Lattice type foundation for wind power tower and construction method of lattice type foundation

Abstract

The invention relates to the technical field of wind power, and discloses a lattice type foundation for a wind power tower and a construction method thereof.The foundation comprises a plurality of bearing platforms, and a cross beam is fixedly connected between every two adjacent bearing platforms; a lattice type wind power tower column can be erected on the upper side of the bearing platform; an embedded pipe is reserved in the center of any bearing platform and used for penetration of a prestressed steel strand, and the prestressed steel strand can be fixed to the top face of the tensioning cavity; a tensioning cavity is formed in the bottom surface of any bearing platform and can be used as a prestressed steel strand tensioning or anchoring operation space; any bearing platform is provided with a pre-stressed anchor bolt assembly, and the pre-stressed anchor bolt assembly is suitable for being fixed to a lattice type wind power tower column. The multiple bearing platforms are adopted for providing support for fixing of the lattice type wind power tower, compared with a fan foundation of a traditional cylinder type tower, the land acquisition area can be remarkably saved, the material cost is reduced, and the wind power tower foundation is suitable for various terrain environments.

Description

Technical Field

[0001] This invention relates to the field of wind power technology, specifically to the foundation for lattice-type wind turbine towers and its construction method. Background Technology

[0002] With the rapid development of onshore wind turbines, a series of lattice (truss) wind turbine tower support structures have emerged on the market. Compared with traditional cylindrical towers, they have a better stiffness-to-weight ratio and material utilization rate. These new support structures have significant advantages in improving the stability and safety of wind turbines, while also providing more flexibility and innovation in tower design.

[0003] However, if truss-type wind turbine tower foundations continue to use traditional wind turbine foundations, a series of practical problems will arise. First, the land area required for wind turbine foundations is excessive, which not only increases land resource consumption and affects the micro-site selection of wind turbine locations, but may also lead to social and environmental problems during land acquisition. Second, using traditional wind turbine foundation methods results in foundations that are too large, which not only increases material costs but may also cause environmental pollution during construction. Furthermore, the construction period for ultra-large volume concrete projects is long, which not only extends the project's investment recovery period but may also affect the overall operational efficiency of the wind farm.

[0004] Furthermore, in the connection area between the tower and the foundation, the abrupt change in stiffness between traditional rigid foundations and flexible tower structures can easily lead to stress concentration and concrete cracking, thereby reducing the overall stability and safety of the wind turbine tower. The crack resistance of concrete is also a challenge in traditional foundation design; the appearance of cracks can severely affect the durability and service life of the structure. Moreover, the issue of hoisting continuity cannot be ignored. Traditional wind turbine foundations may experience inaccurate alignment and installation difficulties during hoisting, which not only increases construction difficulty but may also cause construction safety accidents. Summary of the Invention

[0005] In view of this, the present invention provides a foundation for a lattice-type wind turbine tower and a construction method thereof to solve the above-mentioned problems.

[0006] In a first aspect, the present invention provides a foundation for a lattice-type wind turbine tower, comprising: Several foundations are provided, with crossbeams fixedly connected between two adjacent foundations; the upper part of the foundations is suitable for erecting lattice-type wind turbine tower columns. An embedded pipe is provided at the center of any of the aforementioned piers, the embedded pipe being used for threading prestressed steel strands, the prestressed steel strands being adapted to be fixed to the bottom surface of the pier; The bottom surface of any of the aforementioned piers is provided with a tensioning cavity, which provides operating space for tensioning or anchoring the prestressed steel strands; If the prestressed anchor bolt assembly is used, a prestressed anchor bolt assembly is provided on any of the aforementioned bearing platforms, and the prestressed anchor bolt assembly is adapted to connect and fix the foundation to the tower column of the lattice wind turbine.

[0007] Beneficial Effects: The foundation is a four-point raft foundation, constructed of reinforced concrete, and can be symmetrically arranged. Each foundation is located below the tower column, and all independent foundations are connected as a whole by crossbeams. A tower base connection area is located at the center of the top surface of each independent foundation, where prestressed anchor bolt assemblies are installed. When installing and fixing the lattice-type wind turbine tower, the tower columns are fixed to the foundations, and the prestressed steel strands inside the tower columns are threaded through embedded pipes with their ends fixed to the top surface of the tensioning cavity, thus securing the prestressed steel strands. Prestressed anchor bolt assemblies are installed on any foundation, securing the tower columns to the foundations. This invention uses multiple foundations to provide support for the lattice-type wind turbine tower, significantly saving land area and reducing material costs compared to traditional cylindrical tower foundations.

