A wind turbine tower expansion and modification structure and construction method that does not require the removal of the external space truss.

Abstract

This invention discloses a wind turbine tower expansion and modification structure and construction method that does not require dismantling of the external space truss. The structure includes the original steel tower section, the original foundation and the outer extended foundation, the external space truss, a rigid transition section, and a top-elevated tower section. The outer foundation connecting ring beam is anchored to the periphery of the original foundation. The external space truss is concentrically built around the outside of the original steel tower from bottom to top, with its bottom fixed to the outer extended foundation. The rigid transition section is located between the top-elevated tower section and the top of the external space truss, used to rigidly disperse and evenly transfer the concentrated moment, shear force, and torque of the upper high-power wind turbine to the lower external space truss and the original steel tower. The top-elevated tower section is installed on top of the rigid transition section. This invention provides a clear force transmission path, smooth stiffness transition, effectively avoids local stress concentration and instability, and efficiently improves all-directional stiffness and load-bearing capacity.

Description

Technical Field

[0001] This invention relates to the field of wind power tower renovation engineering and structural reinforcement technology, and in particular to a wind power tower expansion and renovation structure and construction method that does not require dismantling of the external space truss. Background Technology

[0002] With the rapid development of wind power technology, early wind farms generally face the need for capacity expansion through "replacing smaller ones with larger ones" (equipping them with larger, longer-bladed wind turbines). Early wind farms mostly used single-cylinder steel towers, which were relatively low in height and had limited overall lateral stiffness. When faced with the huge overturning moment and dynamic fatigue wind loads brought by new high-power wind turbines, the original steel towers were prone to buckling instability and could not meet the requirements for safe operation.

[0003] The traditional "replacing small with large" renovation approach typically involves completely demolishing and rebuilding the existing steel towers and underground foundations. This method has significant drawbacks: firstly, the construction period is long, leading to prolonged wind farm downtime and substantial economic losses; secondly, demolition and reconstruction costs are exorbitant; and thirdly, the large amount of discarded steel and concrete foundations results in severe resource waste. In particular, the abrupt change in cross-sectional shape between the polygonal lattice truss structure and the cylindrical nacelle load-bearing body easily leads to severe stress concentration and fatigue cracking at the connection points, and traditional renovation methods have not proposed an effective solution for a smooth transition in stiffness. Therefore, there is an urgent need for a renovation solution for old towers that has a clear stress mechanism, high overall stability, and eliminates the need for demolition. Summary of the Invention

[0004] To address the shortcomings of traditional "replacing small with large" retrofitting solutions, this invention provides a wind turbine tower expansion and retrofitting structure and construction method that eliminates the need to dismantle the external space truss.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A wind turbine tower expansion and renovation structure that does not require dismantling of the external space truss includes the original steel tower section, the original foundation, the outer extended foundation, the external space truss, the rigid transition section, and the top raised tower section; The original steel tower serves as the auxiliary load-bearing component of the modified core tube; the original foundation and the outer extended foundation are anchored together to form an integral load-bearing foundation; the outer space truss is a polygonal variable cross-section space truss structure, serving as the main lateral force resisting component after modification, and is concentrically built outside the original steel tower; the rigid transition section component is set at the top of the original steel tower section and the outer space truss, used to support the top raised tower section and assemble and connect with the upper new high-power wind turbine generator set.

[0006] A further improvement of the present invention is that the peripheral extended foundation includes an extended independent pile cap distributed around the original foundation and compression piles arranged below the pile cap; the extended independent pile cap is connected to the original foundation by rebar to resist horizontal forces, and the compression piles are used to resist vertical forces transmitted by the enclosing space truss.

[0007] A further improvement of the present invention is that the outer spatial truss is divided into several prefabricated standard segments along the height direction; each segment consists of horizontal bars, horizontal diaphragms and diagonal bars, and the diagonal bars are arranged in a cross pattern to enhance the shear bearing capacity and out-of-plane stiffness of the truss; the cross-sectional dimensions of the outer spatial truss gradually decrease from bottom to top.

