A foundation structure for onshore wind turbines and its construction method

Abstract

This invention relates to the field of onshore wind turbine foundation technology and discloses an onshore wind turbine foundation structure and its construction method, comprising: a prefabricated outer frame with a narrow top and wide bottom; a prefabricated bottom anti-tilting component including a bottom cylinder disposed in a countersunk hole in the middle of the foundation pit and a reinforcing frame fixed on the bottom cylinder; and a prefabricated top base frame, the top of which sits on top of the prefabricated outer frame, the middle of which is located inside the prefabricated outer frame, and the bottom of which is positioned and engaged with the reinforcing frame, so that the prefabricated outer frame, the prefabricated bottom anti-tilting component, and the prefabricated top base frame are combined into a whole. This invention, through the combined design of the prefabricated outer frame, the prefabricated bottom anti-tilting component, and the prefabricated top base frame, forms a foundation structure with strong integrity and high stability. The connection method between the components can effectively resist lateral forces and overturning moments, ensuring the safe operation of the wind turbine tower.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of land wind turbine foundation, in particular to a land wind turbine foundation structure and a construction method thereof. BACKGROUND

[0002] In the current land wind power field, the design and construction of wind turbine foundation structure face many challenges. The traditional land wind turbine foundation structure has obvious defects in stability. The common foundation structure form is difficult to effectively cope with the huge vertical load generated during the operation of the wind turbine and the lateral force under severe natural conditions such as strong wind. For example, some foundation structures use simple reinforced concrete pouring method, and the steel bar distribution and structure are unreasonable, which cannot form an efficient continuous stress system. During the long-term operation of the wind turbine, the heavy pressure easily leads to deformation of the foundation structure, and when strong wind strikes, the foundation has insufficient anti-inclination ability, which causes the wind turbine to incline or even collapse, seriously affects the safe operation and service life of the wind power facility, and causes huge economic losses. Therefore, we propose a land wind turbine foundation structure and a construction method thereof. SUMMARY

[0003] The purpose of the present application is to provide a land wind turbine foundation structure and a construction method thereof to solve the problems raised in the background.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0005] A land wind turbine foundation structure, comprising:

[0006] a prefabricated outer skeleton with a narrow upper part and a wide lower part, which is arranged in a foundation pit;

[0007] a prefabricated bottom anti-inclination component, which comprises a bottom cylinder arranged in a counterbore in the middle of the foundation pit and a reinforcing skeleton fixed on the bottom cylinder;

[0008] a prefabricated top base skeleton, the top of which is located on the top of the prefabricated outer skeleton and is used for connecting with the wind turbine tower, the middle part of which is located inside the prefabricated outer skeleton and is used for further strengthening the structural strength of the prefabricated outer skeleton, and the bottom of which is positioned and clamped with the reinforcing skeleton, so that the prefabricated outer skeleton, the prefabricated bottom anti-inclination component and the prefabricated top base skeleton are combined into a whole;

[0009] a concrete layer is arranged in the foundation pit and the counterbore, and the concrete layer forms a whole with the prefabricated outer skeleton, the prefabricated bottom anti-inclination component and the prefabricated top base skeleton.

[0010] Preferably, the prefabricated outer skeleton comprises a plurality of side steel bars arranged in a rectangular distribution, upper stirrups fixed at the upper outer sides of the plurality of side steel bars at equal intervals, and lower stirrups fixed at the middle outer sides of the plurality of side steel bars at equal intervals.

[0011] The middle part of the side steel bar is inclined outward, and the size of the lower stirrup gradually increases from top to bottom.

[0012] Preferably, the prefabricated top base framework comprises X-shaped reinforcing members, annular seats fixed at the top of the X-shaped reinforcing members, rectangular columns fixed at the lower end of the middle part of the X-shaped reinforcing members, cross-shaped frameworks arranged on the rectangular columns, and buckle members arranged at the lower part of the rectangular columns for positioning and clamping with the reinforcing frameworks.

[0013] Preferably, the X-shaped reinforcing members are provided with sleeve sockets at the ends, and the sleeve sockets are used for sleeving the top parts of the side steel bars distributed in diagonal lines.

[0014] Preferably, the cross-shaped framework comprises horizontal steel bars fixed in a cross shape on the rectangular columns, and rectangular stirrups fixed outside the horizontal steel bars, wherein the cross-shaped framework is internally provided with first annular steel bars arranged from inside to outside, and the first annular steel bars are located outside the rectangular columns.