[0008] In one optional embodiment, the pier cap is a reinforced concrete structure, and the prestressed anchor bolt assembly includes: The anchor plate of the anchor bolt is embedded inside the bearing cap; Prestressed anchor bolts are embedded inside the foundation, and the bottom end of the prestressed anchor bolt is connected and fixed to the lower anchor plate of the anchor bolt. The upper end of the prestressed anchor bolt extends out of the top surface of the foundation and is connected and fixed to the upper anchor plate of the anchor bolt and the tower flange. The prestressed anchor bolt assembly is used to connect the lattice wind turbine tower column to the foundation.

[0009] Beneficial Effects: The foundation is a reinforced concrete structure, which possesses excellent compressive strength and durability, capable of withstanding the enormous loads transmitted from the superstructure and various external forces. Before pouring the foundation, the construction site needs to be leveled and cleaned, and the reinforcing steel cage needs to be tied according to design requirements. Necessary formwork should be installed to ensure that the shape and dimensions of the foundation meet design standards. The prestressed anchor bolt assembly includes a lower anchor plate, a prestressed anchor bolt, and an upper anchor plate. The lower anchor plate is a metal component whose shape and dimensions are designed according to the actual engineering needs. During the foundation concrete pouring process, the lower anchor plate is precisely placed in the predetermined position and firmly fixed inside the foundation through its connection with the surrounding reinforcing steel and the encapsulation effect of the concrete. It plays a crucial role in transferring force between the prestressed anchor bolt and the foundation, evenly distributing the load borne by the prestressed anchor bolt to the foundation. The prestressed anchor bolt assembly also includes an upper anchor plate, which enhances the stability and reliability of the structural connection. The anchor plate on the anchor bolt is typically made of high-strength, high-toughness steel to ensure sufficient load-bearing capacity and good mechanical properties. In material selection, steel with good corrosion resistance is generally preferred because wind turbine towers are usually located outdoors and exposed to various complex climatic conditions for extended periods; corrosion resistance is crucial for ensuring the durability of the anchor plate. The anchor plate is located on the upper side of the support platform. During installation, specialized lifting equipment is used to smoothly lift the anchor plate onto the platform and precisely align it with the pre-marked position. Furthermore, the anchor plate is suitable for contact with the lattice-type wind turbine tower column. This contact method effectively and evenly transfers the load borne by the wind turbine tower column to the support platform. To ensure a tight and stable contact, the upper surface of the anchor plate is usually flattened, with surface flatness errors controlled within a very small range to ensure a full fit with the contact surface of the wind turbine tower column.

[0010] In one optional embodiment, the prestressed anchor bolt assembly further includes a positioning adjustment bolt, the top end of which is connected to the lower anchor plate of the anchor bolt, and the lower anchor plate of the anchor bolt is adjustable in its connection position on the positioning adjustment bolt. The positioning and adjusting bolt is configured to be pre-embedded and fixed in the bearing platform together with the lower anchor plate after adjusting the height of the anchor bolt.

[0011] Beneficial Effects: The prestressed anchor bolt assembly also includes a positioning and adjusting bolt, which plays a crucial role in precise positioning and fine adjustment throughout the entire wind turbine tower foundation construction process. The positioning and adjusting bolt is made of high-quality, high-strength steel, possessing excellent mechanical properties and fatigue resistance, capable of withstanding various external forces applied during adjustment and subsequent construction. The top of the positioning and adjusting bolt connects to the lower anchor plate of the anchor bolt. The connection position of the lower anchor plate on the positioning and adjusting bolt is adjustable, allowing construction personnel to precisely adjust the height of the lower anchor plate according to the actual conditions of the construction site and design requirements. The positioning and adjusting bolt is configured to be pre-embedded and fixed in the foundation along with the lower anchor plate after adjusting its height. Once the lower anchor plate is adjusted to the predetermined height and repeatedly measured to confirm its accuracy, temporary fixing measures are required to prevent displacement during subsequent concrete pouring. For example, spot welding can be used for local fixation at the connection point, or a special locking device can be used to lock it in place. Subsequently, as the concrete pouring for the foundation commenced, the positioning and adjusting bolts, along with the lower anchor plates of the anchor bolts, were encased in concrete. During the solidification process, the concrete tightly bonded with the positioning and adjusting bolts and the lower anchor plates, forming a robust, integrated structure. Inside the foundation, the positioning and adjusting bolts not only play a supporting role in the initial positioning of the lower anchor plates, but also, throughout the wind turbine's operation, utilize their bond strength with the concrete and their connection with the lower anchor plates to help distribute and transfer the loads from the superstructure. This further enhances the stability of the connection between the foundation and the prestressed anchor bolt assembly, laying a solid foundation for the safe and stable operation of the lattice-type wind turbine.

[0012] In one optional embodiment, both the lower anchor plate and the upper anchor plate of the anchor bolt are annular, and both the lower anchor plate and the upper anchor plate are provided with a plurality of prestressed anchor bolt holes distributed along the annular shape.

