Fan foundation structure

Abstract

The utility model relates to the technical field of wind power generation, in particular to a draught fan foundation structure which comprises a lower barrel, and the lower barrel and a foundation of the draught fan foundation structure form an integral structure. The upper stand is arranged at the top of the lower cylinder, a cavity is formed in the upper stand, and a concrete cushion layer is arranged at the bottom of the upper stand; when the lower cylinder body and the upper stand are in a combined state, horizontal force and bending moment transmitted by the upper fan are balanced through lateral passive soil pressure provided by the covering soil body of the lower cylinder body. According to the scheme, the defect that in the prior art, a traditional gravity expansion type foundation is difficult to meet the bearing requirement under the condition that land use is limited is overcome, the land use area is saved, the bearing capacity and stability of the foundation structure are improved, and meanwhile the overall manufacturing cost of a wind power plant is reduced.

Description

Technical Field

[0001] This utility model relates to the field of wind power generation technology, and in particular to a wind turbine foundation structure. Background Technology

[0002] As the small-capacity wind turbines installed in early wind farms gradually enter their aging stage, the market for retrofitting old wind farms has shown enormous potential.

[0003] Currently, most older wind farms have a single turbine capacity of 1.5MW or less, while the single turbine capacity of modern onshore wind turbines is rapidly increasing, with the largest exceeding 10MW. However, in mountainous wind farms, especially under rock foundation conditions, traditional steel-concrete tower foundations typically employ a gravity-spreading design. When faced with the need for "replacing smaller turbines with larger ones," this traditional gravity-spreading foundation often struggles to meet the new requirements due to limited land availability at turbine sites and potential land restrictions caused by administrative boundaries. Utility Model Content

[0004] This utility model provides a wind turbine foundation structure to solve the defects of traditional gravity-extended foundations in the prior art that are difficult to meet the load-bearing requirements under land-limited conditions. It saves land area, improves the load-bearing capacity and stability of the foundation structure, and reduces the overall cost of the wind farm.

[0005] This utility model provides a wind turbine foundation structure, including: a lower cylinder, which forms an integral structure with the foundation of the wind turbine foundation structure; and an upper column, which is disposed on the top of the lower cylinder, with a cavity inside the upper column and a concrete pad layer at the bottom of the upper column; when the lower cylinder and the upper column are combined, the horizontal force and bending moment transmitted by the upper wind turbine are balanced by the lateral passive earth pressure provided by the soil covering the lower cylinder.

[0006] According to one embodiment of the present invention, the lower cylinder includes a diaphragm wall connected to the foundation, the diaphragm wall being a hole structure formed by rotary drilling for pouring concrete; the inner side of the diaphragm wall is covered with soil to form an integral load-bearing structure.

[0007] According to one embodiment of the present invention, the lower cylinder is entirely buried in the soil layer, and the axial length of the lower cylinder is greater than or equal to the diameter of the lower cylinder.

[0008] According to one embodiment of the present invention, the upper column is provided with column reinforcement bars, and the lower cylinder is provided with a cylinder reinforcement cage; the longitudinal main reinforcement bars of the cylinder reinforcement cage extend toward the upper column and overlap with the column reinforcement bars to form an integral reinforcement connection structure.

[0009] According to one embodiment of the present invention, the cylindrical steel cage is an integral prefabricated structure; the number, diameter and arrangement of the longitudinal steel bars of the cylindrical steel cage are adapted to the column steel bars.

[0010] According to one embodiment of the present invention, the longitudinal steel bars of the cylindrical steel cage have a reserved lap joint at one end facing the upper column, and the reserved lap joint and the column steel bars are bound together to form a rigid connection node.

[0011] According to one embodiment of the present invention, the upper column and the lower cylinder include a main structure formed by pouring C40 / C45 concrete, and the concrete cushion layer is a C20 concrete cushion layer with a thickness of 100mm or more.

[0012] According to one embodiment of the present invention, in the junction area between the lower cylinder and the upper column, the concrete surface of the lower cylinder is provided with a roughened interface to enhance the concrete connection strength with the upper column.

[0013] According to one embodiment of the present invention, a backfill area for filling and compacting a concrete layer is provided around the upper column, and the concrete layer forms a continuous stress transmission path with the lower cylinder and the foundation.

