Expandable fabricated foundation suitable for wind turbine generator and construction method thereof

Abstract

The invention discloses an expandable fabricated foundation suitable for a wind turbine generator and a construction method of the expandable fabricated foundation. The construction method comprises the following steps that a foundation pit is excavated to form a flat ground needed by the foundation; the sleeve is hoisted, the multiple foundation ring pieces are hoisted to the periphery of the sleeve, and the connecting anchor bolts on the foundation ring pieces are inserted into the mounting through holes; the adjacent foundation ring pieces are connected through annular bolts; after hoisting of the foundation ring piece is completed, a foundation anchor rod extends into a ground anchor construction hole to conduct foundation drilling operation, and full-length grouting anchoring operation is conducted after drilling is conducted to the designated depth; pouring grouting liquid into the post-pouring cavity until the grouting liquid seeps into the mounting groove from the mounting through hole; the circumferential bolts are subjected to prestress fastening, and grouting liquid is injected into the connecting holes; according to the requirement for the upper bearing capacity, an expansion pile foundation is constructed on the periphery of the foundation ring piece, and an expansion ring piece is laid; the connecting assemblies are installed in the connecting key grooves and the installation through grooves through high-strength bolts, and then installation of the expansion ring pieces is completed. According to the invention, stable capacity expansion of the wind turbine generator can be realized.

Description

Technical Field

[0001] This invention belongs to the technical field of foundation construction, and specifically relates to an expandable prefabricated foundation suitable for wind turbine units and its construction method. Background Technology

[0002] With the continuous development of my country's new energy sector, the installed capacity and scale of onshore wind power, as well as the size and weight of supporting wind turbine equipment, have all increased to varying degrees.

[0003] With the upgrading of wind turbines, large-capacity units are emerging in large numbers. These large-capacity units often have larger dimensions and weight, placing higher demands on tower dimensions, foundation dimensions, and structural load-bearing capacity. Currently, traditional onshore wind power foundations mainly include gravity spread foundations and pile foundations. When the wind turbines above them reach the end of their service life and need to be expanded, these traditional foundation structures are usually unable to meet the load-bearing requirements of larger-capacity wind turbines. In addition, the main types of wind power foundations currently used are typically cast-in-place in one go, and the large-volume casting places extremely stringent requirements on construction progress and quality management.

[0004] The patent with publication number CN115125987A proposes an onshore wind power foundation structure with expansion capability and its expansion construction method. It mainly achieves the purpose of expansion by drilling additional holes on the original foundation structure to form piles. However, the construction process of these piles formed later is complicated and will also cause some damage to the original foundation structure. The connection between the piles and the original structure is also difficult to meet the load-bearing requirements. At the same time, the economic applicability of the pile structure itself is also poor. Summary of the Invention

[0005] This invention provides an expandable prefabricated foundation suitable for wind turbine units and its construction method, in order to solve the problem that the original foundation is difficult to meet the load-bearing requirements after the unit is expanded.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: On the one hand, this application provides an expandable prefabricated foundation suitable for wind turbine units, including a sleeve, wherein the sleeve is vertically provided with a plurality of anchor bolt reserved holes for connection of wind turbine tower, and the anchor bolt reserved holes are arranged coaxially in multiple turns along the radial direction of the sleeve; Multiple base ring pieces are arranged around the outer periphery of the sleeve. A connecting anchor is provided between the sleeve and the base ring pieces. The upper surface of the base ring pieces is recessed to form an installation groove. The side wall of the installation groove is reserved with ground anchor construction holes and connection holes. Each base ring has an expansion ring on its periphery, and a connecting component is provided between the expansion ring and the base ring to connect the base ring and the expansion ring.

[0007] Furthermore, a post-cast cavity is provided through the middle of the sleeve, and an installation through hole is provided on the side wall of the sleeve, which communicates with the post-cast cavity; The connecting anchor is pre-embedded in the foundation ring and extends out of the side wall of the foundation ring. The connecting anchor is used to be inserted into the mounting through hole and extends into the post-cast cavity.

[0008] Furthermore, the connecting anchor bolt includes a bolt rod and an anchor head. The bolt rod is pre-embedded in the foundation ring, and the anchor head is disposed in the mounting groove and abuts against the side wall of the mounting groove. The outer wall of the base ring is recessed in the protruding area of ​​the bolt to form a post-casting groove. The diameter of the post-casting groove is larger than the diameter of the bolt, and a connecting collar for insertion into the mounting through hole is fixed on the inner wall of the post-casting groove.

