Inverted-cone-shaped precast beam slab fan foundation and construction method thereof

Abstract

The overall form of the inverted-cone-shaped precast beam slab draught fan foundation is inverted-cone-shaped, the inverted-cone-shaped precast beam slab draught fan foundation is mainly formed by splicing a core tube and a trapezoidal beam, a horizontal pre-stressed anchor cable is arranged at the top of the trapezoidal beam to fix the trapezoidal beam and the core tube, and a post-cast strip is arranged at the root of the core tube and the bottom of the trapezoidal beam. The rest abutted seam positions are coated with structural adhesive, so that the consistency of the whole structure is improved; in the vertical connection, an anchor rod hole is preset in the core tube, an anchor rod mechanical connection joint is pre-embedded in the bottom of the anchor rod hole, and the fan head section tower tube is fixedly connected with a fan foundation through an anchor rod. The structure form is reasonable in stress, the inverted cone can effectively restrain the problem of foundation disengagement, the structure is easy to build through prefabricated parts, the foundation excavation work amount can be remarkably reduced, cost increase and environmental influence caused by spoil outward transportation are reduced, installation is easy and convenient, construction is rapid, cost can be greatly reduced, and the construction period is shortened. The method has good engineering economic value and wide application prospect.

Description

Technical Field

[0001] The invention relates to an inverted cone-shaped prefabricated beam and slab fan foundation and a construction method thereof. Background Art

[0002] The wind turbine foundation, as the structural foundation within the wind turbine system, bears the wind turbine's own weight and wind loads, providing load-bearing support. Because wind turbines are tall structures, they experience significant horizontal forces and base bending moments when subjected to horizontal wind loads. Furthermore, wind turbines are sensitive to tower tilt, placing high demands on the foundation's ability to withstand uneven settlement. The foundation must withstand vertical and horizontal loads, uplift forces, and vibrations or dynamic forces generated by the turbine. Traditional wind turbine foundations are mostly gravity-type foundations with a constant volume and horizontal projected area. These are typically cast-in-place concrete structures, requiring on-site reinforcement, concrete pouring, and curing, taking approximately one month. The pouring process for wind turbine foundations is environmentally demanding. Excessively high or low temperatures can affect foundation quality, leading to long construction downtimes in construction sites with volatile climates. Furthermore, pouring and curing are performed on-site by the construction unit, resulting in significant uncertainties in wind turbine foundation construction quality, including the experience of the construction team. There are also reports of inverted cone foundations, but these are also in-situ concrete structures. Generally speaking, the mainstream wind turbine foundation forms on the market are mainly cast on site, but the construction quality of cast on site foundation is difficult to control, the construction period is long, the environmental impact is large, and for special areas, commercial concrete cannot be effectively transported, and the quality of concrete from self-built mixing stations is uncontrollable, which will cause great difficulties for engineering construction. Summary of the Invention

[0003] The purpose of the present invention is to provide an inverted conical prefabricated beam and slab wind turbine foundation, which has better horizontal bearing capacity and bending bearing capacity and is suitable for construction with prefabricated parts in the structure. A further purpose of the present invention is to provide a construction method for this inverted conical prefabricated beam and slab wind turbine foundation, which can at least partially solve the problems of ecological damage, large engineering volume, long construction period and difficult to control construction quality in the current application of wind power foundations.

[0004] To achieve the above object, according to a first aspect of the present invention, the present invention adopts the following technical solution: The truncated frame is provided with a plurality of prefabricated steel beams and a plurality of prefabricated steel beams, and the truncated frame is provided with a plurality of prefabricated steel beams. The truncated frame is provided with a plurality of prefabricated steel beams and a plurality of prefabricated steel beams. The truncated frame is provided with a plurality of prefabricated steel beams and a plurality of prefabricated steel beams. The truncated frame is provided with a plurality of prefabricated steel beams and a plurality of prefabricated steel beams.

