Active and passive combined protection structure considering scouring and protection method

Abstract

The invention discloses an active and passive combined protection structure considering scouring and a protection method, in the aspect of active protection, a special barrel-shaped structure of a single-pile fixing barrel can generate a turbulent flow effect when water flows through, and the turbulent flow effect is similar to the function of a spoiler in the active protection. Before the wind power foundation pile is seriously scoured by water flow, the water flow is interfered and guided, the flow speed and the flow direction distribution of the water flow are changed, the direct impact force of the water flow on the foundation pile is reduced, and therefore the active scour prevention effect is achieved. The combination of the supporting structure and the single-pile structure can also hinder and guide water flow to a certain degree, and the active protection effect is enhanced. In the passive protection aspect, the grouting body enhances structural connection, tiny gaps or cavities generated by scouring can be filled to a certain extent after scouring occurs, the integrity and the anti-scouring capacity of the protection structure are enhanced, and the passive protection effect is improved. Therefore, through the active and passive combined protection structure, the problems existing in the prior art are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the field of offshore wind power single pile foundation installation, wind energy engineering and new energy, and relates to an active and passive combined protection structure and a protection method taking scouring into consideration. Background Art

[0002] Offshore wind power has become a frontier field of wind power development due to its rich resources, high power generation utilization hours, no land occupation and suitability for large-scale development. However, its single pile foundation faces extremely severe scouring problems. The depth of the scouring pit of some single pile foundations can reach half the depth of the pile body into the mud, which poses a great threat to the safe operation of the single pile foundation. Since scouring protection projects are not only time-consuming but also laborious, how to efficiently carry out scouring protection work after the construction is completed has become a difficult problem that needs to be solved urgently.

[0003] Current protection measures can be divided into two categories: active protection and passive protection. Passive protection means that after the scouring pit has appeared, stone throwing or sand laying is carried out to fill the scouring pit. Active protection is to add some spoilers to the structure to perform spoiler operations before scouring occurs, thereby achieving anti-scouring effect.

[0004] However, both active and passive protection technologies have obvious defects and deficiencies. Passive protection is only a compensatory measure after the appearance of scouring pits. It cannot prevent the occurrence of scouring in advance, and it is difficult to ensure the long-term effectiveness and stability of protection by filling the scouring pits after they are formed. It is easy to be scoured again due to subsequent water flow and other factors. Although active protection attempts to intervene when there is no scouring, the setting of the spoiler may not be able to accurately adapt to various complex marine environments and water flow conditions. There is a large uncertainty in its anti-scouring effect, and its anti-scouring function may gradually weaken or fail over time and with the dynamic changes of the marine environment. In summary, the core problem of the existing technology is that it cannot fundamentally, stably and permanently solve the scouring protection problem of offshore wind power monopile foundations. It is difficult to continuously ensure the safe operation of monopile foundations under different marine conditions, and it cannot meet the stringent requirements of offshore wind power for long-term stable operation of monopile foundations. Summary of the invention

[0005] The purpose of the present invention is to solve the problems in the prior art and to provide an active and passive combined protection structure and a protection method taking scouring into consideration.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention proposes an active and passive combined protection structure considering scour, including a single pile structure; A spoiler structure is installed on the outer wall surface of the single pile structure. The spoiler structure includes a support structure and a single pile fixing cylinder. The support structure is located above the single pile fixing cylinder. A grouting body is provided between the single pile structure and the spoiler structure.

[0007] Preferably, the supporting structure and the monopile fixing cylinder are both vertically mounted on the outer wall of the monopile structure.

[0008] Preferably, the support structure is a combination of one or more of a truss support structure, a frame support structure or a cable support structure.

[0009] Preferably, the single pile fixing tube is formed by splicing baffles.

[0010] Preferably, a separation seam is provided on the single pile fixing tube.

[0011] Preferably, there are a plurality of the supporting structures and the single pile fixing cylinders, which are arranged at equal intervals in the radial direction of the single pile structure.

[0012] Preferably, an exhaust pipeline and a drainage pipeline are provided on the single pile fixing cylinder.

[0013] Preferably, the height of the single pile fixing cylinder is greater than the height of the supporting structure.

[0014] Preferably, one end of the support structure abuts against the outer side wall of the grouting body, and the other end of the support structure abuts against the upper end surface of the single pile fixing tube.

