Modular prestressed wind turbine foundation with height adjustment and method of construction

Abstract

The application discloses a height-adjustable modular prestressed fan foundation, which comprises a plurality of assembling units, which are sequentially spliced to form a closed ring structure in the horizontal direction, each assembling unit is composed of a center part and a flange part extended outside the center part; a horizontal connecting piece, which comprises a first fastening bolt and a second fastening bolt arranged on the center part, and a third fastening bolt arranged on the flange part, the first fastening bolt, the second fastening bolt and the third fastening bolt are used for connecting adjacent assembling units; a prestressed locking assembly, which comprises a longitudinal anchor rod arranged on the center part, an upper anchor plate arranged on the top surface of the center part and a lower anchor plate arranged on the bottom surface of the center part, and the longitudinal anchor rod is fastened and connected with the upper anchor plate and the lower anchor plate. The application can produce each module in batches through factory precasting and combine with on-site assembly, greatly improves the construction speed and shortens the construction period; and the height of the center part can be flexibly adjusted according to the construction requirements to meet the flood control requirements of the project.

Description

Technical Field

[0001] This invention relates to the field of wind turbine tower foundation technology, and in particular to a height-adjustable modular prestressed wind turbine foundation and its construction method. Background Technology

[0002] In recent years, with the continuous optimization and adjustment of the national energy structure, wind power generation in the new energy field has received attention. Coupled with strong support from national policies in various aspects, the development of wind power generation in China has been rapid. Traditional wind turbine foundations include ribbed foundations, extended foundations, and anchor foundations, which involve complex and time-consuming steel reinforcement binding, complex formwork support, and difficulty in ensuring construction quality and progress. Secondly, the amount of foundation earthwork and cast-in-place concrete work is large, which has a significant impact on soil and water conservation and the environment. Thirdly, when constructing wind farms in tidal flat areas, flood control needs to be considered, but traditional wind turbine foundations cannot meet the flood control requirements. Finally, existing wind turbines require a large amount of labor and have high construction costs, and after the wind farm's operation period ends, the wind turbine foundations cannot be recycled and reused, resulting in a large waste of resources. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides a modular prestressed wind turbine foundation with adjustable height, low cost, fast construction speed, minimal environmental impact, safety and stability, flood prevention, and recyclability. It also provides a construction method for the aforementioned wind turbine foundation, specifically adopting the following technical solutions:

[0004] The height-adjustable modular prestressed wind turbine foundation of the present invention includes...

[0005] Multiple assembly units are sequentially spliced ​​together in a horizontal direction to form a closed ring structure. Each assembly unit consists of a central part and a flange part extending outside the central part.

[0006] The horizontal connector includes a first fastening bolt and a second fastening bolt disposed at the center, and a third fastening bolt disposed at the flange. The first fastening bolt, the second fastening bolt and the third fastening bolt are all used to connect adjacent splicing units.

[0007] The prestressed locking assembly includes a longitudinal anchor rod disposed at the center, an upper anchor plate disposed at the top surface of the center, and a lower anchor plate disposed at the bottom surface of the center, wherein the longitudinal anchor rod is fastened to the upper anchor plate and the lower anchor plate.

[0008] The splicing surface of the central part has a first mounting hole adapted to the first fastening bolt and a second mounting hole adapted to the second fastening bolt. The first mounting hole is located near the outer wall of the central part and communicates with a first mounting groove on the outer wall of the central part. The second mounting hole is located near the inner wall of the central part and communicates with a second mounting groove on the inner wall of the central part. A rib is provided on the splicing surface of the flange part, and a third mounting hole adapted to the third fastening bolt is provided on the rib.

[0009] The end of the rib extends to the outer edge of the flange, and a partition beam with its end connected to the end of the rib is provided on the flange. The partition beam and the ribs on both sides form a counterweight cavity.

[0010] The splicing surface of the flange portion is provided with a first positioning pair and a second positioning pair.

[0011] The first positioning pair includes a male groove disposed on one side of the splicing surface of the flange portion, and a female groove disposed on the other side of the splicing surface that is adapted to the male groove.

[0012] The second positioning pair includes a positioning rod disposed on one side of the flange splicing surface and an insertion hole disposed on the other side of the splicing surface that is adapted to the positioning rod.

