Wind power tower foundation

Abstract

The invention belongs to the technical field of constructional engineering, and particularly relates to a wind power tower foundation which comprises a bearing platform, the bearing platform comprises a top face and a working face, the top face is connected with the bottom of a tower stand column, the normal of the working face is located between the inclined downward direction and the horizontal direction, and the extending face of the working face and the extending face of the top face intersect on the outer side of a tower body. When the working face is in an exposed state, the outer side forms a prestress system working area. The working face is externally arranged, so that a working cavity does not need to be reserved on the inner side or in the foundation, the size of the foundation is greatly reduced, the construction period can be remarkably shortened, and cost is saved. When the prestressed system needs to be repaired, the ground is excavated from the outer side of the wind power tower to expose the working surface, and the stability and long-term safety of the wind power tower can be ensured by backfilling and burying the foundation after the operation is completed.

Description

Technical Field

[0001] This invention belongs to the field of building engineering technology, and specifically relates to a wind power tower foundation. Background Technology

[0002] The upper part of the steel-concrete lattice tower, where the stress is relatively small, retains the traditional steel tower tube, while the lower part, where the stress is relatively large, adopts steel-concrete lattice columns. That is, a spatial truss structure is formed by welding steel-concrete corner columns and steel pipes, with continuous prestressed tendons inside the corner columns.

[0003] Chinese patent CN121162102A discloses a steel-concrete composite truss hybrid wind turbine tower, comprising a tower, truss units, transition units, and foundation units arranged from top to bottom. Each truss unit includes a main tube body with stranded wires located outside the main tube body. Stranded wire anchors for fixing the lower ends of the stranded wires and embedded pipes for the stranded wires to pass through are located within the foundation foundation. Upper anchoring flanges for fixing the upper ends of the stranded wires are located on the outer periphery of the transition unit truss support. This design exposes the stranded wires outside the main tube body, allowing direct observation of their working condition, but this places extremely high demands on the corrosion resistance of the stranded wires. Furthermore, since the stranded wire anchors are embedded within the foundation foundation, the stranded wires cannot be replaced after corrosion, damage, or breakage, thus affecting the reliability of the tower structure.

[0004] Chinese patent CN120945935A discloses a lattice-type wind turbine tower foundation and its construction method. An embedded pipe is located at the center of the foundation on the lower side of the wind turbine tower column. This embedded pipe is used for threading prestressed steel strands. The prestressed steel strands are adapted to be fixed to the bottom surface of the foundation. A tensioning cavity is provided on the bottom surface of the foundation, providing operational space for tensioning or anchoring the prestressed steel strands. While this structure provides a tensioning cavity and operational space for replacing the steel strands, it also increases the size of the tower foundation, thus increasing the difficulty and cost of foundation construction. Summary of the Invention

[0005] The purpose of this invention is to provide a wind turbine tower foundation that is compact in structure and can meet the needs of steel strand replacement.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: a wind turbine tower foundation, comprising a foundation platform, which includes a top surface and a working surface. The top surface is connected to the bottom of the tower column. The normal of the working surface lies between a downward slope and a horizontal direction. The working surface and the extended surface of the top surface intersect on the outer side of the tower frame. When the working surface is exposed, its outer side constitutes the working area of ​​the prestressed system. A foundation embedded pipe is provided within the foundation platform. One end of the foundation embedded pipe is located on the top surface, and the other end is connected to a lower anchor assembly, which is located at the working surface. The cavity of the foundation embedded pipe communicates with the corresponding cavity of the lower anchor assembly, forming a foundation cable-passing hole that connects the top surface and the working surface. The core line of the foundation cable-passing hole is a curve or a broken line. The lower end of the prestressing tendon passes through the foundation cable-passing hole and is constrained and fixed by the lower anchor assembly, limiting its upward displacement. The prestressing tendons within the foundation embedded pipe are arranged at intervals.

[0007] Compared with existing technologies, this invention has the following technical advantages: By placing the working surface externally, there is no need to reserve a working chamber inside or on the inside of the foundation, greatly reducing the foundation's volume and thus significantly shortening the construction period and saving costs. When repair work on the prestressed system is required, the work can be carried out by excavating the ground outside the wind turbine tower to expose the working surface. After the work is completed, backfilling and burying the foundation ensures the stability and long-term safety of the wind turbine tower. Attached Figure Description

[0008] The following is a brief explanation of the contents depicted in the accompanying drawings and the markings within them:

[0009] Figure 1 This is a basic cross-sectional schematic diagram of Embodiment 1;

[0010] Figure 2-4 This is a basic cross-sectional schematic diagram in other embodiments;

[0011] Figure 5 yes Figure 1 Enlarged schematic diagram of the installation status of the middle and lower anchorage components;

[0012] Figure 6 This is a cross-sectional view of the pre-embedded pipe core perpendicular to the foundation in Embodiment 1.