[0005] On the basis of adopting the above technical solutions, the present invention may also adopt the following further technical solutions, or use these further technical solutions in combination: The wing plate is located at the bottom of the hypotenuse of the trapezoidal main beam and is connected to the secondary beam at the outer end; the wing plates of adjacent trapezoidal beams are connected by structural adhesive to form the bottom surface of the wind turbine foundation, and the secondary beams of adjacent trapezoidal beams are connected as a whole by structural adhesive.

[0006] A second post-cast strip steel bar is provided at the inner end portion of the wing plate, a first post-cast strip steel bar is provided at a position corresponding to the post-cast strip of the trapezoidal main beam, and a third post-cast strip steel bar is provided at a position corresponding to the post-cast strip on the outer side surface of the core tube. The first post-cast strip steel bar, the second post-cast strip steel bar and the third post-cast strip steel bar are all multi-layer U-shaped structures and are plugged together. The first post-cast strip steel bar, the second post-cast strip steel bar and the third post-cast strip steel bar are respectively connected to the steel bars inside the trapezoidal main beam, the core tube and the wing plate.

[0007] The outer side surface of the core tube is a polyhedron, and each side corresponds to a trapezoidal beam with a wing plate.

[0008] The core tube is composed of multiple sections of tube bodies connected together, and each section of the tube body is provided with an anchor hole section that passes through from top to bottom to form an anchor hole. The bottom tube body end is pre-embedded with an anchor mechanical connection joint at the bottom end of the anchor hole. The top surface of the top tube body end is provided with an annular groove for fixing and installing the anchor plate and grouting to form an anchor plate support plane. The anchor rods are used to fasten the sections of the tube body and the first section of the tower tube into a whole; a post-cast strip is provided at the connection between the bottom tube body section and the wing plate, and a second horizontal reserved channel corresponding to the first horizontal reserved channel in the trapezoidal beam is provided in the lower area of ​​the annular groove of the top tube body section for the prestressed anchor cable to pass through.

[0009] The anchor rod passes through the anchor rod hole of the core tube, and the bottom is anchored on the anchor rod mechanical connection joint embedded in the bottom of the core tube. The upper part passes through the anchor plate and is connected to the flange of the wind turbine tower, and prestressed to tension and fix it.

[0010] The core tube is composed of multiple tube sections connected together, and each tube section is a prefabricated reinforced concrete part.

[0011] According to the second aspect of the present invention, the present invention adopts the following technical solutions: A construction method for an inverted conical prefabricated beam-slab fan foundation is provided, wherein the core tube is a single section or is formed by connecting multiple sections. The steps are as follows: Step 1: Excavate the foundation pit according to the design drawings, ensure that the foundation pit slope is consistent with the wing plate angle, perform surface hardening treatment on the soft soil foundation pit slope, and level the foundation pit bottom area; Step 2: After the excavation of the foundation pit and the pouring of the cushion layer, clean the surface of the cushion layer, start to locate the center of the wind turbine foundation circle, and stake out the foundation dimensions. Apply structural adhesive to the bottom of the core tube and then hoist it to the designated position. If the core tube is not segmented, install all anchor rods after hoisting. The anchor rods are anchored to the anchor rod mechanical connection joints at the bottom of the core tube through the anchor rod holes of the core tube. If the core tube is divided into multiple sections, first pre-install several anchor rods evenly at the bottom of the tube section through the anchor rod mechanical connection joints for vertical positioning, and then hoist each section of the tube in sequence. The contact surfaces between different sections of the tube need to be cleaned and coated with structural adhesive. After all sections of the tube are hoisted, install the remaining anchor rods. Step 3: Hoist the trapezoidal beams, mark the center lines of the main trapezoidal beams and the center lines of the corresponding mounting surfaces on the outer wall of the core tube, and position the trapezoidal beams according to the center lines; evenly apply structural adhesive on the contact surfaces between the core tube and the trapezoidal beams, as well as on the contact surfaces between adjacent trapezoidal beams, hoist the trapezoidal beams, and install prestressed anchor cables. Pre-tension the cables before the adhesive dries to ensure the structure fits together; Step 4: After the wind turbine foundation structure is spliced, cast the post-cast strip. When the strength of the post-cast strip reaches the required value, tension the prestressed anchor cable to the design value again. Step 5: Test the connection strength of the anchor rod and the anchor rod mechanical connection joint. If it meets the design requirements, grouting is performed in the annular groove; Step 6: After the prestressing value of each part reaches the design requirements, the foundation pit is backfilled. The backfill soil is filled between each trapezoidal main beam with the wing plate as the bearing surface, and the backfill height is filled to the top of the trapezoidal main beam. Then, the entire wind turbine foundation area is backfilled with a gravel layer except for the core tube. For foundations with waterproofing requirements, geotextiles and geomembranes or waterproof membranes are also laid, and then sand layers and graded gravel layers are paved in sequence. Step 7: Then, the first section of the tower is hoisted, and the first section of the tower and the core tube are connected as a whole using the anchor rods, and prestress is applied to the anchor rods to complete the installation of the wind turbine foundation and the first section of the tower.