[0015] The top part of the annular seat is provided with a plurality of groups of screws at equal intervals, and the screws are locked and fixed by nuts after penetrating through the flanges at the bottom of the fan tower.

[0016] Preferably, the rectangular column is provided with an inner groove at the lower part of the side, the buckle member is a buckle block, the bottom of the buckle block is movably connected in the inner groove by a pin shaft, and the inner side of the bottom of the buckle block is provided with an abutting limiting block.

[0017] Preferably, the reinforcing framework comprises a plurality of groups of circular F-shaped framework assemblies distributed at equal intervals, the F-shaped framework assembly is an F-shaped steel member arranged from inside to outside, the F-shaped steel member comprises top steel bars penetrating and extending out of the upper part of the bottom cylinder and vertical steel bars connected at the bottom of the inner side end of the top steel bars, the top steel bars are connected and fixed by second annular steel bars, the vertical steel bars are located inside the bottom cylinder, and the vertical steel bars are connected and fixed by third annular steel bars.

[0018] The upper part between the innermost vertical steel bars is fixed with a circular connecting block, the middle part of the circular connecting block is provided with a rectangular through groove, and after penetrating and extending out of the rectangular through groove at the bottom of the rectangular column, the buckle block is buckled at the lower end of the circular connecting block.

[0019] The application also provides a construction method of the onshore wind power fan foundation structure, and specifically comprises the following steps:

[0020] S1, according to the design requirements, prefabricating the prefabricated outer framework, the prefabricated bottom anti-inclination assembly and the prefabricated top base framework in the factory;

[0021] S2, excavating a foundation pit and a sink hole at the fan point, and treating the foundation to meet the bearing capacity requirements;

[0022] S3, using the crane to hoist the prefabricated bottom anti-tilting assembly into the counterbore, and carrying out preliminary positioning, using the crane to hoist the prefabricated outer skeleton into the foundation pit, and carrying out preliminary positioning, using the crane to hoist the prefabricated top base skeleton into the foundation pit, and making the top of the prefabricated top base skeleton sit on the top of the prefabricated outer skeleton, the middle part of the prefabricated top base skeleton is located inside the prefabricated outer skeleton, and the bottom of the prefabricated top base skeleton is positioned and connected with the reinforcing skeleton;

[0023] S4, pouring concrete grouting material into the foundation pit and the counterbore, and after the concrete grouting material is cured into a concrete layer, the concrete layer is formed as a whole with the prefabricated outer skeleton, the prefabricated bottom anti-tilting assembly and the prefabricated top base skeleton.

[0024] Compared with the prior art, the beneficial effects of the present application are: the present application forms a foundation structure with high integrity and high stability through the combined design of the prefabricated outer skeleton, the prefabricated bottom anti-tilting assembly and the prefabricated top base skeleton. The connection mode between the parts ensures the effective transmission of the load and the overall stability of the structure, especially in the case of large wind load, which can effectively resist lateral force and overturning moment, and ensure the safe operation of the wind turbine tower. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a three-dimensional structural schematic diagram of the prefabricated outer skeleton, the bottom cylinder, the reinforcing skeleton and the prefabricated top base skeleton of the present application;

[0026] Figure 2 is a sectional view structural schematic diagram of the present application; Figure 1

[0027] Figure 3 is a structural schematic diagram of the present application after construction;

[0028] Figure 4 is an exploded structural schematic diagram of the present application;

[0029] Figure 5 is a three-dimensional structural schematic diagram of the prefabricated outer skeleton of the present application;

[0030] Figure 6 is a three-dimensional structural schematic diagram of the connection between the bottom cylinder and the reinforcing skeleton of the present application;

[0031] Figure 7 is a sectional view structural schematic diagram of the present application; Figure 6

[0032] Figure 8 is a first three-dimensional structural schematic diagram of the prefabricated top base skeleton of the present application;

[0033] Figure 9 is a second three-dimensional structural schematic diagram of the prefabricated top base skeleton of the present application; ​​

[0034] Figure 10 The third perspective view of the prefabricated top base framework of the present application;

[0035] Figure 11 The cross-sectional view of the prefabricated top base framework of the present application;