[0014] According to one embodiment of the present invention, the foundation pit of the backfill area of ​​the upper column is a slope structure formed by sloping excavation, and the slope angle of the slope structure is designed according to the foundation soil and rock conditions.

[0015] The wind turbine foundation structure provided by this utility model effectively solves the problem of traditional gravity-spread foundations failing to meet load-bearing requirements under land-constrained conditions by introducing a design that combines a lower cylinder with an upper support column. Specifically, the lower cylinder extends deep into the foundation and forms an integral structure with it, allowing the entire cylinder and the surrounding soil to work together to provide additional lateral passive earth pressure, thereby balancing the horizontal forces and bending moments transmitted by the upper wind turbine. Simultaneously, the cavity design within the upper support column reduces material usage and lowers its own weight, further reducing pressure on the foundation. This combined structure can significantly reduce the required land area while ensuring or even improving the foundation's load-bearing capacity and stability, making it suitable for wind farm environments with limited land or complex terrain. Therefore, the wind turbine foundation structure provided by this utility model not only achieves the goal of saving land area but also reduces material costs and construction difficulty through optimized structural design, thereby effectively reducing the overall cost of the wind farm. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a cross-sectional structural diagram of the wind turbine foundation structure provided by this utility model.

[0018] Figure 2 This is a schematic diagram of the stress distribution of the wind turbine foundation structure provided by this utility model.

[0019] Figure 3 This is a schematic diagram of the lower cylinder of the fan foundation structure provided by this utility model.

[0020] Figure 4 This is a plan view of the lower cylinder of the fan foundation structure provided by this utility model.

[0021] Figure 5 This is a schematic diagram of the connection structure between the cylindrical steel cage and the column steel bars of the wind turbine foundation structure provided by this utility model.

[0022] Figure label:

[0023] 10. Lower cylinder; 11. Hollow structure; 12. Cylinder reinforcement cage; 13. Reserved lap joint; 20. Upper column; 21. Cavity; 22. Concrete pad; 23. Column reinforcement; 24. Backfill area. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] In the description of the embodiments of this utility model, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance. It should also be noted that in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0026] This invention provides a wind turbine foundation structure that effectively reduces the land area required by introducing a lower cylindrical structure, thereby lowering the overall cost of the wind farm. Compared to traditional designs, this structure significantly reduces the required foundation footprint while ensuring or even improving the foundation's load-bearing capacity and stability. This optimized design is particularly suitable for wind farm environments with limited land or complex terrain, not only improving land use efficiency but also further controlling costs by reducing material usage and construction difficulty.

[0027] The following is combined Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 This invention describes the specific implementation of the wind turbine foundation structure.

[0028] like Figure 1 and Figure 2 As shown, the wind turbine foundation structure provided by this utility model includes: a lower cylinder 10, which forms an integral structure with the foundation of the wind turbine foundation structure; an upper column 20, which is set on the top of the lower cylinder 10, and the interior of the upper column 20 forms a cavity 21, with a concrete pad 22 at the bottom of the upper column 20; when the lower cylinder 10 and the upper column 20 are combined, the lateral passive earth pressure provided by the soil covering the lower cylinder 10 balances the horizontal force and bending moment transmitted by the upper wind turbine. This wind turbine foundation structure, by introducing a design that combines the lower cylinder 10 and the upper column 20, effectively solves the defect of traditional gravity spread foundations that are difficult to meet the load-bearing requirements under limited land conditions.

[0029] Specifically, the lower cylinder 10 is tightly integrated with the foundation, forming a unified structure with the encasing soil. Because the foundation depth is greater than traditional spread foundations, the bearing capacity of the foundation, after modification, can basically meet the required bearing capacity. This design not only improves the overall stability and bearing capacity of the foundation but also reduces the footprint. The cavity 21 formed inside the upper column 20 reduces its self-weight, further reducing pressure on the foundation, while providing necessary space for equipment installation or maintenance. Furthermore, during construction, the lower cylinder 10 is excavated and poured first, then a concrete pad 22 is precisely laid on top, and finally the upper column 20 is poured, ensuring a tight connection between the upper and lower parts to work together to withstand various loads from the upper fan.

