Wind power foundation structure with enhanced cold weld interface connection strength

Abstract

The utility model relates to a kind of wind power foundation structure for enhancing the connection strength of cold joint interface, and the interface of lower pouring layer of wind power foundation is uniformly implanted with several layers of embedded fastener, the arrangement of embedded fastener is annularly arranged, embedded fastener is anchored with lower pouring layer, anchor reinforcement is embedded in embedded fastener, embedded fastener inside and outside are respectively annularly arranged annular reinforcement, and annular reinforcement between embedded fastener inside and outside is connected and fixed by truss reinforcement;The combination mode of the embedded fastener, annular reinforcement and truss reinforcement makes the original steel mesh frame in wind power foundation form a whole, can be stressed in coordination, effectively enhances the connection strength of cold joint interface formed by lower pouring layer and upper pouring layer;Solve the problem that the present method is simply implanted in wind power tower drum foundation cold joint interface, when wind power foundation is stressed, each part cannot be deformed in coordination, reduce the overall foundation bearing capacity and stability.

Description

Technical Field

[0001] This utility model belongs to the field of wind power foundations and relates to a wind power foundation structure that enhances the connection strength of cold joint interfaces. Background Technology

[0002] Cold joints are gaps that form during concrete pouring when the earlier poured concrete has already hardened due to excessively long construction intervals, preventing subsequent pours from bonding properly. In wind turbine foundation construction, cold joints are prone to occur due to the large foundation volume and long construction time. Cold joints mainly appear in three locations, such as... Figure 1 As shown.

[0003] The microstructure of the concrete interface at cold joints differs from that of normal concrete. Because the concrete poured first at the cold joint has already hardened, subsequent concrete bonding at the interface cannot achieve sufficient filling and adhesion of the cement paste, creating a weak point. In wind turbine foundations, the shear force between the tower and the foundation is primarily transferred through the foundation's shear strength. The presence of cold joints reduces shear strength; when the tower is subjected to wind forces and shear stress, the foundation's load-bearing capacity is affected, potentially leading to localized foundation failure or even impacting the overall stability of the tower structure.

[0004] To avoid cold joints in wind turbine foundation construction, common preventative measures focus on material selection and construction techniques. Regarding materials, using high-performance concrete and adding interface reinforcing agents and expanding agents effectively improves the concrete's density, impermeability, and integrity. In terms of construction techniques, rationally scheduling pouring times, employing secondary vibration technology, layered pouring, and setting construction joints and post-pouring strips can reduce the risk of cold joint formation. Furthermore, if cold joints are unavoidable during construction, appropriate measures must be taken to treat the cold joint interface to ensure the overall structural mechanical performance of the foundation. Interface treatment typically involves surface cleaning, roughening, and pre-embedding vertical reinforcing bars to minimize the impact of the cold joint interface on the overall foundation performance.

[0005] However, in existing cold joint interface treatment measures, the practice of pre-embedding reinforcing bars at the cold joint is usually to pre-embedding connecting reinforcing bars with a diameter of 16-25 mm at a spacing of about 200-300 mm at the cold joint of the wind turbine tower foundation. The connecting reinforcing bars are fixed to the underlying concrete by drilling and implanting or pre-embedding. Although this can effectively enhance the connection strength of the cold joint interface, since the wind turbine foundation is a monolithic structure after pouring, the tower foundation needs to resist external forces as a whole under long-term wind action. This method of directly enhancing the connection strength of the cold joint interface by pre-embedding reinforcing bars is prone to fatigue failure during long-term operation of the foundation, thereby reducing the overall bearing capacity and stability of the foundation. It cannot ensure that the wind turbine foundation can effectively transfer shear force when under stress. Summary of the Invention

[0006] In view of this, in order to solve the problem that the above-mentioned method of simply planting rebar at the cold joint interface of the wind turbine tower foundation has the problem that the wind turbine foundation cannot deform in a coordinated manner when under stress, thus reducing the overall foundation bearing capacity and stability, this utility model provides a wind turbine foundation structure that enhances the connection strength of the cold joint interface.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A wind power foundation structure for enhancing the connection strength of cold joint interfaces is disclosed. The lower concrete layer is poured first, and the upper concrete layer is poured later. The cold joint interface is the connection between the upper and lower concrete layers. Several layers of embedding members are uniformly embedded in the lower concrete layer where the upper concrete layer is located. The embedding members are arranged in a ring and anchored to the lower concrete layer. Anchoring steel bars are embedded within the embedding members. Circular steel bars are arranged circumferentially on the inner and outer sides of the embedding members, and the inner and outer circumferential steel bars are connected and fixed by truss steel bars. This combination of embedding members, circumferential steel bars, and truss steel bars allows the original steel mesh in the wind power foundation to form a unified whole, enabling it to share the load and effectively enhancing the connection strength of the cold joint interface formed by the lower and upper concrete layers.

