A prestressed fan load-increased expansion foundation reinforcing method and foundation structure

Abstract

The application belongs to the technical field of wind power generation foundation, and provides a prestressed wind turbine load increasing and expansion foundation reinforcing method and foundation structure, which pours a concrete reinforcing layer on the existing foundation, sets prestressed anchor cables outside the outer ring of the existing foundation, sets U-shaped shear reinforcement on the existing foundation, connects the U-shaped shear reinforcement with prestressed steel strands, sets a channel steel coupling beam on the newly poured concrete reinforcing layer, fixes the prestressed anchor cables and the prestressed steel strands to the channel steel coupling beam after the cables and the strands penetrate through the concrete reinforcing layer, sets L-shaped brackets at the wing positions of the channel steel coupling beam, places jacks under the L-shaped brackets to perform jacking when prestress is applied, and simultaneously applies prestress to the prestressed anchor cables and the prestressed steel strands. Only the prestressed anchor cables and the prestressed steel strands need to be lengthened, then the channel steel coupling beam is jacked to a suitable position, and then a layer of concrete reinforcing layer is newly poured, so that the reinforcing reconstruction is completed. No additional measures are needed, the construction is simple, and the reinforcing effect is not reduced.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation foundation technology, and particularly relates to a method and foundation structure for reinforcing a prestressed wind turbine load expansion foundation. Background Technology

[0002] With the upgrading of the demand for the transformation of wind farms that have been in service for a long time, the significant increase in the load on the foundation structure requires the expansion of the foundation area, which is not in line with the background of increasingly scarce land resources. Secondly, new projects need to demolish the original foundations, but due to the high reinforcement ratio of wind power foundations, the demolition work faces the dilemma of long construction period and high cost, while the construction waste generated also faces environmental pressure.

[0003] Current foundation reinforcement methods can solve the problems of foundation strength and stability after the addition of new loads, but they require a large number of anchor cables, and the existing foundation is easily damaged during the anchor cable construction process. At the same time, as a flexible component, anchor cables cannot solve the problem of shear strength between new and old concrete. Furthermore, under the action of wind turbine cyclic load, cracks gradually appear between the new and old foundations, and the durability of the wind turbine foundation is reduced under the influence of groundwater. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a method and structure for reinforcing the foundation of a prestressed wind turbine for load increase and capacity expansion. The reinforcement and renovation are completed simply by extending the prestressed anchor cables and prestressed steel strands, lifting the channel steel connecting beam to a suitable position, and then pouring a new layer of concrete reinforcement. No additional measures are required, construction is simple, and the reinforcement effect is not diminished.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a method for reinforcing the foundation of a prestressed wind turbine for load increase and capacity expansion, employing the following technical solution: A method for reinforcing the foundation of a prestressed wind turbine for load increase and capacity expansion includes: A concrete reinforcement layer is poured on the existing foundation; prestressed anchor cables are installed around the outer ring of the existing foundation, and U-shaped shear bars are installed on the existing foundation, with the U-shaped shear bars connected to the prestressed steel strands; A channel-shaped steel connecting beam is installed on the newly poured concrete reinforcement layer; prestressed anchor cables and prestressed steel strands are both fixed to the channel-shaped steel connecting beam after passing through the concrete reinforcement layer. An L-shaped bracket is installed at the flange of the channel steel connecting beam. When applying prestress, a jack is placed under the L-shaped bracket to lift it up, so that the prestressed anchor cable and the prestressed steel strand are prestressed at the same time.

[0006] Furthermore, the existing foundation surface is roughened, an interface agent is applied, U-shaped shear reinforcement bars and prestressed anchor bolts are inserted, and flanges are placed. At the location of the prestressed anchor cable, the existing foundation is drilled through and the prestressed anchor cable is anchored. Tie the internal steel bars of the concrete reinforcement layer and reserve sleeves on the outside of the prestressed anchor cables and prestressed steel strands; After pouring the concrete reinforcement layer and reaching the design strength, the channel steel connecting beam is installed. The prestressed anchor cables and prestressed steel strands are passed through the openings in the web of the connecting beam and fixed by anchorages. Place the jacks under the L-shaped brackets and lift all the jacks at the same time to apply prestress to the prestressed anchor cables and prestressed steel strands. After the prestress is applied, use grout or concrete to fill the gap between the channel steel connecting beam and the concrete reinforcement layer.