[0015] The present invention proposes a protection method for an active and passive combined protection structure taking scouring into consideration, comprising: The supporting structure and the monopile fixing tube are both installed on the outer wall of the monopile structure; The single pile fixing tube is sunk into the soil under negative pressure, and the water in the enclosed space is pumped out after entering the soil to achieve pressure difference sinking; A grouting body is provided between the single pile structure and the spoiler structure to complete the protection of the single pile structure.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention proposes an active and passive combined protection structure considering scouring. In terms of active protection, the presence of a single pile fixed cylinder changes the flow pattern of water flow. Its special cylinder structure will produce a disturbing effect when the water flows through, which is similar to the spoiler function in active protection. Before the water flow causes serious scouring to the wind power foundation pile, it interferes with and guides the water flow, changes the flow velocity and flow direction distribution of the water flow, and reduces the direct impact force of the water flow on the foundation pile, thereby playing an active anti-scouring role. Moreover, since it is cylinder-shaped and has a certain area, it can produce an effective disturbing effect under a larger range and more complex water flow conditions compared to traditional spoilers, thereby improving the adaptability and stability of active protection. The combination of the support structure and the single pile structure will also have a certain obstruction and guiding effect on the water flow, further enhancing the effect of active protection, so that the water flow is dispersed and decelerated before approaching the foundation pile, reducing the energy source of scouring. In terms of passive protection, after a certain degree of scouring occurs, the single pile fixed cylinder can be used as a protective body similar to a sandbag or riprap to prevent the water flow from continuing to scour the bottom of the pit and the foundation pile. Its large size and weight can stably lie on the seabed surface. Even if a scour pit occurs, it can reduce the further expansion of the scour pit and play a role in passive filling and protection. The grouting body not only strengthens the structural connection, but also fills the tiny gaps or holes caused by scour to a certain extent after the scour occurs, enhancing the integrity and anti-scour ability of the protective structure, further improving the effect of passive protection, preventing seawater from further eroding the interior of the structure, and ensuring the long-term effectiveness of the protective structure. Therefore, through this active and passive combined protection structure, active protection and passive protection are organically combined, which can play a role in different stages and different water flow conditions, thereby effectively solving the core problem that the existing technology cannot stably, efficiently and permanently solve the scour protection problem of offshore wind power monopile foundation, and better ensure the safe operation of offshore wind power monopile foundation in complex marine environment.

[0017] Furthermore, the separation seams alleviate the local structural deformation and stress concentration problems caused by scouring to a certain extent, so that the entire protective structure can better adapt to the changes in the seabed and water flow environment after scouring during the passive protection process, avoiding the failure of the entire protective structure due to local damage, and improving the reliability and durability of passive protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1It is a top view schematic diagram of the composite reinforcement and reuse structure of the offshore wind power single pile foundation after scouring according to the present invention.

[0020] Figure 2 It is a schematic longitudinal section diagram of the composite reinforcement and reuse structure of the offshore wind power single pile foundation after scouring according to the present invention.

[0021] Among them: 1-single pile structure; 2-support structure; 3-single pile fixing tube; 31-exhaust pipeline; 32-drainage pipeline; 4-grouting body; 5-partition joint. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0025] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0026] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0027] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] The present invention is further described in detail below in conjunction with the accompanying drawings: The present invention proposes an active and passive combined protection structure considering scour, such as Figure 1 and Figure 2 As shown, it includes a single pile structure 1; a spoiler structure is installed on the outer wall of the single pile structure 1, and the spoiler structure includes a support structure 2 and a single pile fixing tube 3, and the support structure 2 is located above the single pile fixing tube 3; a grouting body 4 is provided between the single pile structure 1 and the spoiler structure. A separation seam 5 is opened on the single pile fixing tube 3.

