Old wind power plant fan foundation small-to-large capacity increasing structure and transformation construction method

Abstract

The invention discloses an old wind power plant fan foundation small-to-large capacity increasing structure and a transformation construction method. The old wind power plant fan foundation small-to-large capacity increasing structure comprises an original fan foundation, a newly-poured reinforced concrete foundation, a vertical anchor bolt cage connecting system and a radial anchor bolt connecting system. The connecting structure of the bottom section of the new fan tower drum and the new fan foundation comprises a vertical anchor bolt cage connecting system and a radial anchor bolt connecting system. The vertical anchor bolt cage connecting system is fixed in the original fan foundation, and the radial anchor bolt connecting system is fixed in the newly-poured reinforced concrete foundation. According to the new fan foundation, the diameter of the middle pier is expanded so as to arrange a new tower tube, the height of the middle pier is not changed, the height of the middle pier of the newly-poured foundation almost does not need to be increased, and the using amount of concrete is greatly reduced. Meanwhile, according to the structure, an original vertical anchor bolt cage connecting system is reserved, a radial anchor bolt connecting system is adopted for enhancing connection between the bottom section of the fresh air fan tower barrel and the fan foundation, the transformation cost and the connection reliability are effectively controlled, and the maximization of reutilization of the original fan foundation and the controllability of the cost of the fresh air fan foundation are achieved.

Description

Technical Field

[0001] The present invention relates to a structure for small modification and large capacity increase of a wind turbine foundation in an old wind farm for onshore wind power generation and a construction method for the transformation. Background Art

[0002] At present, the early-built wind farms are gradually facing problems such as small single-unit capacity, low power generation efficiency, and equipment aging, and need to be expanded and upgraded to meet the new development needs. To effectively reduce the technical transformation cost of old wind farms and save land resources, the transformation work of old wind farms should be completed as much as possible on the original wind turbine positions and wind turbine foundations, reducing or avoiding newly acquired land and demolition work. However, the problems and difficulties faced are as follows: (1) The single-unit capacity of the early grid-connected wind turbines is small, the hub height is low, the runner diameter is small, and the load transmitted to the foundation is also small. After replacing with a large-capacity unit, the hub height is higher, the runner diameter is larger, and the load transmitted to the foundation increases significantly, and the size of the original tower also changes.

[0003] (2) In the current "small to large" modification scheme for wind turbine foundations, the "large pressing small" method is usually used. Specifically, a new middle pier is poured above the original middle pier to meet the installation requirements of a larger wind turbine. To ensure the correct arrangement of the anchor bolt cage, the height of the newly poured middle pier must meet specific height requirements. This results in the need to use a large amount of concrete during the transformation of the wind turbine foundation. In addition, the transformed foundation is significantly higher than the ground surface, which is not conducive to the stability of the foundation to a certain extent.

[0004] Based on the above situation, how to directly carry out technical transformation on the old wind turbine foundation to maximize the reuse of the old foundation and control the cost of the new foundation has become a challenge and problem faced by the technical transformation of old wind farms. Summary of the Invention

[0005] The purpose of the present invention is to provide a structure for small modification and large capacity increase of a wind turbine foundation in an old wind farm and a construction method for the transformation to solve the challenges and problems faced by the technical transformation of old wind farms in the above background art. To achieve the above purpose, the present invention provides the following technical solutions: A structure for small modification and large capacity increase of a wind turbine foundation in an old wind farm includes an original wind turbine foundation, a newly poured reinforced concrete foundation, a vertical anchor bolt cage connection system, and a radial anchor bolt connection system; The newly poured reinforced concrete foundation is poured on the original wind turbine foundation to form a new wind turbine foundation integrally; the outer ring of the newly poured reinforced concrete foundation surrounds and covers the outer ring of the original wind turbine foundation from the top and the radial outside, and the middle pier of the newly poured reinforced concrete foundation surrounds the outside of the middle pier of the original wind turbine foundation but is not higher than the middle pier of the original wind turbine foundation, and adapts to the diameter of the bottom section of the new wind turbine tower; The connection structure between the bottom section of the fresh air fan tower barrel and the new fan foundation includes a vertical anchor bolt cage connection system and a radial anchor bolt connection system; the vertical anchor bolt cage connection system is fixed inside the original fan foundation, and the radial anchor bolt connection system is fixed inside the newly cast reinforced concrete foundation.