[0007] Furthermore, the surface of the concrete reinforcement layer is roughened and an interface agent is applied. The prestressed anchor cables and prestressed steel strands are extended by extrusion sleeves, with a sleeve reserved on the outside; The channel steel connecting beam was raised to the preset elevation and temporarily fixed. Re-tie the reinforcing bars and pour a new concrete reinforcement layer; After the newly poured concrete reinforcement layer reaches the design strength, the L-shaped bracket is lifted and the gap between the channel steel connecting beam and the concrete reinforcement layer is filled.

[0008] Furthermore, prestressed anchor bolts are implanted at corresponding positions on the upper tower of the wind turbine, exposing the top concrete reinforcement layer, while flanges are installed between the concrete reinforcement layers on the existing foundation.

[0009] To achieve the above objectives, in a second aspect, the present invention also provides a prestressed wind turbine load-increasing and capacity-expanding foundation structure, employing the following technical solution: A prestressed wind turbine load-expansion foundation structure, obtained by the prestressed wind turbine load-expansion foundation reinforcement method as described in any one of claims 1-4, includes an existing foundation, a concrete reinforcement layer located on the existing foundation, prestressed anchor cables penetrating the concrete reinforcement layer and connected at both ends to the existing foundation and a channel steel connecting beam, U-shaped shear reinforcement bars fixed to the existing foundation, and prestressed steel strands penetrating the concrete reinforcement layer and connected at both ends to the U-shaped shear reinforcement bars and the channel steel connecting beam.

[0010] Furthermore, multiple prestressed anchor cables are provided circumferentially at the edge of the existing foundation.

[0011] Furthermore, multiple channel-shaped steel connecting beams are provided circumferentially on the upper part of the concrete reinforcement layer.

[0012] Furthermore, multiple L-shaped brackets are symmetrically arranged on both sides of the channel steel connecting beam.

[0013] Furthermore, the channel steel connecting beam is provided with multiple openings in the web of the connecting beam.

[0014] Furthermore, prestressed anchor bolts are installed between the existing foundation and the upper tower of the wind turbine; a flange is installed on the prestressed anchor bolt at the connection between the existing foundation and the concrete reinforcement layer.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention involves pouring a concrete reinforcement layer on an existing foundation; installing prestressed anchor cables around the outer ring of the existing foundation, and installing U-shaped shear reinforcement bars on the existing foundation, with the U-shaped shear reinforcement bars connected to prestressed steel strands; installing a channel-shaped steel connecting beam on the newly poured concrete reinforcement layer; both the prestressed anchor cables and prestressed steel strands penetrate the concrete reinforcement layer and are fixed to the channel-shaped steel connecting beam; installing L-shaped brackets at the flange positions of the channel-shaped steel connecting beam, and when applying prestress, placing jacks under the L-shaped brackets to lift the beam, so that the prestressed anchor cables and prestressed steel strands are simultaneously prestressed; simply extend the prestressed anchor cables and prestressed steel strands, lift the channel-shaped steel connecting beam to a suitable position, and then pour a new layer of concrete reinforcement to complete the reinforcement and renovation. No additional measures are required, construction is simple, and the reinforcement effect is not diminished.

[0016] 2. This invention connects the foundation to the wind turbine tower by implanting prestressed anchor bolts, which is not limited by the size of the tower. The flange can convert part of the bond force between the anchor bolts and the concrete into pressure on the newly poured concrete reinforcement layer, giving full play to the advantage of the strong compressive bearing capacity of concrete, and the structure is reliable.

[0017] 3. This invention enables the reinforced foundation to meet the stability and bearing capacity requirements by adding a new concrete reinforcement layer and prestressed steel strands. The shear resistance of the new and old concrete is enhanced by U-shaped shear reinforcement bars, and the prestress applied by the prestressed steel strands tightly connects the existing foundation and the concrete reinforcement layer, preventing cracking at the interface between the new and old concrete under cyclic loading.

[0018] 4. The prestressed anchor cable of this invention adopts a pressure dispersion type to avoid cracking of the anchor body under prestress. It is connected to the prestressed steel strand through the channel steel connecting beam at the top of the reinforcement layer to strengthen the overall integrity of the foundation. Jacks are set under the L-shaped bracket to allow the anchor cable and steel strand to be prestressed at the same time, saving procedures and construction time.

[0019] 5. This invention is designed to accommodate multiple load increases and capacity expansions of the wind turbine. The prestressed anchor cables and steel strands are extended, then the channel steel connecting beam is adjusted to a suitable position. Finally, a new concrete reinforcement layer is poured between the connecting beam and the first concrete reinforcement layer. Construction is simple and convenient, and the reinforcement effect is not diminished. Attached Figure Description

[0020] The accompanying drawings, which form part of this embodiment, are used to provide a further understanding of this embodiment. The illustrative embodiments and their descriptions are used to explain this embodiment and do not constitute an improper limitation of this embodiment.