[0036] Figure 12 The enlarged view of the structure at A in the present application Figure 11

[0037] In the figure: 1, prefabricated outer framework; 101, upper stirrup; 102, lower stirrup; 103, side steel bar; 2, bottom cylinder; 3, reinforcing framework; 301, second ring-shaped steel bar; 302, top steel bar; 303, vertical steel bar; 304, circular connecting block; 305, rectangular through slot; 306, third ring-shaped steel bar; 4, prefabricated top base framework; 401, ring-shaped seat; 402, screw rod; 403, sleeve joint cylinder; 404, X-shaped reinforcing member; 405, rectangular column; 406, buckle block; 407, horizontal steel bar; 408, rectangular stirrup; 409, inner groove; 410, abutting limiting block; 411, pin shaft; 412, first ring-shaped steel bar; 5, foundation pit; 6, counterbore. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0039] Embodiment:

[0040] Please refer to Figures 1-12 The present application provides a technical solution:

[0041] A land-based wind turbine foundation structure comprises:

[0042] The prefabricated outer framework 1 has a narrow upper part and a wide lower part. This design can effectively disperse the upper load, reduce the stress concentration at the bottom of the foundation, and enhance the overall stability. At the same time, this shape helps to resist the lateral force generated by wind load and seismic load, preventing the foundation from tilting or deforming.

[0043] The prefabricated outer framework 1 is arranged in the foundation pit 5, and the prefabricated outer framework 1 is arranged in the foundation pit 5 and forms an integral whole with the foundation pit 5 through a concrete layer. This connection method can ensure the close combination between the foundation and the foundation, and enhance the overturning resistance and overall stability of the foundation.

[0044] ​The prefabricated outer framework 1 comprises a plurality of groups of rectangularly distributed side steel bars 103, upper stirrups 101 fixed at the outer sides of the upper portions of the plurality of groups of side steel bars 103 at equal intervals, and lower stirrups 102 fixed at the outer sides of the middle portions of the plurality of groups of side steel bars 103 at equal intervals;

[0045] The middle portions of the side steel bars 103 are outwardly inclined at an angle of 5°-15°. This can further enhance the lateral force resistance of the framework, especially in the case of large wind loads, and the inclined steel bars can better resist bending moments and shear forces.

[0046] The sizes of the lower stirrups 102 distributed at equal intervals upward and downward gradually increase from top to bottom, and the ratio of the gradual increase of the sizes of the lower stirrups 102 from top to bottom is 1:1.2-1:1.5. That is, the size of the uppermost lower stirrup 102 is the smallest, and the size of the lowermost lower stirrup 102 is the largest. The gradual increase of the sizes of the lower stirrups 102 from top to bottom can effectively disperse loads and ensure that the bearing capacity of the foundation bottom is stronger, preventing uneven settlement or local damage of the foundation.

[0047] The prefabricated bottom anti-inclination assembly comprises a bottom cylinder 2 arranged in a counterbore 6 at the middle of a foundation pit 5 and a reinforcing framework 3 fixed on the bottom cylinder 2;

[0048] The bottom cylinder 2 is arranged in the counterbore 6, which can effectively enhance the overturning resistance of the foundation, especially in the case of large wind loads, the bottom cylinder 2 can provide additional overturning resistance moment.

[0049] The reinforcing framework 3 comprises a plurality of groups of circularly and equally spaced F-shaped framework assemblies, which can further enhance the structural strength of the bottom cylinder 2 and prevent it from deforming or being damaged under load.

[0050] The F-shaped framework assembly is an F-shaped steel bar member arranged from inside to outside, which comprises a top steel bar 302 extending through the upper portion of the bottom cylinder 2 and a vertical steel bar 303 connected to the bottom of the inner side end of the top steel bar 302;

[0051] The top steel bars 302 are connected and fixed by a second annular steel bar 301, which greatly enhances the integrity of the top structure of the reinforcing framework 3. In actual application scenarios, the wind turbine will be subjected to various forces in various directions, including wind force, vibration force generated by its own operation, etc.

[0052] The presence of the second ring-shaped steel bars 301 makes the top steel bars 302 form a stable overall structure, like a strong hoop, tightly constraining each top steel bar 302 together, effectively preventing relative displacement or deformation between the top steel bars 302 under external forces, thereby ensuring the stability of the top of the entire reinforcing framework 3. This stability is crucial for the safety of the wind turbine foundation, as it can ensure that the wind turbine foundation can still reliably support the wind turbine tower under harsh natural environments and complex working conditions, reducing the safety hazards caused by unstable top structures.