[0013] In one alternative embodiment, the through hole in the middle of the anchor plate on the anchor bolt is suitable for threading a prestressed steel strand.

[0014] In one optional embodiment, the lower anchor plate of the anchor bolt is provided with a plurality of positioning adjustment bolt screw holes, the upper end of the positioning adjustment bolt passes through the positioning adjustment bolt screw hole, and the positioning adjustment bolt is provided with a positioning nut, and there is one positioning nut on the top surface and one on the bottom surface of the lower anchor plate of the anchor bolt.

[0015] In one alternative embodiment, the foundation for the lattice-type wind turbine tower further includes a steel strand anchor plate, which is located on the bottom surface of the foundation and is adapted to be fixed to the prestressed steel strand, which is fixed to the bottom surface of the foundation via the steel strand anchor plate.

[0016] Beneficial Effects: The foundation embedded pipe, located within the foundation cap, is a tubular structure pre-installed before the concrete is poured. It is typically made of high-strength steel or high-quality plastic to ensure it does not deform or break during concrete pouring and long-term use. Its internal space forms the prestressed steel strand channels, providing pathways for the arrangement and tensioning of the prestressed steel strands. The primary function of the foundation embedded pipe is to protect the prestressed steel strands. During concrete pouring, it prevents concrete from entering the prestressed steel strand channels and affecting the strand threading and tensioning. Simultaneously, the foundation embedded pipe provides a relatively independent space for the steel strands, reducing corrosion and damage from external factors and extending their service life. Furthermore, the installation of the foundation embedded pipe helps control the position and orientation of the prestressed steel strands, ensuring they are accurately arranged within the foundation cap according to design requirements, thereby better utilizing the prestressing effect and improving the foundation's bearing capacity and deformation resistance. The steel strand anchor plates are located on the bottom surface of the foundation. A steel strand anchor plate is typically a metal plate of a certain thickness and strength, with a specially treated surface to ensure good contact and anchoring performance with the prestressed steel strands and tensioning equipment. The main function of the steel strand anchor plate is to evenly transfer the tension of the prestressed steel strands to the bearing platform. When the prestressed steel strands are tensioned, the preload is distributed over a large area through the anchor plate, preventing localized stress concentrations that could damage the bearing platform. Simultaneously, the anchor plate also serves to fix the prestressed steel strands in place. In conjunction with the anchoring devices, it securely fixes the steel strands to the bearing platform, ensuring that the prestress is effectively applied to the foundation structure.

[0017] In one alternative embodiment, the foundation for the lattice-type wind turbine tower further includes a plurality of piles, the tops of which are fixed to the foundation cap, and the piles are adapted to be inserted into the foundation soil.

[0018] A construction method includes the following steps: Pile and column construction; Foundation excavation; Construction of the periphery and bottom of the tensioning cavity; The prestressed anchor bolt assembly is installed, the upper part of the tension cavity is constructed, and after the construction is completed, the lattice wind turbine tower column is fixed to the foundation.

[0019] This construction method is suitable for technical upgrade projects replacing small-scale wind turbine units with large-scale ones. It allows for direct excavation and construction of independent column foundations around the foundation of the smaller turbine, reducing project costs and offering greater design flexibility. For mountainous projects with uneven terrain, the independent column foundation can be adapted to lattice-type tower structures with varying leg heights, significantly reducing the amount of earthwork (rock) excavation. Independent column foundations are suitable for projects spanning ponds and ditches, facilitating optimized micro-site selection of wind turbine locations. They are also suitable for projects in flood discharge areas, as the small cross-sectional area of ​​the foundation columns minimizes resistance to flood discharge. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a top view of a lattice-type wind turbine tower foundation according to an embodiment of the present invention; Figure 2 This is a cross-sectional view of a lattice-type wind turbine tower foundation structure according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the prestressed anchor bolt assembly in a lattice-type wind turbine tower foundation according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the anchor plate under the anchor bolt in a lattice-type wind turbine tower foundation according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the anchor plate on the anchor bolt in a lattice-type wind turbine tower foundation according to an embodiment of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Foundation body; 101. Tensioning cavity; 102. Pier; 103. Pile; 2. Crossbeam; 3. Prestressed steel strand; 4. Lower anchor plate of anchor bolt; 401. Positioning and adjusting bolt screw hole; 5. Prestressed anchor bolt; 6. Positioning and adjusting bolt; 7. Upper anchor plate of anchor bolt; 8. Embedded pipe; 9. Steel strand anchor plate; 10. Tower column flange; 11. Grouting layer. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] With the rapid development of onshore wind turbines, a series of lattice (truss) wind turbine tower support structures have emerged on the market. Compared with traditional cylindrical towers, they have a better stiffness-to-weight ratio and material utilization rate. These new support structures have significant advantages in improving the stability and safety of wind turbines, while also providing more flexibility and innovation in tower design.