[0008] A further improvement of the present invention is that the rigid transition section component is a conical or box-shaped rigid conversion solid structure welded from thick steel plates; the lower end of the rigid transition section is provided with an inner connection interface that connects to the top flange of the original steel tower section, and an outer support that connects to the ends of each chord of the outer space truss; the upper end of the rigid transition section component is provided with an annular flange that is anchored to the bottom flange of the top-elevated tower section.

[0009] A further improvement of the present invention is that all splicing welds of the outer space truss and rigid transition section are completed in the factory and pass the flaw detection test, and the structural splicing on the project site is all connected by high-strength bolts.

[0010] A further improvement of the present invention is that the top-elevated tower section is installed at the very top of the rigid transition section component, and a transition section flange is provided at its top for connecting to the nacelle of the new high-power wind turbine generator set by means of high-strength bolts.

[0011] A construction method for upgrading and retrofitting wind turbine towers without dismantling the external space truss includes: In the context of foundation preparation and bottom construction, the periphery of the original foundation is excavated, the lower compression piles are arranged, and the extended independent pile cap is constructed by rebar installation to form an integral bearing foundation with the original foundation. In truss hoisting scenarios, the outer space truss segments are inserted one by one to complete the anchoring of the bottom and the outer extended foundation, and the axial rigid connection of the truss is completed by flanges and high-strength bolts. In the scenario of rigid transition section connection and top elevation, the prefabricated rigid transition section is hoisted into place, and its lower inner connection interface is connected to the top flange of the original steel tower section. At the same time, its outer support is rigidly connected to the top chord end of the outer space truss. The top-elevated tower section is spliced ​​to the top flange of the rigid transition section with high-strength bolts, and then the hoisting of the new high-power nacelle and wind turbine is completed.

[0012] A further improvement of this invention lies in that, in the context of foundation preparation and bottom construction, the perimeter of the original foundation is excavated, lower compression piles are arranged, and an extended independent pile cap is constructed through rebar installation, forming an integral load-bearing foundation with the original foundation, including: The soil around the original foundation is cleared, and compression piles are driven at the designed positions around the original foundation to bear the new vertical load. Then, holes are drilled in the side wall of the original foundation and high-strength chemical anchoring is carried out. The steel cage is tied and concrete is poured to form an independent pile cap for the outer extended foundation. The independent pile cap forms an integral part with the original foundation, jointly resisting horizontal shear force and providing pre-embedded anchor supports for the subsequent external space truss.

[0013] A further improvement of this invention lies in that, in the truss hoisting scenario, the outer spatial truss segments are sequentially inserted to complete the anchoring of the bottom to the outer extended foundation, and the axial rigid connection of the truss is completed through flanges and high-strength bolts, including: Using large hoisting equipment, the prefabricated outer space truss bottom section is inserted and lowered from the top of the original steel tower section. After it is in place, its bottom is anchored to the embedded parts of the outer extended foundation. Then, the upper section of the outer space truss is hoisted upwards section by section. The upper and lower sections are connected by flanges and high-strength bolts until the outer space truss is spliced ​​to the top elevation of the original steel tower section.

[0014] A further improvement of this invention lies in that, in the scenario of rigid transition section connection and top elevation, the prefabricated rigid transition section is hoisted into place, its lower inner connection interface is connected to the top flange of the original steel tower section, and its outer support is simultaneously rigidly connected to the top chord end of the outer space truss, including: The rigid transition section, manufactured in the factory and with weld flaw detection completed, was hoisted into place as a whole; its lower inner interface was aligned with the top flange of the original steel tower section, and high-strength bolts were inserted for connection and fastening; simultaneously, its lower outer connecting support was fully bolted to the end of the main chord of the top layer of the outer space truss; thus, the structural closure and force coordination between the external space truss and the internal original steel tower section were achieved at the top.

[0015] Compared with the prior art, the present invention has at least the following beneficial technical effects: (1) Smooth transition of abrupt section stiffness, improving fatigue life: The introduction of rigid transition section components successfully solved the problem of section form transition between large-diameter circular tube and polygonal multi-chord space truss. The internal stiffening diaphragm system can evenly distribute its huge wind load bending moment and torque from concentrated force into multi-path component resistance, preventing local tearing and fatigue failure at the connection edge.

