Fan foundation structure

Abstract

The invention relates to the technical field of wind power generation, in particular to a fan foundation structure which comprises a lower barrel, and the lower barrel and a foundation of the 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] The present invention relates to the technical field of wind power generation, and in particular to a wind turbine foundation structure. Background Art

[0002] As the small-capacity wind turbines installed in early wind farms gradually enter the aging stage, the renovation market of old wind farms has shown great potential. It is predicted that by 2030, the total capacity of retired wind turbines will exceed 40 million kilowatts. At present, the strategy of "replacing small with large" is generally adopted for the upgrading and renovation of old wind farms, that is, replacing old small-capacity units with new wind turbines with larger capacity. This strategy has been actively supported and effectively promoted both at the national policy level and at the local implementation level.

[0003] At present, the unit capacity of old wind farms is mostly 1.5MW or less, while the unit capacity of modern onshore wind turbines is increasing rapidly, with the largest exceeding 10MW. However, in mountainous wind farms, especially under rock foundation conditions, traditional steel-concrete tower foundations usually adopt a gravity expansion design. When faced with the need to "replace small with large", this traditional gravity expansion foundation is often difficult to meet new requirements due to the limited land use of the machine site and the possible land use restrictions caused by administrative boundaries. Summary of the invention

[0004] The present invention provides a wind turbine foundation structure to solve the defect in the prior art that the traditional gravity expansion foundation is difficult to meet the bearing requirements under the condition of limited land use, thereby saving land area, improving the bearing capacity and stability of the foundation structure, and reducing the overall cost of the wind farm.

[0005] The present invention provides a fan foundation structure, comprising: a lower cylinder, wherein the lower cylinder and the foundation of the fan foundation structure form an integral structure; an upper column, which is arranged on the top of the lower cylinder, the interior of the upper column forms a cavity, and the bottom of the upper column is provided with a concrete cushion layer; when the lower cylinder and the upper column are in a combined state, the lateral passive earth pressure provided by the soil body covered by the lower cylinder balances the horizontal force and bending moment transmitted by the upper fan.

[0006] According to one embodiment of the present invention, the lower cylinder includes an underground continuous wall connected to the foundation, and the underground continuous wall is a hole structure formed by rotary drilling for pouring concrete; the inner side of the underground continuous wall is covered with soil to form an overall 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, column steel bars are provided in the upper column, and a cylinder steel bar cage is provided in the lower cylinder; the longitudinal main bars of the cylinder steel bar cage extend toward the upper column and overlap with the column steel bars to form an integral steel bar 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 reinforcement of the cylindrical reinforcement cage has a reserved overlap portion at one end facing the upper column, and the reserved overlap portion and the column reinforcement are tied 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 greater than or equal to 100 mm.

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

[0013] According to one embodiment of the present invention, a backfill area for filling a vibrated and compacted concrete layer is provided around the upper column, and the concrete layer forms a continuous stress transfer 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 pedestal is a slope structure formed by slope excavation, and the slope angle of the slope structure is designed according to the foundation rock and soil conditions.

[0015] The wind turbine foundation structure provided by the present invention effectively solves the defect that the traditional gravity expansion foundation is difficult to meet the bearing requirements under the condition of limited land use by introducing the design of combining the lower cylinder and the upper column. Specifically, the lower cylinder penetrates into the foundation and forms an integral structure with it, so that the entire cylinder and the surrounding soil body work together to provide additional lateral passive earth pressure, thereby balancing the horizontal force and bending moment transmitted by the upper wind turbine. At the same time, the cavity design formed inside the upper column reduces the amount of material used and reduces the deadweight, further reducing the pressure on the foundation. This combined structure can significantly reduce the required land area while ensuring or even improving the bearing capacity and stability of the foundation, and is suitable for wind farm environments with tight land use or complex terrain. Therefore, the wind turbine foundation structure provided by the present invention not only achieves the goal of saving land area, but also reduces material costs and construction difficulty by optimizing the structural design, thereby effectively reducing the overall cost of the wind farm. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic cross-sectional structural diagram of the fan foundation structure provided by the present invention.

[0018] Figure 2 It is a schematic diagram of stress distribution of the wind turbine foundation structure provided by the present invention.

[0019] Figure 3 It is a structural schematic diagram of the lower cylinder of the fan foundation structure provided by the present invention.

[0020] Figure 4 It is a plan view of the lower cylinder of the fan foundation structure provided by the present invention.

