling beam. In order to ensure the overall stiffness of the box-shaped coupling beam 4 and avoid the reduction of the foundation fatigue life caused by stress concentration, longitudinal inner partition 41 and transverse inner partition 42 are arranged inside the box-shaped coupling beam 4 in this invention patent to ensure the integrity of the coupling beam. Inner stiffening rib plates 43 are arranged at the welding or component connection corner points between the longitudinal inner partition 41, the transverse inner partition 42 and the box-shaped coupling beam 4, so as to avoid local stress concentration and improve the load transfer mechanism.

[0064] Preferably, a number of shear keys 12 are axially arranged along the inner side of the transition section central cylinder 5, and a grouting layer 13 is poured in the space between the transition section central cylinder 5 and the single pile 14.

[0065] The shear keys 12 in the cylinder and the group bucket tripod foundation - a bucket are used as the installation positioning and pile stabilizing system of the single pile 14, and at the same time improve the integrity of the single pile 14 and the group bucket tripod; the single pile 14 and the transition section central cylinder 5 are connected through the grouting layer 13 in the cylinder. Based on the group bucket tripod foundation in shallow water areas, combined with structures such as the shear keys 12 in the cylinder, the grouting layer 13 in the cylinder and the single pile 14, a large-diameter single pile 14 - group bucket tripod composite foundation suitable for the soft seabed in the offshore areas of our country is formed.

[0066] As Figure 15 is the installation process schematic diagram of this embodiment, and the specific construction process is as follows:

[0067] Step 1, floating and positioning: First, the group bucket tripod structure composed of the suction bucket foundation 1, the transition section central cylinder 5, the top reinforcement plate 3 and the prestressed cable is hoisted to the designated construction position and prepared for self-weight sinking.

[0068] Step 2, self-weight penetration: Lower the above-mentioned bucket group tripod structure to the seabed surface, and the bucket group tripod structure completes the initial penetration under its own weight.

[0069] Step 3, suction penetration: After completing the self-weight penetration, pump out the seawater inside the suction bucket through the pumping hole 2 to form an internal and external pressure difference and a seepage field, further complete the penetration process of the bucket group tripod structure, and at the same time control the levelness of the foundation by controlling the pumping speed of the three negative pressure suction buckets 1 during the installation process.

[0070] Step 4, driving the single pile 14: After the complete penetration of the suction bucket, pass the single pile 14 through the central cylinder 5 of the transition section. The bucket group tripod structure serves as a pile stabilizing system to ensure the stability of the single pile 14 during the driving process, and drive the single pile 14 to the specified depth.

[0071] Step 5, node grouting: After driving the single pile 14 to the specified depth, grout the grouting layer 13 inside the node grouting cylinder to ensure the integrity of the foundation.

Claims

1. A multi-barrel composite foundation system for connecting box girders of offshore wind turbines, characterized in that, It includes a negative pressure suction bucket, a transition section central cylinder, and box-shaped connecting beams. A number of box-shaped connecting beams are equidistantly arranged circumferentially outside the transition section central cylinder, and a negative pressure suction bucket is arranged below each box-shaped connecting beam; Inside the box-shaped connecting beam, there are internal longitudinal partition plates, internal transverse partition plates, and internal reinforcing rib plates of the connecting beam. The internal longitudinal partition plates of the connecting beam are vertically arranged along the longitudinal direction of the box-shaped connecting beam, the internal transverse partition plates of the connecting beam are vertically arranged perpendicular to the internal longitudinal partition plates, and internal reinforcing rib plates of the connecting beam are arranged at the upper and lower edges of the connecting beam; A top reinforcing plate is arranged between the box-shaped connecting beam and the negative pressure suction bucket. The bottom surface of the top reinforcing plate is connected to the top of each negative pressure suction bucket, the top surface of the top reinforcing plate is connected to each box-shaped connecting beam, and a through hole for fitting the transition section central cylinder is arranged in the middle of the top reinforcing plate; The edge shape of the top reinforcing plate between two adjacent box-shaped connecting beams is an arc-shaped concave inward; A prestressed tension anchor is arranged at the end of the box-shaped connecting beam. One end of the prestressed tension anchor is connected to the end of the box-shaped connecting beam far from the transition section central cylinder, the other end of the prestressed tension anchor is connected to the transition section central cylinder, and the horizontal projection of the prestressed tension anchor coincides with the center line of the box-shaped connecting beam; At least two annular local transverse reinforcing plates are arranged on the inner wall of the transition section central cylinder, and local longitudinal reinforcing ribs are arranged between adjacent local transverse reinforcing plates. The local longitudinal reinforcing ribs are equidistantly arranged around the inner wall of the transition section central cylinder, and the position where the prestressed tension anchor is connected to the transition section central cylinder corresponds to the local longitudinal reinforcing ribs; A lifting ring is arranged outside the transition section central cylinder. The height of the lifting ring is located between two adjacent local transverse reinforcing plates. Local longitudinal reinforcing ribs are arranged on the inner side of the transition section central cylinder at the corresponding position of the lifting ring; A locking buckle is arranged at the top of the box-shaped connecting beam far from the transition section central cylinder. One end of the prestressed tension anchor is connected to the lifting ring, the other end is connected to the locking buckle, and a tensiometer is arranged on the prestressed tension anchor.

2. The multi-barrel combined foundation system for connecting offshore wind power box girders according to claim 1, characterized in that, The number of the negative pressure suction buckets and the box-shaped connecting beams is three.

3. The multi-barrel combined foundation system for connecting offshore wind power box girders according to claim 1, characterized in that, Pumping holes are respectively arranged on both sides of the box-shaped cross beam at the top of the negative pressure suction bucket.

4. The multi-barrel combined foundation system for connecting offshore wind power box girders according to claim 1, characterized in that A single pile is sleeved inside the transition section central cylinder. A number of shear keys inside the cylinder are arranged along the axial direction of the inner wall of the transition section central cylinder, and a grouting layer inside the cylinder is poured into the space between the transition section central cylinder and the single pile.

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