[0053] The vertical steel bars 303 are located inside the bottom cylinder 2, and the third ring-shaped steel bars 306 are used to connect and fix between the vertical steel bars 303;

[0054] The design of the third ring-shaped steel bars 306 connecting and fixing the vertical steel bars 303 is also of great significance. The vertical steel bars 303 are located inside the bottom cylinder 2 and are the vertical support structure of the reinforcing framework 3, mainly responsible for bearing the vertical load from the top and transmitting it to the bottom of the foundation.

[0055] The third ring-shaped steel bars 306 connect these vertical steel bars 303 together to form a stable vertical support system. During the operation of the wind turbine, the foundation will be subjected to forces from different directions, including horizontal wind and earthquake forces. The presence of the third ring-shaped steel bars 306 enables the vertical steel bars 303 to better resist these horizontal forces, preventing the vertical steel bars 303 from bending or losing stability. It is like a stabilizer that tightly links each vertical steel bar 303 together, enhancing the lateral displacement resistance and stability of the entire vertical support system.

[0056] The vertical steel bars 303 are the key components of the reinforcing framework 3 to bear vertical loads. The connection of the third ring-shaped steel bars 306 enables the vertical steel bars 303 to jointly bear vertical loads, improving the vertical bearing capacity of the entire structure. At the same time, the third ring-shaped steel bars 306 can also constrain the lateral deformation of the vertical steel bars 303, preventing local buckling during compression, thereby ensuring that the vertical steel bars 303 can fully exert their bearing capacity.

[0057] The upper part of the innermost vertical steel bars 303 is fixed with a circular connecting block 304, and a rectangular through slot 305 is provided in the middle of the circular connecting block 304; the size of the rectangular through slot 305 matches the size of the bottom of the rectangular column 405.

[0058] When the rectangular column 405 penetrates and extends out of the rectangular through slot 305, the buckle block 406 comes into contact with the inner wall of the rectangular through slot 305, so that the buckle block 406 rotates inward with the pin shaft 411 as the center and then closes, so that the buckle block 406 retracts in the inner groove 409;

[0059] After the rectangular column 405 penetrates the rectangular through slot 305, the buckle block 406 rotates outward with the pin shaft 411 as the center under its own gravity, and then expands, so that the top of the buckle block 406 protrudes out of the inner recess 409, and the buckle block 406 is buckled at the lower end of the circular connecting block 304, and the abutting limiting block 410 provided at the bottom of the buckle block 406 abuts against the inner wall of the inner recess 409.

[0060] Automatic buckling mechanism: After the rectangular column 405 penetrates the rectangular through slot 305, the buckle block 406 can automatically expand and buckle at the lower end of the circular connecting block 304 by its own gravity. This automatic buckling mechanism simplifies the assembly process, reduces manual intervention, and improves assembly efficiency.

[0061] No need for additional fixing devices: Since the buckle block 406 can automatically buckle at the lower end of the circular connecting block 304, additional fixing devices (such as bolts, welding, etc.) are not needed, further simplifying the assembly process and reducing assembly difficulty and cost.

[0062] Precise positioning: After the buckle block 406 contacts the inner wall of the rectangular through slot 305, it can rotate inward to close with the pin shaft 411 as the center, ensuring precise positioning of the rectangular column 405 when it penetrates the rectangular through slot 305. This design can effectively prevent deviation during assembly and improve assembly accuracy.

[0063] Reliable connection: The buckle block 406 automatically expands and buckles at the lower end of the circular connecting block 304 under its own gravity, ensuring a firm connection between the two. The design of the abutting limiting block 410 can prevent the buckle block 406 from expanding too much, ensuring the reliability of the connection.

[0064] Enhance the stability and anti-overturning ability of the structure:

[0065] Firm connection: The top of the buckle block 406 is buckled at the lower end of the circular connecting block 304, which can ensure the firm connection between the prefabricated top base skeleton 4 and the reinforcing skeleton 3. This connection method can effectively transfer the upper load and enhance the stability and anti-overturning ability of the overall structure.