[0006] On the basis of adopting the above technical solutions, the present invention can also adopt the following further technical solutions and use these further technical solutions in combination: The bottom section of the fresh air fan tower barrel is arranged on the pier jointly formed by the pier of the newly cast reinforced concrete foundation and the pier of the original fan foundation. There is a tower barrel bottom plate at the bottom of the bottom section of the fresh air fan tower barrel, and vertical holes are reserved on the tower barrel bottom plate. The size, quantity and position of the vertical holes match the vertical anchor bolts of the vertical anchor bolt cage connection system of the original fan foundation for installing the vertical anchor bolts; there is a wedge-shaped haunch area at the junction of the inner side wall of the bottom section of the fresh air fan tower barrel and the tower barrel bottom plate. The inclined surface of the wedge-shaped haunch area is perpendicular to the radial anchor bolts. There are through holes in the wedge-shaped haunch area and the side of the tower barrel. The size, quantity and position of these holes match the radial anchor bolts of the radial anchor bolt connection system for installing the radial anchor bolts.

[0007] The vertical anchor bolt cage connection system retains the connection components of the original fan foundation, including the lower anchor plate of the original foundation, the vertical anchor bolts, and the upper anchor plate of the original foundation; when hoisting the bottom section of the fresh air fan tower barrel, the vertical anchor bolts pass through the vertical holes in the tower barrel bottom plate and are fastened by nuts to reliably connect the bottom section of the fresh air fan tower barrel with the fresh air fan foundation jointly formed by the newly cast reinforced concrete foundation and the original fan foundation.

[0008] The radial anchor bolt connection system includes an annular anchor plate, radial anchor bolts and embedded steel sleeves; the length of the radial anchor bolts is less than or equal to the inner diameter of the bottom section of the fresh air fan tower barrel so that the radial anchor bolts can be installed from the inside of the bottom section of the fresh air fan tower barrel. There are also external threads at the outer ends of the radial anchor bolts for fixing with the embedded steel sleeves; the embedded steel sleeves include a sleeve body, multiple bamboo joint-shaped enlarged rings on the outer wall of the sleeve body, external threads at the inner end of the sleeve, and internal threads at the outer end of the sleeve; the internal threads at the outer end of the sleeve match the external threads at the outer ends of the radial anchor bolts for fixing the radial anchor bolts; the sleeve body is thinner at the inner end and thicker at the outer end.

[0009] An elastic cushion or epoxy resin grouting material is provided between the bottom section of the fresh air fan tower barrel and the newly cast reinforced concrete foundation. The elastic cushion or epoxy resin grouting material can prevent local stress concentration of the foundation caused by lateral micro-deformation of the tower barrel.

[0010] The annular anchor plate is formed by splicing two semi-circular parts into a circle, with its inner diameter matching the outer diameter of the bottom section of the new fan tower barrel, and it is arranged around the outer wall of the bottom section of the new fan tower barrel; both ends of each semi-circular part of the annular anchor plate are provided with lapping sections, and the lapping sections and the main body of the annular anchor plate are configured in a stepped shape; the annular anchor plate is provided with a plurality of sleeve threaded holes penetrating the anchor plate along its length direction, and the external thread at the inner end of the embedded steel sleeve is thread-matched with the sleeve threaded hole. The inner end of the embedded steel sleeve is fixedly connected to the annular anchor plate by threading, and the outer end is tied or welded to the foundation reinforcement for fixation.

[0011] The capacity-increasing structure of the present invention is further provided with a plurality of level adjusters. When the annular anchor plate is installed, it is positioned and leveled through the level adjusters; a support platform for the level adjusters is processed on the outer ring of the original fan foundation.

[0012] The level adjuster includes a base, a long screw, a lower nut, an upper nut, a bracket, an annular anchor plate support and a support bolt; a bracket is provided on the base, and the bracket includes a diagonal brace; an annular anchor plate support is provided above the bracket, and the annular anchor plate support is provided with a vertical hole and a support bolt; a level adjuster threaded hole matching the annular anchor plate is provided at the bottom of the annular anchor plate. After the vertical hole is aligned with the level adjuster threaded hole of the annular anchor plate, the leveled level adjuster and the annular anchor plate are fixed through the support bolt.

[0013] Horizontal foundation lateral implanted bars connecting the outer ring of the original fan foundation and the side of the newly poured reinforced concrete foundation are provided on the outer ring of the original fan foundation and the side of the newly poured reinforced concrete foundation. The outer end of the horizontal foundation lateral implanted bar is bent and fixed on the reinforcement of the newly poured reinforced concrete foundation.