[0009] Furthermore, the outer edge of the base ring is recessed downward to form a connecting keyway, and the extension ring is also recessed downward to form a mounting through groove. The connecting component is simultaneously engaged in the connecting keyway and the mounting through groove.

[0010] Furthermore, the connecting assembly includes a steel base, which includes a vertical portion and a horizontal portion that are perpendicular to each other. The vertical portion is used to fit against the side wall of the connecting keyway, and the horizontal portion is used to fit against the bottom wall of the connecting keyway and the mounting through groove. A wedge-shaped reinforcing block is provided between the vertical portion and the horizontal portion. Both the vertical and horizontal sections have pre-drilled mounting screw holes, and the steel base and the base ring, as well as the steel base and the extension ring, are all fixed together by bolts.

[0011] Furthermore, the ground anchor construction hole is set in the bottom wall of the installation groove and the connecting keyway, and a foundation anchor rod is driven into the stratum through the ground anchor construction hole at the bottom of the foundation ring plate; The bottom of the extended ring is provided with a foundation anchor or an extended pile foundation.

[0012] Furthermore, the bottom wall of the installation channel is provided with a post-cast connection groove, which includes an enlarged groove communicating with the installation channel and a reduced diameter groove penetrating the bottom wall of the extended ring piece. The extended pile foundation is accommodated in the reduced diameter groove, and the reserved reinforcing steel of the extended pile foundation is accommodated in the enlarged groove.

[0013] Furthermore, the connecting hole penetrates the outer wall of the base ring piece, and the connecting keyway sidewall is also provided with a connecting hole, which penetrates the sidewall of the extension ring piece; Connecting keys are post-cast between adjacent extended ring pieces and between adjacent base ring pieces.

[0014] Furthermore, the thickness of the base ring gradually increases along the radial direction of the sleeve towards the sleeve, and multiple sets of connecting anchors are spaced apart along the height direction of the base ring.

[0015] On the other hand, this application provides a construction method for an expandable prefabricated foundation suitable for wind turbine generators, for realizing the construction of the aforementioned expandable prefabricated foundation, including the following steps: Step 1: Excavate the foundation pit to the design elevation, clear and level the surface, and then pour the foundation concrete to form the flat ground required for the foundation. Step 2: Hoist the sleeve to the center of the bottom of the foundation pit, hoist several foundation ring pieces around the sleeve, and insert the connecting anchors on the foundation ring pieces into the installation through holes; at the same time, connect adjacent foundation ring pieces with circumferential bolts until the foundation ring pieces are connected to form a complete circular ring structure; Step 3: After the foundation ring is hoisted, the foundation anchor rods are inserted into the ground anchor construction holes for foundation drilling. After drilling to the specified depth, full-length grouting and anchoring are carried out, and the exposed foundation anchor rods are sealed and tightened. Step 4: Pour grout into the cavity until the grout seeps from the installation through hole into the installation groove; pre-stress the circumferential bolts and inject grout into the connection hole; Step 5: According to the bearing capacity requirements of the upper part, construct the extended pile foundation around the foundation ring and lay the extended ring. During the laying process, insert the pile head of the extended pile foundation into the post-cast connection groove and grout to fill the post-cast connection groove. Step 6: Use high-strength bolts to install the connecting components into the connecting keyway and the mounting through slot, thereby completing the installation of the expansion ring.

[0016] The present invention can achieve the following beneficial effects: 1. The expandable prefabricated foundation of this application forms an initial load-bearing system through sleeves and outer foundation rings, which can meet the load-bearing requirements of conventional capacity wind turbine units. When the unit is upgraded and expanded and requires higher load-bearing capacity, there is no need to demolish or destroy the original foundation structure. Only by adding expansion rings around the foundation rings and cooperating with expansion piles, the load-bearing area and anti-uplift and anti-overturning capacity of the foundation can be quickly improved, adapting to the usage requirements of large-capacity units, thereby efficiently solving the problem that traditional foundations are difficult to adapt to unit expansion.