[0021] Figure 5 It is a schematic diagram of the connection structure of the cylinder steel cage and the column steel bars of the fan foundation structure provided by the present invention.

[0022] Reference numerals: 10. Lower cylinder; 11. Hole structure; 12. Cylinder steel cage; 13. Reserved lap joint; 20. Upper column; 21. Cavity; 22. Concrete cushion; 23. Column steel bars; 24. Backfill area. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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.

[0024] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] The present invention provides a wind turbine foundation structure, which effectively reduces the land area by introducing a lower cylinder design, thereby reducing the overall cost of the wind farm. Compared with the traditional design scheme, the structure significantly reduces the required foundation footprint while ensuring or even improving the foundation bearing capacity and stability. This optimized design is particularly suitable for wind farm environments with limited land or complex terrain. It not only improves land use efficiency, but also further controls costs by reducing material usage and construction difficulty.

[0026] Combine the following Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 A specific embodiment of the wind turbine foundation structure of the present invention is described.

[0027] like Figure 1 and Figure 2 As shown, the wind turbine foundation structure provided by the present invention comprises: a lower cylinder 10, the lower cylinder 10 and the foundation of the wind turbine foundation structure form an integral structure; an upper column 20, which is arranged at the top of the lower cylinder 10, the interior of the upper column 20 forms a cavity 21, and the bottom of the upper column 20 is provided with a concrete cushion 22; when the lower cylinder 10 and the upper column 20 are combined, the lateral passive earth pressure provided by the soil body covered by the lower cylinder 10 balances the horizontal force and bending moment transmitted by the upper wind turbine. The wind turbine foundation structure effectively solves the defect that the traditional gravity expansion foundation is difficult to meet the bearing requirements under the condition of limited land use by introducing the design of combining the lower cylinder 10 with the upper column 20.

[0028] Specifically, the lower cylinder 10 is tightly combined with the foundation, and the entire cylinder and the enclosed soil form an integral structure. Since the foundation is buried deeper than the traditional extended foundation, the bearing capacity of the foundation can basically meet the required bearing capacity requirements after correction. This design not only improves the overall stability and bearing capacity of the foundation, but also reduces the floor space. The cavity 21 formed inside the upper column 20 reduces its own weight and further reduces the pressure on the foundation, while providing the necessary space for equipment installation or maintenance. In addition, during the construction process, the lower cylinder 10 is first excavated and cast, and then the concrete cushion layer 22 is accurately laid on its top, and finally the upper column 20 is cast to ensure that the upper and lower parts are tightly connected and work together to withstand various loads from the upper fan.

[0029] Furthermore, in the above technical solution, the construction of the underground continuous wall of the lower cylinder 10 can be completed by rotary drilling, which not only improves the hole-making accuracy, but also effectively copes with complex geological conditions. The steel cage can be used as the main reinforcement material of the lower cylinder 10. The number and diameter of its longitudinal steel bars should be designed according to the actual load-bearing requirements, and it should be firmly overlapped with the steel bars of the upper column 20. In addition, at the junction of the two parts, the cylinder concrete can also be roughened to enhance the bonding strength between the upper and lower parts to ensure the integrated performance of the entire foundation structure.

[0030] This type of wind turbine foundation structure is built on the rock foundation of a mountain wind farm. The upper platform 20 can be constructed by conventional excavation or blasting, while the lower cylindrical underground continuous wall is more difficult to construct due to its special geological conditions and design requirements. It is preferred to use rotary drilling to dig holes to ensure hole accuracy and construction efficiency. Figure 3 and Figure 4 As shown, according to a wind turbine foundation structure of the present invention, the lower cylinder 10 includes an underground continuous wall connected to the foundation, and the underground continuous wall is a hole structure 11 for pouring concrete formed by rotary drilling; the inner side of the underground continuous wall is covered with soil to form an integral bearing structure. Specifically, during the construction process, a rotary drilling rig is first used to accurately drill holes at predetermined positions 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 underground continuous wall can penetrate deep into the foundation and be closely integrated with it, thereby enhancing the stability and bearing capacity of the entire foundation structure. Then, a steel cage can be installed in the drilled holes. After the installation of the steel cage is completed, the concrete pouring operation is carried out to ensure that the concrete fully fills and wraps the steel cage to form a solid underground continuous wall.