[0013] Figure 7 , 8 This is a cross-sectional view of the pre-embedded pipe core perpendicular to the foundation in other embodiments;

[0014] Figure 9 This is a half-sectional schematic diagram of the pre-embedded pipe core in the foundation of Example 1;

[0015] Figure 10 This is a half-sectional schematic diagram of the partition block and the positioning tube in their working state. Detailed Implementation

[0016] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and through the description of the examples.

[0017] A wind turbine tower foundation includes a pile cap 10. Example 1 is attached. Figure 1 As shown, the foundation 10 includes a top surface 11 and a working surface 12. The top surface 11 is connected to the bottom of the tower column A. The normal of the working surface 12 lies between a downward slope and a horizontal direction. The working surface 12 intersects with the extension surface of the top surface 11 at the outer side of the tower frame, i.e., the working surface 12 faces the outer side of the wind turbine tower. During the construction phase, the foundation 10 is located within the cavity of the excavated pit, and the outer side of the working surface 12 is exposed. At this time, the outer side of the working surface 12 can be used by workers for prestressing system operations, and the outer side of the working surface 12 constitutes the prestressing system operation area. For this purpose, the lower anchor of the prestressing system needs to be set at the working surface 12. Specifically, a foundation embedded pipe 21 is provided inside the foundation 10. One end of the foundation embedded pipe 21 is located at the top surface 11, and the other end is connected to the lower anchor assembly 22, which is set at the location of the working surface 12. The cavity of the foundation pre-embedded pipe 21 is connected to the cavity correspondingly provided in the lower anchor assembly 22 to form a foundation cable-passing hole 15 that connects the top surface 11 and the working surface 12. The lower end of the prestressed tendon 30 passes through the foundation cable-passing hole 15 and is constrained and fixed by the lower anchor assembly 22 to limit its upward displacement.

[0018] In this embodiment, the working surface 12 is changed from being conventionally placed inside the foundation or inside the wind turbine tower to being placed outside. This eliminates the need to reserve a working chamber inside the foundation, greatly reducing the foundation volume and thus significantly shortening the construction period and saving costs. When it is necessary to replace the prestressing tendons 30, the ground outside the wind turbine tower is excavated to expose the working surface 12, allowing the work to proceed. After the work is completed, the foundation is backfilled and buried to ensure the stability of the wind turbine tower.

[0019] In this embodiment, since the two ends of the foundation cable-passing hole 15 are arranged at an angle, its core line is a curve or a broken line. In the preferred embodiment, in order to ensure the anchoring effect of the lower end of the prestressing tendon 30 and to facilitate the design and arrangement of the lower anchor assembly 22, the core line of the lower end hole segment 15a arranged near the working surface 12 at the lower end of the foundation cable-passing hole 15 is a straight line segment perpendicular to the working surface 12. The upper end of the lower end hole segment 15a is connected to the cavity of the tower column through the transition hole segment 15b. In this embodiment, in order to ensure the reliable arrangement of the prestressing tendon 30, the core line of the transition hole segment 15b is a curved segment. Furthermore, the core line at the upper end of the transition hole segment 15b is tangent to the core line of the cavity of the tower column, or the core line of the upper section of the transition hole segment 15b is parallel to the core line of the cavity of the tower column, so as to ensure the smooth connection of the prestressing tendon 30 at the joint between the foundation 10 and the tower column A.

[0020] As attached Figure 4In the illustrated embodiment, the top surface 11 is horizontally arranged, the working surface 12 is vertically arranged, and the foundation 10 has a square cross-section. This makes the shape of the foundation 10 simple, but the volume of the foundation 10 is relatively large, and the upper part of the outer side of the foundation 10 contributes little to its load-bearing capacity. Therefore, this embodiment includes... Figure 1 As shown, the working surface 12 and the top surface 11 are arranged at an acute angle. If the working surface 12 and the top surface 11 were directly connected, the foundation 10 would have a large top surface 11 and a small outer section thickness at the top, contributing little to the foundation's bearing capacity. Therefore, in this embodiment, the upper edge of the working surface 12 connects to the transition surface 13. The working surface 12 and the transition surface 13 are arranged facing the outer side of the tower frame, forming a protruding shoulder 14. Below the shoulder 14, a prestressed working space with a higher outer edge and a lower inner edge is formed. Here, "outer" refers to the side away from the wind turbine tower, and "inner" refers to the side adjacent to the center of the wind turbine tower. The specific shape and contour of the shoulder 14 can be adjusted according to requirements. In this embodiment, the working surface 12 and the transition surface 13 form an angle. To ensure the reliability of the foundation 10 structure, the angle between the working surface 12 and the transition surface 13 is greater than or equal to 90°, and the upper part of the transition surface 13 is connected to the top surface 11 through a vertical plane. (See attached diagram) Figure 3 In the illustrated embodiment, the transition surface 13 is directly connected to the top surface 11, making the mold assembly of the support platform 10 simpler and more convenient. Another embodiment is shown in the attached figure. Figure 2 As shown, a vertically arranged transition surface 13 is provided along the upper edge of the working surface 12, and the upper edge of the transition surface 13 is connected to another inner surface by a slope. In other embodiments, the top surface 11 may also have a certain slope as needed.