[0016] (2) The overall structural stability is significantly improved: the external space truss with the introduction of the cross diagonal web system greatly improves the lateral stiffness of the structure; the thick node plate and rigid linkage mechanism ensure the reliable transmission of bending moment and shear force at the node, reducing the risk of local instability in the renovation of the old tower.

[0017] (3) Retain existing assets and reduce economic costs: Reinforcement and elevation were carried out without demolishing the original steel tower and underground foundation, achieving zero waste of the original structure and saving huge demolition and foundation reconstruction costs in the renovation project.

[0018] (4) Modular design shortens the construction cycle: The variable cross-section space truss and the high fatigue-resistant rigid transition section can be prefabricated in the factory in a standardized manner, and only fully assembled bolt construction is required on site. This construction method compresses the traditional renovation cycle of several months to several weeks, minimizing the downtime power generation loss of the wind farm. Attached Figure Description

[0019] 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.

[0020] Figure 1 General structural drawing for the expansion and renovation of the external space truss of wind turbine towers without the need for dismantling; Figure 2 A 3D view of the top-elevated tower section; Figure 3 3D diagram of the external space truss; Figure 4 Figures (a) and (b) are three-dimensional diagrams of the rigid transition section; Figure 5 A three-dimensional diagram of the original foundation and its surrounding extended foundation; Figure 6 This is a schematic diagram of the on-site hoisting and layered construction process of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Top-elevated tower section; 2. Rigid transition section; 3. External space truss; 4. Original steel tower section; 5. Original foundation and external extended foundation; 11. Upper annular flange; 12. Steel tower section; 13. Lower annular flange; 21. Annular flange; 22. Rigid transition section cylinder; 23. First internal stiffening rib; 24. Second internal stiffening rib; 31. Tower column; 32. Diagonal member; 33. Horizontal diaphragm; 34. Horizontal member; 51. Original foundation; 52. External independent foundation; 53. Pile; 54. Connecting beam between original foundation and external extended foundation. Detailed Implementation

[0022] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0027] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0030] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] Example 1 like Figure 1 As shown, the present invention provides a wind turbine tower expansion and modification structure that does not require dismantling of the external space truss, including the original steel tower section 4, the original foundation and the outer extended foundation 5, the external space truss 3, the rigid transition section 2 and the top raised tower section 1; The original steel tower tube serves as an auxiliary load-bearing component of the modified core tube. The outer space truss 3 is a polygonal variable cross-section space truss structure, which serves as the main lateral force resisting component after the modification and is concentrically built outside the original steel tower. The rigid transition section 2 is located on the top of the outer space truss 3 and is used to support the top raised tower section 1 and assemble and connect with the upper new high-power wind turbine generator set.

[0032] In this embodiment, the original foundation and the peripheral extended foundation are anchored together; the peripheral extended foundation includes extended independent pile caps distributed around the original foundation and compression piles below them; the independent pile caps are connected to the original foundation by rebar to specifically resist horizontal shear force, and the compression piles below are used to specifically resist the vertical pressure and pull-out force transmitted from the outer space truss 3, so as to achieve a reasonable division of the foundation bearing capacity.

[0033] In this embodiment, the outer space truss 3 is divided into several prefabricated standard segments along the height direction. Each segment consists of horizontal bars, horizontal diaphragms, and diagonal bars. The diagonal bars are arranged in a cross pattern to enhance the shear bearing capacity and out-of-plane stiffness of the truss. The cross-sectional dimensions of the outer space truss 3 gradually decrease from bottom to top.

[0034] In this embodiment, the rigid transition section 2 is a conical or box-shaped rigid transition solid structure made of thick steel plates welded together; the lower end of the rigid transition section 2 is provided with a chord connection support that is axially rigidly connected to each chord of the outer space truss 3, and the upper end of the rigid transition section 2 is provided with an annular flange that is anchored to the bottom flange of the top raised tower section 1.

[0035] In this embodiment, the rigid transition section 2 component is provided with a fatigue-resistant stiffening baffle system arranged radially inside, which is used to achieve a smooth transition of stiffness from tubular section load to polygonal lattice truss section load and to dissipate local stress.