[0066] Prevent relative displacement: The abutting limiting block 410 abuts against the inner wall of the inner recess 409, which can prevent the buckle block 406 from relative displacement under the action of load, ensuring the firmness and stability of the connection.

[0067] The design of the circular connecting block 304 and the rectangular through slot 305 can ensure the precise positioning and firm connection between the prefabricated top base skeleton 4 and the reinforcing skeleton 3, prevent relative displacement between the two, and enhance the stability of the overall structure.

[0068] The connection mode of the reinforcing frame 3 and the prefabricated top base frame 4 through the buckle block 406 and the rectangular through slot 305 can ensure accurate positioning and firm connection between the two, prevent relative displacement, and enhance the stability of the overall structure.

[0069] The prefabricated top base frame 4 is located at the top of the prefabricated outer frame 1 and is used to connect with the fan tower, and the top of the prefabricated outer frame 1 is connected with the prefabricated top base frame 4 to form an overall structure, which can effectively transfer the upper load and ensure the stability of the fan tower.

[0070] The middle part of the prefabricated top base frame 4 is located inside the prefabricated outer frame 1 and is used to further strengthen the structural strength of the prefabricated outer frame 1, and the bottom of the prefabricated top base frame 4 is positioned and connected with the reinforcing frame 3, so that the prefabricated outer frame 1, the prefabricated bottom anti-tilting assembly and the prefabricated top base frame 4 are combined into an overall structure.

[0071] The prefabricated top base frame 4 includes an X-shaped reinforcing member 404, a ring-shaped seat 401 fixed at the top of the X-shaped reinforcing member 404, a rectangular column 405 fixed at the lower end of the middle part of the X-shaped reinforcing member 404, a cross-shaped frame provided on the rectangular column 405, and a buckle member provided at the lower part of the rectangular column 405 for positioning and connecting with the reinforcing frame 3.

[0072] The X-shaped reinforcing member 404 is provided with a sleeve socket 403 at the end, which is used to be sleeved on the top of the side steel bar 103 distributed in a diagonal line. The prefabricated top base frame 4 is connected with the side steel bar 103 of the prefabricated outer frame 1 through the sleeve socket 403 to form an overall structure, which can effectively transfer the upper load and ensure the stability of the fan tower.

[0073] The X-shaped reinforcing member 404 can effectively enhance the structural strength of the prefabricated top base frame 4, especially in the case of large wind load, the X-shaped reinforcing member 404 can provide additional bending and shear resistance to prevent deformation or damage of the frame.

[0074] The cross-shaped frame includes horizontal steel bars 407 fixed in a cross shape on the rectangular column 405 and rectangular hoop reinforcement 408 fixed outside the horizontal steel bars 407.

[0075] The cross-shaped frame forms a stable cross-shaped support structure, which can uniformly distribute the load transmitted by the upper fan tower to the prefabricated outer frame 1 and the prefabricated bottom anti-tilting assembly. This design optimizes the load transfer path, reduces local stress concentration, and enhances the bending and shear resistance of the overall structure.

[0076] Under the action of wind load and seismic load, the wind turbine tower will produce complex bending moment and shear force. The cross-shaped skeleton can effectively resist these complex loads and prevent the structure from deforming or being damaged through the cross-shaped distribution of horizontal steel bars 407 and rectangular stirrups 408.

[0077] The cross-shaped skeleton is connected with the side steel bars 103 of the prefabricated outer skeleton 1 through the sleeve 403, forming an integral structure. This connection mode can ensure that the upper load is uniformly transmitted to the prefabricated outer skeleton 1 through the cross-shaped skeleton, enhancing the stability of the overall structure.

[0078] The first annular steel bars 412 are arranged inside the cross-shaped skeleton and from inside to outside, and the first annular steel bars 412 are located outside the rectangular column 405;

[0079] The first annular steel bars 412 inside the cross-shaped skeleton can further enhance the stiffness and anti-deformation ability of the cross-shaped skeleton. The first annular steel bars 412 are arranged from inside to outside, which can effectively resist the circumferential stress generated by external load and prevent local damage to the structure.

[0080] And the diameter of the outermost second annular steel bar 301 is larger than that of the outermost first annular steel bar 412, which is of great significance. From the perspective of structural stability, the larger diameter of the second annular steel bar 301 can provide a wider support range for the top of the reinforcing skeleton 3. When the wind turbine is subjected to external forces from various directions, the larger diameter means that the second annular steel bar 301 can better disperse these external forces and prevent force from concentrating on a local area, thereby avoiding structural deformation or damage due to excessive local stress.