[0021] Figure 1 This forms the basis for the embodiments of the present invention; Figure 2 This is a basic planar schematic diagram of an embodiment of the present invention; Figure 3 This is a schematic diagram of the connection between the U-shaped shear reinforcement and the prestressed steel strand in an embodiment of the present invention; Figure 4 This is a schematic diagram of a channel steel connecting beam according to an embodiment of the present invention; The components include: 1. Existing foundation; 2. Concrete reinforcement layer; 3. Prestressed anchor cable; 4. Channel steel connecting beam; 5. L-shaped corbel; 6. U-shaped shear reinforcement; 7. Prestressed steel strand; 8. Prestressed anchor bolt; 9. Flange; 10. Opening in the web of the connecting beam. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] As described in the background section, the position of the new foundation ring is determined by positioning and leveling. Then, a layer of concrete is poured on top of the existing wind turbine foundation. After the concrete reaches the design strength, the new foundation ring is anchored to the existing wind turbine foundation using a second anchor cable, and prestress is applied. Although this method can solve the problem of foundation strength and stability under new loads, it requires a large number of anchor cables, and the existing foundation can easily be damaged during anchor cable construction. In addition, as a flexible component, the anchor cable cannot solve the problem of shear strength between the old and new concrete.

[0025] An additional section of the foundation slab was constructed around the original wind turbine foundation base slab, and an additional section of the foundation column was constructed outside the original wind turbine foundation column. Rock anchors were connected to the original wind turbine foundation base slab and the additional section of the foundation slab, and the rock anchors were tied together with the underlying rock. The rock anchors were only used to enhance the foundation's resistance to overturning, and shear steel bars were used to connect the old and new concrete. However, under the cyclic load of the wind turbine, cracks gradually appeared between the old and new foundations, and the durability of the wind turbine foundation was reduced due to the influence of groundwater.

[0026] To address at least one of the aforementioned problems, one embodiment of the present invention provides a method for reinforcing the foundation of a prestressed wind turbine for load increase and capacity expansion. This method can prevent cracking between the old and new concrete while ensuring the foundation's strength and stability, and simultaneously preserve the conditions for continued load increase and capacity expansion. The construction includes the following steps: S101. Roughen the surface of the existing foundation 1, apply interface agent, insert U-shaped shear steel bars 6 and prestressed anchor bolts 8 at the corresponding positions, and place the flange 9.

[0027] S102. At the location of the prestressed anchor cable 3, the existing foundation is drilled through and the anchor body of the prestressed anchor cable 3 is constructed. The prestressed anchor cable 3 is preferably of the pressure dispersion type.

[0028] S103. Tie the internal steel bars of the concrete reinforcement layer 2, and reserve sleeves on the outside of the prestressed anchor cable 3 and prestressed steel strand 7 to ensure the length of the free section.

[0029] S104. After pouring the concrete reinforcement layer 2 and reaching the design strength, place the channel steel connecting beam 4, and pass the prestressed anchor cable 3 and prestressed steel strand 7 through the opening 10 in the web of the connecting beam and fix them with anchors.

[0030] S105. Place the jacks under the L-shaped bracket 5 and lift all the jacks at the same time to apply prestress to the prestressed anchor cable 3 and prestressed steel strand 7. After the prestress is applied, use high-strength grout or fine stone concrete to fill the gap between the channel steel connecting beam 4 and the concrete reinforcement layer 2.

[0031] In another embodiment, if the foundation requires multiple load increases, expansions, reinforcements, and modifications, the specific construction method is as follows: S201. Roughen the surface of the concrete reinforcement layer 2 and apply an interface agent.

[0032] S202. The prestressed anchor cable 3 and the prestressed steel strand 7 are extended by extrusion sleeve, with a sleeve reserved on the outside.

[0033] S203. Raise the channel steel connecting beam 4 to a suitable elevation and temporarily fix it with stirrups or similar materials.

[0034] S204. Re-tie the reinforcing bars and pour a new concrete reinforcement layer 2.

[0035] S205. After the newly poured concrete reinforcement layer 2 reaches the design strength, the L-shaped bracket is lifted and the gap between the channel steel connecting beam 4 and the concrete reinforcement layer 2 is filled tightly.

