A double-conical onshore wind turbine foundation

Abstract

The present invention relates to a double-conical onshore wind turbine foundation, comprising a connected column pier and a cantilever plate, wherein the upper and lower surfaces of the cantilever plate are both conical, and the slope of the lower surface cone is greater than the slope of the upper surface cone. Compared with the prior art, the double-conical foundation of the present invention is easy to vibrate and compact, overcoming the problems of the regular cone foundation in this regard; when the horizontal projection area of ​​the foundation and the load are the same, the double-conical foundation has a smaller settlement than the regular cone foundation, and the bottom surface of the double-conical foundation is an inclined surface, and the contact area with the soil is larger than that of the regular cone foundation; the double-conical foundation is in a three-way compression state, which offsets the internal tensile stress of the foundation and is more favorable for force.

Description

Technical Field

[0001] The present invention relates to the technical field of onshore wind turbine structures, and in particular to a double-conical onshore wind turbine foundation. Background Art

[0002] Wind power generation is the most scalable and commercially promising way of utilizing renewable energy. It is an important national green energy investment project and plays an important role in the development of my country's national economy.

[0003] At present, according to the characteristics of geological conditions, onshore wind power foundation forms can be divided into gravity extended foundation, rock anchor foundation, pile foundation and beam-slab foundation, among which gravity extended foundation and pile foundation are mainly used. These two foundation forms have the characteristics of stable force, simple construction and wide application range.

[0004] At present, the conventional form of pile foundation is a positive cone, and its cross-sectional distribution is closer to the bending moment diagram of the foundation cantilever plate under the action of the foundation reaction force; however, the development direction of wind turbines is to increase the capacity of a single unit and improve the economic requirements. As a result, the diameter of the wind wheel increases, the tower height increases, the foundation load increases, but the total volume of concrete fails to increase in the same proportion. During the design, the thickness of the foundation cantilever plate at the root increases and the thickness of the edge decreases, resulting in an increasing slope on the upper surface of the cantilever plate. The larger slope makes it difficult to vibrate and compact the concrete during construction, and it is more difficult to finish the surface. Construction quality defects such as construction joints, honeycomb holes, and temperature shrinkage cracks often appear on the slope and column piers. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of the existing positive conical pile foundation and provide a double-conical onshore wind turbine foundation with simple construction and reasonable force, which is suitable for pile foundation.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A double-conical onshore wind turbine foundation comprises a double-conical foundation. The double-conical foundation comprises a connected column pier and a cantilever plate, and the upper and lower surfaces of the cantilever plate are both conical.

[0008] In an optional embodiment, the slope of the cone on the lower surface of the cantilever plate is greater than the slope of the cone on the upper surface.

[0009] In an optional embodiment, the conical slope of the upper surface of the cantilever plate is 5° to 10°, and the conical slope of the lower surface is 25° to 30°.

[0010] In an optional embodiment, the bottom area of ​​the cantilever plate is equal to the cross-sectional area of ​​the pier.

[0011] In an optional embodiment, it further includes a plain concrete cushion layer located at the bottom of the double-conical foundation, and a concrete cushion layer is arranged between the plain concrete cushion layer and the double-conical foundation.

[0012] In an optional embodiment, a groove for setting the concrete cushion layer is formed in the middle of the plain concrete cushion layer.

[0013] In an optional embodiment, the double-conical foundation is a reinforced concrete cast-in-place structure.

[0014] In an optional embodiment, the double-conical onshore wind turbine foundation further includes a prestressed anchor assembly that penetrates the double-conical foundation and applies prestress between the upper and lower surfaces of the double-conical foundation.

[0015] In an optional embodiment, high-strength grouting material is also provided between the prestressed anchor assembly and the upper surface of the double-conical foundation.

[0016] In an optional embodiment, the double-conical onshore wind turbine foundation is a pile foundation, and further comprises piles, wherein a plurality of the piles are evenly arranged along a circumference, and the piles are embedded in the double-conical foundation.

[0017] In an optional embodiment, the length of the pile embedded in the double-conical foundation is 50-100 mm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] (1) The present invention improves the construction quality and ensures the bearing strength of the structure. Compared with the traditional technology, the double-cone foundation is easier to construct and vibrate to compact it, which can reduce the construction quality defects such as construction joints, honeycomb holes, temperature shrinkage cracks, etc. between the slope and the column pier due to the large slope, which makes it difficult to vibrate and compact the concrete during construction and the difficulty in finishing the surface.