[0012] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention designs an inverted cone-shaped prefabricated structure. Compared with the traditional gravity foundation, the base area of ​​this foundation is small, which is conducive to releasing the huge bending moment of the base. The contact area between the side wall of the foundation and the soil is increased, which can mobilize more soil to resist external loads and improve the bearing capacity of the foundation. This foundation form can effectively suppress the problem of foundation bottom surface detachment caused by horizontal loads in existing foundation structures.

[0013] (2) The inverted tapered beam-slab fan foundation of the present invention is suitable for construction using factory-prefabricated components. The structural dimensions can be more precisely controlled, and modular production can greatly improve production efficiency, saving time and material costs. Furthermore, factory-prefabricated products can eliminate interference from weather factors, thus preventing construction difficulties or interruptions that may cause cold joints and other construction quality problems.

[0014] (3) The present invention adopts a combination of dry and wet treatment for different parts of the wind turbine foundation. For the bottom area of ​​the core tube where the shear force is relatively large, a post-cast strip wet treatment is used on site. This can not only adjust the foundation installation error but also enhance the shear resistance of the core area. For horizontal loads, the connection between the core tube and the trapezoidal beam is strengthened by dry treatment of prestressed anchor cables, making the overall stress of the foundation structure more reasonable, safe and reliable.

[0015] (4) The wind turbine foundation of the present invention is not only suitable for construction using factory prefabricated parts, but also can effectively reduce the amount of earth and stone required for foundation excavation compared to existing foundation forms. The excavated soil can be used to backfill the conical bowl-shaped lattice voids formed by the wind turbine foundation wing plates, thereby reducing the cost of transporting waste soil and also reducing the impact on the ecological environment.

[0016] In summary, the inverted conical prefabricated beam-slab wind turbine foundation proposed in the present invention not only maintains the stress-bearing advantages of the inverted conical wind turbine foundation, but also greatly reduces on-site operation time and shortens construction period. It is efficient and environmentally friendly while having good applicability and economy. It can be widely used in the construction of natural foundation wind farms under various terrain conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a three-dimensional schematic diagram of a wind turbine foundation according to an embodiment of the present invention; Figure 2 This is a top view of the wind turbine foundation according to an embodiment of the present invention; Figure 3 This is a three-dimensional schematic diagram of a trapezoidal beam with wing plates according to an embodiment of the present invention; Figure 4 This is a front view of a trapezoidal beam with wing plates according to an embodiment of the present invention; Figure 5 This is a top view of a trapezoidal beam with wing plates according to an embodiment of the present invention; Figure 6 This is a top view of the connection between the trapezoidal beam with wing plates and the core tube according to an embodiment of the present invention; Figure 7 Schematic diagram of a trapezoidal beam with wing plates and a post-cast strip of a core tube according to an embodiment of the present invention; Figure 8 This is a longitudinal cross-sectional view of the core tube of an embodiment of the present invention; Figure 9 This is a basic longitudinal cross-sectional view of an embodiment of the present invention. DETAILED DESCRIPTION