[0017] 2. The sleeve and the foundation ring are fixed by multiple means, including connecting anchor bolts, connecting collars and post-grouting. The foundation rings and the extension rings are tightly connected by circumferential bolts, connecting keys and grouting. The steel base and wedge-shaped reinforcement blocks of the connecting components further enhance the connection rigidity between the foundation rings and the extension rings, thus making the entire prefabricated foundation form a more complete stress system, effectively transferring the upper load to the ground, reducing the risk of poor connection between the new structure and the original structure, and improving the long-term stability of the foundation.

[0018] 3. Components such as sleeves, foundation rings, and extension rings are all prefabricated in the factory, ensuring high dimensional accuracy and stable quality. On-site construction mainly involves hoisting, assembly, and post-grouting, which reduces the need for large-volume concrete pouring for cast-in-place foundations, lowers dependence on the construction environment and schedule, and reduces quality problems such as cracks and insufficient density that are prone to occur in cast-in-place construction. This results in a shorter construction cycle and more convenient quality management.

[0019] 4. The foundation ring adopts a radially gradually varying thickness design, which increases the structural strength at the connection between the sleeve and the foundation ring, and can better transfer the load borne by the wind turbine tower to the foundation. The multiple sets of vertically spaced connecting anchors and the full-length grouting anchoring of the foundation anchor rods and extended piles all improve the foundation's pull-out resistance, overturning resistance and corrosion resistance. The grouting sealing of each connection effectively isolates external moisture and harmful substances, reduces component corrosion, extends the service life of the foundation and improves the economic applicability of the project. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a schematic diagram of the overall structure of an expandable prefabricated foundation for wind turbine generators according to the present invention. Figure 2 This is a partial structural diagram of the connection between the sleeve and the base ring of the present invention; Figure 3 This is a partial structural diagram of the connection between the basic ring plate and the widened ring plate of the present invention; Figure 4 This is a cross-sectional schematic diagram of an expandable prefabricated foundation for wind turbine generators according to the present invention.

[0021] The attached diagram lists the components represented by each number as follows: 1. Sleeve; 11. Anchor bolt reserved hole; 12. Post-cast cavity; 13. Installation through hole; 2. Foundation ring; 21. Connecting anchor bolt; 211. Bolt rod; 212. Anchor head; 22. Installation groove; 23. Ground anchor construction hole; 24. Connection hole; 25. Post-cast cylinder groove; 26. Connecting collar; 27. Connecting keyway; 3. Expansion ring; 31. Installation through groove; 32. Post-cast connection groove; 321. Enlarged groove; 322. Reduced diameter groove; 4. Connecting assembly; 41. Steel base; 411. Vertical part; 412. Horizontal part; 413. Wedge-shaped reinforcing block; 5. Foundation anchor; 6. Extended pile foundation. Detailed Implementation

[0022] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0023] like Figures 1 to 4 As shown, an expandable prefabricated foundation suitable for wind turbine units includes a sleeve 1, a foundation ring 2 disposed around the sleeve 1, and an extension ring 3 disposed around the foundation ring 2. A connecting assembly 4 is provided between the extension ring 3 and the foundation ring 2. The sleeve 1 is located at the center of the foundation, and several anchor bolt pre-drilled holes 11 are vertically formed downwards on its top wall. The anchor bolt pre-drilled holes 11 are arranged in multiple circles coaxially along the radial direction of the sleeve 1. Specifically, the anchor bolt pre-drilled holes 11 are divided into two to three groups according to the radius of different distances from the center of the sleeve 1. The anchor bolt pre-drilled holes 11 are through holes, used to connect wind turbine towers of different diameters after the foundation structure is installed, so as to achieve the purpose of expanding the capacity of wind turbine units of different capacities. A post-cast cavity 12 is formed through the middle of the sleeve 1, and a corresponding installation through hole 13 is formed on the side wall of the sleeve 1. The installation through hole 13 is connected to the post-cast cavity 12, providing a channel for subsequent grouting connection.

[0024] Multiple foundation ring plates 2 are arranged around the outer perimeter of the sleeve 1. These foundation ring plates 2 are spliced ​​together to form a complete circular structure, which, together with the sleeve 1, constitutes the core load-bearing part of the foundation. The upper surface of the foundation ring plate 2 is recessed to form an installation groove 22. The installation groove 22 is designed to achieve a more stable connection between adjacent foundation ring plates 2, between foundation ring plates 2 and the sleeve 1, between foundation ring plates 2 and the ground layer, and between foundation ring plates 2 and extension ring plates 3.