[0020] (2) The present invention saves the amount of concrete. The edge of the cantilever plate of the double-conical foundation can be made very thin, and the bottom has a slope, such as the edge thickness can be 0.5m to 1m, and the bottom slope can be 25° to 30°, and the foundation volume is smaller, thereby reducing the amount of concrete used.

[0021] (3) The foundation settlement of the present invention is smaller. When the horizontal projection area of ​​the foundation and the load are the same, the bottom surface of the double-conical foundation is an inclined surface, which has a larger contact area with the soil and can reduce the foundation settlement.

[0022] (4) The force of the present invention is more reasonable. Due to the increased horizontal force of the bottom slope, the double-cone foundation is in a three-dimensional compression state in the soil, and the tensile stress inside the foundation is offset, which can give full play to the force-bearing property of concrete that is stronger in compression than in tension. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 A bottom view of the present invention;

[0025] Figure 3 is a side view of the present invention;

[0026] Figure 4 It is a schematic diagram of the component combination of the double-conical foundation of the present invention;

[0027] Figure 5 for Figure 3 AA cross-sectional diagram of ;

[0028] Explanation of the reference numerals in the accompanying drawings: 1. Double-conical onshore wind power foundation; 2. Pile; 3. Plain concrete cushion; 4. Conical foundation pit; 5. Double-conical foundation; 11. Cantilever plate; 12. Column pier; 13. Prestressed anchor bolt assembly; 14. High-strength grouting material; 15. Concrete cushion; 21. First circle of piles; 22. Second circle of piles; 23. Third circle of piles. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0030] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] refer to Figure 1 As shown, this embodiment provides a double-conical onshore wind turbine foundation 1, including a double-conical foundation 5, the double-conical foundation 5 includes a connected column pier 12 and a cantilever plate 11, the upper and lower surfaces of the cantilever plate 11 are both conical, and the slope of the lower surface cone is greater than the slope of the upper surface cone. The lower surface of the wind turbine foundation 1 is a larger slope, and the upper surface retains a smaller slope, balancing the construction difficulty of the upper and lower surfaces, thereby avoiding quality defects caused by the difficulty of the upper surface construction, and at the same time saving the amount of concrete, reducing the foundation settlement, and making the foundation force more reasonable.

[0032] The structure adopts a double-conical foundation, which has the following characteristics: first, the double-conical foundation is easy to vibrate and compact, overcoming the problems of the regular cone foundation in this regard; second, when the horizontal projection area of ​​the foundation and the load are the same, the double-conical foundation has a smaller settlement than the regular cone foundation, and the bottom surface of the double-conical foundation is an inclined surface, and the contact area with the soil is larger than that of the regular cone foundation; in addition, the double-conical foundation is in a three-way compression state (the bottom inclined surface increases the horizontal component of force), which offsets the tensile stress inside the foundation and is more favorable for force.

[0033] In an optional embodiment, the conical slope of the upper surface of the cantilever plate 11 is 5° to 10°, and the conical slope of the lower surface is 25° to 30°.

[0034] The edge of the cantilever plate 11 can be made very thin to save concrete, and when the foundation horizontal projection area and the load are the same, the bottom surface of the double-cone foundation 5 is an inclined surface, and the contact area with the soil is larger than that of the positive cone foundation, and the double-cone foundation 5 has a smaller settlement than the positive cone foundation. Optionally, the edge thickness of the cantilever plate 11 is 0.5m to 1m.

[0035] The bottom area of ​​the cantilever plate 11 is equal to the cross-sectional area of ​​the column pier 12 .

[0036] In an optional embodiment, the double-conical onshore wind turbine foundation 1 further includes a plain concrete cushion layer 3 laid at the bottom of the double-conical foundation 5, and a concrete cushion layer 15 is arranged between the plain concrete cushion layer 3 and the double-conical foundation 5. In one embodiment, a groove for arranging the concrete cushion layer 15 is formed in the middle of the plain concrete cushion layer 3, and the thickness of the concrete cushion layer 15 is 250 mm.

[0037] In an optional embodiment, the double-conical foundation 5 is a reinforced concrete cast-in-place structure.

[0038] Preferably, it also includes a prestressed anchor assembly 13 that penetrates the double-conical foundation 5. The prestressed anchor assembly 13 applies prestress to the upper and lower surfaces of the double-conical foundation 5. There is a high-strength grouting material 14 between the upper surface and the prestressed anchor assembly 13. At the same time, the upper part of the prestressed anchor assembly 13 is used to connect to the wind turbine tower.