[0030] Furthermore, in the above technical solution, rotary drilling can be used to construct the diaphragm wall of the lower cylinder 10, which not only improves the drilling accuracy but also effectively addresses complex geological conditions. The reinforcing cage can serve as the main reinforcement material for the lower cylinder 10; the quantity and diameter of its longitudinal reinforcing bars should be designed according to actual load-bearing requirements and securely lapped with the reinforcing bars of the upper column 20. In addition, at the junction of the two parts, the concrete of the cylinder can be roughened to enhance the bond strength between the upper and lower parts, ensuring the integrated performance of the entire foundation structure.

[0031] The foundation structure of this type of wind turbine is located on a rocky foundation in a mountain wind farm. The upper platform (20-meter slab) can be constructed using conventional excavation or blasting methods. However, the lower cylindrical diaphragm wall presents significant construction challenges due to its unique geological conditions and design requirements. Rotary drilling is the preferred method to ensure drilling accuracy and construction efficiency. In preferred cases, such as... Figure 3 and Figure 4 As shown, according to a wind turbine foundation structure of this utility model, the lower cylinder 10 includes a diaphragm wall connected to the foundation. The diaphragm wall is a hole structure 11 formed by rotary drilling for pouring concrete. The inner side of the diaphragm wall is covered with soil to form an integral load-bearing structure. Specifically, during construction, a rotary drilling rig is first used to precisely drill holes at predetermined locations to form holes suitable for pouring concrete. These holes are closely arranged around the circumference, which not only provides space for subsequent concrete pouring but also ensures that the diaphragm wall can penetrate deep into the foundation and be tightly integrated with it, enhancing the stability and load-bearing capacity of the entire foundation structure. Next, a reinforcing cage can be installed in the drilled holes. After the reinforcing cage is installed, concrete is poured to ensure that the concrete fully fills and encloses the reinforcing cage, forming a solid diaphragm wall.

[0032] The thickness and length of the lower cylinder 10 can be calculated and designed based on the parameter information of the upper column 20. Preferably, according to the wind turbine foundation structure of this invention, the lower cylinder 10 is entirely buried in the soil, and the axial length of the lower cylinder 10 is greater than or equal to its diameter. Specifically, during the design phase, a comprehensive assessment of the geological conditions of the construction site is required, including key factors such as soil type and foundation bearing capacity. Based on these data and the design parameters of the upper column 20 (such as dimensions, weight, and the load it bears), the optimal thickness and length of the lower cylinder 10 are calculated through detailed mechanical analysis. Generally, a longer cylinder can provide a greater burial depth, thereby utilizing deeper layers of foundation material to enhance the overall bearing capacity and improving structural stability through lateral earth pressure.

[0033] During construction, a rotary drilling rig is first used to precisely drill holes according to predetermined design parameters, forming suitable cavities for concrete pouring. Then, the customized reinforcing cage is hoisted into the hole, and after ensuring its accurate positioning, concrete pouring is carried out. Furthermore, the axial length of the lower cylinder 10 is preferably not less than the cylinder diameter, which not only effectively distributes the load transferred to the foundation but also utilizes the passive earth pressure provided by the surrounding soil to further enhance the stability and seismic performance of the foundation structure.

[0034] In preferred cases, such as Figure 1 and Figure 5 As shown, according to a wind turbine foundation structure of this utility model, the upper column 20 is provided with column reinforcing bars 23, and the lower cylinder 10 is provided with a cylinder reinforcing cage 12; the longitudinal main bars of the cylinder reinforcing cage 12 extend upward to the upper column 20 and overlap with the column reinforcing bars 23 to form an integral reinforcing bar connection structure. Specifically, during construction, a rotary drilling rig is first used to precisely drill holes at predetermined locations to form holes suitable for concrete pouring. Next, a prefabricated cylinder reinforcing cage 12 is installed in the holes. This reinforcing cage consists of multiple longitudinal main bars and transverse stirrups, the size and specifications of which need to be determined according to detailed mechanical calculations to meet actual load-bearing requirements. After the installation of the cylinder reinforcing cage 12 is completed, concrete pouring is carried out to ensure that the concrete fully fills and encloses the reinforcing cage, forming a solid lower cylinder 10. The reinforcing bars of the upper column 20 are tied, including overlapping and tying the reserved longitudinal main bars of the cylinder reinforcing cage 12 with the reinforcing bars in the upper column 20 to form a continuous integral reinforcing bar structure. This connection method ensures a more uniform and effective transfer of force between the upper and lower parts, improving the overall integration and stability of the foundation structure. Finally, the concrete for the upper column 20 is poured, and the formwork is removed after reaching the specified demolding strength.

