Foundation reinforcing structure for replacing small foundation with large foundation for wind turbine generator

Abstract

The utility model discloses a foundation reinforcing structure for replacing a small foundation with a large foundation, and relates to the technical field of wind turbine generators. Comprising an original fan foundation; the mounting part is arranged on a newly-added foundation above the original fan foundation, a tensioning cavity is formed between the mounting part and the original fan foundation, and the prestressed steel strand is arranged in the tensioning cavity; and the fixing part comprises a pre-stressed anchor rod vertically penetrating through the original fan foundation and the newly-added foundation, and embedded steel bars arranged on the original fan foundation and the newly-added foundation. According to the device, an original foundation ring foundation or a pre-stressed anchor bolt foundation does not need to be demolished through blasting, only a foundation ring or an anchor bolt, exposed above the ground, of the original foundation needs to be cut off, reliable connection between new concrete and old concrete is achieved, the modified foundation has excellent stress performance, and it is guaranteed that deformation coordination and common stress are achieved between the new concrete and the old concrete.

Description

Technical Field

[0001] This utility model relates to the technical field of wind turbine generators, and in particular to a wind turbine generator reinforcement structure that uses a large foundation instead of a small one. Background Technology

[0002] Early-stage wind farms, even those in areas with good wind resources, are entering their later operational phases. However, their turbines often have low rated power and their power generation efficiency declines over time. Upgrading to larger turbines can effectively utilize resources, expand installed capacity, and improve efficiency. In the era of grid parity for wind power, the single-unit capacity and rotor diameter of wind turbines are increasing rapidly. Under this trend towards larger turbines, hybrid support towers have become the preferred support structure for large-capacity turbines because they can solve the vibration problems of pure steel towers. Steel-concrete hybrid support towers account for 30% of the market for onshore wind turbines, and are basically used for turbines over 140 meters high. Therefore, using steel-concrete hybrid towers for the "larger-to-smaller" upgrade of wind farms is currently the best option. Utility Model Content

[0003] In view of the problems existing in the current wind turbine reinforcement structure that uses large foundations instead of small foundations, this utility model is proposed.

[0004] Therefore, this utility model provides a wind turbine reinforcement structure that replaces small foundations with large ones. Its purpose is to solve the problem that wind farms put into operation in the early stage have good wind energy resources in the later stage of operation, but the rated power of the units is small and the power generation efficiency decreases after long operation.

[0005] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a wind turbine reinforcement structure that replaces small foundations with large foundations, including the original wind turbine foundation; an installation part, a new foundation set above the original wind turbine foundation, forming a tension cavity with the original wind turbine foundation, and prestressed steel strands set in the tension cavity; and a fixing part, including prestressed anchor rods vertically penetrating the original wind turbine foundation and the new foundation, and rebars set in the original wind turbine foundation and the new foundation.

[0006] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, the bottom diameter of the newly added foundation is larger than the bottom diameter of the original wind turbine foundation.

[0007] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, which uses a large foundation to replace a small foundation, the original wind turbine foundation includes a foundation ring-type wind turbine foundation and a prestressed anchor bolt foundation.

[0008] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, which uses a large foundation to replace a small foundation, the newly added pile foundation is provided at the bottom of the newly added foundation, and a PVC sleeve is provided inside the newly added foundation.

[0009] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, which uses a large foundation instead of a small foundation, the inner diameter of the PVC sleeve is larger than the outer diameter of the prestressed anchor rod.

[0010] The prestressed anchor rod penetrates the original wind turbine foundation and is inserted into the PVC sleeve, forming a non-bonded gap with the PVC sleeve.

[0011] As a preferred embodiment of the wind turbine reinforcement structure of the present invention, which uses a large foundation instead of a small foundation, the tensioning cavity is provided with a cover plate at the top and a ladder is provided inside the tensioning cavity.

[0012] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, which uses a large foundation instead of a small foundation, the prestressed steel strands are arranged in a ring array and are evenly distributed in the circumferential direction of the tensioning cavity.

[0013] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, which uses a large foundation instead of a small foundation, the arrangement direction of the prestressed steel strands is spatially orthogonal to the vertical prestressed anchor rods.