[0025] However, if truss-type wind turbine tower foundations continue to use traditional wind turbine foundations, a series of practical problems will arise. First, the land area required for wind turbine foundations is too large, increasing land resource occupation and affecting the micro-site selection of wind turbine locations. Second, using traditional wind turbine foundation methods will result in oversized foundations, which not only increases material costs but may also cause environmental pollution during construction. Furthermore, the construction period for ultra-large volume concrete projects is long, which not only extends the project's investment recovery period but may also affect the overall operational efficiency of the wind farm.

[0026] More importantly, in the stiffness transition zone between the tower and the foundation, the abrupt change in stiffness between traditional rigid foundations and flexible tower structures can easily lead to stress concentration, thereby reducing the overall stability and safety of the wind turbine tower. Simultaneously, the crack resistance of concrete is a challenge in traditional foundation design; the appearance of cracks can severely affect the durability and service life of the structure. Furthermore, the issue of hoisting continuity cannot be ignored. Traditional wind turbine foundations may experience inaccurate alignment and installation difficulties during hoisting, which not only increases construction difficulty but may also lead to construction safety accidents.

[0027] The following is combined Figures 1 to 5 The following describes embodiments of the present invention.

[0028] According to embodiments of the present invention, in one aspect, a foundation for a lattice-type wind turbine tower is provided, such as... Figure 1 and Figure 2As shown, the structure includes several foundations 102, with a crossbeam 2 fixedly connected between adjacent foundations 102; the upper side of the foundations 102 is suitable for erecting the columns of a lattice-type wind turbine tower; a pre-embedded pipe 8 is provided at the center of any foundation 102, the pre-embedded pipe 8 is used for threading prestressed steel strands 3, and the prestressed steel strands 3 are suitable for fixing to the bottom surface of the foundation 102; a tensioning cavity 101 is provided on the bottom surface of any foundation 102, the tensioning cavity 101 provides operating space for tensioning or anchoring the prestressed steel strands 3; several prestressed anchor bolt assemblies are provided, and prestressed anchor bolt assemblies are provided on any foundation 102, the prestressed anchor bolt assemblies are suitable for connecting and fixing to the columns of the lattice-type wind turbine tower.

[0029] In this embodiment, the foundation body 1 includes a tension cavity 101 and a foundation 102. The foundation 102 is a four-point raft foundation, and is a reinforced concrete structure that can be symmetrically arranged. The foundations 102 are located below the tower columns, and each independent foundation 102 is connected as a whole by a crossbeam 2. A tower base connection area is set at the center of the top surface of each independent foundation 102, and a prestressed anchor bolt assembly is installed in the tower base connection area. When installing and fixing the lattice-type wind turbine tower, the tower columns of the lattice-type wind turbine tower are fixed to the foundation 102, and the prestressed steel strands 3 inside the tower columns of the lattice-type wind turbine tower are passed through embedded pipes 8 and their ends are fixed to the top surface of the tension cavity 101, thereby fixing the prestressed steel strands 3. A prestressed anchor bolt assembly is provided on any foundation 102, and the tower column of the lattice-type wind turbine tower is fixed to the foundation 102 through the prestressed anchor bolt assembly. In this embodiment, multiple piers 102 are used to provide support for the lattice-type wind turbine tower. Compared with the traditional cylindrical tower wind turbine foundation, this can significantly save land area and reduce material costs.

[0030] In one embodiment, the foundation 102 is a reinforced concrete structure, and the prestressed anchor bolt assembly includes a lower anchor plate 4 and a prestressed anchor bolt 5. The lower anchor plate 4 is embedded inside the foundation 102; the prestressed anchor bolt 5 is embedded inside the foundation 102, and the bottom end of the prestressed anchor bolt 5 is connected and fixed to the lower anchor plate 4. The upper end of the prestressed anchor bolt 5 extends out of the top surface of the foundation 102 and is connected and fixed to the upper anchor plate 7 and the tower flange 10. The prestressed anchor bolt assembly is used to connect the lattice wind turbine tower column to the foundation.

[0031] The foundation 102 is a reinforced concrete structure. This type of concrete has good compressive strength and durability, capable of withstanding the enormous loads transmitted from the superstructure and various external forces. Before pouring the foundation 102, the construction site needs to be leveled and cleaned, and the reinforcing steel cage needs to be tied according to the design requirements. Necessary formwork needs to be set up to ensure that the shape and dimensions of the foundation 102 meet the design standards. The prestressed anchor bolt assembly includes the lower anchor plate 4 and the prestressed anchor bolt 5. The lower anchor plate 4 is a metal component, and its shape and dimensions are designed according to the actual needs of the project. During the concrete pouring of the foundation 102, the lower anchor plate 4 is precisely placed in the predetermined position and is firmly fixed inside the foundation 102 through the connection with the surrounding reinforcing steel and the encapsulation effect of the concrete. It plays an important role in connecting the prestressed anchor bolt 5 and the foundation 102, and can evenly transfer the load borne by the prestressed anchor bolt 5 to the foundation 102.