[0035] The wind turbine foundation structure consists of two parts: an upper support column and a lower cylinder. Construction can be completed in two stages. Therefore, to simplify the construction process and ensure structural integrity, the cylinder reinforcement should preferably be fabricated as a single precast reinforcement cage. The number and diameter of its longitudinal reinforcement bars should be consistent with those of the upper support column 20, allowing for direct hoisting and installation after the excavation of the diaphragm wall openings. Preferably, according to this wind turbine foundation structure, the cylinder reinforcement cage 12 is a precast structure; the number, diameter, and arrangement of the longitudinal reinforcement bars in the cylinder reinforcement cage 12 are compatible with those of the support column reinforcement 23. Specifically, the number, diameter, and arrangement of the longitudinal reinforcement bars in the cylinder reinforcement cage 12 are compatible with those of the upper support column 20 to ensure reliable connection and form a unified, integral reinforcement structure.

[0036] In practice, the specific parameters of the cylindrical steel cage 12 are first determined based on detailed geological survey data and structural design requirements, including the quantity and diameter of longitudinal steel bars and the spacing of transverse stirrups. These parameters can be determined through precise calculations to meet actual load-bearing requirements and ensure that the steel cage has sufficient strength and rigidity. After the excavation of the diaphragm wall opening is completed, the prefabricated cylindrical steel cage 12 is hoisted to the predetermined position. Since the steel cage is designed according to the same specifications as the upper column 20, attention needs to be paid to the reserved length of the longitudinal steel bars during installation to ensure that they can be smoothly overlapped with the steel bars in the upper column 20.

[0037] Preferably, the longitudinal main bars of the reinforcing cage can be reserved with a certain lap length for subsequent binding and connection with the upper column 20 reinforcing bars, forming a solid integral reinforcing steel structure. After the installation of the cylindrical reinforcing cage 12 is completed, concrete pouring is carried out to ensure that the concrete fully fills the interior and surrounding space of the reinforcing cage, forming a solid lower cylinder 10. After the lower cylinder 10 reaches the specified strength, a concrete pad 22 is laid on top of it, followed by the binding of the upper column 20 reinforcing bars. During this process, the reserved longitudinal reinforcing bars of the cylindrical reinforcing cage 12 are lapped and bound with the upper column 20 reinforcing bars to ensure more uniform and effective force transfer between the upper and lower parts. Finally, the concrete pouring of the upper column 20 is carried out, and the formwork is removed after reaching the specified demolding strength.

[0038] Preferably, such as Figure 1 and Figure 3As shown, according to a wind turbine foundation structure of this utility model, the longitudinal reinforcing bars of the cylindrical steel cage 12 have a reserved lap joint 13 at the end facing the upper column 20. The reserved lap joint 13 and the column reinforcing bars 23 are tied together to form a rigid connection node. Specifically, during the design phase, the reinforcement layout of the cylindrical steel cage 12 and the upper column 20 needs to be planned in detail to determine the quantity, diameter, and arrangement of the longitudinal reinforcing bars, and to ensure the matching and compatibility between the two. Sufficient length should be reserved as a lap joint at the end of the longitudinal reinforcing bars of the cylindrical steel cage 12 near the upper column 20. Usually, this part of the reinforcing bar will extend a certain distance beyond the top of the cylinder to facilitate subsequent connection with the upper column 20 reinforcing bars. During construction, the drilling of the lower cylinder 10 and the installation of the reinforcing cage are completed first. After the reinforcing cage is hoisted into place, it is precisely adjusted to ensure that the reserved lap joint 13 of the longitudinal reinforcing bars is accurately positioned. Next, concrete pouring is carried out to ensure that the interior and surrounding space of the cylinder are fully filled and solidified to form a solid foundation structure.