[0014] The present invention also provides a renovation construction method for the capacity-increasing structure of the small renovation and large capacity increase of the fan foundation in the old wind farm, adopting any one of the above-mentioned capacity-increasing structures of the small renovation and large capacity increase of the fan foundation in the old wind farm, and including the following steps: Step 1: Demolish the original fan and the original tower barrel, excavate the original foundation backfill area, chisel out small steps on the top surface of the outer ring of the original fan foundation to increase the bonding force between the new and old concretes, and chisel out a platform on the top surface of the outer ring of the original foundation directly below the annular anchor plate for arranging the level adjusters; Step 2: In the area where the foundation is expanded, implant pile foundations; Step 3: Drill holes on the top surface of the outer ring of the original fan foundation to install the level adjusters, and level and adjust the height; Step 4: Connect the two semi-circular parts of the annular anchor plate and position them on the level adjusters; Step 5: Drill holes, grout on the surface of the outer ring of the original fan foundation, and respectively place horizontal foundation lateral implanted bars and vertical implanted bars; Step 6: Bind the reinforcement bars of the newly cast reinforced concrete foundation, and bind this reinforcement with the vertically implanted reinforcement bars; screw the embedded steel sleeve tightly to the annular anchor plate, and bind the outer end of the embedded steel sleeve with the reinforcement bars; in addition, when a concealed beam is added between the pile foundation and the newly cast reinforced concrete foundation, bind or weld the exposed pile reinforcement bars with the concealed beam reinforcement bars to strengthen the connection between the edge of the newly cast reinforced concrete foundation and the pile. Step 7: Support the formwork and pour the newly cast reinforced concrete foundation. Step 8: After the strength of the newly cast concrete reaches the requirement, hoist the bottom section of the new wind turbine tower; after successful positioning, connect the bottom section of the new wind turbine tower to the new wind turbine foundation jointly formed by the newly cast reinforced concrete foundation and the original wind turbine foundation through the vertical anchor bolt cage connection system and utilize the structure of the original wind turbine foundation that has been connected to the vertical anchor bolt cage connection system; moreover, connect the bottom section of the new wind turbine tower to the new wind turbine foundation jointly formed by the newly cast reinforced concrete foundation and the original wind turbine foundation by using the radial anchor bolt connection system to achieve a reliable connection.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The radial anchor bolt connection system is adopted to connect the newly cast reinforced concrete foundation and the bottom section of the new wind turbine tower. The radial anchor bolts are arranged substantially parallel to the top surface of the foundation, and the bottom section of the new wind turbine tower is arranged above the middle pier of the old wind turbine foundation, almost without increasing the height of the middle pier of the newly cast foundation, greatly reducing the concrete consumption.

[0016] (2) The vertical anchor bolt cage connection system can be utilized to connect the original wind turbine foundation and the bottom section of the new wind turbine tower with an enlarged diameter. The connection system of the old wind turbine foundation is fully utilized, not only improving the connection reliability, but also effectively controlling the transformation cost. Description of the Drawings

[0017] Figure 1 It is a sectional view of the structure of the small modification and large capacity increase of the wind turbine foundation in the embodiment of the present invention; Figure 2 It is a top view of the structure of the small modification and large capacity increase of the wind turbine foundation in the embodiment of the present invention; Figure 3 It is a sectional view of the connection structure between the bottom section of the new wind turbine tower and the new wind turbine foundation in the embodiment of the present invention; Figure 4 It is a three-dimensional schematic diagram of the annular anchor plate in the embodiment of the present invention; Figure 5 It is a three-dimensional schematic diagram of the embedded steel sleeve in the embodiment of the present invention; Figure 6 It is a sectional view of the embedded steel sleeve in the embodiment of the present invention; Figure 7 It is a three-dimensional schematic diagram of the leveler in the embodiment of the present invention; Figure 8 It is a front view of the leveler in the embodiment of the present invention. Detailed implementation manners

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0019] An old and dilapidated wind farm fan foundation small modification and large capacity increase structure provided by the present invention is applicable to extended fan foundations (including circular and octagonal extended fan foundations), and realizes the goals of maximizing the reuse of the original fan foundation and controlling the cost of the new fan foundation.