[0025] The sleeve 1 and the foundation ring 2 are connected by connecting anchor bolts 21. Specifically, the connecting anchor bolt 21 includes a bolt rod 211 and an anchor head 212. The bolt rod 211 is pre-embedded in the foundation ring 2 and partially extends out of the side wall of the foundation ring 2. The anchor head 212 is accommodated in the mounting groove 22 and abuts against the side wall of the mounting groove 22. When connecting the foundation ring 2 and the sleeve 1, the connecting anchor bolts 21 pre-embedded in the foundation ring 2 are inserted one by one into the mounting through holes 13 and extend into the post-cast cavity 12. Furthermore, a post-pouring groove 25 is formed in the recessed area of ​​the protruding area of ​​the bolt 211 on the outer wall of the foundation ring 2. The diameter of the post-pouring groove 25 is larger than the diameter of the bolt 211, and a connecting collar 26 is fixed on the inner wall of the post-pouring groove 25. The connecting collar 26 is used to be inserted into the installation through hole 13 of the sleeve 1. As a result, during the later grouting, the contact surface between the foundation ring 2 and the sleeve 1 is less prone to grout leakage, making the connection between the foundation ring 2 and the sleeve 1 more precise and firm.

[0026] To achieve efficient connection of the extended ring 3, a connecting keyway 27 is formed by a downward indentation on the outer edge of the base ring 2. Anchor holes 23 are pre-drilled in the bottom walls of both the mounting groove 22 and the connecting keyway 27, and connecting holes 24 are pre-drilled in the side walls of both. Foundation anchor rods 5 are driven into the ground through the anchor holes 23 at the bottom of the base ring 2. After being fully grouted and anchored, the foundation anchor rods 5 are tightly bonded to the ground, enhancing the foundation's resistance to overturning and pull-out.

[0027] The bottom of the extended ring 3 is provided with a foundation anchor 5 or an extended pile foundation 6. If the foundation surface at the bottom of the extended ring 3 is relatively flat and the load-bearing requirements can be met by the foundation anchor 5, only the foundation anchor 5 needs to be constructed below the extended ring 3. The construction method of the foundation anchor 5 is the same as that of the foundation anchor 5 below the foundation ring 2. When higher load-bearing capacity is required, or when the foundation surface at the bottom of the extended ring 3 is inclined, an extended pile foundation 6 can be selected. The extended pile foundation 6 can be a precast pipe pile or a cast-in-place pile foundation. The extended pile foundation 6 can extend above the ground and a ground beam can be cast at the same horizontal level to provide a flat installation platform for the extended foundation.

[0028] Furthermore, the bottom wall of the installation channel 31 is provided with a post-cast connection channel 32. The post-cast connection channel 32 includes an enlarged channel 321 that communicates with the installation channel 31 and a reduced-diameter channel 322 that penetrates the bottom wall of the extended ring plate 3. The extended pile foundation 6 is accommodated in the reduced-diameter channel 322, and the reserved steel bars of the extended pile foundation 6 are accommodated in the enlarged channel 321. By injecting grout into the enlarged channel 321, the extended pile foundation 6 and the extended ring plate 3 form an integral load-bearing structure.

[0029] The thickness of the foundation ring 2 gradually increases radially towards the sleeve 1, and multiple sets of connecting anchor bolts 21 are spaced apart along the height of the foundation ring 2. This design can strengthen the connection strength at the connection between the sleeve 1 and the foundation ring 2, thereby better transferring the load borne by the wind turbine tower to the foundation and making the core bearing area stronger.

[0030] Each base ring 2 has a corresponding extended ring 3 with a downwardly recessed mounting groove 31. The connecting component 4 is simultaneously engaged in the connecting keyway 27 of the base ring 2 and the mounting groove 31 of the extended ring 3, achieving a firm connection between the two. The connecting component 4 includes a steel base 41, which includes a vertical part 411 and a horizontal part 412 that are perpendicular to each other. The vertical part 411 is used to fit against the side wall of the connecting keyway 27, and the horizontal part 412 is used to fit against the bottom wall of the connecting keyway 27 and the bottom wall of the mounting groove 31. A wedge-shaped reinforcing block 413 is provided between the vertical part 411 and the horizontal part 412. The wedge-shaped reinforcing block 413 can connect the vertical part 411 and the horizontal part 412, thereby connecting the horizontal part 412 and the vertical part into a whole, so as to improve the overall structural rigidity of the steel base 41.