[0081] In terms of load transmission, this design of diameter difference helps to achieve a more reasonable load transmission path. Various loads generated during the operation of the wind turbine are transmitted to the reinforcing skeleton 3 through the top base skeleton 4. Since the second annular steel bar 301 has a larger diameter, it can receive more loads transmitted from the first annular steel bar 412 and uniformly disperse these loads to each top steel bar 302, and then to the structure below. Such a design makes the load transmission smoother and avoids the accumulation of loads in a local area, improving the carrying capacity and stability of the entire foundation structure.

[0082] The annular seat 401 is provided with a plurality of groups of screw rods 402 at equal intervals at the top, and the screw rods 402 are locked and fixed by nuts after penetrating the flange at the bottom of the wind turbine tower. The screw rods 402 provided at the top of the annular seat 401 can ensure the firm connection between the wind turbine tower and the prefabricated top base skeleton 4, preventing the wind turbine tower from displacing or tilting under the action of wind load.

[0083] The lower side of the rectangular column 405 is provided with an inner groove 409, the buckle member is a buckle block 406, the bottom of the buckle block 406 is movably connected in the inner groove 409 by a pin shaft 411, and the inner side of the bottom of the buckle block 406 is provided with an abutting limiting block 410.

[0084] The foundation pit 5 and the sink hole 6 are provided with a concrete layer, which forms an integral whole with the prefabricated outer framework 1, the prefabricated bottom anti-inclination assembly and the prefabricated top base framework 4.

[0085] The concrete layer forms an integral whole with the prefabricated outer framework 1, the prefabricated bottom anti-inclination assembly and the prefabricated top base framework 4, which can effectively enhance the integrity and stability of the foundation and prevent local damage or uneven settlement of the foundation under load. The concrete layer forms an integral whole with these prefabricated components, which can ensure the close combination between the foundation and the ground and enhance the overturning resistance and overall stability of the foundation.

[0086] The concrete grouting material (with a compressive strength generally not less than 60 MPa) is composed of the following components:

[0087] Cement: as the main cementing material, providing the strength basis.

[0088] Aggregate: fine sand or micro aggregate, used for filling and reinforcement.

[0089] Admixtures: such as water reducing agent, expanding agent, early strength agent, etc., used for improving fluidity, expansibility and strength development.

[0090] Mineral admixtures: such as silica fume, fly ash, etc., used for improving durability and strength.

[0091] The application also provides a construction method of the onshore wind turbine foundation structure, specifically comprising the following steps:

[0092] S1, according to the design requirements, prefabricating the prefabricated outer framework 1, the prefabricated bottom anti-inclination assembly and the prefabricated top base framework 4 in a factory;

[0093] S2, excavating the foundation pit 5 and the sink hole 6 at the wind turbine point and treating the ground to meet the bearing capacity requirements;

[0094] S3, using a crane to hoist the prefabricated bottom anti-inclination assembly into the sink hole 6 and preliminarily positioning, using the crane to hoist the prefabricated outer framework 1 into the foundation pit 5 and preliminarily positioning, using the crane to hoist the prefabricated top base framework 4 into the foundation pit 5, so that the top of the prefabricated top base framework 4 is located on the top of the prefabricated outer framework 1, the middle part of the prefabricated top base framework 4 is located inside the prefabricated outer framework 1, and the bottom of the prefabricated top base framework 4 is positioned and clamped with the reinforcing framework 3;

[0095] S4, pouring concrete grout into the foundation pit 5 and the counterfort 6, and after the concrete grout is cured to form a concrete layer, the concrete layer is integrated with the prefabricated outer framework 1, the prefabricated bottom anti-inclination assembly and the prefabricated top base framework 4.

[0096] While embodiments of the application have been shown and described, it is to be understood that the embodiments described are merely divergences and modifications and not limitations of the scope of the application, which is defined by the appended claims and their equivalents.