[0020] Please refer to Figures 1 - 8 , the fan foundation small modification and large capacity increase structure includes an existing original fan foundation 1, a newly poured reinforced concrete foundation 2, a vertical anchor bolt cage connection system 102, and a radial anchor bolt connection system 202.

[0021] The original fan foundation 1 includes a middle pier 103 and an outer ring 101, which is a reinforced concrete structure and is cast integrally. In this embodiment, the outer ring 101 of the original fan foundation 1 is generally conical as a whole.

[0022] The newly poured reinforced concrete foundation 2 is poured outside the existing original fan foundation 1 to form a new fan foundation together; wherein, the newly poured reinforced concrete foundation 2 includes a middle pier 208 and an outer ring 201. Among them, the outer ring 201 surrounds and covers the outer ring 101 of the original fan foundation 1 from the top and the radial outside, and the middle pier 208 surrounds the outside of the middle pier 103 of the original fan foundation 1 but is not higher than the middle pier 103, preferably with the same height. By setting the new middle pier 208, the outer diameter of the middle pier jointly composed of the middle pier 208 of the newly poured reinforced concrete foundation 2 and the middle pier 103 of the original fan foundation 1 matches the outer diameter of the bottom section 3 of the new fan tower, so as to arrange the bottom section 3 of the new fan tower. Reference numeral 2080 is the outer contour of the middle pier 208, and reference numeral 1030 is the original outer contour of the middle pier 103.

[0023] The middle pier 103 of the original fan foundation 1 is higher than its outer ring 101, and the inner end of the outer ring 201 of the newly poured reinforced concrete foundation 2 is higher than the newly built middle pier 208. The newly poured reinforced concrete foundation 2 is provided with a radial anchor bolt connection system 202 inside along the radial direction, which is basically parallel to the top surface 1011 of the outer ring of the original fan foundation 1. The radial anchor bolt connection system 202 is arranged in a radial pattern when viewed from above, and more preferably, it is inclined to the horizontal plane. The bottom section 3 of the new fan tower and the new fan foundation jointly composed of the newly poured reinforced concrete foundation 2 and the original fan foundation 1 are connected by the radial anchor bolt connection system 202 on the one hand and by the vertical anchor bolt cage connection system 102 on the other hand. The vertical anchor bolt cage connection system 102 exists inside the original fan foundation 1 and can utilize the structure of the original fan foundation 1 to connect the bottom section 3 of the new fan tower.

[0024] The diameter of the bottom section 3 of the new fan tower barrel is larger than that of the bottom section of the original old tower barrel. To arrange the bottom section 3 of the new fan tower barrel on the middle pier, an elastic cushion layer or epoxy resin grouting material 204 is also arranged on the side of the bottom section 3 of the new fan tower barrel. The elastic cushion layer or epoxy resin grouting material 204 is located between the inner end of the outer ring 201 of the bottom section 3 of the new fan tower barrel and the newly poured reinforced concrete foundation 2, which can prevent local stress concentration of the foundation caused by lateral micro-deformation at the bottom of the tower barrel. The middle pier 208 of the newly poured reinforced concrete foundation 2 expands the diameter to match the outer diameter of the bottom section 3 of the new fan tower barrel on the basis of the middle pier 103 of the original fan foundation 1, and the height of the middle pier 208 of the newly poured reinforced concrete foundation 2 is still the same as that of the middle pier 103 of the original fan foundation 1. A tower barrel bottom plate 301 is provided at the bottom of the bottom section 3 of the new fan tower barrel. Vertical holes are reserved on the tower barrel bottom plate 301. The size, quantity and position of the vertical holes are matched with the vertical anchor bolts 1022 in the vertical anchor bolt cage connection system 102 of the original fan foundation 1, so that the vertical anchor bolts 1022 of the original fan foundation 1 can be applied and installed. A wedge-shaped haunch area 302 is provided at the junction of the inner side wall of the bottom section 3 of the new fan tower barrel and the tower barrel bottom plate 301. The inclined surface of the wedge-shaped haunch area 302 is perpendicular to the radial anchor bolt 2022. Through holes are provided in the wedge-shaped haunch area 302 and the tower barrel wall. The size, quantity and position of the through holes are matched with the radial anchor bolt 2022 to facilitate the installation of the radial anchor bolt 2022.