[0031] The connecting holes 24, pre-reserved on the sidewalls of the mounting groove 22 and the connecting keyway 27, penetrate the sidewalls of the base ring 2 and the extended ring 3. Specifically, adjacent extended rings 3 and adjacent base rings 2 are connected by grouting into the connecting holes 24 to form connecting keys, making the connection between the rings tighter and forming a complete annular force-bearing system. Mounting screw holes are pre-reserved on both the vertical part 411 and the horizontal part 412. The steel base 41 and the base ring 2, and the steel base 41 and the extended ring 3 are all fixed by bolts. The bolts passing through the vertical part 411 pass through the connecting holes 24 on the sidewalls of the connecting keyway 27 and extend into the mounting groove 22. Grouting is then performed in the connecting holes 24 to improve the connection stability between the extended ring 3 and the base ring 2.

[0032] This application presents an expandable prefabricated foundation suitable for wind turbine generators. Through prefabricated design and post-grouting process, it enables faster, more stable, and more efficient expansion construction of wind turbine foundations without the need to demolish the original foundation. Expansion can be achieved simply by adding an expansion ring 3 to the original foundation. The design of the expansion ring 3 can adapt to different terrain environments and different strata, and can achieve stability and connection with the foundation ring 2.

[0033] On the other hand, this application provides a construction method for an expandable prefabricated foundation suitable for wind turbine generators, for realizing the construction of the aforementioned expandable prefabricated foundation, including the following steps: Step 1: Before construction, determine the excavation scope, depth, and installation positioning parameters of each component based on the design documents. Excavate the foundation pit to the design elevation, then clean the bottom of the pit, removing loose soil, debris, and soft soil layers to ensure the foundation soil is uniform and firm. Next, pour the foundation concrete. Once the foundation concrete reaches its design strength, a level ground surface is formed, providing a stable working surface for subsequent component installation.

[0034] Step 2: Using hoisting equipment, lift sleeve 1 to the center position at the bottom of the foundation pit. Adjust the horizontal and vertical alignment of sleeve 1 using measuring instruments to ensure accurate positioning. Next, hoist several foundation ring pieces 2 around sleeve 1 sequentially. During hoisting, simultaneously insert the connecting anchor bolts 21 and connecting collars 26 on the foundation ring pieces 2 into the mounting through holes 13 of sleeve 1 to initially position the foundation ring pieces 2 and sleeve 1. At the same time, connect adjacent foundation ring pieces 2 with circumferential bolts, tightening them one by one to ensure uniform gaps between the ring pieces, until all foundation ring pieces 2 are connected to form a complete circular structure. Recheck the overall horizontal alignment and concentricity with sleeve 1 of the foundation ring pieces 2, adjusting them to meet design requirements.

[0035] Step 3: After the foundation ring 2 is hoisted and initially connected, the foundation anchor 5 is inserted into the ground through the ground anchor construction hole 23 on the bottom wall of the installation groove 22 and the connecting keyway 27. Drilling is performed using drilling equipment, controlling the drilling depth and verticality. Drilling is stopped after reaching the designated depth, and grouting fluid is injected into the borehole for full-length grouting and anchoring to ensure full adhesion between the foundation anchor 5 and the ground. After grouting, the exposed portion of the foundation anchor 5 is sealed and tightened to prevent corrosion from the external environment.

[0036] Step 4: Pour grout into the post-pour cavity 12. During the pouring process, control the grouting speed and pressure to ensure that the grout fully fills the post-pour cavity 12 until the grout seeps from the installation through hole 13 into the installation groove 22, indicating that the post-pour cavity 12 is completely filled. Then, prestress the circumferential bolts to enhance the connection rigidity between the foundation rings 2. Finally, inject grout into each connection hole 24 to form an integrated structure between adjacent foundation rings 2 and between the foundation rings 2 and the sleeve 1, and achieve anchoring to the stratum through the foundation anchor rods 5.