[0036] One embodiment of the present invention also provides a prestressed wind turbine load-increasing and capacity-expanding foundation structure, obtained by a reinforcement method, such as... Figure 1 and Figure 2As shown, the basic structure includes an existing foundation 1, a concrete reinforcement layer 2 set on the existing foundation 1, and prestressed anchor cables 3 set around the existing foundation, mainly addressing the issues of foundation bearing capacity and stability. Prestressed anchor bolts 8 are inserted at corresponding positions on the upper tower of the wind turbine, with the top exposed above the concrete reinforcement layer 2, tightly connecting the tower to the foundation. At the same time, a flange 9 is installed between the existing foundation 1 and the concrete reinforcement layer 2, converting part of the bond force between the anchor bolts and the concrete into pressure on the newly poured concrete reinforcement layer, leveraging the high compressive bearing capacity of concrete.

[0037] The concrete reinforcement layer 2 is located above the existing foundation 1. The top of the concrete reinforcement layer 2 is set as a plane. The concrete reinforcement layer 2 has reserved ducts for prestressed anchor cables 3 and prestressed steel strands 7. The grade, thickness and internal reinforcement of these ducts are determined according to the wind turbine load. The size and model of the reserved prestressed anchor cables 3 are determined according to the wind turbine load.

[0038] like Figure 1 and Figure 3 As shown, U-shaped shear reinforcement 6 is implanted on top of the existing foundation to enhance the shear resistance between the existing foundation 1 and the concrete reinforcement layer 2. Prestressed steel strands 7 pass through the U-shaped shear reinforcement 6 and extend to the top of the concrete reinforcement layer 2. Prestress is applied through the steel strands to ensure a tight fit between the concrete reinforcement layer 2 and the existing foundation 1, preventing interface cracking under the cyclic load of the wind turbine.

[0039] The length of the prestressed steel strand 7 should be sufficient to extend beyond the top surface of the concrete reinforcement layer 2, and the top should retain the condition for extending the steel strand.

[0040] like Figure 1 and Figure 4 As shown, a channel-shaped steel connecting beam 4 is installed on top of the concrete reinforcement layer 2. The web of the beam has openings 10, through which prestressed steel strands 7 and prestressed anchor cables 3 are fixed, enhancing the overall integrity of all prestressed components. L-shaped brackets 5 are installed at the flanges of the channel-shaped steel connecting beam 4. When applying prestress, jacks are placed below the L-shaped brackets 5 for lifting, allowing simultaneous application of prestress to the anchor cables and steel strands, saving steps and construction time.

[0041] A channel-shaped steel connecting beam 4 is installed on the top surface of the concrete reinforcement layer 2. The width of the channel-shaped steel connecting beam 4 is sufficient to accommodate the anchorage of the lower prestressed component. The web of the channel-shaped steel connecting beam 4 has pre-reserved openings 10 according to the positions of the prestressed steel strands 7 and prestressed anchor cables 3. L-shaped brackets 5 are installed at certain intervals on both sides of the channel-shaped steel connecting beam 4. The area below the L-shaped brackets 5 is sufficient to accommodate jacks.

[0042] Understandably, this invention retains the conditions for multiple load-increasing and capacity-expanding foundation reinforcement and modification. The reinforcement and modification can be completed simply by extending the prestressed anchor cables 3 and prestressed steel strands 7, then lifting the channel steel connecting beam 4 to a suitable position, and finally pouring a new concrete reinforcement layer 2. No additional measures are required, construction is simple, and the reinforcement effect is not diminished.

[0043] The above description is merely a preferred embodiment of this practice and is not intended to limit the scope of this practice. Various modifications and variations can be made to this practice by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this practice should be included within the protection scope of this practice.

Claims

1. A method for reinforcing the foundation of a prestressed wind turbine for load increase and capacity expansion, characterized in that, include: A concrete reinforcement layer (2) is poured on the existing foundation (1); prestressed anchor cables (3) are installed on the outer ring of the existing foundation (1); U-shaped shear reinforcement (6) is installed on the existing foundation (1); and the U-shaped shear reinforcement (6) is connected to the prestressed steel strands (7). The U-shaped shear reinforcement (6) is used to enhance the shear resistance between the existing foundation (1) and the concrete reinforcement layer (2); A channel steel connecting beam (4) is installed on the newly poured concrete reinforcement layer (2); the prestressed anchor cable (3) and the prestressed steel strand (7) are both fixed to the channel steel connecting beam (4) after passing through the concrete reinforcement layer (2); An L-shaped bracket (5) is set at the flange position of the channel steel connecting beam (4). When applying prestress, the jack is placed under the L-shaped bracket (5) to lift it up, so that the prestressed anchor cable (3) and the prestressed steel strand (7) are prestressed at the same time. To allow for multiple load increases and capacity expansions of the wind turbine, the prestressed anchor cables and steel strands were extended. Then, the channel steel connecting beam was adjusted to a suitable position, and finally, a new concrete reinforcement layer was poured between the connecting beam and the first concrete reinforcement layer.