[0032] The prestressed anchor bolt 5 is a specially designed and processed high-strength bolt, typically made of high-strength alloy steel, possessing high tensile strength and fatigue resistance. The prestressed anchor bolt 5 is also pre-embedded inside the foundation 102, and its bottom end is tightly fixed to the lower anchor plate 4 via welding, threaded connection, or other reliable fixing methods. This connection method ensures that no relative displacement occurs between the prestressed anchor bolt 5 and the lower anchor plate 4 under load, thus guaranteeing the stability of the entire structure. The upper end of the prestressed anchor bolt 5 extends beyond the surface of the foundation 102, with the extension length precisely controlled according to the connection requirements of the lattice-type wind turbine tower column. The upper end of the prestressed anchor bolt 5 is connected and fixed to the upper anchor plate 7 and the tower column flange 10. The prestressed anchor bolt assembly is used to connect the lattice-type wind turbine tower column to the foundation. During the connection process, specialized connecting nuts, washers, and other accessories are typically used to securely connect the tower column flange 10 to the prestressed anchor bolt 5. This connection method effectively transfers the load of the wind turbine tower to the foundation 102. Simultaneously, the prestressing effect of the prestressed anchor bolts 5 reduces deformation and crack development of the foundation 102 under load, improving the reliability and safety of the entire wind turbine tower foundation structure. The prestressed anchor bolt assembly also includes an upper anchor plate 7, which enhances the stability and reliability of the structural connection. The upper anchor plate 7 is typically made of high-strength, high-toughness steel to ensure sufficient load-bearing capacity and good mechanical properties. In material selection, steel with good corrosion resistance is generally preferred, as wind turbine towers are typically located outdoors and exposed to various complex climatic conditions for extended periods; corrosion resistance is crucial for ensuring the durability of the upper anchor plate 7. The upper anchor plate 7 is located on the upper side of the foundation 102. During installation, specialized lifting equipment is used to smoothly lift the upper anchor plate 7 onto the foundation 102 and precisely align it with the pre-marked position. Furthermore, the anchor plate 7 on the anchor bolt is adapted to abut against the tower flange 10. This abutment method can effectively transfer the load borne by the wind turbine tower column to the pier cap 102 evenly. To ensure the tightness and stability of the abutment, the upper surface of the anchor plate 7 on the anchor bolt is usually flattened, and the surface flatness error is controlled within a very small range to ensure that the contact surface with the wind turbine tower column can be fully fitted.

[0033] After passing through the upper anchor plate 7, the upper end of the prestressed anchor bolt 5 is suitable for connection with the tower flange 10. Holes corresponding to the number and position of the prestressed anchor bolts 5 are pre-set on the upper anchor plate 7. The diameter and tolerance of these holes are designed to ensure that the prestressed anchor bolts 5 can pass through smoothly and that the gap between them and the holes is reasonable. After the prestressed anchor bolt 5 passes through the upper anchor plate 7, its upper end will connect to the lattice wind turbine tower column. Common connection methods include using high-strength nuts for tightening. During the tightening process, a certain preload is applied, pressing the upper anchor plate 7 tightly against the bearing platform 102, and simultaneously forming a tight connection between the tower flange 10 and the upper anchor plate 7. To prevent the nuts from loosening, anti-loosening washers, double nuts, and other anti-loosening measures are also used.

[0034] In one embodiment, the prestressed anchor bolt assembly further includes a positioning adjustment bolt 6, the top of which is connected to the lower anchor plate 4 of the anchor bolt, and the connection position of the lower anchor plate 4 on the positioning adjustment bolt 6 is adjustable; the positioning adjustment bolt 6 is configured to adjust the height of the lower anchor plate 4 and then be cast and fixed together with the lower anchor plate 4 in the foundation 102.