[0036] In this embodiment, the welding of all newly added steel components is completed in the factory and the weld quality is ensured by flaw detection. Standard high-strength bolts are used for assembly and connection on the project site.

[0037] In this embodiment, the top-elevated tower section 1 is a steel tubular tower structure, and its bottom flange is connected to the top flange of the rigid transition section 2 by high-strength bolts. Its top is provided with a transition section flange for docking with the new type of cabin.

[0038] Example 2 This invention also provides a construction method for the capacity expansion and renovation of wind turbine towers without dismantling the external space truss, comprising the following steps: Step 1: Foundation preparation and bottom construction; Arrange compression piles around the original foundation, and construct the extended independent pile cap and piles by rebar installation; Step 2: Truss hoisting; insert the prefabricated outer space truss 3, and use high-strength bolts to complete the splicing of each segment from bottom to top; Step 3: Connecting the rigid transition section 2; The rigid transition section 2 is hoisted and connected to the top layer of the original steel tower section 4 and the truss, and the coordinated fixation of the top of the old and new structures is completed simultaneously to achieve the closure of the force system; Step 4: Top Elevation Tower Section 1 and Unit Installation; Top Elevation Tower Section 1 is spliced ​​with high-strength bolts, and then the new high-power nacelle and wind turbine are hoisted.

[0039] In this embodiment, in step 1, the soil covering the original foundation is cleared, and compression piles are driven at the designed position on the periphery of the original foundation to bear the new vertical load; then, holes are drilled in the side wall of the original foundation and high-strength chemical anchoring is carried out, the steel cage is tied and concrete is poured to form an independent pile cap of the outer extended foundation; the independent pile cap forms an integral part with the original foundation, jointly resisting the horizontal shear force, and providing pre-embedded anchor supports for the subsequent outer space truss 3.

[0040] In this embodiment, in step 2, a large hoisting device is used to insert the bottom section of the prefabricated outer space truss 3 from the top of the original steel tower section 4 and lower it down. After precise positioning, its bottom is anchored to the embedded parts of the outer extended foundation. Then, the upper sections of the outer space truss 3 are hoisted upwards one by one, and the upper and lower sections are connected by flanges and high-strength bolts. The whole process does not require on-site high-altitude welding until the outer space truss 3 is spliced ​​to the top elevation of the original steel tower section 4.

[0041] In this embodiment, in step 3, the rigid transition section 2, which has been manufactured in the factory and has undergone weld flaw detection, is hoisted into place as a whole; its lower inner interface is aligned with the top flange of the original steel tower section 4, and high-strength bolts are inserted for connection and fastening; simultaneously, its lower outer connecting support is fully bolted to the end of the main chord of the top layer of the outer space truss 3; thus, the structural closure and force coordination between the external space truss and the internal original steel tower section 4 are achieved at the top.

[0042] In this embodiment, in step 4, the steel tubular top-lifting tower section 1 is lifted as a whole, aligned with the annular flange at the upper end of the rigid transition section 2, and slowly lowered. After drilling, a hydraulic torque wrench is used to finally tighten the high-strength bolts, completing the upward lifting and capping of the structure. Finally, at the top flange face of the top-lifting tower section 1, the conventional hoisting and commissioning operations of the nacelle, generator, and ultra-long blades of the new high-power wind turbine are completed in sequence.

[0043] Example 3 like Figure 1As shown, the present invention provides a wind turbine tower expansion and modification structure that does not require dismantling of the external space truss, comprising a top-elevated tower section 1, a rigid transition section 2, an external space truss 3, the original steel tower section 4, and the original foundation and the outer extended foundation 5. The original steel tower section 4 is retained in its original position as the core internal component after modification; the external space truss 3 is a polygonal variable cross-section space truss structure, concentrically built outside the original steel tower section 4, serving as the main lateral force resisting component of the entire tower; the rigid transition section 2 is located at the top of the original steel tower section 4 and the external space truss 3, used to achieve a rigid and coordinated connection between the old and new structures, and to support the top-elevated tower section 1.