[0029] Preferably, the support structure 2 and the single pile fixing tube 3 are both vertically mounted on the outer wall of the single pile structure 1. The vertical installation enables the support structure 2 and the single pile fixing tube 3 to form a more stable three-dimensional support system with the single pile structure 1. When subjected to horizontal external forces such as lateral water flow impact force and wind force, the vertically mounted components can effectively transfer these horizontal forces to the single pile structure 1 and the seabed foundation below it, forming a moment to resist overturning, greatly reducing the risk of the entire structure overturning due to lateral force, and ensuring the stability of the offshore wind power single pile foundation in a complex marine environment. This vertical installation method is conducive to transferring the vertical loads borne by the single pile structure 1 (such as the weight of the wind turbine itself, the load transmitted from the upper structure, etc.) to the seabed foundation more directly and evenly. The monopile fixing tube 3 can be used as an effective force transmission component to disperse the vertical force of the monopile structure 1 to a larger seabed contact area (if the bottom of the monopile fixing tube 3 and the seabed have a suitable connection design), reducing the pressure per unit area at the bottom of the monopile structure 1, and reducing the probability of problems such as seabed settlement caused by excessive vertical loads. At the same time, the support structure 2 can also play an auxiliary support role in the vertical direction, sharing part of the vertical load, further enhancing the bearing capacity of the entire structural system for vertical loads, and ensuring that the offshore wind power facilities can safely bear their own weight and various vertical loads generated during operation, similar to the piers and support structures of a bridge working together to bear vertical loads such as the bridge deck and vehicles. The vertically installed support structure 2 and the monopile fixing tube 3 will change the flow state of the water when the water passes through. They are like obstacles in the water, forcing the water flow to bypass these components when approaching the single pile structure 1, thereby disrupting the water flow path that may have been relatively concentrated and directly impacted the single pile structure 1, causing the water flow to form eddies in local areas or change the flow velocity distribution, reducing the direct scouring force of the water flow on the single pile structure 1, playing a certain active protective role, and reducing the damage to the single pile foundation caused by scouring. The single pile fixing tube 3 surrounds the outer wall of the single pile structure 1 and is installed vertically. It can itself serve as a protective barrier to prevent the water flow from directly scouring the outer wall of the single pile structure 1. Especially after a certain degree of scouring occurs, the single pile fixing tube 3 can reduce the possibility of further expansion of the scouring pit, and play a role similar to the protective body such as riprap and sand blanket in passive protection. It is stably located near the seabed surface, providing continuous protection for the single pile structure 1, and preventing the erosion and further scouring damage of the single pile structure 1 by seawater. Moreover, the coordinated cooperation between the supporting structure 2 and the single pile fixing tube 3 forms a relatively complete protection area around the single pile structure 1, further enhancing the scour protection effect on the single pile foundation, so that the single pile foundation can be more comprehensively and effectively protected in the complex and changeable ocean current environment, thereby extending the service life of the single pile foundation.

[0030] Preferably, the support structure 2 is a combination of one or more of a truss support structure, a frame support structure or a cable support structure.

[0031] Among them, the truss support structure is usually composed of multiple rods through welding, bolt connection and other methods. These rods include chords (upper chord and lower chord) and webs (diagonal webs and vertical webs). The chord is generally arranged along the main force direction of the support structure to form the outline frame of the structure. For example, when connecting the foundation and the single pile fixing cylinder, the upper and lower chords are at different height levels, forming a shape similar to a bridge truss. The web is connected between the chords to transfer and distribute the load and enhance the stability of the structure. The truss support structure has good force-bearing performance. It can effectively decompose and transfer loads from all directions (such as the horizontal thrust of water flow, the vertical load from the single pile fixing cylinder, etc.) through the coordinated work of the rods. Compared with some solid structures, the truss structure has a relatively light weight, which can reduce the additional deadweight load that the foundation needs to bear in the marine environment. At the same time, its spatial structural form can also reduce the resistance of water flow to the structure to a certain extent, reduce the impact of water scouring on itself, and facilitate construction and installation. It can be assembled in sections at sea and then connected to the corresponding position as a whole.

[0032] The frame support structure is composed of crisscross beams and columns to form rectangular or square frame units. Multiple such frame units are combined to form the entire support structure. The beams are generally placed horizontally, bearing the vertical load from the single pile fixing tube and transferring it to the columns. The columns are perpendicular to the seabed and further transfer the load to the foundation. The frames can be connected by rigid connection or hinge connection to ensure the integrity and stability of the structure. The force of the frame support structure is relatively intuitive and clear. The vertical load is transferred from the beam to the column and then to the foundation. The horizontal load (such as water flow impact force, wind load, etc.) is resisted by the lateral stiffness of the entire frame. Its various frame units work together with each other, have high spatial stability, and can provide reliable support for the single pile fixing tube in different directions. Moreover, this structural form is convenient for mechanical analysis and calculation in the design stage. The size and reinforcement parameters of the beams and columns can be accurately determined according to the actual load conditions to ensure the safety and reliability of the structure.