[0021] In a prestressed system, multiple prestressing tendons 30 are usually bundled together to bear the load. In order to avoid the accumulation of adjacent prestressing tendons 30 at the turning point of the foundation cable hole 15, which would cause the prestressing tendons 30 to be squeezed and damaged, in this embodiment, the prestressing tendons 30 located in the foundation embedded pipe 21 are arranged at intervals, so that the prestressing tendons 30 can be replaced.

[0022] To achieve the single-interval arrangement of the entire bundle of prestressed tendons 30, as shown in the attached diagram. Figure 7In the illustrated embodiment, each foundation embedded pipe 21 allows a single prestressing tendon 30 to pass through. Therefore, two or more foundation embedded pipes 21 need to be pre-embedded within the foundation cap 10, ensuring that the number of foundation embedded pipes 21 is greater than or equal to the number of prestressing tendons 30. In this scheme, the foundation embedded pipe 13 is integrally bonded to the concrete of the foundation cap 10, and the interior can contain exposed steel strands. To further protect the steel strands and prevent damage or corrosion during threading or tensioning, a preferred scheme is to thread steel strands covered with an outer sheath within the foundation embedded pipe 21. However, this scheme places high demands on the pre-embedding operation of the foundation embedded pipes 21. The inner diameter of the foundation embedded pipe 21 must be larger than that of the prestressing tendon 30, and a gap must be maintained between adjacent foundation embedded pipes 21 to allow concrete to enter, thus requiring the foundation cap 10 to have a larger volume.

[0023] Better implementation, for example, attached Figure 8 As shown, the foundation embedded pipe 21 contains two or more prestressing tendons 30, and the foundation embedded pipe 21 contains a continuous passage 211 for a single prestressing tendon 30 to pass through. Adjacent continuous passages 211 are arranged at intervals, and the number of continuous passages 211 is greater than or equal to the number of prestressing tendons 30. That is, the foundation embedded pipe 21 contains a pipe or channel for a single prestressing tendon 30 to pass through, and the cavity of the pipe or the cavity of the channel constitutes the continuous passage 211.

[0024] The foundation pre-embedded pipe 21, which has a continuous passage 211 inside, can be pre-embedded in the foundation 10. (See attached image) Figure 8 , 10 In the illustrated embodiment, the foundation embedded pipe 21 is provided with partition blocks 23, and two or more partition blocks 23 are spaced apart along the length of the foundation embedded pipe 21. Through holes 231 are formed on the partition blocks 23, and the core of the through holes 231 is parallel or tangential to the core of the foundation embedded pipe 21. Positioning pipes 232 pass sequentially through the corresponding through holes 231 on each partition block 23. The positioning pipes 232 and the partition blocks 23 form a limiting fit along the length of the positioning pipes 232, and the cavity of the positioning pipes 232 forms a continuous passage 211. (See attached...) Figure 8 , 9 In the embodiment shown, the foundation pre-embedded pipe 21 has a partition block 23 arranged along the length of the pipe, and a through hole 231 is formed on the partition block 23. The cavity of the through hole 231 forms a continuous passage 211.