[0013] The central part has a longitudinal through hole, and a PVC corrugated pipe is installed on the inner wall of the longitudinal through hole. The longitudinal anchor rod is wound with steel strand and installed inside the corrugated pipe. The longitudinal anchor rod and the corrugated pipe are fixed together by injecting cement grout.

[0014] The central section includes a fixed section at the bottom and an adjustable section at the top.

[0015] A longitudinal waterstop strip is provided on the longitudinal splicing surface of the central part, located between the longitudinal anchor rod and the first fastening bolt, and a circumferential waterstop strip is provided on the transverse splicing surface of the central part, located between the longitudinal anchor rod and the second fastening bolt.

[0016] A construction method for a highly adjustable modular prestressed wind turbine foundation includes the following steps:

[0017] The first step is to excavate the foundation pit and pour a concrete cushion layer at the bottom of the pit;

[0018] The second step is to hoist the assembly units one by one to the predetermined position and complete the assembly. Then, install the third fastening bolt, the second fastening bolt, and the first fastening bolt in sequence. When tightening the third fastening bolt, the second fastening bolt, and the first fastening bolt, the odd number should be tightened first and the even number should be tightened later, and the top and bottom bolts should be tightened simultaneously. After that, install the prestressed locking assembly.

[0019] The third step is to backfill the foundation pit, and determine whether to backfill within the center of the closed ring structure formed by each assembly unit based on the geological conditions. The backfill soil is then compacted in layers until it is level with the ground level, thus completing the construction.

[0020] The height-adjustable modular prestressed wind turbine foundation provided by this invention can greatly improve construction speed and shorten the construction cycle by combining factory prefabrication of each module with on-site assembly. It can also flexibly adjust the height of the center part according to construction requirements to meet the flood control requirements of the project. In addition, the project investment cost can be reduced by recycling and reusing each assembly unit. The wind turbine foundation with the above structure saves materials and has low investment during construction. It is quick and convenient to hoist and install, which greatly meets the flood control requirements when building wind farms in tidal flat areas.

[0021] Compared with the prior art, the advantages of the present invention are as follows:

[0022] 1. The central part of the assembly unit of this invention is divided into upper and lower sections, and the height can be adjusted according to flood control requirements, which greatly improves the safety of the wind farm. Increasing the height of the foundation (i.e. the central part) can reduce the height of the steel tower, thereby improving the overall rigidity of the tower, effectively reducing noise and tower vibration, which is beneficial to environmental protection and increasing power generation.

[0023] 2. All assembly units of the present invention are connected by bolts, resulting in a high degree of mechanization and reducing the construction work area by more than half compared to traditional methods, thus reducing labor input; multiple positioning mechanisms are provided between each assembly unit for easy positioning, high fit between modules, and uniform overall stress distribution;

[0024] 3. The lower anchor plate of the present invention is connected to the height adjustment bolt, which can flexibly control the anchor installation space and make anchor installation more convenient;

[0025] 4. The present invention constructs a prestressed hybrid anchor rod by winding steel strands around the vertical anchor rod. When under stress, it has the hybrid characteristics of anchor rod and anchor cable, can withstand greater upper loads, can reduce the amount of anchor rod steel used, and is more applicable to foundation caps of different heights.

[0026] 5. The present invention provides a PVC corrugated pipe on the inner wall of the anchor bolt installation hole, which allows the anchor bolt to be more fully integrated with the foundation, adjusts the stress condition of the anchor bolt, and helps to reduce the amount of maintenance work required for the anchor bolt;

[0027] 6. During installation, the various connecting bolts are tightened in a certain order, which optimizes the connection structure of the splicing unit and makes the wind turbine foundation more uniformly stressed.

[0028] 7. The modular adjustable wind turbine foundation of the present invention is a prefabricated splicing product. The components are easy to disassemble and move, the installation is flexible and simple, and it can be recycled and reused.

[0029] 8. The flange of the assembly unit of the present invention is provided with a triangular counterweight cavity composed of partition beams and rib beams. Different graded sand and gravel or locally sourced materials can be used for counterweight according to the upper load of the wind turbine foundation, thereby reducing the amount of concrete used and further reducing the project cost.