[0014] As a preferred embodiment of the wind turbine reinforcement structure of the present invention, the prestressed anchor rod includes anchor rod one and anchor rod two. Anchor rod one is set between the original wind turbine foundation plate and the newly added foundation plate, and anchor rod one is set between the original wind turbine foundation plate and the newly added foundation column pier.

[0015] As a preferred embodiment of the wind turbine reinforcement structure of this utility model, which uses a large foundation instead of a small foundation, anchor bolt one and anchor bolt two are arranged in parallel.

[0016] The beneficial effects of this utility model are: it does not require blasting to demolish the original foundation ring foundation or prestressed anchor bolt foundation, but only requires cutting off the foundation ring or anchor bolts exposed above the ground, so as to achieve a reliable connection between the old and new concrete and make the modified foundation have excellent stress performance, ensuring that the old and new foundations deform in coordination and share the stress. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a cross-sectional view of the ring-shaped wind turbine foundation in the wind turbine generator reinforcement structure that uses a large foundation to replace a small foundation according to this utility model.

[0019] Figure 2This is a cross-sectional view of the prestressed anchor bolt foundation in a wind turbine reinforcement structure that uses a large foundation instead of a small foundation, according to this utility model.

[0020] Figure 3 This is a basic cross-sectional view of Example 2.

[0021] Figure 4 This is a basic cross-sectional view of Example 3.

[0022] Figure 5 This is a basic cross-sectional view of Example 4. Detailed Implementation

[0023] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0024] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an embodiment that is mutually exclusive, either alone or selectively, with other embodiments.

[0026] Secondly, this utility model is described in detail with reference to the schematic diagrams. When describing the embodiments of this utility model, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of this utility model. In addition, actual manufacturing should include the three-dimensional spatial dimensions of length, width, and depth.

[0027] Example 1

[0028] In this embodiment, to reduce the cost of retrofitting the support structure of early small-capacity wind turbine units and minimize environmental damage, the original wind turbine foundation 1 is retained and connected to the new foundation 21 through prestressed anchor rods 31 and rebar 32 to form an integrated load-bearing system. This avoids blasting demolition, saving both construction time and resources. At the same time, the reinforced foundation can meet the load-bearing requirements of large-capacity units.

[0029] The original wind turbine foundation 1 includes a foundation ring-type wind turbine foundation 11 and a prestressed anchor bolt foundation 12. The foundation ring-type wind turbine foundation 11 consists of a pre-embedded steel annular flange and a reinforced concrete foundation. The foundation ring is typically a cylindrical steel structure with a flange, directly cast on top of the concrete foundation. (See reference...) Figure 1 The steel tower is connected to the flange at the top of the foundation ring by bolts to form a rigid fixation. It is suitable for sites with good geological conditions and no need for complex anti-pull design. The contact surface between the foundation ring wind turbine foundation 11 and the concrete is prone to stress concentration. After long-term operation, fatigue or loosening may occur. When upgrading to a large-capacity unit, the size and strength of the original foundation ring may not meet the stress requirements of the new tower.

[0030] Prestressed anchor bolt foundation 12 uses a group of prestressed anchor bolts instead of a foundation ring. The lower end of the anchor bolt is anchored within the concrete foundation, and the upper end extends beyond the top surface of the foundation. (Refer to...) Figure 2 The steel tower is prestressed by the nuts at the top of the anchor bolts, forming a tight connection with the foundation. The anchor bolts are usually arranged in a ring array and are numerous. This method is suitable for units that require higher overturning resistance and dynamic load adaptability. The prestress is adjustable, which can better resist the overturning moment caused by wind loads. The elastic deformation capacity of the anchor bolts is better than that of the rigid foundation ring, reducing the risk of concrete cracking.

[0031] The new foundation 21 is placed on top of the original wind turbine foundation 1 and anchored using prestressed anchor rods 31 and rebar 32. Its bottom diameter can be enlarged or additional piles can be added to increase the bottom area of ​​the new foundation 21 and distribute the new load. A tensioning cavity 22 is formed within the new foundation 21, providing space for the construction of prestressed steel strands 23. This not only meets the higher requirements of large-capacity units for foundation bearing capacity but also provides prestressing tensioning space for the concrete sections of the hybrid tower.