[0039] When pouring concrete, the strength grade of the concrete can be selected by the designer based on the specific environmental category of the project and the corresponding specifications. Preferably, according to the wind turbine foundation structure of this utility model, the upper column 20 and the lower cylinder 10 include a main structure formed by pouring C40 / C45 concrete, and the concrete cushion layer 22 is a C20 concrete cushion layer with a thickness greater than or equal to 100mm. Specifically, for the main structure of the lower cylinder 10 and the upper column 20, C40 or C45 concrete is used. This high-strength concrete provides excellent compressive and tensile strength, making it suitable for bearing large loads. The concrete cushion layer 22 uses C20 concrete. Although its strength is lower than the concrete used in the main structure, its main function is to provide a flat and stable base surface, therefore C20 concrete is sufficient to meet the requirements.

[0040] After completing the drilling of the diaphragm wall and the installation of the reinforcing cage, concrete pouring for the lower cylinder 10 begins. C40 / C45 concrete is evenly injected into the holes using pumping equipment, ensuring the reinforcing cage is completely encased without gaps. During pouring, careful compaction is crucial to prevent honeycombing, pitting, and other quality issues. Once the lower cylinder 10 reaches the specified strength, a C20 concrete pad 22 with a thickness of at least 100mm is laid on top. This pad not only provides a smooth foundation surface for the upper column 20 but also enhances the bond strength between the upper and lower sections. After completing the reinforcing steel binding (including lapping and binding the longitudinal reinforcing bars of the cylinder's reinforcing cage 12 to the upper column 20's reinforcing bars), and confirming that the concrete pad 22 has cured and its surface treatment is satisfactory, concrete pouring for the upper column 20 commences. C40 / C45 concrete is also used, and thorough vibration during pouring is ensured to achieve uniform concrete distribution, guaranteeing the structural integrity and stability.

[0041] In order to ensure the connection quality between the upper column 20 and the lower cylinder 10 after the lower cylinder 10 is poured, it is preferable to roughen the concrete of the cylinder. Preferably, according to the wind turbine foundation structure of this utility model, the concrete surface of the lower cylinder 10 is provided with a roughened interface in the junction area between the lower cylinder 10 and the upper column 20 to enhance the connection strength with the upper column 20. Specifically, the lower cylinder 10 concrete is roughened when it reaches a certain strength but has not yet fully hardened (usually within 24 to 48 hours after pouring). Using a special tool such as a chisel or an electric roughening machine, the area where the top of the lower cylinder 10 meets the upper column 20 is roughened to form a surface with a certain roughness. This process not only removes the laitance layer on the surface, but also increases the friction and bonding area of ​​the concrete surface, which is beneficial to the subsequent bonding of the upper column 20 concrete. After the roughening treatment is completed, the roughened interface must be thoroughly cleaned to remove all loose particles and dust, ensuring that the surface is clean and free of impurities. Cleaning can be done using a high-pressure water gun or compressed air to prepare for the next stage of construction.

[0042] After the concrete foundation is constructed, to ensure that the foundation stress can be transferred to the ground more efficiently, it is preferable to fill the gaps around the upper column 20 with concrete and then vibrate it. Specifically, according to a wind turbine foundation structure of this utility model, a backfill area 24 for filling and compacting a concrete layer is provided around the upper column 20, forming a continuous stress transfer path between the concrete layer, the lower cylinder 10, and the ground. In particular, the backfill area 24 for filling and compacting the concrete layer ensures that a continuous stress transfer path is formed between the concrete layer, the lower cylinder 10, and the ground, enhancing the stability and load-bearing capacity of the overall structure.

[0043] Before backfilling, thoroughly clean the void area around the upper column 20, removing all loose soil, gravel, and other debris to ensure the backfill area 24 is clean and free of impurities, providing a good foundation for subsequent concrete filling. C40 / C45 concrete can be used to fill the voids around the upper column 20. During the filling process, simultaneous vibration compaction should be performed. Use an immersion vibrator or other suitable compaction tools to ensure the newly filled concrete is fully compacted, removing internal air and excess moisture, and avoiding voids or insufficient compaction. Through these steps, not only is the void around the upper column 20 effectively filled, but the stress of the entire foundation structure is also ensured to be efficiently transferred to the subgrade along a continuous path.