[0031] The thickness and length of the cylinder can be calculated and designed in combination with the parameter information of the upper column 20. Preferably, according to a wind turbine foundation structure of the present invention, the lower cylinder 10 is entirely buried in the soil layer, and the axial length of the lower cylinder 10 is greater than or equal to the diameter of the lower cylinder 10. Specifically, during the design phase, it is first necessary to conduct a comprehensive assessment of the geological conditions of the construction site, 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 size, 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 foundation materials to enhance the overall bearing capacity and improve the stability of the structure with the help of lateral soil pressure.

[0032] During the construction process, a rotary drilling rig is first used to accurately drill holes according to predetermined design parameters to form holes suitable for pouring concrete. Then, the customized steel cage is hoisted into the hole, and after ensuring that its position is accurate, the concrete pouring operation is carried out. In addition, the axial length of the lower cylinder 10 is preferably not less than the cylinder diameter, which can not only effectively disperse the load transmitted to the foundation, but also use the passive earth pressure provided by the surrounding soil to further enhance the stability and seismic performance of the foundation structure.

[0033] Preferably, if Figure 1 and Figure 5 As shown, according to a wind turbine foundation structure of the present invention, a column steel bar 23 is provided in the upper column 20, and a cylinder steel bar cage 12 is provided in the lower cylinder 10; the longitudinal main bars of the cylinder steel bar cage 12 extend to the upper column 20, and overlap with the column steel bar 23 to form an integral steel bar connection structure. Specifically, during the construction process, a rotary drilling rig is first used to accurately drill holes at predetermined positions to form holes suitable for pouring concrete. Then, a prefabricated cylinder steel bar cage 12 is installed in the hole. The steel bar cage is composed of a plurality of longitudinal main bars and transverse stirrups, and its size and steel bar specifications need to be determined according to detailed mechanical calculations to meet the actual load-bearing requirements. After the installation of the cylinder steel bar cage 12 is completed, the concrete pouring operation is carried out to ensure that the concrete fully fills and wraps the steel bar cage to form a solid lower cylinder 10. The steel bars of the upper column 20 are tied, including overlapping and tying the reserved longitudinal main bars of the cylinder steel bar cage 12 with the steel bars in the upper column 20 to form a continuous integral steel bar structure. This connection mode ensures that the transmission of force between the upper and lower parts is more uniform and effective, and improves the integration performance and stability of the entire infrastructure. Finally, the upper column 20 is poured with concrete, and the template is removed after reaching the specified demoulding strength.

[0034] The wind turbine foundation structure is divided into two parts: the upper pedestal and the lower cylinder, and the construction can be completed in two pouring operations. Therefore, in order to simplify the construction process and ensure the integrity of the structure, the cylinder reinforcement should be made into an integral reinforcement cage, and the number and diameter of its longitudinal reinforcements should be consistent with the upper pedestal 20, so that it can be directly hoisted and installed after the excavation of the underground continuous wall holes is completed. Preferably, according to a wind turbine foundation structure of the present invention, the cylinder reinforcement cage 12 is an integral prefabricated structure; the number, diameter and arrangement of the longitudinal reinforcements of the cylinder reinforcement cage 12 are adapted to the pedestal reinforcement 23. Specifically, the number, diameter and arrangement of the longitudinal reinforcements of the cylinder reinforcement cage 12 are adapted to the reinforcements of the upper pedestal 20 to ensure that the two can be reliably connected to form a unified integral reinforcement structure.

[0035] During the specific implementation, firstly, the specific parameters of the cylindrical steel cage 12, including the number and diameter of the longitudinal steel bars and the spacing of the transverse stirrups, are determined based on the detailed geological survey data and structural design requirements. These parameters can be determined by precise calculation to meet the actual load-bearing requirements and ensure that the steel cage has sufficient strength and rigidity. After the excavation of the underground continuous wall hole 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, during the installation process, it is necessary to pay attention to the reserved length of the longitudinal steel bars so that it can be smoothly overlapped with the steel bars in the upper column 20.