[0025] Example 1 is attached. Figure 1 , 6As shown in Figure 9, a foundation pre-embedded pipe 21 is pre-embedded in the foundation pier 10, and a grouting hole 24 is provided in the foundation pier 10 to connect the working surface 12 and the cavity of the foundation pre-embedded pipe 21. After the prestressing tendon 30 passes through the foundation cable-passing hole 15, the lower end of the foundation cable-passing hole 15 is closed, and grout is injected into the foundation pre-embedded pipe 21 through the grouting hole 24. After the grout solidifies, it forms a separator block 23. In order to facilitate the grout entering the gap between adjacent prestressing tendons 30, and thus ensure that the prestressing tendons 30 located in the foundation pre-embedded pipe 21 are arranged at intervals, this embodiment provides a separator element 34 on the outer periphery of the prestressing tendon 30. It should be emphasized that since the foundation pre-embedded pipe 21 is embedded in the foundation pier 10, it is impossible to observe the arrangement of the prestressing tendons 30 or the separator element 34 within it. In order to ensure the separation effect while facilitating construction, the separator element 34 is preferably a component attached to the prestressing tendon 30. As shown in the attached figure Figure 6 , 9 As shown, the separating element 34 is a closed ring-shaped component sleeved around the periphery of the prestressing tendon 30. In other embodiments, the separating element 34 may also be an open ring-shaped component sleeved around the periphery of the prestressing tendon 30, or a block sandwiched between adjacent prestressing tendons 30, or a flexible rope wrapped around the periphery of the prestressing tendon 30, or an adhesive tape covering the periphery of the prestressing tendon 30. Further, to ensure that the grout can fill the foundation embedded pipe 21 and fill the gap between it and the prestressing tendon 30, the separating elements 34 attached to adjacent prestressing tendons 30 are staggered in the length direction of the prestressing tendon 30 to ensure the fluidity of the grout filling the foundation embedded pipe 21 in the length direction of the foundation embedded pipe 21. After the grout solidifies, the separating block 23 and the separating element 34 are connected as one unit, so that the separating block 23 and the separating element 34 together form a continuous passage 211 through which the prestressing tendon 30 passes.

[0026] In order to achieve reliable corrosion protection for the prestressing tendons 30 while maintaining the ability to replace them, this embodiment is illustrated in the appendix. Figure 7 As shown, the prestressing tendon 30 comprises, from the inside out, steel strands 31, lubricating grease 32, and a sheath 33. The outer diameter of the tangent circle of the steel strand 31, formed by a bundle of several steel wires, is smaller than the inner diameter of the sheath 33. The lubricating grease 32 fills the gap between the steel strands 31 and the sheath 33, effectively preventing corrosion and maintaining the outer circumferential contour of the sheath 33. In conventional unbonded prestressing tendons, the sheath 33 is attached to the steel strand body 31, and the contour of the steel strand body 31 is visible. In this case, the inner diameter of the sheath 33 is larger than the outer diameter of the steel strand 31, requiring more lubricating grease 32 to fill it completely, thus exposing the contour of the sheath 33 itself. This ensures sufficient lubrication when the steel strand body 31 moves relative to the sheath 33 along the length of the steel strand 30, maintaining the integrity of the inner surface of the outer sheath 33, meeting the requirements for the extraction and insertion of the steel strand body 31, and achieving the effect of replaceable steel strand body 31.

[0027] After the grout injected into the foundation pre-embedded pipe 21 solidifies, the separator 23 and the sheath pipe 33 are connected as one unit, and a passage for the steel strand 31 is formed inside the sheath pipe 33. When replacing the steel strand 31, the damaged steel strand 31 is pulled out at the lower anchor assembly 22. The steel strand 31 can be pulled outward along the length of the sheath pipe 33 under the lubrication of the lubricating grease 32, which also facilitates the insertion of the new steel strand 31.

[0028] It should be further explained that in existing technologies, when steel strand replacement work is required, if it is carried out inside the foundation, the small working chamber inside the foundation limits the use of small-sized equipment. This not only prevents high-power operations but also restricts operation and affects the construction progress. If it is carried out on top of the tower, there are difficulties in hoisting and installing the equipment, and high-altitude operations have high safety requirements, which also significantly increases construction costs. In this embodiment, the working surface 12 is external. This allows the excavation to be carried out according to the size of the required working area, ensuring that the construction area outside the working surface 12 meets the requirements. The size of the site and the selection of equipment for prestressed system construction are no longer constrained by the construction environment.

Claims

1. A wind turbine tower foundation, comprising a pile cap (10), characterized in that: The foundation (10) includes a top surface (11) and a working surface (12). The top surface (11) is connected to the bottom of the tower column (A). The normal of the working surface (12) is located between the oblique downward direction and the horizontal direction. The working surface (12) and the extension surface of the top surface (11) intersect on the outside of the tower frame. When the working surface (12) is exposed, its outer side constitutes the working area of ​​the prestressed system. The foundation (10) is provided with a foundation pre-embedded pipe (21). One end of the foundation pre-embedded pipe (21) is located at the top surface (11), and the other end is connected to the lower anchor assembly (22). The lower anchor assembly (22) is located at the working surface (12). The cavity of the foundation pre-embedded pipe (21) is connected to the cavity of the corresponding hole set in the lower anchor assembly (22) to form a foundation cable-passing hole (15) that connects the top surface (11) and the working surface (12). The core line of the foundation cable-passing hole (15) is a curve or a broken line. The lower end of the prestressing tendon (30) passes through the foundation cable-passing hole (15) and is constrained and fixed by the lower anchor assembly (22) to limit its upward displacement. The prestressing tendons (30) located in the foundation pre-embedded pipe (21) are arranged at intervals.