[0044] Furthermore, according to the wind turbine foundation structure of this utility model, the foundation pit of the backfill area 24 of the upper column 20 is a slope structure formed by sloping excavation, and the slope angle of the slope structure is designed according to the foundation soil and rock conditions. Specifically, before construction, a comprehensive survey and analysis of the foundation soil and rock conditions at the construction site is conducted. This includes key parameters such as soil type, water content, and bearing capacity. Based on these data, engineers can determine a suitable slope angle to ensure slope stability and avoid the risk of landslides or collapses. Based on the geological survey results and combined with engineering mechanics calculations, a suitable slope angle is designed. Generally, for looser soils, the slope angle is smaller to increase slope stability; while for hard and stable rock foundations, a steeper slope angle can be used. For example, in cohesive soils, the slope angle may be between 30° and 45°, while in hard rock, the angle can be close to vertical. In some cases, to further enhance slope stability, additional reinforcement measures may be taken, such as installing anchor bolts, laying wire mesh, or spraying concrete.

[0045] According to the preferred embodiment of the wind turbine foundation structure of this utility model, the entire construction process can be divided into several key steps to ensure that the final wind turbine foundation is both sturdy and efficient.

[0046] First, the foundation pit for the abutment is excavated on-site with a slope. This stage requires a detailed geological survey to determine the appropriate slope angle, ensuring the stability and safety of the slope. For looser soils, a smaller slope angle (e.g., 30° to 45°) is typically used, while on hard rock foundations, a near-vertical slope angle can be used. During excavation, excavators or other appropriate machinery are used to gradually excavate downwards, forming a slope structure with the predetermined gradient, and the actual slope is regularly checked to ensure it meets design requirements.

[0047] The next step is to drill holes according to the marked locations to form the diaphragm wall openings. This prepares for the subsequent installation of the cylindrical diaphragm wall. A rotary drilling rig is used to precisely drill holes at the predetermined locations, ensuring that the size and depth of the holes meet design requirements. During drilling, it is necessary to carefully control the drilling speed and the quality of the mud slurry wall support to prevent hole collapse or hole diameter reduction. Furthermore, it is preferable to adjust drilling parameters according to actual conditions to cope with complex geological conditions.

[0048] Next, install the reinforcing mesh cage for the underground wall of the cylindrical structure, and pre-install longitudinal reinforcing bars extending into the abutment columns. The prefabricated reinforcing cage should be manufactured according to the specific parameters in the design plan, including the quantity, diameter, and arrangement of the longitudinal reinforcing bars. These reinforcing cages not only need sufficient strength and rigidity but also must be able to securely lap with the reinforcing bars in the upper abutment column 20. During hoisting, ensure the reinforcing cage is positioned accurately, paying particular attention to the pre-installed length of the longitudinal reinforcing bars for subsequent connection with the reinforcing bars in the upper abutment column 20. After installation, the reinforcing cage must be secured to prevent displacement during concrete pouring.

[0049] Subsequently, the concrete for the lower cylinder was poured, and the area where it met the abutment column was roughened. C40 / C45 concrete was evenly injected into the holes using pumping equipment, ensuring the reinforcing cage was completely enclosed without gaps. Throughout the pouring process, vibration compaction was performed simultaneously to remove internal air and excess moisture, ensuring concrete quality. After the lower cylinder 10 concrete reached its initial strength, the area where it met the upper abutment column 20 was roughened at the top to increase surface roughness and improve the bond between the old and new concrete. The roughened surface was then cleaned to remove loose particles and dust.

[0050] Next, the surface of the column base is cleaned, and the foundation pad concrete is poured. To provide a flat and stable foundation surface for the upper column 20, a C20 concrete pad 22 with a thickness of not less than 100mm is laid on top of the lower cylinder 10. This not only helps to enhance the bond strength between the upper and lower parts but also provides a good working surface for subsequent construction. Before pouring the pad concrete, the base surface is cleaned to ensure that no debris will affect the quality of the concrete. After pouring, it is also necessary to vibrate it thoroughly to ensure that the pad concrete is dense and free of defects.

[0051] Next, the reinforcing bars 23 of the abutment columns are tied and the foundation formwork is installed. After the curing of the foundation concrete is completed, the reinforcing bar tying work for the upper abutment column 20 begins. The longitudinal reinforcing bars of the cylindrical steel cage 12 are lapped and tied to the reinforcing bars inside the upper abutment column 20 to form a solid integral steel structure. After tying is completed, the foundation formwork is installed, ensuring that the formwork is accurately positioned and firmly supported to prevent deformation or grout leakage during concrete pouring.