[0033] The cable support structure consists of cables, anchoring devices and towers. The cables are generally made of high-strength steel strands or wire ropes. One end of the cables is connected to the foundation structure (such as the decommissioned monopile structure) and the other end is connected to the monopile fixing cylinder. The stability of the monopile fixing cylinder is maintained by the tension of the cables. The tower supports the cables, adjusts the angle of the cables and transfers the load. It can be an independent steel tower or combined with other structures. The anchoring device is used to firmly fix the cables to the corresponding foundation and monopile fixing cylinder to ensure that the cables will not loosen or slip during the force process. The cable support structure uses the tension of the cables to balance the external load. Its biggest advantage is that it can provide greater support force with less material consumption. When the cables are subjected to tension, the strength of the materials can be fully utilized. Compared with some solid support structures, it can greatly reduce the deadweight of the structure, while effectively limiting the swing and displacement of the monopile fixing cylinder.

[0034] Preferably, the single pile fixing tube 3 is formed by splicing baffles.

[0035] Preferably, there are several supporting structures 2 and single pile fixing cylinders 3, which are arranged at equal intervals in the radial direction of the single pile structure 1. Multiple supporting structures 2 and single pile fixing cylinders 3 distributed at equal intervals can evenly distribute the vertical load (such as wind turbine deadweight, operating load, etc.) borne by the single pile structure 1 to a larger area and more supporting points, avoiding the concentrated force on a single or a few components, thereby reducing the pressure borne by each component, reducing the risk of structural deformation, damage or even failure due to excessive local pressure, and greatly improving the bearing capacity and stability of the entire foundation structure for vertical loads. When facing horizontal forces in the marine environment, multiple radially distributed supporting structures 2 and single pile fixing cylinders 3 form a ring-like lateral force resistance system. Since the supporting structures 2 and single pile fixing cylinders 3 are arranged at equal intervals in the radial direction of the single pile structure 1, they can interfere with and guide the water flow from multiple directions when the water flows through. Each component will change the velocity and direction of the surrounding water flow, so that the water flow forms a complex flow pattern, such as turbulence, eddy current, etc., when passing through the monopile structure 1, thereby reducing the direct scouring energy of the water flow on the monopile structure 1. This all-round water flow interference effect is more significant than the protective effect of a single or a few components, and can more effectively reduce the degree of scouring suffered by the monopile structure 1 and protect the integrity of the monopile foundation.

[0036] Preferably, an exhaust pipe 31 and a drainage pipe 32 are provided on the single pile fixing tube 3 .

[0037] Preferably, the height of the monopile fixing barrel 3 is greater than the height of the supporting structure 2. 1) A higher monopile fixing barrel 3 can protect the monopile structure 1 within a larger vertical height range. When water flows through, the monopile fixing barrel 3 can block the direct scouring of the upper area of ​​the monopile structure 1 by the water flow, change the flow direction and velocity distribution of the water flow, and make the water flow form turbulence or eddy current around the monopile fixing barrel 3, thereby reducing the scouring energy of the water flow on the monopile structure 1. In contrast, if the height of the monopile fixing barrel 3 is low, it may not be able to effectively protect the upper exposed part of the monopile structure 1, which may easily cause the area to be scoured and eroded, affecting the stability and durability of the monopile foundation. 2) Since the height of the monopile fixing barrel 3 is greater than the height of the supporting structure 2, the flow pattern change area formed in the water flow is larger. In the area below the monopile fixing barrel 3 and between the supporting structure 2, the water flow will form a more complex flow pattern after being blocked by the monopile fixing barrel 3, such as generating eddy currents. The larger height of the monopile fixing tube 3 allows these eddies to have enough space for energy dissipation and flow adjustment after they are formed, reducing the scouring effect of the eddies on the lower part of the monopile structure 1 and the area near the seabed. If the height of the monopile fixing tube 3 is insufficient, the eddies may directly act on the key parts of the lower part of the monopile structure 1, accelerating the scouring of the seabed and the local damage of the monopile foundation. 3) The higher monopile fixing tube 3 increases the center of gravity height of the entire structure, but due to its synergistic effect with the monopile structure 1 and the supporting structure 2, it actually enhances the anti-overturning ability of the structure. The monopile fixing tube 3 is equivalent to adding a larger mass stabilizing component on the upper part of the monopile structure 1. When subjected to lateral forces (such as strong winds, water flow impact, etc.), the monopile fixing tube 3 can generate a larger anti-overturning moment, and work together with the supporting structure 2 to make the entire structure more difficult to overturn. This is just like setting a heavier damper or stabilizing structure on the top of a high-rise building to improve the stability of the building under lateral forces. 4) The height of the monopile fixing tube 3 is relatively large. When bearing the upper load (such as the weight of the wind turbine, wind load, etc.), the load can be transferred to the monopile structure 1 and the supporting structure 2 more evenly, avoiding local stress concentration. Its higher part can act like a vertical force transmission rod, dispersing the upper load along the tube wall to the lower connection part with the monopile structure 1 and the supporting structure 2, so that each component can reasonably share the load according to its own mechanical properties, thereby improving the bearing capacity and reliability of the entire structural system.