[0030] 9. The assembly modules of this invention are manufactured in factories, eliminating the need for on-site concrete pouring. The construction process is simple and the construction progress is guaranteed. Due to the small installation work area and the small foundation excavation range, the impact on soil and water and the environment can be greatly reduced, meeting the increasingly stringent construction requirements.

[0031] 10. The present invention provides water-stop strips between the splicing surfaces of the assembly units, which greatly improves the durability and corrosion resistance of the wind turbine foundation. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0033] Figure 2 yes Figure 1 Top view (backfill soil omitted).

[0034] Figure 3 yes Figure 2 Enlarged view of the central part.

[0035] Figure 4 This is a schematic diagram of the structure of Embodiment 2 of the present invention. Detailed Implementation

[0036] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the scope of protection of the present invention is not limited to the following embodiments.

[0037] Example 1:

[0038] like Figure 1-3 As shown, the height-adjustable modular prestressed wind turbine foundation of this invention comprises eight assembly units (the number can be adjusted according to specific circumstances). These assembly units have identical structures and are sequentially assembled horizontally, forming a hollow closed-loop structure through horizontal connectors and prestressed locking components. Each assembly unit consists of a central portion and a flange extending outwards from the central portion. The central portion is higher, with its top used for mounting the wind turbine (i.e., the wind turbine support). The flange is designed to increase the stability of the central portion, and related mechanisms can be installed on the flange for assembly positioning and fastening.

[0039] Specifically, each assembly unit's flange includes a base plate 1.1 extending outward from the center, ribs 1.2 on both sides of the base plate 1.1, and a partition beam 1.3 connected to the ends of the ribs 1.2. The ends of the ribs 1.2 extend to the edge of the base plate 1.1, and the triangular counterweight cavity formed by the ribs 1.2 and the partition beam 1.3 can hold different grades of sand and gravel or use locally sourced materials for counterweighting, reducing concrete usage and lowering project costs. To facilitate the assembly and positioning of the assembly units, a first positioning pair 2.1 and a second positioning pair 2.2 are provided on the flange's splicing surface. The first positioning pair includes a male groove on one side of the rib 1.2 and a female groove on the other side of the rib 1.2, with corresponding positions and matching shapes. The second positioning pair 2.2 includes a positioning rod on one side of the base plate 1.1 and an insertion hole on the other side of the base plate 1.1, with corresponding positions and matching shapes. The aforementioned positioning mechanism can ensure the accuracy of the assembly of the units in all aspects and reduce the uneven stress on the wind turbine foundation caused by misalignment during installation.

[0040] The aforementioned horizontal connector includes a first fastening bolt 3.1 and a second fastening bolt 3.2 for connecting the centers of adjacent assembly units, and a third fastening bolt 3.3 for connecting adjacent rib beams 1.2. The first fastening bolt 3.1 is located near the outer side of the center and is a straight bolt; the second fastening bolt 3.2 is located near the inner side of the center and is a bent bolt. To facilitate the installation of the first fastening bolt 3.1, two first mounting holes adapted to the first fastening bolt 3.1 and two second mounting holes adapted to the second fastening bolt 3.2 are respectively provided on the two splicing surfaces of the center. Furthermore, two first mounting grooves 3.4 are provided on the outer wall of the center, communicating with the two first mounting holes respectively, for inserting straight bolts and screwing fastening nuts at their ends. Similarly, to facilitate the installation of the second fastening bolt 3.2, two second mounting grooves 3.5 are provided on the inner wall of the center, communicating with the two second mounting holes respectively. Each rib 1.2 of the assembly unit has a third mounting hole that matches the third fastening bolt 3.3. Typically, these third mounting holes are arranged in rows, with multiple rows in total. PVC pipes are fitted onto the inner walls of the aforementioned insertion holes, first mounting holes, second mounting holes, and third mounting holes.