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

[0019] The inverted conical prefabricated beam-slab wind turbine foundation of the present invention is an inverted conical foundation as a whole, which is formed by splicing a plurality of prefabricated components of trapezoidal beams with wing plates and prefabricated components of a core tube through prestressed anchor cables, post-cast strips, and structural adhesives. After the trapezoidal beams with wing plates are hoisted and spliced ​​with the core tube, their tops are tensioned and fixed by prestressed anchor cables, and the fixed ends are respectively arranged at the outer ends of the trapezoidal beams with wing plates and the inner side of the core tube; their bottoms are cast into a whole through post-cast strips, and the remaining contact surfaces (including the contact surfaces between the wing plates and the contact surfaces between the secondary beams) are all coated with structural adhesive. In order to better match the current connection form between the wind turbine tower and the foundation, an annular reserved hole is provided vertically on the core tube, and the anchor rod is fixed to the mechanical joint embedded in the bottom of the core tube through the reserved hole, and the anchor plate is fixed in the annular groove at the top of the core tube, which is convenient for the installation and fixation of the wind turbine tower. The following is a further detailed explanation with reference to the accompanying drawings.

[0020] See also Figures 1-9 This embodiment provides an inverted conical prefabricated beam-slab wind turbine foundation, comprising a plurality of trapezoidal beams 1 with wing plates, prestressed anchor cables 106, and a core tube 2 arranged in the center of the wind turbine foundation; the trapezoidal beams 1 with wing plates and the core tube 2 are prefabricated reinforced concrete components.

[0021] In this embodiment, for the convenience of transportation and manufacturing, the core tube 2 is composed of multiple sections, each of which is a prefabricated reinforced concrete part and is assembled into the core tube 2 during on-site construction.

[0022] The plurality of trapezoidal beams 1 with wing plates are arranged around the side of the core tube 2 to form an inverted cone structure, wherein the trapezoidal beam 1 is a prefabricated concrete component consisting of a trapezoidal main beam 101, a wing plate 102, and a secondary beam 103, wherein the trapezoidal main beam 101 is a variable-section main beam, and the trapezoidal main beam 101 of each trapezoidal beam 1 is arranged radially and intersects perpendicularly with the outer surface of the core tube 2, and the secondary beam is located at the outer end of the trapezoidal main beam 101, intersecting perpendicularly with the trapezoidal main beam 101, and forming a T-shaped configuration, and the wing plate 102 is connected to the trapezoidal main beam 101 and the The secondary beam 103 is connected, and a first horizontal reserved channel 105 is provided on the top of the trapezoidal beam 1, through which a prestressed anchor cable 106 passes, and is horizontally connected to the core tube 2 through the prestressed anchor cable 106. The bottom of the trapezoidal beam 1 is fixedly connected to the core tube 2 through a post-cast strip 104; the core tube 2 is provided with an anchor hole 206, and the anchor rod 201 passes through the anchor hole 206. The bottom of the anchor rod 201 is threadedly connected to the anchor rod mechanical connection joint 205 embedded in the bottom of the core tube 2, and the anchor rod 201 is connected to the first section of the tower tube 300.

[0023] The wing panels 102 are located at the bottom of the hypotenuse of the trapezoidal main beam 101, and are provided with post-cast reinforcement bars 1042 at their inner ends. The wing panels 102 are connected to the secondary beams 103 at their outer ends. The wing panels of adjacent trapezoidal beams 1 are connected with structural adhesive, forming the bottom surface of the wind turbine foundation. The secondary beams 103 of adjacent trapezoidal beams 1 are also connected with structural adhesive, forming a single body.