[0039] The double-conical onshore wind turbine foundation is suitable for a double-conical foundation of a pile foundation. In one embodiment, the double-conical onshore wind turbine foundation is a pile foundation, and further comprises piles 2, a plurality of piles 2 are evenly arranged along the circumference, and the piles 2 are embedded in the lower end of the double-conical foundation 5. Preferably, the length of the piles 2 embedded in the double-conical foundation 5 is 50-100 mm.

[0040] In one embodiment, the piles 2 are three circles of piles evenly distributed along the circumference, including a plurality of first circle piles 21 evenly distributed along the circle, a plurality of second circle piles 22 evenly distributed along the circle, and a plurality of third circle piles 23 evenly distributed along the circle.

[0041] The construction method of the above-mentioned double-conical onshore wind turbine foundation comprises the following steps:

[0042] A. First, the site is leveled according to the nature of the proposed site, and then the conical foundation pit 4 is excavated. The conical foundation pit 4 is excavated according to the shape characteristics of the double-conical foundation 5 and matches the shape of its lower surface. The foundation plane position should be determined by on-site lofting according to the coordinate value of the center point of the wind turbine foundation. 30cm above the excavation foundation surface is reserved before pouring concrete. The foundation surface foundation is compacted and leveled before the pile foundation project can be carried out.

[0043] B. Piles 2 are arranged symmetrically from the middle to the surrounding areas.

[0044] C. After the pile foundation project is completed, clean up the loose soil and disturbed stones at the bottom of the foundation pit, bury the cable pipe, and then pour the plain concrete cushion layer 3.

[0045] D. After the plain concrete cushion layer 3 is poured, the steel bars inside the foundation are processed and installed, and the prestressed anchor assembly 13 is installed. The horizontality and verticality of the anchor assembly are adjusted to meet the requirements, and then a 250mm concrete cushion layer 15 is poured at the bottom.

[0046] E. After the concrete cushion layer 15 is poured, a double-cone foundation 5 concrete pouring formwork is built to pour the double-cone foundation 5 concrete. The double-cone foundation 5 is poured in layers continuously, and the layer thickness does not exceed the maximum effective thickness of the vibration. The key parts such as the gap between each adjacent anchor bolt in the annular direction are vibrated, and the concrete is cured. Seven days after the double-cone foundation 5 concrete pouring is completed, the high-strength grouting material 14 is constructed. After the concrete formwork is removed, the part below the ground is backfilled.

[0047] F. After the concrete strength of the double-conical foundation 5 reaches 100% and the high-strength grouting material 14 is cured to reach the required strength, the hoisting construction is carried out, the anchor bolts are tensioned to the designed pre-tension, and the overall construction of the double-conical wind power foundation is completed.

[0048] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, which may refer to mechanical connection or electrical connection, or internal communication between two components, or direct connection. "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change;

[0049] Secondly: In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other;

[0050] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A double-conical onshore wind turbine foundation, characterized in that: The double-conical foundation (5) comprises a column pier (12) and a cantilever plate (11) connected to each other, wherein the upper and lower surfaces of the cantilever plate (11) are both conical, and the slope of the conical shape of the lower surface of the cantilever plate (11) is greater than the slope of the conical shape of the upper surface; The conical slope of the upper surface of the cantilever plate (11) is 5° to 10°, and the conical slope of the lower surface is 25° to 30°; The bottom surface area of ​​the cantilever plate (11) is equal to the cross-sectional area of ​​the column pier (12); It also comprises a plain concrete cushion layer (3) located at the bottom of the double-conical foundation (5), a concrete cushion layer (15) being arranged between the plain concrete cushion layer (3) and the double-conical foundation (5), and a groove for arranging the concrete cushion layer (15) being formed in the middle of the plain concrete cushion layer (3); The double-conical onshore wind turbine foundation further comprises a prestressed anchor bolt assembly (13) that penetrates the double-conical foundation (5) and applies prestress between the upper and lower surfaces of the double-conical foundation (5); a high-strength grouting material (14) is also provided between the prestressed anchor bolt assembly (13) and the upper surface of the double-conical foundation (5); The double-conical onshore wind turbine foundation is a pile foundation, and further comprises piles (2), wherein a plurality of the piles (2) are evenly arranged along a circumference, and the piles (2) are embedded in the double-conical foundation (5).

2. The double-conical onshore wind turbine foundation according to claim 1, characterized in that: The double-conical foundation (5) is a reinforced concrete cast-in-place structure.

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