[0032] The tensioning cavity 22 is located between the old and new foundations, and is topped with a cover plate 221. A ladder 222 is installed inside to facilitate the operation of the prestressed steel strands 23 by construction personnel. The prestressed steel strands 23 are distributed in a ring array, orthogonal to the vertical anchor space, which can apply circumferential prestress to the concrete tower, improve its crack resistance and stiffness, and solve the vibration problem of the tower of large-capacity units.

[0033] The vertical prestressed anchor rods 31 are divided into anchor rod one 311 and anchor rod two 312. The foundation ring-type wind turbine foundation 11 or prestressed anchor bolt foundation 12 is connected to the new foundation 21 through prestressed anchor rod one and anchor rod two 312 and rebar 32. Among them, the construction method of anchor rod one 311 and anchor rod two 312 is relatively special. They are first drilled in the original wind turbine foundation 1, and the drilling depth must reach the bottom of the original foundation slab. Then, grouting is performed to bond the anchor rods to the original wind turbine foundation 1, ensuring that the two can be tightly connected and share the load. In the new concrete foundation, prestressed anchor rod one and anchor rod two 312 pass through the pre-embedded PVC sleeve and are in an unbonded state. This design allows the prestressed anchor rods 31 to better exert their prestressing effect in the new foundation 21, avoids unnecessary constraints between them and the new concrete, and thus more effectively adjusts the stress distribution between the old and new foundations.

[0034] Rebar 32 is inserted into the roughened area of ​​the original foundation surface, and interface adhesive is applied before binding it to the new foundation rebar. This enhances the shear resistance of the interface between the old and new concrete, prevents interface slippage, and improves the overall integrity of the foundation. A PVC sleeve pre-embedded in the new foundation 21 has an inner diameter larger than the anchor rod, forming a non-bonded gap that allows the anchor rod to deform freely, avoiding the influence of concrete constraint on prestressing application and ensuring effective transmission of prestress to the old and new foundations. When the foundation bearing capacity is insufficient, additional piles 211 can be arranged in the extended area at the bottom of the new foundation 21 for reinforcement.

[0035] Example 2

[0036] This embodiment is an upgrade and renovation project that involves increasing the diameter of the foundation ring and adding piles to the outer ring, a "larger-than-smaller" approach. It is applicable to wind turbines that originally used a foundation ring type foundation. (Reference 11) Figure 3 However, the foundation diameter is insufficient and the bearing capacity of the foundation is low. It is necessary to increase the foundation diameter and add pile foundations to meet the upgrade requirements of large-capacity units.

[0037] Specifically, the foundation ring above ground of the foundation ring wind turbine foundation 11 is removed, while the foundation ring wind turbine foundation 11 is retained. The top surface of the foundation ring wind turbine foundation 11 is roughened and a structural interface adhesive is applied to enhance the bond between the new and old concrete. The foundation ring wind turbine foundation 11 is excavated to the design depth to expand the diameter of the foundation pit. According to the geological survey report, pile foundations are added to the outer ring to improve the overturning resistance and bearing capacity.

[0038] Drill holes from the top surface of the original foundation to the bottom of the base plate, insert anchor rod 311 and anchor rod 312, and grout to anchor them. Within the range of the new foundation 21, insert anchor rod 311 and anchor rod 312 into PVC sleeve 212 to ensure that they can be tensioned later. Tie the steel bars of the new foundation 21 and connect them with the rebar 32 to form an integral load-bearing structure.

[0039] Concrete is poured to form a prestressed tension cavity 22. The bottom of the cavity is leveled with plain concrete. After the concrete strength reaches the standard, anchor rod 1 311 and anchor rod 2 312 are tensioned to make the old and new foundations bear the force together. Cover plate 221 is installed to seal the cavity, and ladder 222 is set up for easy maintenance.

[0040] Preserving the original foundation avoids demolition by blasting, reducing renovation costs and environmental impact. Adding pile foundations enhances the bearing capacity of the foundation, making it suitable for soft soil foundations. Prestressed anchor rods 31 ensure that the new and old foundations work together, improving overall stability.

[0041] Example 3

[0042] This embodiment is an upgrade and renovation project that involves increasing the diameter of the prestressed anchor bolt foundation 12 and adding piles to the outer ring, essentially replacing a smaller foundation with a larger one. It is applicable to wind turbines that originally used prestressed anchor bolt foundations 12. Figure 4 It needs to be upgraded to a large-capacity unit, but the original foundation diameter is insufficient and the bearing capacity of the foundation is insufficient, so the foundation needs to be expanded and piles added.