[0038] Preferably, one end of the support structure 2 abuts against the outer wall of the grouting body 4, and the other end of the support structure 2 abuts against the upper end surface of the single pile fixing tube 3. When the single pile structure is subjected to the vertical load transmitted from the upper wind turbine, the load is transmitted downward through the single pile itself, and at the same time, part of the force is transmitted to the support structure 2 through the single pile fixing tube. Since one end of the support structure 2 abuts against the upper end surface of the single pile fixing tube 3, the vertical load can be effectively transferred from the single pile fixing tube 3 to the support structure 2, and then transferred to the grouting body 4 and the wider foundation structure. Such a force transmission path avoids the single pile from being subjected to excessive vertical pressure locally, evenly distributes the load to a larger structural area, improves the bearing capacity of the entire foundation structure for vertical loads, and reduces the risk of local damage or settlement of the single pile due to vertical force concentration. One end of the support structure 2 is in contact with the outer wall of the grouting body 4. When subjected to horizontal force, the support structure 2 can transmit the horizontal force to the grouting body 4 and the foundation structure part connected thereto, and resist the horizontal force by means of the friction between the grouting body 4 and the foundation and the anchoring effect of the foundation. At the same time, the contact with the upper end surface of the single pile fixing tube 3 allows the support structure 2 to limit the horizontal displacement of the single pile fixing tube 3, forming a stable triangular support system, enhancing the resistance of the entire structure to horizontal force, effectively preventing the single pile fixing tube from excessively shaking or deflecting due to horizontal force, and ensuring the safe and stable operation of the single pile foundation. The contact between the support structure 2 and the outer wall of the grouting body 4 and the upper end surface of the single pile fixing tube 3 forms a close contact relationship at the connection part. This contact not only transmits force, but also can constrain the relative displacement between the components to a certain extent, so that the support structure 2, the single pile fixing tube 3 and the grouting body 4 form an organic whole. Compared with connection methods that simply rely on bolt connection or welding, this abutment method increases the redundancy of the connection. Even if the local connection is slightly loose or damaged, the friction and mutual support between the abutment surfaces can still maintain the overall stability of the structure, thereby improving the reliability of the structure's long-term operation in complex marine environments.

[0039] The single pile fixing cylinder 3 proposed in the present invention can be a perforated structure or a non-perforated structure, which depends on the specific design requirements and application scenarios: the perforated structure is suitable for use in sea areas with fast water flow, obvious wave action and high requirements for structural fatigue resistance, such as some open coastal areas, which are often affected by the combined action of wind and waves. The porous single pile fixing cylinder can effectively cope with this complex marine dynamic environment and protect the single pile foundation through the water flow regulation effect of the holes. The non-perforated structure is in some seabeds with complex geological conditions, where silt deposition is prone to occur and the scouring effect of water flow is mainly concentrated in the nearshore area outside the fixing cylinder. The non-perforated single pile fixing cylinder can rely on its own complete structure to prevent a large amount of silt from pouring into the interior and affecting the stability of the single pile, while stably bearing the impact of external water flow to ensure the normal operation of the single pile foundation.