[0052] Next, the foundation concrete is poured. C40 / C45 concrete is used to pour the upper column 20, ensuring that the concrete is evenly distributed and fully vibrated to ensure compaction. After pouring, the concrete is properly cured to prevent problems such as early cracking and ensure that it reaches the specified strength standard.

[0053] Finally, after the foundation strength reaches the demolding strength, the foundation formwork is removed, and plain concrete is backfilled into the backfill area 24 on the side of the foundation, followed by vibration and compaction. Once the concrete of the upper column 20 reaches the specified demolding strength, the formwork is removed, and the construction site is cleaned. Then, the gaps around the upper column 20 are filled with C40 / C45 concrete, which is then thoroughly vibrated to ensure a tight bond between the backfill concrete and the original foundation, forming a continuous stress transfer path.

[0054] Through the above construction steps, the wind turbine foundation structure of this utility model not only achieves efficient land use, but also significantly improves the load-bearing capacity and stability of the foundation structure. It is suitable for wind farm construction under various complex terrains and geological conditions, effectively solves the limitations of traditional gravity-extended foundations under land-limited conditions, and reduces engineering costs and maintenance costs, thus promoting the sustainable development of wind power projects.

[0055] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "method," "specific method," or "some methods," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or method is included in at least one embodiment or method of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or method. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or methods. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or methods described in this specification, as well as the features of different embodiments or methods.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A wind turbine foundation structure, characterized in that, include: The lower cylinder body forms an integral structure with the foundation of the wind turbine foundation structure; An upper column is located at the top of the lower cylinder, and a cavity is formed inside the upper column. A concrete pad layer is provided at the bottom of the upper column. When the lower cylinder and the upper column are combined, the lateral passive earth pressure provided by the soil covering the lower cylinder balances the horizontal force and bending moment transmitted by the upper fan.

2. The wind turbine foundation structure according to claim 1, characterized in that, The lower cylinder includes a diaphragm wall connected to the foundation, and the diaphragm wall is a hole structure formed by rotary drilling for pouring concrete. The inner side of the diaphragm wall is covered with soil to form an integral load-bearing structure.

3. The wind turbine foundation structure according to claim 1, characterized in that, The lower cylinder is entirely buried in the soil, and the axial length of the lower cylinder is greater than or equal to the diameter of the lower cylinder.

4. The wind turbine foundation structure according to claim 1, characterized in that, The upper column is provided with column reinforcement bars, and the lower cylinder is provided with a cylinder reinforcement cage; The longitudinal main bars of the cylindrical steel cage extend toward the upper column and overlap with the column bars to form an integral steel reinforcement connection structure.

5. The wind turbine foundation structure according to claim 4, characterized in that, The cylindrical steel cage is an integral prefabricated structure; The quantity, diameter, and arrangement of the longitudinal reinforcing bars in the cylindrical steel cage are adapted to the column reinforcing bars.

6. The wind turbine foundation structure according to claim 5, characterized in that, The longitudinal steel bars of the cylindrical steel cage have a reserved lap joint at one end facing the upper column, and the reserved lap joint and the column steel bars are tied together to form a rigid connection node.

7. The wind turbine foundation structure according to any one of claims 1 to 6, characterized in that, The upper column and the lower cylinder include a main structure formed by pouring C40 / C45 concrete, and the concrete cushion layer is a C20 concrete cushion layer with a thickness of 100mm or more.

8. The wind turbine foundation structure according to claim 7, characterized in that, In the area where the lower cylinder meets the upper column, the concrete surface of the lower cylinder is provided with a roughened interface to enhance the concrete connection strength with the upper column.

9. The wind turbine foundation structure according to any one of claims 1 to 6, characterized in that, The upper column is surrounded by a backfill area for filling and compacting a concrete layer, and the concrete layer forms a continuous stress transfer path with the lower cylinder and the foundation.

10. The wind turbine foundation structure according to claim 9, characterized in that, The foundation pit of the backfill area of ​​the upper column is a slope structure formed by sloping excavation, and the slope angle of the slope structure is designed according to the foundation soil and rock conditions.

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