[0025] As described above, in the present invention, the connection structure between the bottom section 3 of the new fan tower barrel and the new fan foundation includes a vertical anchor bolt cage connection system 102 and a radial anchor bolt connection system 202. The vertical anchor bolt cage connection system 102 retains the components connected to the original fan foundation 1, specifically including the original foundation lower anchor plate 1021, the vertical anchor bolt 1022, and the original foundation upper anchor plate 1023. When hoisting the bottom section 3 of the new fan tower barrel, the vertical anchor bolt 1022 passes through the reserved holes in the tower barrel bottom plate 301 and is fastened by nuts, so as to connect the bottom section 3 of the new fan tower barrel with the new fan foundation jointly formed by the newly poured reinforced concrete foundation 2 and the original fan foundation 1 by using the vertical anchor bolt cage connection system 102 and the structure of the original fan foundation 1 that cooperates with the vertical anchor bolts.

[0026] The radial anchor bolt connection system 202 includes an annular anchor plate 2021, radial anchor bolts 2022, and embedded steel sleeves 2023. The length of the radial anchor bolts 2022 is less than or equal to the inner diameter of the bottom section 3 of the fresh air fan tower cylinder, so as to facilitate the installation of the radial anchor bolts 2022. An external thread 2022-1 is also provided at the outer end thereof for fixing to the embedded steel sleeve 2023. The embedded steel sleeve 2023 includes a sleeve body 2023-1, multiple bamboo joint-shaped enlarged rings 2023-2 located on the outer wall of the sleeve body, an external thread 2023-3 at the inner end of the sleeve, and an internal thread 2023-4 at the outer end of the sleeve. The internal thread 2023-4 at the outer end of the sleeve matches the external thread 2022-1 at the outer end of the radial anchor bolt for fixing the radial anchor bolt 2022. The sleeve body 2023-1 is in a conical shape with a thinner inner end in the radial direction and a thicker outer end in the radial direction, which is beneficial to preventing the embedded steel sleeve 2023 from being pulled out of the fan foundation. The bamboo joint-shaped enlarged rings 2023-2 increase the contact area and biting force between the embedded steel sleeve 2023 and the concrete.

[0027] The annular anchor plate 2021 is formed into a circle by splicing two semi-circular parts. Its inner diameter matches the outer diameter of the bottom section 3 of the fresh air fan tower cylinder and is arranged around the outer wall of the bottom section 3 of the fresh air fan tower cylinder. Lap joints 2021-1 are provided at both ends of each semi-circular part of the annular anchor plate 2021. The lap joints 2021-1 and the main body of the annular anchor plate 2021 are configured in a stepped shape for splicing the two semi-circular parts. Threaded holes 2021-2 are provided in the lap joints. After the two semi-circular parts are spliced, they are fixed by lap joint bolts 2021-3. The lap joint bolts 2021-3 can be embedded into the annular anchor plate 2021 to prevent protrusions on the outer surface of the annular anchor plate 2021. A plurality of through-anchor plate sleeve threaded holes 2021-4 are provided along the length direction of the annular anchor plate 2021. Internal threads are provided in the sleeve threaded holes 2021-4, and the external thread 2023-3 at the inner end of the embedded steel sleeve matches the internal thread in the sleeve threaded hole 2021-4. The inner end of the embedded steel sleeve 2023 is fixed to the annular anchor plate 2021 by threaded connection and is bound or welded to the steel reinforcement in the newly poured reinforced concrete foundation 2 on the outside.

[0028] When the annular anchor plate 2021 is installed, it is positioned and leveled by a leveler 203. At least three levelers 203 are arranged along the circumferential direction to ensure the stability of the annular anchor plate 2021. The leveler 203 includes a base 2031, a long screw 2032, a lower nut 2033, an upper nut 2034, a bracket 2035, an annular anchor plate support 2036 and a support bolt 2037. A bracket 2035 is provided on the base 2031, and the bracket 2035 includes diagonal braces to increase stability. An annular anchor plate support 2036 is provided above the bracket 2035, and a vertical hole is provided on the annular anchor plate support 2036. A leveler threaded hole 2021-5 matching the vertical hole is provided at the bottom of the annular anchor plate 2021. After the vertical hole is aligned with the leveler threaded hole 2021-5 of the annular anchor plate, the leveled leveler 203 and the annular anchor plate 2021 are fixed by a support bolt 2037.