[0040] 1) In the case of holes: Regulating water flow: holes are opened on the wall of the single pile fixed cylinder (3). When water flows through, part of the water can enter the fixed cylinder through these holes, changing the original impact path and flow state of the water flow, playing a role in dispersing the energy of the water flow, thereby reducing the direct scouring force of the water flow on the fixed cylinder itself and the internal single pile, and achieving a certain degree of active protection effect. For example, in sea areas with fast water flow and changeable flow direction, the holes can allow the water flow to have more buffering and diversion paths, avoiding the concentrated impact of the water flow on a certain part of the fixed cylinder, causing local scouring damage. Balancing the internal and external water pressure: The holes help to balance the water pressure inside and outside the fixed cylinder to a certain extent, reducing the risk of structural damage caused by excessive internal and external water pressure differences. Especially in sea areas with obvious tidal fluctuations or large wave fluctuations, the water pressure changes frequently. The holes can allow the internal and external water bodies to exchange, ensuring that the overall force of the fixed cylinder structure is more uniform, avoiding excessive structural internal forces due to water pressure differences, and improving the stability and durability of the structure. Easy to inspect and maintain: The holes can be used as inspection and maintenance channels. Workers can use relevant equipment (such as underwater cameras, etc.) through these openings to check the conditions of the single pile inside the fixed tube and the structure itself, such as whether there are corrosion, cracks and other problems. It is also convenient to perform some simple maintenance operations, such as placing anti-corrosion and anti-rust materials, which is conducive to timely discovery and handling of potential structural safety hazards and extending the service life of the fixed tube.

[0041] Considerations for opening form and size: Shape: The shapes of holes include round, square, rectangular, etc. The stress concentration phenomenon of circular holes is relatively small. When subjected to water flow pressure and other loads, the structure is relatively more evenly stressed, and the risk of local damage to the tube wall is lower; square or rectangular holes are convenient for construction and production in some cases. Size: The size of the hole should take into account factors such as the water flow regulation effect, structural strength, and the impact on single pile protection. Smaller holes can be increased in number to achieve better water flow dispersion and water pressure balance effects, but too many holes may affect the overall strength of the fixed tube; although larger holes have an obvious effect on water flow regulation, they may weaken the structural bearing capacity of the fixed tube itself, so it is necessary to reasonably determine the size and distribution density of the holes through detailed hydraulic calculations and structural mechanics analysis to ensure that the structure is safe while achieving the function.

[0042] 2) Situation without holes: Structural strength guarantee: The overall structural integrity of the monopile fixed cylinder without holes is better, and the cylinder wall can more effectively withstand various external loads, including water flow impact, vertical load transmitted by the monopile, and possible additional pressure caused by marine organisms. For some sea areas with extremely strong water flow impact, harsh marine environment and extremely high requirements for monopile foundation protection, such as deep sea areas or sea areas that are often affected by extreme weather such as typhoons and cause strong water flow impact, the complete cylinder wall structure can better resist external forces with its continuous force characteristics, ensure the safety of the internal monopile, and avoid the damage of structural weak links caused by holes. Protection performance requirements: When the monopile needs to be strictly isolated and protected to prevent impurities such as seawater, silt, and marine organisms from entering the fixed cylinder and causing erosion, wear and other adverse effects on the monopile, the fixed cylinder without holes can provide a better sealing environment. Construction and cost factors: The manufacturing process of the fixed tube without holes is relatively simple, which reduces the number of holes to be opened and the processes of reinforcement and treatment of the holes to be opened, which can reduce the difficulty of construction, improve the production efficiency, and also save costs to a certain extent. Especially in some offshore wind power projects where the performance requirements of the fixed tube are not particularly dependent on the hole function and the engineering cost and construction period need to be controlled, it is more appropriate to choose a design without holes.

[0043] The present invention adopts a semi-arc design, and the single-sided structure has four compartments (the upper end is closed and the lower part is open). During the sinking process, it can be hoisted into the water, and at the same time, the air can be injected into the closed space to make the structure float beside the structure. After adjusting the position, the gas in the compartment is released to make the arc-shaped structure sink slowly. After the lower end enters the soil, the gas in the compartment can be completely discharged, and the water pump can be turned on to pump water. Under the action of the internal and external pressure difference, the structure is sunk into place. After it is in place, reverse grouting can be performed in the pumping pipeline to make the entire protective structure more stable. An exhaust 31 and a pumping pipeline 32 are arranged on the upper part of each compartment. The structure proposed by the present invention has the following advantages: 1) The steel structure is first spliced ​​and reinforced, and then grouting is used to reinforce and finally form a new type of "old pile new barrel composite foundation"; 2) It can be used for anti-scouring structures after scouring, and can also be used to realize rapid reinforcement "replacement" of the foundation at the original position after the bearing capacity of the machine position is insufficient. The wind turbine tower can be removed without dismantling, saving offshore hoisting costs and precious construction windows; 3) The protective measures can protect the soil on the seabed around the pile from being scoured by the disturbance flow, and the protection range can reach a diameter of 20-54m. The setting of the diagonal brace can play the role of a spoiler, change the flow state around the pile, and further reduce the scouring phenomenon. It is a combination of active and passive anti-scouring structure. 4) After being sunk in place, the exhaust and drainage pipelines can be used as grouting pipelines to grout and reinforce the internal cavity structure, so that the structure, soil and structure form an integral structure, making the protection more effective.