[0041] The aforementioned prestressed locking assembly includes a longitudinal anchor rod 4.1 located at the center, an upper anchor plate 4.2 located on the top surface of the center, and a lower anchor plate 4.3 located on the bottom surface of the center. Both the upper anchor plate 4.2 and the lower anchor plate 4.3 are annular plates. The longitudinal anchor rod 4.1 is formed by winding steel strands to form a prestressed anchor rod, which is installed in a longitudinal through-hole in the center by injecting cement grout. A PVC corrugated pipe is fitted onto the inner wall of the longitudinal through-hole to ensure full integration with the longitudinal anchor rod 4.1 and the center. During installation, the lower anchor plate 4.3 is placed below the center, and its height is adjusted using the height adjusting bolt 4.4. Then, the longitudinal anchor rod 4.1, the lower anchor plate 4.3, and the upper anchor plate 4.2 are connected together using nuts.

[0042] To prevent water from entering the joint and corroding the metal parts, a longitudinal waterstop strip 5.1 is provided on the longitudinal splicing surface in the center, located between the longitudinal anchor rod 4.1 and the first fastening bolt 3.1.

[0043] Example 2:

[0044] To address flood control issues, simplify construction, and reduce investment costs, the central section is prefabricated into two parts: a fixed section 6.1 connected to the lower flange and a separately prefabricated upper section 6.2. Typically, the number of upper sections 6.2 and fixed sections 6.1 is the same. However, while meeting splicing requirements and maintaining the splicing and locking structures, the number of upper sections 6.2 can be reduced to allow for large-volume prefabrication, thereby reducing prefabrication and hoisting workload. When assembling upper sections 6.2 and fixed sections 6.1, the upper anchor plate 4.2 is located on the top surface of upper section 6.2, and the lower anchor plate 4.3 is located on the bottom surface of fixed section 6.1. Longitudinal anchor bolts 4.1 pass through both upper sections 6.2 and fixed sections 6.1 to secure them. A circumferential waterstop strip 5.2 should be installed on the transverse splicing surface between the longitudinal anchor bolt 4.1 and the second fastening bolt 3.2. All other components are the same as in Example 1.

[0045] The construction method for the height-adjustable modular prestressed wind turbine foundation described in this invention includes the following steps:

[0046] The first step is to excavate the foundation pit and pour a concrete cushion layer at the bottom of the pit;

[0047] The second step is to hoist the assembly units one by one to the predetermined position and complete the assembly. Then, install the third fastening bolt, the second fastening bolt, and the first fastening bolt in sequence. When tightening the third fastening bolt, the second fastening bolt, and the first fastening bolt, the odd number should be tightened first and the even number should be tightened later, and the top and bottom bolts should be tightened simultaneously. After that, install the prestressed locking assembly.

[0048] The third step is to backfill the foundation pit, and determine whether to backfill within the center of the closed ring structure formed by each assembly unit based on the geological conditions. The backfill soil is then compacted in layers until it is level with the ground level, thus completing the construction.

[0049] Specifically, the following describes the specific construction steps using the wind turbine foundation described in Example 2:

[0050] The first step is to excavate the foundation pit and pour a concrete cushion layer at the bottom of the pit. The cushion layer needs to be poured flat to facilitate the positioning, assembly and fastening of the assembly units, and to ensure that the assembled wind turbine foundation is subjected to uniform stress.

[0051] The second step involves installing the longitudinal waterstop strip 5.1 in its corresponding position on each assembly unit. Then, each assembly unit, including the fixed section 6.1, is hoisted and placed in its designated position. Positioning and assembly are completed using the matching positioning rods, insertion holes, internal grooves, and external grooves. Next, the third fastening bolt 3.3 at the rib beam, the second fastening bolt 3.2 on the inner side of the center, and the first fastening bolt 3.1 on the outer side of the center are installed sequentially. When tightening the third fastening bolt 3.3, the second fastening bolt 3.2, and the first fastening bolt 3.1, the odd-numbered bolts are tightened first, followed by the next. The process proceeds in an even-numbered sequence, starting simultaneously from top to bottom. Next, the lower anchor plate 4.3 and longitudinal anchor rod 4.1 are installed. Then, circumferential waterstop strips 5.2 are installed at corresponding positions on the upper surface of the assembled fixed section 6.1. Then, the assembly units consisting of the height adjustment sections 6.2 are hoisted one by one, ensuring their longitudinal through holes correspond to the longitudinal anchor rods 4.1. After installing the height adjustment section 6.2 onto the fixed section 6.1, it is secured with the second fastening bolt 3.2 and the first fastening bolt 3.1. The upper anchor plate 4.2 is then installed, and the longitudinal anchor rods 4.1 are locked with fastening nuts.