[0036] Preferably, a certain overlap length can be reserved for the longitudinal main reinforcement of the steel cage so that it can be subsequently tied and connected with the upper column 20 steel bars to form a solid overall steel structure. After the installation of the cylinder steel cage 12 is completed, the concrete pouring operation is carried out to ensure that the concrete fully fills the interior and surrounding space of the steel cage to form a solid lower cylinder 10. After the lower cylinder 10 reaches the specified strength, a layer of concrete cushion 22 is laid on its top, and then the steel bars of the upper column 20 are tied. In this process, the reserved longitudinal steel bars of the cylinder steel cage 12 are overlapped and tied with the steel bars of the upper column 20 to ensure that the force transmission between the upper and lower parts is more uniform and effective. Finally, the concrete pouring operation of the upper column 20 is carried out, and the formwork is removed after the specified demolding strength is reached.

[0037] Preferably, if Figure 1 and Figure 3As shown, according to a wind turbine foundation structure of the present invention, the longitudinal reinforcement of the cylinder reinforcement cage 12 has a reserved overlap 13 at one end facing the upper column 20, and the reserved overlap 13 and the column reinforcement 23 are tied to form a rigid connection node. Specifically, in the design stage, it is necessary to plan the reinforcement layout of the cylinder reinforcement cage 12 and the upper column 20 in detail, determine the number, diameter and arrangement of the longitudinal reinforcement, and ensure the matching and compatibility between the two. The longitudinal reinforcement of the cylinder reinforcement cage 12 should reserve enough length as the overlap at one end close to the upper column 20, and usually this part of the reinforcement will exceed the top of the cylinder by a certain distance to facilitate the subsequent connection with the reinforcement of the upper column 20. During the construction process, the drilling of the lower cylinder 10 and the installation of the reinforcement cage are first completed. After the reinforcement cage is hoisted in place, it is precisely adjusted to ensure that the reserved overlap 13 of the longitudinal reinforcement is accurately positioned. Next, the concrete pouring operation is carried out to ensure that the space inside and around the cylinder is fully filled and solidified to form a solid foundation structure.

[0038] When performing concrete pouring operations, the strength grade of the concrete can be selected by the designer based on the specific environmental category of the project and the corresponding specification requirements. Preferably, according to a wind turbine foundation structure of the present invention, the upper column 20 and the lower cylinder 10 include a main structure cast by C40 / C45 concrete, and the concrete cushion 22 is a C20 concrete cushion 22 with a thickness greater than or equal to 100 mm. 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 can provide excellent compressive and tensile properties and is suitable for carrying larger loads. The concrete cushion 22 uses C20 concrete. Although its strength is lower than that of the concrete used in the main structure, since its main function is to provide a flat and stable base surface, C20 concrete is sufficient to meet the needs.

[0039] After completing the drilling of the underground continuous wall and the installation of the steel cage, start pouring concrete for the lower cylinder 10. Use pumping equipment to evenly inject C40 / C45 concrete into the hole to ensure that the steel cage is completely wrapped and there are no gaps. During the pouring process, attention should be paid to vibrating and compacting to avoid quality problems such as honeycombs and rough surfaces. When the lower cylinder 10 reaches the specified strength, a layer of C20 concrete cushion 22 with a thickness of not less than 100mm is laid on its top. This cushion not only provides a flat foundation surface for the upper column 20, but also enhances the bonding strength between the upper and lower parts. After completing the steel bar binding work (including overlapping and binding the longitudinal steel bars of the cylinder steel cage 12 with the steel bars of the upper column 20), and confirming that the concrete cushion 22 has been cured and the surface treatment is qualified, the concrete pouring of the upper column 20 is carried out. Also use C40 / C45 concrete, and ensure that the vibration is sufficient during the pouring process to make the concrete evenly distributed to ensure the integrity and stability of the structure.

[0040] Among them, after the lower cylinder 10 is poured, in order to ensure the connection quality between the upper column 20 and the lower cylinder 10, the cylinder concrete is preferably roughened. Preferably, according to a wind turbine foundation structure of the present invention, in the border area between the lower cylinder 10 and the upper column 20, the concrete surface of the lower cylinder 10 is provided with a roughening interface for enhancing the concrete connection strength with the upper column 20. Specifically, when the concrete of the lower cylinder 10 reaches a certain strength but has not yet completely hardened (usually within 24 to 48 hours after pouring), it is roughened. Use special tools such as a chisel or an electric roughening machine to roughen the area where the top of the lower cylinder 10 connects to the upper column 20 to form a surface with a certain roughness. This process not only removes the floating slurry 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 completing the roughening treatment, the roughening interface needs to be thoroughly cleaned to remove all loose particles and dust to ensure that the surface is clean and free of impurities. It can be cleaned by flushing with a high-pressure water gun or blowing with compressed air to prepare for the next construction.