2. The wind turbine tower foundation according to claim 1, characterized in that: The top surface (11) is arranged horizontally, and the working surface (12) is arranged at an acute angle with the top surface (11). The upper edge of the working surface (12) is connected to the transition surface (13). The working surface (12) and the transition surface (13) are arranged facing the outside of the tower frame and form an outwardly protruding shoulder (14). The area below the shoulder (14) forms a prestressed working space. The angle between the working surface (12) and the transition surface (13) is greater than or equal to 90°.

3. The wind turbine tower foundation according to claim 1, characterized in that: The core line of the lower end section (15a) of the basic cable-passing hole (15) is a straight line perpendicular to the working surface (12). The upper end of the lower end section (15a) is connected to the cavity of the tower column (A) through the transition section (15b). The core line of the transition section (15b) is a curved section. The core line of the hole at the upper end of the transition section (15b) is tangent to the core line of the cavity of the tower column, or the core line of the upper section of the transition section (15b) is arranged parallel to the core line of the cavity of the tower column.

4. The wind turbine tower foundation according to claim 1, characterized in that: There are two or more foundation embedded pipes (21) pre-embedded in the foundation (10), and each foundation embedded pipe (21) allows a single prestressed tendon (30) to pass through.

5. The wind turbine tower foundation according to claim 1, characterized in that: The foundation pre-embedded pipe (21) is provided with two or more prestressed tendons (30), and the foundation pre-embedded pipe (21) is provided with a continuous passage (211) for a single prestressed tendon (30) to pass through. The adjacent continuous passages (211) are arranged at intervals, and the number of continuous passages (211) is greater than or equal to the number of prestressed tendons (30).

6. The wind turbine tower foundation according to claim 5, characterized in that: The foundation pre-embedded pipe (21) is provided with a partition block (23). There are two or more partition blocks (23) spaced apart along the length of the foundation pre-embedded pipe (21). Through holes (231) are opened on the partition blocks (23). The core of the through hole (231) is parallel or tangent to the core of the foundation pre-embedded pipe (21). The positioning pipe (232) passes through the corresponding through holes (231) on each partition block (23) in sequence. The positioning pipe (232) and the partition block (23) form a limiting fit along the length of the positioning pipe (232). The cavity of the positioning pipe (232) forms a continuous passage (211).

7. The wind turbine tower foundation according to claim 5, characterized in that: The foundation pre-embedded pipe (21) has a partition block (23) arranged along the length of the pipe. A through hole (231) is opened on the partition block (23), and the cavity of the through hole (231) forms a continuous passage (211).

8. The wind turbine tower foundation according to claim 7, characterized in that: The foundation (10) is provided with a grouting hole (24) connecting the working surface (12) and the cavity of the foundation pre-embedded pipe (21); after the prestressed tendon (30) passes through the foundation cable hole (15), grout is injected into the foundation pre-embedded pipe (21) from the grouting hole (24), and the grout solidifies to form a partition block (23).

9. The wind turbine tower foundation according to claim 8, characterized in that: The prestressed tendon (30) consists of steel strand (31), lubricating grease (32) and sheath (33) from the inside out. The outer diameter of the bundled steel strand (31) is smaller than the inner diameter of the sheath (33). The lubricating grease (32) fills the gap between the steel strand (31) and the sheath (33) to maintain the outer periphery of the sheath (33). The separator (23) is connected to the sheath (33) as a whole.

10. The wind turbine tower foundation according to claim 8, characterized in that: The prestressing tendon (30) is provided with a partition element (34) on its outer periphery. The partition element (34) is a closed ring-shaped component sleeved on the outer periphery of the prestressing tendon (30), an open ring-shaped component sleeved on the outer periphery of the prestressing tendon (30), a block sandwiched between adjacent prestressing tendons (30), a flexible rope wrapped around the outer periphery of the prestressing tendon (30), or a tape covering the outer periphery of the prestressing tendon (30). The partition block (23) is connected to the partition element (34) as a whole.

11. The wind turbine tower foundation according to claim 10, characterized in that: The separating element (34) attached to the adjacent prestressing tendons (30) is staggered in the length direction of the prestressing tendon (30).

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