[0052] The third step is to backfill the foundation pit, and determine whether to backfill within the center of the closed ring structure formed by each assembly unit based on the geological conditions. The backfill soil is then compacted in layers until it is level with the ground level, thus completing the construction.

[0053] It should be noted that in the description of this invention, terms such as "front," "rear," "left," "right," "vertical," "horizontal," "inner," and "outer" indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to 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 this invention.

Claims

1. A height-adjustable modular prestressed wind turbine foundation, characterized in that: The wind turbine foundation includes Multiple assembly units are sequentially spliced ​​together in a horizontal direction to form a closed ring structure. Each assembly unit consists of a central part and a flange part extending outside the central part. The horizontal connector includes a first fastening bolt and a second fastening bolt disposed at the center, and a third fastening bolt disposed at the flange. The first fastening bolt, the second fastening bolt and the third fastening bolt are all used to connect adjacent splicing units. The prestressed locking assembly includes a longitudinal anchor rod disposed at the center, an upper anchor plate disposed at the top surface of the center, and a lower anchor plate disposed at the bottom surface of the center, wherein the longitudinal anchor rod is fastened to the upper anchor plate and the lower anchor plate; The splicing surface of the central part has a first mounting hole adapted to the first fastening bolt and a second mounting hole adapted to the second fastening bolt. The first mounting hole is located near the outer wall of the central part and communicates with a first mounting groove on the outer wall of the central part. The second mounting hole is located near the inner wall of the central part and communicates with a second mounting groove on the inner wall of the central part. The splicing surface of the flange part is provided with a rib beam, and the rib beam has a third mounting hole adapted to the third fastening bolt. The end of the rib extends to the outer edge of the flange, and a partition beam with its end connected to the end of the rib is provided on the flange. The partition beam and the ribs on both sides form a counterweight cavity. The splicing surface of the flange portion is provided with a first positioning pair and a second positioning pair; The central section includes a fixed section at the bottom and an adjustable section at the top.

2. The height-adjustable modular prestressed wind turbine foundation according to claim 1, characterized in that: The first positioning pair includes a male groove disposed on one side of the splicing surface of the flange portion, and a female groove disposed on the other side of the splicing surface that is adapted to the male groove.

3. The height-adjustable modular prestressed wind turbine foundation according to claim 1, characterized in that: The second positioning pair includes a positioning rod disposed on one side of the flange splicing surface and an insertion hole disposed on the other side of the splicing surface that is adapted to the positioning rod.

4. The height-adjustable modular prestressed wind turbine foundation according to claim 1, characterized in that: The central part has a longitudinal through hole, and a PVC corrugated pipe is installed on the inner wall of the longitudinal through hole. The longitudinal anchor rod is wound with steel strand and installed inside the corrugated pipe. The longitudinal anchor rod and the corrugated pipe are fixed together by injecting cement grout.

5. The height-adjustable modular prestressed wind turbine foundation according to claim 1, characterized in that: A longitudinal waterstop strip is provided on the longitudinal splicing surface of the central part, located between the longitudinal anchor rod and the first fastening bolt, and a circumferential waterstop strip is provided on the transverse splicing surface of the central part, located between the longitudinal anchor rod and the second fastening bolt.

6. A construction method for a height-adjustable modular prestressed wind turbine foundation as described in claim 1, characterized in that: Includes the following steps: The first step is to excavate the foundation pit and pour a concrete cushion layer at the bottom of the pit; The second step is to hoist the assembly units one by one to the predetermined position and complete the assembly. Then, install the third fastening bolt, the second fastening bolt, and the first fastening bolt in sequence. When tightening the third fastening bolt, the second fastening bolt, and the first fastening bolt, the odd number should be tightened first and the even number should be tightened later, and the top and bottom bolts should be tightened simultaneously. After that, install the prestressed locking assembly. The third step is to backfill the foundation pit, and determine whether to backfill within the center of the closed ring structure formed by each assembly unit based on the geological conditions. The backfill soil is then compacted in layers until it is level with the ground level, thus completing the construction.

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