[0043] Remove the anchors above ground of the prestressed anchor foundation 12, retain the structure of the prestressed anchor foundation 12, roughen the top surface of the original foundation and apply interface adhesive, enlarge the diameter of the foundation pit, add outer ring pile foundation to improve the bearing capacity, drill holes on the top surface of the prestressed anchor foundation 12, insert anchor rod 1 311 and anchor rod 2 312, grout and anchor, and insert PVC sleeve 212 into the new foundation 21.

[0044] The steel bars are tied, concrete is poured to form a tension cavity 22, and anchor rods 311 and 312 are tensioned. The cavity is then sealed and a cover plate 221 is installed.

[0045] Suitable for anchor bolt foundation renovation, improving pull-out and overturning resistance, dual reinforcement of pile foundation + spread foundation, suitable for foundations with insufficient bearing capacity.

[0046] Example 4

[0047] This embodiment serves as a reference for "replacing small with large" upgrades and renovations without increasing the foundation diameter, where the anchor bolts are directly anchored into the rock. Figure 5 It is suitable for foundations located in moderately weathered or more weathered rock strata with sufficient compressive bearing capacity but insufficient overturning resistance. There is no need to enlarge the foundation diameter; only the anchor bolts need to be extended to the rock strata.

[0048] The above-ground structure was removed, and the original wind turbine foundation 1 was retained. A hole was drilled from the top surface of the original wind turbine foundation 1 down to the stable rock layer. Anchor bolts 311 and 312 were inserted and grouted for anchoring. The new foundation 21 was poured to form a tension cavity 22.

[0049] No need to expand the foundation, saving construction costs, rock anchors provide strong pull-out resistance and are suitable for rock foundations.

[0050] It should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A wind turbine reinforcement structure that uses a large foundation instead of a small one, characterized in that: include, Original fan foundation (1); The installation part (2) includes a new foundation (21) set above the original fan foundation (1) and forming a tension cavity (22) between it and the original fan foundation (1), and a prestressed steel strand (23) set in the tension cavity (22); as well as The fixing part (3) includes a prestressed anchor rod (31) that runs vertically through the original wind turbine foundation (1) and the new foundation (21), and a rebar (32) installed on the original wind turbine foundation (1) and the new foundation (21).

2. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 1, characterized in that: The bottom diameter of the newly added foundation (21) is larger than the bottom diameter of the original wind turbine foundation (1).

3. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 2, characterized in that: The original wind turbine foundation (1) includes a foundation ring wind turbine foundation (11) and a prestressed anchor bolt foundation (12).

4. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 1, characterized in that: The new pile foundation (211) is set at the bottom of the new foundation (21), and the PVC sleeve (212) is set in the new foundation (21).

5. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 4, characterized in that: The inner diameter of the PVC sleeve (212) is larger than the outer diameter of the prestressed anchor rod (31); The prestressed anchor rod (31) penetrates the original wind turbine foundation (1) and is inserted into the PVC sleeve (212), forming a non-adhesive gap with the PVC sleeve (212).

6. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 1, characterized in that: The tensioning cavity (22) is provided with a cover plate (221) on the upper part, and a ladder (222) is provided inside the tensioning cavity (22).

7. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 1, characterized in that: The prestressed steel strands (23) are arranged in a ring array and are evenly distributed in the circumferential direction of the tension cavity (22).

8. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 7, characterized in that: The arrangement direction of the prestressed steel strands (23) is spatially orthogonal to the vertical prestressed anchor rods (31).

9. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 1, characterized in that: The prestressed anchor (31) includes anchor one (311) and anchor two (312). Anchor one (311) is set between the base plate of the original wind turbine foundation (1) and the base plate of the new foundation (21). Anchor one (311) is set between the base plate of the original wind turbine foundation (1) and the column pier of the new foundation (21).

10. The wind turbine reinforcement structure using a large foundation instead of a small foundation as described in claim 9, characterized in that: Anchor bolt 1 (311) and anchor bolt 2 (312) are set in parallel.

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