[0044] like Figure 2 As shown, the top-elevated tower section 1 includes an upper annular flange 11, a steel tower section 12, and a lower annular flange 13. The steel tower section 12 is a cylindrical structure that gradually tapers upwards, with the upper annular flange 11 welded to its top and the lower annular flange 13 welded to its bottom. The upper annular flange 11 is used for butt-fitting connection with the nacelle flange of the new high-power wind turbine unit via high-strength bolts; the lower annular flange 13 is used for connection with the rigid transition section 2 below.

[0045] like Figure 3 As shown, the rigid transition section 2 is a rigid conversion solid component welded from thick steel plates, including an annular flange 21 and a rigid transition section cylinder 22. To strictly ensure the unobstructed passage of personnel and cable laying routes inside the wind turbine, the rigid transition section cylinder 22 is a hollow shell without supports or partitions. Note: In actual manufacturing, the original first internal stiffening rib 23 and second internal stiffening rib 24 were discarded, and the local wall thickness was increased to meet the rigidity requirements. The lower end of this component is rigidly bolted to the top flange of the original steel tower section 4 and the end of the tower column 31 of the outer space truss 3; the annular flange 21 at its upper end is used to support the top-elevated tower section 1.

[0046] like Figure 4 As shown, the external spatial truss 3 is divided into several prefabricated standard segments along its height. Each segment consists of tower columns 31, diagonal members 32, transverse diaphragms 33, and cross members 34. The diagonal members 32 are arranged in a cross pattern to enhance the truss's shear capacity and out-of-plane stiffness; the transverse diaphragms 33 and cross members 34 are used to maintain the truss's cross-sectional shape. The bottom of the external spatial truss 3 is anchored to the original foundation and the outer extended foundation 5, and the tower columns 31 at its top extend upwards to the docking position of the rigid transition section 2.

[0047] like Figure 5As shown, the original foundation and the outer extended foundation 5 include the original foundation 51, the outer independent foundations 52, piles 53, and the connecting beams 54 between the original foundation and the outer extended foundation. The outer independent foundations 52 (i.e., extended independent pile caps) are distributed around the original foundation 51, and compression piles 53 are arranged below them to specifically resist the huge vertical pressure and uplift force transmitted by the outer space truss 3. The outer independent foundations 52 and the central original foundation 51 are connected by the connecting beams 54 between the original foundation and the outer extended foundation (or combined with rebar anchoring technology) to form an integral bearing foundation that jointly resists horizontal shear force and overturning moment.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0049] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A wind turbine tower expansion and modification structure that does not require the removal of the external space truss, characterized in that, This includes the original steel tower section, the original foundation, the external extended foundation, the external space truss, the rigid transition section, and the top-elevated tower section; The original steel tower serves as the core tube and auxiliary load-bearing component in the modified structure; the original foundation and the peripheral extended foundation are anchored together to form an integral load-bearing foundation. The outer space truss is a polygonal variable cross-section space truss structure, which serves as the main lateral force resisting component after the modification and is concentrically built outside the original steel tower. The rigid transition section component is set at the top of the original steel tower section and the outer space truss, and is used to support the top raised tower section and assemble and connect with the new high-power wind turbine generator set above.

2. The wind turbine tower expansion and modification structure that does not require dismantling of the external space truss as described in claim 1, characterized in that, The extended foundation includes extended independent pile caps distributed around the original foundation and compression piles arranged below the pile caps; the extended independent pile caps are connected to the original foundation by rebar to resist horizontal forces, and the compression piles are used to resist vertical forces transmitted by the enclosing space truss.

3. The wind turbine tower expansion and modification structure that does not require dismantling of the external space truss as described in claim 1, characterized in that, The enclosing space truss is divided into several prefabricated standard segments along the height direction; each segment consists of horizontal bars, horizontal diaphragms and diagonal bars, and the diagonal bars are arranged in a cross pattern to enhance the shear bearing capacity and out-of-plane stiffness of the truss; the cross-sectional dimensions of the enclosing space truss gradually decrease from bottom to top.