[0035] The prestressed anchor bolt assembly also includes a positioning and adjusting bolt 6, which plays a crucial role in precise positioning and fine adjustment throughout the wind turbine tower foundation construction process. The positioning and adjusting bolt 6 is made of high-quality, high-strength steel, possessing excellent mechanical properties and fatigue resistance, capable of withstanding various external forces applied during adjustment and subsequent construction. The top of the positioning and adjusting bolt 6 connects to the lower anchor plate 4 of the anchor bolt. The connection position of the lower anchor plate 4 on the positioning and adjusting bolt 6 is adjustable, allowing construction personnel to precisely adjust the height of the lower anchor plate 4 according to the actual conditions of the construction site and design requirements. The positioning and adjusting bolt 6 is configured to adjust the height of the lower anchor plate 4 and is cast and fixed together with the lower anchor plate 4 within the foundation 102. After the lower anchor plate 4 is adjusted to the predetermined height and repeatedly measured to confirm its accuracy, temporary fixing measures are required to prevent displacement during subsequent concrete pouring. For example, spot welding can be used for local fixing at the connection point, or a special locking device can be used to lock it in place. Subsequently, as the concrete pouring of the foundation 102 commenced, the positioning and adjusting bolts 6 and the lower anchor plates 4 were encased in concrete. During the solidification process, the concrete tightly bonded with the positioning and adjusting bolts 6 and the lower anchor plates 4, forming a robust integrated structure. Inside the foundation 102, the positioning and adjusting bolts 6 not only served as an auxiliary anchor to the lower anchor plates 4 in the initial stages, but also, throughout the wind turbine's operation, aided in distributing and transferring the loads from the superstructure through their adhesion to the concrete and their connection with the lower anchor plates 4. This further enhanced the stability of the connection between the foundation 102 and the prestressed anchor assembly, laying a solid foundation for the safe and stable operation of the lattice-type wind turbine.

[0036] In one embodiment, a grouting layer 11 is provided between the anchor plate 7 on the anchor bolt and the foundation 102. The grouting layer 11 plays an important role in load transfer and dispersion. When the lattice wind turbine tower is subjected to various external forces such as wind, the load of the tower column is transferred to the grouting layer 11 through the anchor plate 7 on the anchor bolt. The grouting layer 11 then evenly distributes the load onto the foundation 102, avoiding local stress concentration that could damage the foundation 102 and improving the load-bearing capacity and stability of the entire foundation structure.

[0037] In one embodiment, such as Figure 4 and Figure 5 As shown, both the lower anchor plate 4 and the upper anchor plate 7 are annular, and each has several prestressed anchor holes distributed along the annular shape. The annular design of both the lower anchor plate 4 and the upper anchor plate 7 provides good symmetry and can evenly distribute loads from all directions. During the operation of a lattice-type wind turbine tower, it is subjected to complex external forces such as wind and seismic forces, the directions of which are variable. The annular anchor plates can evenly transfer these external forces to the surrounding concrete foundation 102 or other connecting components, avoiding the problem of local stress concentration, thereby improving the stability and load-bearing capacity of the entire structure.

[0038] In one embodiment, the through hole in the middle of the anchor plate 7 on the anchor bolt is suitable for threading the prestressed steel strand 3. The through hole in the middle of the anchor plate 7 on the anchor bolt is connected to the channel of the prestressed steel strand 3 on the bearing platform 102, so as to avoid the anchor plate 7 on the anchor bolt affecting the threading of the prestressed steel strand 3.

[0039] In one embodiment, such as Figure 4 As shown, the lower anchor plate 4 of the anchor bolt is provided with several positioning adjustment bolt screw holes 401. The upper end of the positioning adjustment bolt 6 passes through the positioning adjustment bolt screw hole 401, and the positioning adjustment bolt 6 is provided with a positioning nut. There is a positioning nut on the top surface and the bottom surface of the lower anchor plate 4 of the anchor bolt.

[0040] The positioning and adjusting bolt holes 401 on the lower anchor plate 4 are regularly distributed on the lower anchor plate 4. The distribution pattern is typically determined based on the shape and size of the lower anchor plate 4 and the stress characteristics of the entire foundation structure. Generally, the bolt holes are arranged in a circular or matrix pattern around the center of the lower anchor plate 4 to ensure that the adjusting force in all directions is applied evenly when adjusting the position of the lower anchor plate 4, thereby ensuring the accuracy and stability of the position adjustment of the lower anchor plate 4 in space. The upper end of the positioning and adjusting bolt 6 passes through the positioning and adjusting bolt hole 401, and the lower end of the positioning and adjusting bolt 6 can be pre-fixed to the internal reinforcing steel of the foundation 102. Two nuts are installed on the upper end of the positioning and adjusting bolt 6, located on the upper and lower sides of the lower anchor plate 4 respectively, to fix the lower anchor plate 4. By rotating the nuts, the height of the lower anchor plate 4 can be precisely adjusted.

[0041] In one embodiment, the foundation for the lattice wind turbine tower also includes a steel strand anchor plate 9, which is located on the bottom surface of the foundation 102 and is suitable for fixing to the prestressed steel strand 3. The prestressed steel strand 3 is fixed to the top surface of the tension cavity 101 via the steel strand anchor plate 9.