[0041] After the construction of the concrete foundation is completed, in order to ensure that the foundation stress can be more efficiently transmitted to the foundation, it is preferred to fill the gaps around the upper column 20 with concrete and perform a vibration treatment. Specifically, according to a wind turbine foundation structure of the present invention, a backfill area 24 for filling a vibrated and compacted concrete layer is provided around the upper column 20, and the concrete layer forms a continuous stress transfer path with the lower cylinder 10 and the foundation. Specifically, the backfill area 24 for filling a vibrated and compacted concrete layer ensures that a continuous stress transfer path is formed between the concrete layer and the lower cylinder 10 and the foundation, thereby enhancing the stability and bearing capacity of the overall structure.

[0042] Before backfilling, thoroughly clean the void area around the upper column 20, remove all loose soil, gravel and other debris, ensure that the backfill area 24 is clean and free of impurities, and provide good basic conditions for the subsequent filling of concrete. C40 / C45 concrete can be used to fill the voids around the upper column 20. During the filling process, vibration treatment is carried out simultaneously. Use an inserted vibrator or other suitable vibration tools to ensure that the newly filled concrete can be fully compacted, remove internal air and excess moisture, and avoid voids or looseness. Through the above steps, not only is the effective filling of the voids around the upper column 20 achieved, but it also ensures that the stress of the entire infrastructure can be efficiently transmitted to the foundation along a continuous path.

[0043] Further, according to a wind turbine foundation structure of the present invention, the foundation pit of the backfill area 24 of the upper column 20 is a slope structure formed by slope excavation, and the slope angle of the slope structure is designed according to the foundation rock and soil conditions. Specifically, before construction, the foundation rock and soil conditions of the construction site are first comprehensively surveyed and analyzed. 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 the stability of the slope and avoid the risk of landslides or collapse. According to the results of geological surveys, combined with engineering mechanics calculations, a suitable slope angle is designed. Generally, for looser soils, the slope angle will be smaller to increase the stability of the slope; while for hard and stable rock foundations, a steeper slope angle can be used. For example, in clay soil, the slope angle may be between 30° and 45°, while in hard rock, the angle can be close to vertical. In some cases, in order to further enhance the stability of the slope, additional reinforcement measures may be taken, such as installing anchors, laying wire mesh or spraying concrete.

[0044] According to the wind turbine foundation structure of the preferred embodiment of the present invention, during implementation, the entire construction process can be divided into a plurality of key steps to ensure that the wind turbine foundation finally formed is both strong and efficient.

[0045] First, the foundation pit of the platform column is excavated on site. This stage requires detailed geological surveys to determine the appropriate slope angle to ensure the stability and safety of the slope. For loose soil, a smaller slope angle (such as 30° to 45°) is usually used, while on hard rock foundations, a nearly vertical slope angle can be used. During the excavation process, an excavator or other appropriate mechanical equipment is required to gradually dig downward to form a slope structure with a predetermined slope, and regularly check whether the actual slope meets the design requirements.

[0046] The next step is to drill holes according to the layout points to form underground continuous wall holes. This is to prepare for the installation of the subsequent underground continuous wall of the cylinder. Use a rotary drilling rig to accurately drill holes at the predetermined locations to ensure that the size and depth of the holes meet the design requirements. During the drilling process, it is necessary to pay attention to controlling the drilling speed and the quality of the mud wall to avoid hole wall collapse or hole diameter reduction. In addition, it is also preferred to adjust the drilling parameters according to the actual situation to cope with complex geological conditions.

[0047] Next, install the steel mesh cage of the underground wall of the cylinder and reserve the longitudinal steel bars to extend into the column. The prefabricated steel cage should be made according to the specific parameters in the design plan, including the number, diameter and arrangement of the longitudinal steel bars. These steel cages must not only have sufficient strength and rigidity, but also be able to be firmly overlapped with the steel bars in the upper column 20. During the hoisting process, ensure that the position of the steel cage is accurate, and pay special attention to the reserved length of the longitudinal steel bars so that they can be connected to the upper column 20 steel bars later. After the steel cage is installed, it needs to be fixed to prevent displacement during the pouring of concrete.