[0009] Furthermore, the upper part of the insert has a threaded channel, and one end of the anchoring steel bar is provided with an external thread that matches the threaded channel.

[0010] Furthermore, the insert is cylindrical or cuboid in shape.

[0011] Furthermore, the insert is shaped like a frustum, narrow at the top and wide at the bottom.

[0012] Furthermore, the connection method of the truss reinforcement between the circumferential reinforcement bars is serrated or grid-like.

[0013] Furthermore, the connection between the truss reinforcement and the anchor reinforcement is fixed by welding.

[0014] Furthermore, the interface of the lower pouring layer in the area where the upper pouring layer is located is roughened.

[0015] The beneficial effects of this utility model are as follows:

[0016] 1. The wind power foundation structure for enhancing the connection strength of cold joint interfaces disclosed in this utility model uses a high-pressure water jet flushing method to roughen the interface surface of the lower pouring layer. This method can better handle the cold joint interface formed by the dense steel mesh of the wind power tower foundation, get rid of the limitations of traditional mechanical and manual roughening treatment, and reduce the cost of manpower, material resources and time cycle.

[0017] 2. The wind power foundation structure for enhancing the connection strength of cold joint interfaces disclosed in this utility model increases the interlocking area with the lower concrete layer by embedding a fastener in the area where the wind power foundation is poured, thus preventing it from being pulled out during foundation stress. The conical design of the fastener reduces the difficulty of construction.

[0018] 3. The wind power foundation structure for enhancing the connection strength of cold joint interfaces disclosed in this utility model has a mechanical connection in which the anchoring steel bars are mechanically connected by the internal threaded holes of the embedded fasteners and the threads on one side of the anchoring steel bars being screwed into each other. The anchoring steel bars are more secure and less likely to come out, and can play a better connection role in the long-term operation of the foundation.

[0019] 4. The wind power foundation structure for enhancing the connection strength of cold joint interfaces disclosed in this utility model increases the contact area of ​​the anchoring steel bars in the upper cast layer by arranging circumferential steel bars on the inner and outer sides of the embedding members, and fixing them together with truss steel bars. This allows for coordinated stress distribution and effectively enhances the connection strength of the cold joint interface formed by the upper and lower cast layers. Compared with the traditional method of simply installing rebar, this wind power foundation allows for coordinated deformation of various parts under stress, resulting in better overall foundation bearing capacity and stability.

[0020] Other advantages, objectives, and features of this invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination and study, or may be learned from practice of this invention. The objectives and other advantages of this invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the preferred embodiments of this utility model will be described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1 This is a schematic diagram showing the location of cold joints in the foundation of a wind turbine tower in the background art of this utility model;

[0023] Figure 2 This is a schematic diagram of the wind turbine foundation with cold joints according to this utility model;

[0024] Figure 3 This is a schematic diagram of the installation of circumferential reinforcing bars in a wind turbine foundation for enhancing the connection strength of cold joint interfaces according to this utility model.

[0025] Figure 4 This is a schematic diagram of the installation of circumferential reinforcing bars and embedding components in a wind turbine foundation for enhancing the connection strength of cold joint interfaces according to this utility model.

[0026] Figure 5This is a schematic diagram of the embedded fastener in a wind power foundation for enhancing the connection strength of cold joint interfaces according to this utility model.

[0027] Attached reference numerals: 1. Lower pouring layer; 2. Upper pouring layer; 3. Circumferential reinforcement; 4. Embedded component; 5. Anchor reinforcement; 6. Truss reinforcement. Detailed Implementation

[0028] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model.

[0029] like Figures 2-5 The wind power foundation structure shown is designed to enhance the connection strength of the cold joint interface. The lower concrete area of ​​the wind power foundation is poured first as the lower pouring layer 1, and the upper concrete area is poured later as the upper pouring layer 2. The cold joint interface is the connection between the upper pouring layer 2 and the lower pouring layer 1. Seven layers of embedding members 4 are evenly embedded in the lower pouring layer 1 in the area where the upper pouring layer 2 is located. The embedding members 4 are in the shape of a frustum with a narrow top and a wide bottom. The embedding members 4 are arranged in a ring. The innermost embedding member 4 is adapted to the tower. The embedding member 4 is anchored to the lower pouring layer 1. The upper part of the embedding member 4 has a threaded channel. One end of the anchoring steel bar 5 is provided with an external thread adapted to the threaded channel.