Claims

1. An onshore windmill foundation structure, characterized in that, include: A prefabricated outer frame with a narrow top and wide bottom is installed inside the foundation pit; The prefabricated bottom anti-tilting component includes a bottom cylinder set in a sinkhole in the middle of the foundation pit and a reinforcing frame fixed on the bottom cylinder; The prefabricated top base frame sits on top of the prefabricated outer frame and is used to connect with the wind turbine tower. The middle part of the prefabricated top base frame is located inside the prefabricated outer frame and is used to further strengthen the structural strength of the prefabricated outer frame. The bottom of the prefabricated top base frame is positioned and snapped with the reinforcing frame, so that the prefabricated outer frame, the prefabricated bottom anti-tilting component and the prefabricated top base frame are combined into a whole. The foundation pit and sinkhole are equipped with a concrete layer, which forms an integral whole with the precast outer frame, the precast bottom anti-tilting component and the precast top base frame. The prefabricated outer frame includes several rectangularly distributed side steel bars, upper stirrups fixed at equal intervals on the outer side of the upper part of several groups of side steel bars, and lower stirrups fixed at equal intervals on the outer side of the middle part of several groups of side steel bars. The middle part of the side reinforcement bars is inclined outward, and the size of the lower stirrups gradually increases from top to bottom; The prefabricated top base frame includes an X-shaped reinforcing member, an annular seat fixed to the top of the X-shaped reinforcing member, a rectangular column fixed to the lower middle part of the X-shaped reinforcing member, a cross-shaped frame set on the rectangular column, and a buckle set at the lower part of the rectangular column for positioning and engaging with the reinforcing frame. The lower side of the rectangular column is provided with an inner groove, and the fastener is a fastening block. The bottom of the fastening block is movably connected to the inner groove by a pin, and the bottom inner side of the fastening block is provided with an abutment limiting block. The reinforcing frame includes several sets of F-shaped frame components distributed at equal intervals in a circular shape. The F-shaped frame components are F-shaped steel bars distributed from the inside to the outside. The F-shaped steel bars include a top steel bar that extends through and protrudes from the upper part of the bottom cylinder and a vertical steel bar connected to the bottom of the inner end of the top steel bar. The top steel bars are connected and fixed with a second ring steel bar. The vertical steel bars are located inside the bottom cylinder and are connected and fixed with a third ring steel bar. A circular connecting block is fixed at the top between the innermost vertical steel bars. A rectangular through groove is provided in the middle of the circular connecting block. After the rectangular through groove is extended through the bottom of the rectangular column, the top of the snap-on block snaps onto the lower end of the circular connecting block.

2. An onshore windmill foundation structure according to claim 1, characterized in that: The X-shaped reinforcing member has a sleeve at its end, which is used to fit onto the top of the diagonally distributed side reinforcing bars.

3. An onshore windmill foundation structure according to claim 1, characterized in that: The cross-shaped frame includes horizontal steel bars fixed in a cross shape on a rectangular column and rectangular stirrups fixed on the outside of the horizontal steel bars. The cross-shaped frame is provided with a first ring steel bar, which is arranged from the inside to the outside and is located on the outside of the rectangular column.

4. An onshore windmill foundation structure according to claim 1, characterized in that: The top of the annular seat is provided with several sets of screws at equal intervals, and the screws are locked and fixed with nuts after passing through the flange at the bottom of the wind turbine tower.

5. A method of construction of a foundation structure for an onshore wind turbine according to any one of claims 1-4, characterized in that: Specifically, the following steps are included: S1. According to the design requirements, prefabricate the prefabricated outer frame, prefabricate the bottom anti-tilting components and prefabricate the top base frame in the factory; S2. Excavate foundation pits and sinkholes at the wind turbine locations, and treat the foundation to meet the bearing capacity requirements; S3, using the crane to hoist the prefabricated bottom anti-tilting assembly into the counterfort, and preliminarily positioning, using the crane to hoist the prefabricated outer skeleton into the foundation pit, and preliminarily positioning, using the crane to hoist the prefabricated top base skeleton into the foundation pit, and making the top of the prefabricated top base skeleton sit on the top of the prefabricated outer skeleton, the middle part of the prefabricated top base skeleton is located inside the prefabricated outer skeleton, and the bottom of the prefabricated top base skeleton is positioned and connected with the reinforcing skeleton; S4, pouring the concrete grouting material into the foundation pit and the counterfort, and after the concrete grouting material is cured into a concrete layer, making the concrete layer form an integral whole with the prefabricated outer skeleton, the prefabricated bottom anti-tilting assembly and the prefabricated top base skeleton.

Images