[0029] A platform is chiseled on the top surface of the outer ring 101 of the original fan foundation 1 to place the base 2031 of the leveler 203, and a long screw 2032 is pre-embedded by drilling a hole on the platform, and its position corresponds to the vertical hole on the base. After installing the lower nut 2033 on the long screw, the base 2031 of the leveler 203 is installed, and then the upper nut 2034 is installed, and the height is adjusted by the upper and lower nuts to fix the leveler 203.

[0030] The outer ring 201 of the newly poured reinforced concrete foundation 2 is provided with an outer ring edge 209 and is wrapped around the radial outside of the outer ring 101 of the original fan foundation, and is provided with foundation outer radial implanted steel bars 205 connecting each other. To increase the connection reliability, the outer end of the foundation outer radial implanted steel bar 205 is bent at 90° and fixed to the reinforcement of the newly poured reinforced concrete foundation 2.

[0031] Please refer to Figure 3 , to increase the bonding strength between the new and old concretes, vertical implanted steel bars 206 are added on the top surface of the outer ring 101 of the original fan foundation, and the vertical implanted steel bars 206 protrude from the top surface; to enhance the bearing capacity of the newly poured reinforced concrete foundation 2, a pile foundation 207 is added between the outer ring edge 209 of the newly poured reinforced concrete foundation 2 and the foundation. A concealed beam is added to the connection node between the newly poured reinforced concrete foundation 2 and the pile foundation to resist the working condition of one-sided tension and excessive tensile stress.

[0032] Based on the above structure of the present invention, a construction method for small-to-large transformation of old wind farm fan foundations is as follows: Step 1: Demolish the original fan and the original tower barrel, excavate the original foundation backfill area, chisel out a small step on the top surface 1011 of the outer ring of the original fan foundation 1 to increase the bite force between the new and old concretes, and chisel out a platform on the top surface 1011 of the outer ring of the original fan foundation 1 directly below the designed position of the annular anchor plate 2021 for arranging the leveler 203.

[0033] Step 2: In the area where the fan foundation is enlarged, implant the pile foundation 207.

[0034] Step 3: Drill holes on the platform chiseled on the top surface 1011 of the outer ring of the original fan foundation 1 to install the leveler 203, and adjust the level and height through the upper nut and the lower nut.

[0035] Step 4: Connect the two petals of the semi-circular annular anchor plate 2021 and position it on the leveler 203.

[0036] Step 5: Drill holes, grout, and respectively place the radially implanted bars 205 and vertically implanted bars 206 on the surface of the outer ring 101 of the original fan foundation 1.

[0037] Step 6: Bind the reinforcement bars of the newly poured reinforced concrete foundation 2, and bind these reinforcement bars with the vertically implanted bars 206. At the same time, screw the embedded steel sleeve 2023 tightly to the annular anchor plate 2021, and bind the outer end of the embedded steel sleeve 2023 with the reinforcement bars. In addition, when a concealed beam is added between the newly poured reinforced concrete foundation 2 and the pile foundation, the exposed pile bars are bound or welded to the concealed beam bars to strengthen the connection between the edge of the newly poured reinforced concrete foundation and the pile.

[0038] Step 7: Formwork and pour the newly poured reinforced concrete foundation 2.

[0039] Step 8: After the strength of the newly poured concrete reaches the requirement, hoist the bottom section 3 of the new fan tower; after successful positioning, connect the bottom section 3 of the new fan tower with the new fan foundation formed by the combination of the newly poured reinforced concrete foundation 2 and the original fan foundation 1 through the vertical anchor bolt cage connection system 102 and utilize the structure of the original fan foundation 1 that has been connected to the vertical anchor bolt cage connection system 102; and, connect the bottom section 3 of the new fan tower with the new fan foundation formed by the combination of the newly poured reinforced concrete foundation 2 and the original fan foundation 1 through the radial anchor bolt connection system 202 to achieve a reliable connection. Specifically, apply structural adhesive on the radial anchor bolts 2022, insert them from the inside of the tower into the inside of the embedded steel sleeve 2023, tighten the radial anchor bolts 2022, and then fasten the connection between the bottom section of the new fan tower and the new fan foundation with nuts. Finally, arrange an elastic cushion or epoxy grouting material 204 between the side edge of the bottom section of the new fan tower and the newly poured reinforced concrete foundation 2.