[0042] The foundation embedded pipe 8 is located within the foundation cap 102 and is a tubular structure pre-installed before the concrete pouring of the foundation cap 102. The foundation embedded pipe 8 is typically made of high-strength steel or high-quality plastic to ensure it does not deform or become damaged during concrete pouring and subsequent long-term use. Its internal space forms the prestressed steel strand channels, providing a pathway for the threading and tensioning of the prestressed steel strands 3. The main function of the foundation embedded pipe 8 is to protect the prestressed steel strands 3. During concrete pouring, it prevents concrete from entering the prestressed steel strand channels, avoiding direct contact between the steel strands and concrete that could affect threading or tensioning. Simultaneously, the foundation embedded pipe 8 provides a relatively independent space for the steel strands, reducing corrosion and damage from external factors and extending their service life. Furthermore, the installation of the foundation embedded pipe 8 helps control the position and orientation of the prestressed steel strands 3, ensuring they are accurately arranged within the foundation cap 102 according to design requirements, thereby better utilizing the prestressing effect and improving the foundation's bearing capacity and resistance to deformation. The steel strand anchor plate 9 is located at the top of the tensioning cavity 101, a space specifically reserved within the bearing platform 102 for tensioning the prestressed steel strands 3. The steel strand anchor plate 9 is typically a metal plate of a certain thickness and strength, with a specially treated surface to ensure good contact and anchoring performance with the prestressed steel strands 3 and the tensioning equipment. The main function of the steel strand anchor plate 9 is to evenly transfer the tension of the prestressed steel strands 3 to the bearing platform 102. When the prestressed steel strands 3 are tensioned, the preload is distributed over a large area through the steel strand anchor plate 9, preventing localized stress concentration from damaging the bearing platform 102. Simultaneously, the steel strand anchor plate 9 also serves to fix the prestressed steel strands 3, securely fixing them to the bearing platform 102 in conjunction with the anchoring device, ensuring that the prestress is effectively applied to the foundation structure.

[0043] In one embodiment, the foundation body 1 further includes a plurality of piles 103, the top of which is fixed to the pile cap 102, and the piles 103 are adapted to be inserted into the foundation soil.

[0044] The pile 103 is typically made of reinforced concrete and contains a certain number and specifications of steel reinforcement bars to enhance its load-bearing capacity. The pile 103 is suitable for insertion into the foundation soil, and its main function is to transfer the load of the wind turbine tower to deeper, higher-bearing-capacity soil layers. The pile 103 can be arranged in one or multiple rings.

[0045] The lattice-type wind turbine tower foundation provided in this embodiment is suitable for technical upgrade projects replacing small-scale wind turbine units with large-scale ones. It allows for direct excavation and construction of independent column foundations around the foundation of the small turbine, reducing project costs and offering greater design flexibility. For mountainous projects with uneven terrain, the independent column foundation can be adapted to lattice-type tower structures with varying leg heights, significantly reducing the amount of earthwork (rock) excavation. Independent column foundations are suitable for projects spanning ponds and ditches, facilitating optimized micro-site selection of wind turbine locations. They are also suitable for flood discharge area projects, as the small cross-sectional area of ​​the foundation columns minimizes resistance to flood discharge.

[0046] According to an embodiment of the present invention, another aspect provides a construction method, comprising the following steps: Pile and column construction; Foundation excavation; Construction of the periphery and bottom of the tension cavity 101 in the foundation body 1; The prestressed anchor bolt assembly is installed, and the upper part of the tension cavity 101 in the foundation body 1 is constructed. After the construction is completed, the lattice wind turbine tower column is fixed to the foundation 102.

[0047] In this embodiment, as Figure 3 As shown, the foundation body 1 is divided into area A and area B. The periphery and bottom of the tension cavity 101 are area A, and the upper part of the tension cavity 101 is area B. Area A and area B are constructed separately.

[0048] The foundation construction in Area A mainly includes: subgrade construction → preparation of the pouring surface (formwork erection, waterproofing, rebar tying) → quality inspection and acceptance of the pouring surface → concrete pouring (material preparation, mixing, transportation, placement, vibration) → curing → formwork removal → quality inspection → defect repair → backfilling. Alternatively, the concrete in Area A can be prefabricated in the factory, then transported to the construction site, settled into place, and then backfilled.

[0049] The foundation construction in Zone B mainly includes: subbase construction → preparation of the pouring surface (binding of bottom reinforcement, positioning of embedded pipes and anchor plate assemblies, positioning of prestressed anchor bolt assemblies, erection of upper reinforcement, and formwork) → quality inspection and acceptance of the pouring surface → concrete pouring (material preparation, mixing, transportation, placement, and vibration) → curing → formwork removal → quality inspection → repair of defects → grouting of the top surface of the foundation → backfilling of earthwork → curing.