[0044] A protection method for an active and passive combined protection structure considering scour, comprising the following steps: Step 1: Install the support structure 2 and the monopile fixing tube 3 on the outer wall of the monopile structure 1; Step 2: The single pile fixing tube 3 is sunk into the soil under negative pressure, and the water in the enclosed space is pumped out after the enclosed space is buried to achieve pressure difference sinking; Step 3: a grouting body 4 is provided between the single pile structure 1 and the spoiler structure to complete the protection of the single pile structure 1.

[0045] Specifically, firstly, strength test and scheme design are carried out, and then reinforcement construction of the offshore position is started, and the assembled single pile fixing tube 3 is successively sunk into place, generally using a two-piece combined installation method, and after being sunk into place, underwater welding of the structure is carried out, the mud and sand in the grouting body 4 area is cleaned, and grouting reinforcement is carried out to form a new composite foundation. The single pile fixing tube 3 is not limited to the two-piece type of the present invention, and a multi-piece structure design can be carried out in combination with actual geological survey data. The single-piece structure is provided with 2-4 compartments to realize the autonomous sinking process.

[0046] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An active and passive combined protection structure considering scour, characterized in that: It includes a monopile structure (1); A flow-disrupting structure is installed on the outer wall surface of the monopile structure (1), the flow-disrupting structure comprising a supporting structure (2) and a monopile fixing cylinder (3), the supporting structure (2) being located above the monopile fixing cylinder (3); and a grouting body (4) is provided between the monopile structure (1) and the flow-disrupting structure.

2. The active and passive combined protection structure considering scour according to claim 1 is characterized in that: The supporting structure (2) and the monopile fixing cylinder (3) are both vertically mounted on the outer wall of the monopile structure (1).

3. The active and passive combined protection structure considering scour according to claim 1 is characterized in that: The support structure (2) is a combination of one or more of a truss support structure, a frame support structure or a cable support structure.

4. The active and passive combined protection structure considering scour according to claim 1 is characterized in that: The single pile fixing cylinder (3) is formed by splicing baffles.

5. The active and passive combined protection structure considering scour according to claim 1 is characterized in that: A separation seam (5) is provided on the single pile fixing cylinder (3).

6. The active and passive combined protection structure considering scour according to claim 1 is characterized in that: There are a plurality of the support structures (2) and the single pile fixing cylinders (3), which are arranged at equal intervals in the radial direction of the single pile structure (1).

7. The active and passive combined protection structure considering scour according to claim 6 is characterized in that: An exhaust pipeline (31) and a drainage pipeline (32) are provided on the single pile fixing cylinder (3).

8. The active and passive combined protection structure considering scour according to claim 1 is characterized in that: The height of the single pile fixing cylinder (3) is greater than the height of the supporting structure (2).

9. The active and passive combined protection structure considering scour according to claim 1, characterized in that: One end of the support structure (2) abuts against the outer side wall of the grouting body (4), and the other end of the support structure (2) abuts against the upper end surface of the single pile fixing tube (3).

10. A protection method for active and passive combined protection structures taking scouring into consideration, characterized in that: The active and passive combined protection structure considering scour as described in any one of claims 1 to 9 comprises: Installing the supporting structure (2) and the monopile fixing cylinder (3) on the outer wall surface of the monopile structure (1); The single pile fixing cylinder (3) is sunk into the soil under negative pressure, and after the closed space is buried, the water in it is pumped out to achieve pressure difference sinking; A grouting body (4) is provided between the single pile structure (1) and the flow-disturbing structure to complete the protection of the single pile structure (1).

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