[0030] The inner and outer sides of the insert 4 are respectively arranged with circumferential reinforcing bars 3. The inner and outer circumferential reinforcing bars 3 of the insert 4 are connected and fixed by truss reinforcing bars 6. The connection of the truss reinforcing bars 6 between the circumferential reinforcing bars 3 is serrated. The connection between the truss reinforcing bars 6 and the anchoring reinforcing bars 5 is fixed by welding. The combination of the insert 4, the circumferential reinforcing bars 3 and the truss reinforcing bars 6 makes the original steel mesh in the wind power foundation form a whole, which can work together to bear the force and effectively enhance the connection strength of the cold joint interface formed by the lower pouring layer 1 and the upper pouring layer 2.

[0031] The wind turbine foundation construction method for enhancing the connection strength of cold joint interfaces includes the following steps:

[0032] S1. The concrete of the lower pouring layer 1, which has been pre-set at the cold joint interface, is roughened by high-pressure water jet flushing to wash away the surface slurry layer, expose the coarse aggregate of the concrete, and form a concrete surface with a certain roughness. The bonding ability between the new and old foundation concrete is enhanced by the design of the embedded fastener 4.

[0033] S2. Several layers of embedding members 4 are implanted in the post-cast area of ​​the wind power foundation. The embedding members 4 are arranged in a ring. The embedding members are anchored to the lower cast layer by special anchoring adhesive. The upper part of the embedding member 4 has a pre-set internal thread channel. During construction, the pre-processed external thread section on one side of the anchoring steel bar 5 is screwed into the channel of the embedding member 4. The threads interlock to form a stable mechanical connection.

[0034] S3, circumferential reinforcing bars 3 are arranged on the inner and outer sides of the anchoring reinforcing bars 5, and the inner and outer circumferential reinforcing bars 3 are connected and fixed by truss reinforcing bars 6. The connection method of the truss reinforcing bars 6 between the circumferential reinforcing bars 3 is sawtooth or grid. The connection between the circumferential reinforcing bars 3, the truss reinforcing bars 6 and the anchoring reinforcing bars 5 is fixed by welding.

[0035] S4. Due to various reasons, the concrete pouring work of the wind power foundation was interrupted. The concrete area poured later on the wind power foundation covered the concrete area poured earlier and solidified in advance. The combination of the embedded part 4, the circumferential reinforcement 3, and the connecting reinforcement 6 made the original steel mesh in the wind power foundation interlock and overlap. After the concrete was poured, an overall stress mode was formed, and the foundation as a whole was stressed. This effectively enhanced the connection strength of the cold joint interface formed by the upper pouring layer 2 and the lower pouring layer 1, and strengthened the overall bearing capacity and stability of the foundation.

[0036] Finally, 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 this technical solution, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A wind power foundation structure for enhancing the connection strength of cold joint interfaces, characterized in that, The lower concrete area of ​​the wind power foundation is the lower pouring layer (1), and the upper concrete area is the upper pouring layer (2). The cold joint interface is the connection between the upper pouring layer (2) and the lower pouring layer (1). Several layers of embedding members (4) are evenly embedded in the lower pouring layer (1) in the area where the upper pouring layer (2) is located. The embedding members (4) are arranged in a ring. The embedding members (4) are anchored to the lower pouring layer (1). Anchoring steel bars (5) are embedded in the embedding members (4). Circular steel bars (3) are arranged circumferentially on the inner and outer sides of the embedding members (4). The circumferential steel bars (3) on the inner and outer sides of the embedding members (4) are connected and fixed by truss steel bars (6). The combination of the embedding members (4), circumferential steel bars (3), and truss steel bars (6) makes the original steel mesh in the wind power foundation form a whole, which can work together to bear the force and effectively enhance the connection strength of the cold joint interface formed by the lower pouring layer (1) and the upper pouring layer (2).

2. The wind power foundation structure for enhancing the connection strength of cold joint interfaces as described in claim 1, characterized in that, The upper part of the insert (4) is provided with a threaded channel, and one end of the anchoring steel bar (5) is provided with an external thread that matches the threaded channel.

3. The wind power foundation structure for enhancing the connection strength of cold joint interfaces as described in claim 2, characterized in that, The insert (4) is cylindrical or cuboid in shape.

4. The wind power foundation structure for enhancing the connection strength of cold joint interfaces as described in claim 2, characterized in that, The insert (4) is a frustum shape that is narrow at the top and wide at the bottom.

5. The wind power foundation structure for enhancing the connection strength of cold joint interfaces as described in claim 1, characterized in that, The connection method of the truss reinforcement (6) between the circumferential reinforcement (3) is sawtooth or grid.

6. The wind power foundation structure for enhancing the connection strength of cold joint interfaces as described in claim 1, characterized in that, The truss reinforcement (6) and the anchor reinforcement (5) are fixed by welding.

7. The wind power foundation structure for enhancing the connection strength of cold joint interfaces as described in claim 1, characterized in that, The interface of the lower pouring layer (1) in the area where the upper pouring layer (2) is located is roughened.

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