[0050] The prestressed anchor bolt assembly is positioned as follows: Locate and fix the positioning adjusting bolt 6 (with threaded body for easy connection of the nut) on the bottom surface of the foundation 102; then connect the lower anchor plate 4 of the anchor bolt to the positioning adjusting bolt 6 using a nut, adjusting the height of the lower anchor plate by tightening the nut; then pass the prestressed anchor bolt 5 through the lower anchor plate 4 from bottom to top, connecting and fixing the prestressed anchor bolt 5 to the lower anchor plate 4. After the grouting layer 11 is poured and cured, position the upper anchor plate 7 of the anchor bolt; during the hoisting of the tower bottom, place the connecting tower flange 10 on the top surface of the upper anchor plate 7, ensuring that the prestressed anchor bolt 5 completely passes through the upper anchor plate 7 and the tower flange 10; finally, tension and lock the prestressed anchor bolt 5.

[0051] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A foundation for a lattice-type wind turbine tower, characterized in that, include: Several foundations (102) are provided, and a crossbeam (2) is fixedly connected between two adjacent foundations (102); the upper side of the foundations (102) is suitable for erecting the columns of a lattice wind turbine tower; An embedded pipe (8) is provided at the center of any of the aforementioned piers (102), the embedded pipe (8) is used for threading prestressed steel strands (3), and the prestressed steel strands (3) are adapted to be fixed on the bottom surface of the piers (102); The bottom surface of any of the aforementioned piers (102) is provided with a tensioning cavity (101), which provides operating space for tensioning or anchoring the prestressed steel strands (3); If the prestressed anchor bolt assembly is used, a prestressed anchor bolt assembly is provided on any of the foundations (102), and the prestressed anchor bolt assembly is suitable for connecting and fixing the foundation to the tower column of the lattice wind turbine.

2. The foundation for a lattice-type wind turbine tower according to claim 1, characterized in that, The foundation (102) is a reinforced concrete structure, and the prestressed anchor bolt assembly includes: The anchor plate (4) of the anchor bolt is embedded inside the bearing platform (102); The prestressed anchor bolt (5) is embedded inside the foundation (102), and the bottom end of the prestressed anchor bolt (5) is connected and fixed to the lower anchor plate (4) of the anchor bolt. The upper end of the prestressed anchor bolt (5) extends out of the top surface of the foundation (102) and is connected and fixed to the upper anchor plate (7) of the anchor bolt and the tower flange (10). The prestressed anchor bolt assembly is used to connect the lattice wind turbine tower column to the foundation.

3. The foundation for a lattice-type wind turbine tower according to claim 2, characterized in that, The prestressed anchor bolt assembly also includes a positioning adjustment bolt (6), the top of which is connected to the lower anchor plate (4) of the anchor bolt, and the lower anchor plate (4) of the anchor bolt is adjustable in position on the positioning adjustment bolt (6); The positioning adjustment bolt (6) is configured to be pre-embedded and fixed in the bearing platform (102) together with the lower anchor plate (4) after adjusting the height of the anchor bolt.

4. The foundation for a lattice-type wind turbine tower according to claim 3, characterized in that, Both the lower anchor plate (4) and the upper anchor plate (7) of the anchor bolt are annular, and both the lower anchor plate (4) and the upper anchor plate (7) of the anchor bolt are provided with a number of prestressed anchor bolt holes distributed along the annular shape.

5. The foundation for a lattice-type wind turbine tower according to claim 4, characterized in that, The through hole in the middle of the anchor plate (7) of the anchor bolt is suitable for threading prestressed steel strands (3).

6. The foundation for a lattice-type wind turbine tower according to claim 3, characterized in that, The lower anchor plate (4) of the anchor bolt is provided with a plurality of positioning adjustment bolt screw holes (401). The upper end of the positioning adjustment bolt (6) passes through the positioning adjustment bolt screw hole (401), and the positioning adjustment bolt (6) is provided with a positioning nut. The top surface and bottom surface of the lower anchor plate (4) of the anchor bolt each have a positioning nut.

7. The foundation for a lattice-type wind turbine tower according to any one of claims 1-6, characterized in that, It also includes a steel strand anchor plate (9), which is located on the bottom surface of the bearing platform (102) and is adapted to be fixed with the prestressed steel strand (3). The prestressed steel strand (3) is fixed on the bottom surface of the bearing platform (102) by the steel strand anchor plate (9).

8. The foundation for a lattice-type wind turbine tower according to any one of claims 1-6, characterized in that, It also includes a number of piles (103), the top of which is fixed to the pile cap (102), and the piles (103) are suitable for being inserted into the foundation soil.

9. A construction method for a foundation of a lattice-type wind turbine tower as described in any one of claims 1-8, characterized in that, Includes the following steps: Construction of pile column (103); Foundation excavation; Construction of the periphery and bottom of the tensioned cavity (101); The prestressed anchor bolt assembly was installed, and the foundation (102) was constructed. After the construction was completed, the lattice wind turbine tower column was fixed to the foundation (102).

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