[0037] Step 5: During later use, determine whether it is necessary to install the extension ring 3 based on the load-bearing capacity requirements of the upper wind turbine unit. If expansion is required, construct the extension pile foundation 6 at the designed position around the foundation ring 2. The following explanation uses the construction of the cast-in-place extension pile foundation 6 as an example. After drilling to the designed depth, pour concrete to form the extension pile foundation 6. After the extension pile foundation 6 reaches the design strength, hoist the extension ring 3 to the designated position. During the laying process, ensure that the installation through groove 31 of the extension ring 3 is aligned with the connecting keyway 27 of the foundation ring 2. At the same time, accurately insert the pile head of the extension pile foundation 6 into the reduced diameter groove 322 of the post-cast connection groove 32. The reserved reinforcing steel of the extension pile foundation 6 extends into the enlarged groove 321. Then, grout is injected into the post-cast connection groove 32 to fill it, so that the extension pile foundation 6 and the extension ring 3 are firmly connected.

[0038] Step Six: Place the steel base 41 of the connecting component 4 into the connecting keyway 27 and the mounting through groove 31, ensuring that the vertical part 411 of the steel base 41 is flush with the side wall of the connecting keyway 27 and the horizontal part 412 is flush with the bottom wall of the connecting keyway 27 and the mounting through groove 31. Secure the steel base 41 to the base ring 2 and the extension ring 3 using high-strength bolts passing through the mounting screw holes on the steel base 41. Check the connection's firmness point by point to complete the installation of the extension ring 3, thus completing the entire foundation construction. Furthermore, after the extension ring 3 is installed and all components are connected, the mounting groove 22 can be filled with grout, forming an integrated structure between the extension ring 3 and the base ring 2.

[0039] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An expandable prefabricated foundation suitable for wind turbine generators, characterized in that: The utility model provides a wind turbine tower sleeve structure, including sleeve (1), the sleeve (1) is vertically opened with a plurality of anchor bolt reservation hole (11) for wind turbine tower connection, the anchor bolt reservation hole (11) is provided with multiple turns coaxially along the sleeve (1) radially, The outer periphery of the sleeve (1) is arranged with a plurality of base ring pieces (2), a connecting anchor (21) is arranged between the sleeve (1) and the base ring piece (2), a mounting groove (22) is formed on the upper surface of the base ring piece (2), and a ground anchor construction hole (23) and a connecting hole (24) are reserved on the side wall of the mounting groove (22). Each base ring piece (2) is correspondingly provided with an expansion ring piece (3) on the outer periphery, and a connecting assembly (4) for connecting the base ring piece (2) and the expansion ring piece (3) is arranged between the expansion ring piece (3) and the base ring piece (2).

2. A scalable assembled foundation suitable for use with a wind turbine generator according to claim 1, wherein: A post-cast cavity (12) is formed in the middle of the sleeve (1), and a mounting through hole (13) is formed in the side wall of the sleeve (1), which communicates with the post-cast cavity (12); The connecting anchor (21) is embedded in the base ring piece (2) and protrudes from the side wall of the base ring piece (2), and is inserted into the mounting through hole (13) and extends into the post-cast cavity (12).

3. A scalable assembled foundation suitable for use with a wind turbine generator according to claim 2, wherein: The connecting anchor (21) includes a bolt rod (211) and an anchor head (212), the bolt rod (211) is embedded in the base ring piece (2), the anchor head (212) is arranged in the mounting groove (22), and the anchor head (212) is tightly arranged on the side wall of the mounting groove (22). The outer side wall of the base ring piece (2) is recessed to form a post-cast cylinder groove (25) in the area where the bolt rod (211) protrudes, the aperture of the post-cast cylinder groove (25) is larger than the diameter of the bolt rod (211), and a connecting sleeve ring (26) for being inserted into the mounting through hole (13) is fixed on the inner wall of the post-cast cylinder groove (25).

4. The scalable assembled foundation for a wind turbine generator according to claim 1, wherein: The outer edge of the base ring piece (2) is recessed downward to form a connecting key groove (27), and the expansion ring piece (3) is also recessed downward to form a mounting through groove (31), and the connecting assembly (4) is clamped in the connecting key groove (27) and the mounting through groove (31) at the same time.