[0048] Subsequently, the concrete of the cylinder is poured, and the area bordering the column is roughened. Use pumping equipment to evenly inject C40 / C45 concrete into the hole to ensure that the steel cage is completely wrapped and has no gaps. During the entire pouring process, it is necessary to vibrate and compact it simultaneously to remove internal air and excess moisture to ensure the quality of the concrete. After the concrete of the lower cylinder 10 reaches the initial strength, the area at the top of the cylinder that connects with the upper column 20 is roughened to increase the surface roughness and improve the bonding between the new and old concrete. Clean the roughened surface to remove loose particles and dust.

[0049] Next, clean the surface of the base of the column and pour the foundation cushion concrete. In order to provide a flat and stable foundation surface for the upper column 20, a C20 concrete cushion 22 with a thickness of not less than 100 mm is laid on the top of the lower cylinder 10. It not only helps to enhance the bonding strength between the upper and lower parts, but also provides a good working surface for subsequent construction. Before pouring the cushion concrete, clean the surface of the base to ensure that there are no debris that affects the quality of the concrete. After pouring, it is also necessary to fully vibrate to ensure that the cushion concrete is dense and defect-free.

[0050] Then, tie the column reinforcement 23 and install the foundation formwork. After the cushion concrete is cured, the reinforcement tying work of the upper column 20 begins. The longitudinal reinforcement of the cylinder reinforcement cage 12 is overlapped and tied with the reinforcement in the upper column 20 to form a solid overall reinforcement structure. After the tying is completed, the foundation formwork is installed to ensure that the template is accurately positioned and firmly supported to prevent deformation or leakage during concrete pouring.

[0051] After that, pour the main concrete of the foundation. Use C40 / C45 concrete to pour the upper column 20, ensuring that the concrete is evenly distributed and fully vibrated and compacted. After pouring, proper maintenance can be carried out on the concrete to prevent early cracking and ensure that it reaches the specified strength standard.

[0052] Finally, after the foundation strength reaches the demolding strength, the foundation formwork is removed and the foundation side backfill area 24 is backfilled with plain concrete, vibrated and compacted. When the upper column 20 concrete reaches the specified demolding strength, the formwork is removed and the construction site is cleaned. Then the gap around the upper column 20 is filled with C40 / C45 concrete, and fully vibrated to ensure that the backfill concrete is tightly combined with the original foundation to form a continuous stress transfer path.

[0053] Through the above-mentioned construction steps, the wind turbine foundation structure of the present invention not only realizes efficient land utilization, but also significantly improves the bearing capacity and stability of the foundation structure. It is suitable for the construction of wind farms under various complex terrains and geological conditions, and effectively solves the limitations of traditional gravity extension foundations under limited land use conditions. At the same time, it reduces project costs and maintenance costs, and promotes the sustainable development of wind power projects.

[0054] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A fan foundation structure, characterized in that: include: A lower cylinder, wherein the lower cylinder and the foundation of the fan foundation structure form an integral structure; An upper column is arranged on the top of the lower cylinder, a cavity is formed inside the upper column, and a concrete cushion layer is arranged at the bottom of the upper column; When the lower cylinder and the upper column are in a combined state, the lateral passive earth pressure provided by the soil body covered by 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 an underground continuous wall connected to the foundation, and the underground continuous wall is a hole structure formed by rotary drilling for pouring concrete; The inner side of the underground continuous wall is covered with soil to form an integral bearing structure.

3. The wind turbine foundation structure according to claim 1, characterized in that: 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.

4. The wind turbine foundation structure according to claim 1, characterized in that: The upper column is provided with column reinforcement, and the lower cylinder is provided with a cylinder reinforcement cage; The longitudinal main reinforcement of the cylindrical reinforcement cage extends toward the upper column and overlaps with the column reinforcement to form an integral 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 number, diameter and arrangement of the longitudinal steel bars of the cylindrical steel cage are adapted to the steel bars of the column.

6. The wind turbine foundation structure according to claim 5, characterized in that: The longitudinal reinforcement of the cylindrical reinforcement cage has a reserved overlap portion at one end facing the upper column, and the reserved overlap portion and the column reinforcement 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 greater than or equal to 100 mm.

8. The wind turbine foundation structure according to claim 7, characterized in that: In the bordering area between the lower cylinder and the upper column, the concrete surface of the lower cylinder is provided with a roughened interface for enhancing 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: A backfill area for filling a vibrated and compacted concrete layer is arranged around the upper column, and the concrete layer, the lower cylinder and the foundation form a continuous stress transfer path.

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

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