[0040] Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A structure for increasing the capacity of wind turbine foundations in old wind farms, characterized in that: It comprises an original wind turbine foundation (1), a newly poured reinforced concrete foundation (2), a vertical anchor bolt cage connection system (102) and a radial anchor bolt connection system (202); The newly cast reinforced concrete foundation (2) is cast on the original fan foundation (1) to form a new fan foundation together; the outer ring (201) of the newly cast reinforced concrete foundation (2) surrounds and covers the outer ring (101) of the original fan foundation (1) from the top and radially outward, and the middle pier (208) of the newly cast reinforced concrete foundation (2) surrounds the outside of the middle pier (103) of the original fan foundation (1) but is not higher than the middle pier (103) of the original fan foundation (1), and is adapted to the diameter of the bottom section (3) of the new fan tower; The connection structure between the new wind turbine tower bottom section (3) and the new wind turbine foundation comprises a vertical anchor bolt cage connection system (102) and a radial anchor bolt connection system (202); the vertical anchor bolt cage connection system (102) is fixed inside the original wind turbine foundation (1), and the radial anchor bolt connection system (202) is fixed inside the newly poured reinforced concrete foundation (2).

2. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 1 is characterized in that: The new wind turbine tower bottom section (3) is arranged on a middle pier formed by the middle pier (208) of the newly cast reinforced concrete foundation (2) and the middle pier (103) of the original wind turbine foundation (1). A tower bottom plate (301) is provided at the bottom of the new wind turbine tower bottom section (3). Vertical holes are reserved on the tower bottom plate (301). The size, number and position of the vertical holes match the vertical anchor bolts of the vertical anchor bolt cage connection system (102) of the original wind turbine foundation, so as to facilitate the installation of the vertical anchor bolts. Anchor bolts (1022); a wedge-shaped axil area (302) is provided at the junction of the inner side wall of the bottom section (3) of the fresh air turbine tower and the tower bottom plate (301); the inclined surface of the wedge-shaped axil area (302) is perpendicular to the radial anchor bolts (2022); and through holes are provided in the wedge-shaped axil area (302) and the side of the tower; the size, number and position of the holes match the radial anchor bolts (222) of the radial anchor bolt connection system (202) so as to install the radial anchor bolts (2022).

3. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 1 is characterized in that: The vertical anchor cage connection system (102) retains the connection components of the original wind turbine foundation (1), including the original foundation lower anchor plate (1021), the vertical anchor bolts (1022), and the original foundation upper anchor plate (1023); when the new wind turbine tower bottom section (3) is hoisted, the vertical anchor bolts (1022) pass through the vertical holes of the tower bottom plate (301) and are fastened by nuts to connect the new wind turbine tower bottom section (3) with the new wind turbine foundation formed by the newly cast reinforced concrete foundation (2) and the original wind turbine foundation (1).

4. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 1 is characterized in that: The radial anchor connection system (202) comprises an annular anchor plate (2021), a radial anchor (2022) and a pre-buried steel casing (2023); the length of the radial anchor (2022) is less than or equal to the inner diameter of the bottom section (3) of the fresh air blower tower, so that the radial anchor (2022) can be installed from the inside of the bottom section (3) of the fresh air blower tower; the outer end of the radial anchor (2022) is also provided with an external thread (2022-1) for fixing with the pre-buried steel casing (2023); The buried steel casing (2023) comprises a casing body (2023-1), a plurality of bamboo-shaped expansion rings (2023-2) located on the outer wall of the casing body, an external thread (2023-3) at the inner end of the casing, and an internal thread (2023-4) at the outer end of the casing; the internal thread (2023-4) at the outer end of the casing matches the external thread (2022-1) at the outer end of the radial anchor bolt and is used to fix the radial anchor bolt (2022); the casing body (2023-1) is thin at the inner end and thick at the outer end.

5. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 1 is characterized in that: An elastic cushion layer or epoxy resin grouting material (204) is provided between the bottom section (3) of the new wind turbine tower and the newly cast reinforced concrete foundation (2); the elastic cushion layer or epoxy resin grouting material (204) can prevent local stress concentration on the foundation caused by lateral micro-deformation of the tower.

6. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 4 is characterized in that: The annular anchor plate (221) is formed by splicing two semicircular pieces into a circle, and its inner diameter matches the outer diameter of the bottom section (3) of the fresh air fan tower, and is arranged around the outer wall of the bottom section (3) of the fresh air fan tower; overlapping sections (221-1) are provided at both ends of each piece of the annular anchor plate (221), and the overlapping sections (221-1) and the main body of the annular anchor plate (2021) are configured in a step shape; the annular anchor plate (2021) is provided with a plurality of sleeve threaded holes (221-4) penetrating the anchor plate along its length direction, and the outer thread (223-3) of the inner end of the embedded steel sleeve (2023) matches the thread of the sleeve threaded hole (2021-4), the inner end of the embedded steel sleeve (2023) is fixed to the annular anchor plate (2021) by threaded connection, and the outer end is tied or welded to the foundation reinforcement.

7. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 4 is characterized in that: A plurality of levelers (203) are also provided, and the annular anchor plate (2021) is positioned and leveled by the levelers (203) during installation; a support platform for the levelers (203) is processed on the outer ring (101) of the original fan foundation (1).

8. The structure for increasing the capacity of old wind farm wind turbine foundations by upgrading them to larger ones according to claim 7, characterized in that: The leveler (203) comprises a base (2031), a long screw (2032), a lower nut (2033), an upper nut (2034), a bracket (2035), an annular anchor plate support (2036) and a support bolt (2037); the base (2031) is provided with a bracket (2035), and the bracket (2035) comprises an oblique brace; an annular anchor plate support (2036) is provided above the bracket (2035), and the annular anchor plate support (2036) is provided with a vertical hole and a support bolt (2037); the bottom of the annular anchor plate (221) is provided with a matching leveler threaded hole (221-5), and after the vertical hole is aligned with the leveler threaded hole (2021-5) of the annular anchor plate, the leveler (203) and the annular anchor plate (2021) are fixed by the support bolt (2037).

9. The structure for increasing the capacity of wind turbine foundations in old wind farms according to claim 1 is characterized in that: The outer ring (101) of the original fan foundation and the side surface of the newly cast reinforced concrete foundation (2) are provided with foundation outer side horizontal embedded bars (205) connected to each other, and the outer ends of the foundation outer side horizontal embedded bars (205) are bent and fixed to the reinforcement of the newly cast reinforced concrete foundation (2).

10. A reconstruction construction method for converting an old wind farm wind turbine foundation into a large capacity-increasing structure, characterized in that: This is achieved by the small-scale conversion and large-scale capacity increase structure of the old wind farm wind turbine foundation as described in any one of claims 1 to 9, and the specific steps are as follows: Step 1: dismantle the original wind turbine and the original tower, excavate the original foundation backfill area, chisel out a small step on the top surface (1011) of the outer ring of the original wind turbine foundation to increase the bite force between the new and old concrete, and chisel out a platform on the top surface (1011) of the outer ring of the original wind turbine foundation directly below the annular anchor plate (2021) for arranging the leveler (203); Step 2: implanting pile foundation (207) in the area where the foundation is enlarged; Step 3: Drill holes on the outer ring top surface (1011) of the original fan foundation to install the leveler (203), and level and adjust the height; Step 4: Connect the two halves of the semicircular annular anchor plate (2021) and position them on the leveler (203); Step 5: drilling holes on the surface of the outer ring (101) of the original fan foundation, grouting, and inserting horizontal reinforcement bars (205) and vertical reinforcement bars (206) on the outer side of the foundation respectively; Step 6: Tie the reinforcement of the newly cast reinforced concrete foundation (2), and tie the reinforcement with the vertical embedded reinforcement; screw and fix the embedded steel casing (223) to the annular anchor plate (221), and tie the outer end of the embedded steel casing (223) with the reinforcement; in addition, when a hidden beam is added between the pile foundation and the newly cast reinforced concrete foundation (2), the exposed reinforcement of the pile is tied or welded with the hidden beam steel bars to strengthen the connection between the edge of the newly cast reinforced concrete foundation (2) and the pile; Step 7: Formwork and pouring of new reinforced concrete foundation (2); Step 8: After the strength of the newly poured concrete reaches the required level, the bottom section (3) of the new wind turbine tower is hoisted; after successful positioning, the bottom section (3) of the new wind turbine tower is connected to the new wind turbine foundation (2) and the original wind turbine foundation (1) by means of the vertical anchor bolt cage connection system (102) and the structure already connected to the vertical anchor bolt cage connection system (102) of the original wind turbine foundation (1); and the bottom section (3) of the new wind turbine tower is connected to the new wind turbine foundation (2) and the original wind turbine foundation (1) by means of the radial anchor bolt connection system (202) to achieve a reliable connection.

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