2. The method for reinforcing a prestressed wind turbine foundation for load increase and capacity expansion as described in claim 1, characterized in that, Roughen the surface of the existing foundation (1), apply an interface agent, insert U-shaped shear reinforcement (6) and prestressed anchor bolts (8), and place flanges (9). At the location of the prestressed anchor cable (3), the existing foundation (1) is drilled through and the prestressed anchor cable (3) is anchored. Tie the internal steel bars of the concrete reinforcement layer (2) and reserve sleeves on the outside of the prestressed anchor cable (3) and prestressed steel strand (7); After pouring the concrete reinforcement layer (2) and reaching the design strength, place the channel steel connecting beam (4), and pass the prestressed anchor cable (3) and prestressed steel strand (7) through the opening (10) in the web of the connecting beam and fix them with anchors; Place the jacks under the L-shaped bracket (5), and lift all the jacks at the same time to apply prestress to the prestressed anchor cable (3) and prestressed steel strand (7). After the prestress is applied, use grout or concrete to fill the gap between the channel steel connecting beam (4) and the concrete reinforcement layer (2).

3. The method for reinforcing the foundation of a prestressed wind turbine for load increase and capacity expansion as described in claim 2, characterized in that, Roughen the surface of the concrete reinforcement layer (2) and apply an interface agent; The prestressed anchor cable (3) and prestressed steel strand (7) are extended by extrusion sleeve, with a sleeve reserved on the outside; The channel steel connecting beam (4) is raised to the preset elevation and temporarily fixed; Re-tie the reinforcing bars and pour a new concrete reinforcement layer; After the newly poured concrete reinforcement layer (2) reaches the design strength, the L-shaped bracket (5) is lifted and the gap between the channel steel connecting beam (4) and the concrete reinforcement layer (2) is filled.

4. The method for reinforcing a prestressed wind turbine foundation for load increase and capacity expansion as described in claim 2, characterized in that, Prestressed anchor bolts (8) are inserted at the corresponding positions on the upper tower of the wind turbine, and the top is exposed with concrete reinforcement layer (2). At the same time, flanges (9) are installed between the concrete reinforcement layers (2) on the existing foundation (1).

5. A prestressed wind turbine load-increasing and capacity-expanding foundation structure, characterized in that, The method for strengthening the foundation of a prestressed wind turbine by increasing load and expanding capacity as described in any one of claims 1-4 includes an existing foundation (1), a concrete reinforcement layer (2) located on the existing foundation (1), a prestressed anchor cable (3) that penetrates the concrete reinforcement layer (2) and is connected at both ends to the existing foundation (1) and the channel steel connecting beam (4), a U-shaped shear steel bar (6) fixed to the existing foundation (1), and a prestressed steel strand (7) that penetrates the concrete reinforcement layer (2) and is connected at both ends to the U-shaped shear steel bar (6) and the channel steel connecting beam (4).

6. The prestressed wind turbine load-increasing and capacity-expanding foundation structure as described in claim 5, characterized in that, Multiple prestressed anchor cables (3) are provided circumferentially at the edge of the existing foundation (1).

7. The prestressed wind turbine load-increasing and capacity-expanding foundation structure as described in claim 5, characterized in that, On the upper part of the concrete reinforcement layer (2), multiple channel steel connecting beams (4) are provided along the circumference.

8. The prestressed wind turbine load-increasing and capacity-expanding foundation structure as described in claim 5, characterized in that, Multiple L-shaped brackets (5) are symmetrically arranged on both sides of the channel steel connecting beam (4).

9. The prestressed wind turbine load-increasing and capacity-expanding foundation structure as described in claim 5, characterized in that, The channel steel connecting beam (4) is provided with multiple connecting beam web openings (10).

10. The prestressed wind turbine load-increasing and capacity-expanding foundation structure as described in claim 5, characterized in that, A prestressed anchor bolt (8) is provided between the existing foundation (1) and the upper tower of the wind turbine; a flange (9) is provided on the prestressed anchor bolt (8) at the connection between the existing foundation (1) and the concrete reinforcement layer (2).

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