5. A scalable assembled foundation suitable for use with a wind turbine generator according to claim 4, wherein: The connecting assembly (4) includes a steel base (41), the steel base (41) includes a vertical part (411) and a horizontal part (412) perpendicular to each other, the vertical part (411) is used for abutting with the side wall of the connecting key groove (27), the horizontal part (412) is used for abutting with the bottom wall of the connecting key groove (27) and the mounting through groove (31), and a wedge-shaped reinforcing block (413) is arranged between the vertical part (411) and the horizontal part (412). Mounting screw holes are reserved on the vertical part (411) and the horizontal part (412), and the steel base (41) and the base ring piece (2) and the steel base (41) and the expansion ring piece (3) are fixed by bolt connection.

6. A scalable assembled foundation suitable for use with a wind turbine generator according to claim 4, wherein: The ground anchor construction hole (23) is arranged at the bottom wall of the installation groove (22) and the connecting key groove (27), and the bottom of the foundation ring piece (2) is punched into the stratum by the ground anchor construction hole (23) to have the foundation anchor rod (5); The bottom of the expansion ring piece (3) is provided with the foundation anchor rod (5) or the expansion pile foundation (6).

7. A scalable assembled foundation suitable for use with a wind turbine generator according to claim 6, wherein: The bottom wall of the installation through groove (31) is provided with a post-poured connecting groove (32), the post-poured connecting groove (32) comprises an enlarged groove (321) in communication with the installation through groove (31) and a reduced-diameter groove (322) penetrating the bottom wall of the expansion ring piece (3), the expansion pile foundation (6) is accommodated in the reduced-diameter groove (322), and the reserved steel bars of the expansion pile foundation (6) are accommodated in the enlarged groove (321).

8. The scalable assembled foundation suitable for use with a wind turbine generator according to claim 1, wherein: The connecting hole (24) penetrates the outer side wall of the foundation ring piece (2), and the side wall of the connecting key groove (27) is also provided with the connecting hole (24), and the connecting hole (24) penetrates the side wall of the expansion ring piece (3); The connecting keys are formed by post-pouring between adjacent expansion ring pieces (3) and between adjacent foundation ring pieces (2).

9. The scalable assembled foundation suitable for use with a wind turbine generator according to claim 1, wherein: The thickness of the foundation ring piece (2) gradually thickens along the radial direction of the sleeve (1) towards the sleeve (1), and the connecting anchor bolts (21) are arranged in multiple groups along the height direction of the foundation ring piece (2).

10. A construction method of a scalable assembled foundation for a wind turbine generator, for implementing a scalable assembled foundation for a wind turbine generator according to any one of claims 1-9, characterized in that, The method comprises the following steps: Step one, the foundation pit is excavated to the design elevation, and after the surface is leveled and smoothed, the cushion concrete is poured to form a flat ground required by the foundation; Step two, the sleeve (1) is hoisted to the center of the bottom of the foundation pit, a plurality of foundation ring pieces (2) are hoisted to the periphery of the sleeve (1), and the connecting anchor bolts (21) on the foundation ring pieces (2) are inserted into the installation through holes (13); at the same time, the adjacent foundation ring pieces (2) are connected by the ring bolts until the foundation ring pieces (2) are connected to form a complete circular structure; Step three, after the hoisting of the foundation ring pieces (2) is completed, the foundation anchor rod (5) is inserted into the ground anchor construction hole (23) to perform the foundation drilling operation, and after drilling to the specified depth, the full-length grouting anchoring operation is performed, and the part of the foundation anchor rod (5) exposed outside is sealed and fastened; Step four, the grouting liquid is poured into the post-poured cavity (12) until the grouting liquid seeps from the installation through hole (13) to the installation groove (22); the ring bolts are prestressed and fastened, and the grouting liquid is injected into the connecting hole (24); Step five, according to the need of the upper bearing capacity, the expansion pile foundation (6) is constructed on the periphery of the foundation ring piece (2), and the expansion ring piece (3) is laid, in the laying process, the pile head of the expansion pile foundation (6) is inserted into the post-poured connecting groove (32), and the post-poured connecting groove (32) is filled by grouting; Step six, the connecting assembly (4) is installed into the connecting key groove (27) and the installation through groove (31) by using high-strength bolts, and then the installation of the expansion ring piece (3) is completed.

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