4. The wind turbine tower expansion and modification structure that does not require dismantling of the external space truss as described in claim 1, characterized in that, The rigid transition section component is a conical or box-shaped rigid conversion solid structure welded from thick steel plates; the lower end of the rigid transition section is provided with an inner connection interface that connects to the top flange of the original steel tower section, and an outer support that connects to the ends of each chord of the outer space truss; the upper end of the rigid transition section component is provided with an annular flange that is anchored to the bottom flange of the top raised tower section.

5. The wind turbine tower expansion and modification structure that does not require dismantling of the external space truss as described in claim 1, characterized in that, All splicing welds of the external space truss and rigid transition section were completed in the factory and passed the flaw detection test. All structural splices on the project site were connected with high-strength bolts.

6. The wind turbine tower expansion and modification structure that does not require dismantling of the external space truss as described in claim 1, characterized in that, The top-elevated tower section is installed at the very top of the rigid transition section component, and its top is equipped with a transition section flange for connecting to the nacelle of the new high-power wind turbine generator set via high-strength bolts.

7. A construction method for expanding and upgrading a wind turbine tower without dismantling its external space truss, characterized in that... include: In the context of foundation preparation and bottom construction, the periphery of the original foundation is excavated, the lower compression piles are arranged, and the extended independent pile cap is constructed by rebar installation to form an integral bearing foundation with the original foundation. In truss hoisting scenarios, the outer space truss segments are inserted one by one to complete the anchoring of the bottom and the outer extended foundation, and the axial rigid connection of the truss is completed by flanges and high-strength bolts. In the scenario of rigid transition section connection and top elevation, the prefabricated rigid transition section is hoisted into place, and its lower inner connection interface is connected to the top flange of the original steel tower section. At the same time, its outer support is rigidly connected to the top chord end of the outer space truss. The top-elevated tower section is spliced ​​to the top flange of the rigid transition section with high-strength bolts, and then the hoisting of the new high-power nacelle and wind turbine is completed.

8. The construction method for capacity expansion and renovation of wind turbine towers without dismantling the external space truss as described in claim 7, characterized in that, In the context of foundation preparation and bottom construction, the perimeter of the original foundation is excavated, the underlying compression piles are installed, and an extended independent pile cap is constructed using rebar installation to form an integral load-bearing foundation with the original foundation, including: The soil around the original foundation is cleared, and compression piles are driven at the designed positions around the original foundation to bear the new vertical load. Then, holes are drilled in the side wall of the original foundation and high-strength chemical anchoring is carried out. The steel cage is tied and concrete is poured to form an independent pile cap for the outer extended foundation. The independent pile cap forms an integral part with the original foundation, jointly resisting horizontal shear force and providing pre-embedded anchor supports for the subsequent external space truss.

9. The construction method for capacity expansion and renovation of wind turbine towers without dismantling the external space truss as described in claim 7, characterized in that, In truss hoisting scenarios, the outer truss segments are fitted one by one to complete the anchoring of the bottom to the outer extended foundation, and the axial rigid connection of the truss is completed by flanges and high-strength bolts, including: Using large hoisting equipment, the prefabricated outer space truss bottom section is inserted and lowered from the top of the original steel tower section. After it is in place, its bottom is anchored to the embedded parts of the outer extended foundation. Then, the upper section of the outer space truss is hoisted upwards section by section. The upper and lower sections are connected by flanges and high-strength bolts until the outer space truss is spliced ​​to the top elevation of the original steel tower section.

10. The construction method for capacity expansion and renovation of wind turbine towers without dismantling the external space truss as described in claim 7, characterized in that, In scenarios involving rigid transition section connections and top elevation, the prefabricated rigid transition section is hoisted into place, its lower inner connection interface is connected to the top flange of the original steel tower section, and simultaneously its outer support is rigidly connected to the end of the topmost chord of the outer space truss, including: The rigid transition section, manufactured in the factory and with weld flaw detection completed, was hoisted into place as a whole; its lower inner interface was aligned with the top flange of the original steel tower section, and high-strength bolts were inserted for connection and fastening; simultaneously, its lower outer connecting support was fully bolted to the end of the main chord of the top layer of the outer space truss; thus, the structural closure and force coordination between the external space truss and the internal original steel tower section were achieved at the top.

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