[0024] A second post-cast joint steel bar 1042 is provided at the inner end of the wing plate 102, a first post-cast joint steel bar 1041 is provided at a position of the trapezoidal main beam 101 corresponding to the post-cast joint 104, and a third post-cast joint steel bar 1043 is provided on the outer side surface of the core tube corresponding to the position of the post-cast joint 104. The first post-cast joint steel bar 1041, the second post-cast joint steel bar 1042 and the third post-cast joint steel bar 1043 are all multi-layer U-shaped structures and are plugged together. The first post-cast joint steel bar 1041, the second post-cast joint steel bar 1042 and the third post-cast joint steel bar 1043 are respectively connected to the steel bars inside the trapezoidal main beam 101, the core tube 2 and the wing plate 102, thereby further improving the structural strength of the post-cast joint 104 and the integrity of the wind turbine foundation.

[0025] The outer side surface of the core tube 2 is a polyhedron, and each side corresponds to a trapezoidal beam 1 with a wing plate.

[0026] As previously mentioned, the core tube 2 is constructed by connecting multiple sections of the tube body. Each section of the tube body is provided with two vertically connected anchor hole sections, forming an anchor hole 206. The bottom section of the tube body has an anchor mechanical connection joint 205 embedded at the bottom end of the anchor hole. The anchor mechanical connection joint 205 is truncated cone-shaped, with a large bottom diameter and a small top diameter. Its internal thread matches the anchor 201. An annular groove 204 is provided on the top surface of the top end of the tube body for fixing and installing the annular anchor plate 202 and grouting to form the anchor plate support plane. The anchor rod 201 is used to fasten the various sections of the tube body and the first tower section 300 (the first tower section 300 has a flange at the bottom) into a single unit. A post-cast strip 104 is provided at the connection between the bottom section of the tube body and the wing plate. The top section of the tube body has a second horizontal reserved channel 203 below the annular groove 204. The second horizontal reserved channel 203 can be arranged in multiple rows. The number, location, and dimensions of the second horizontal pre-reserved channels 203 correspond exactly to those of the first horizontal pre-reserved channels 105, ensuring that prestressed anchor cables 106 can pass through the core tube 2 and the trapezoidal beam 1. One end of these pre-reserved anchor cables is anchored to the inner wall of the core tube 2, and the other end is anchored to the outer end of the trapezoidal beam 1. Radially, the core tube 2 and the trapezoidal beam 1 are secured at the top by the prestressed anchor cables 106 and at the bottom by the post-cast strips 104.

[0027] This embodiment also provides a construction method for constructing the above-mentioned inverted tapered prefabricated beam-slab fan foundation, the steps of which are as follows: Step 1: Excavate the foundation pit according to the design drawings, control the foundation pit slope to be consistent with the angle of the wing plate 102, perform surface hardening treatment on the soft soil foundation pit slope, and level the foundation pit bottom area.

[0028] Step 2: After the excavation of the foundation pit and the pouring of the cushion layer, clean the surface of the cushion layer, start to locate the center of the wind turbine foundation, mark the foundation size, apply structural glue to the bottom of the core tube 2, and then hoist it to the designated position. When the core tube 2 is not segmented, install all anchor rods 201 after hoisting. The anchor rods 201 are anchored to the anchor rod mechanical connection joint 205 at the bottom of the core tube through the anchor rod hole 206 of the core tube 2; when the core tube 2 is divided into multiple sections, first pre-install several anchor rods 201 evenly at the bottom tube section through the anchor rod mechanical connection joint 205 for vertical positioning, and then complete the hoisting of each section of the tube in turn. The contact surfaces between different sections of the tube need to be cleaned and coated with structural glue. After all sections of the tube are hoisted, install the remaining anchor rods 201.

[0029] Step 3: Hoist the trapezoidal beam 1. Mark the centerline of the main trapezoidal beam 101 and the centerline of the corresponding mounting surface on the outer wall of the core tube 2. Position the trapezoidal beam 1 according to the centerline. Evenly apply structural adhesive to the contact surfaces between the core tube 2 and the trapezoidal beam 1, as well as to the contact surfaces of adjacent trapezoidal beams 1 (i.e., the side surfaces of the wing panels 102 and the end surfaces of the secondary beams 103). Hoist the trapezoidal beam 1 and install the prestressed anchor cables 106. Pre-tension the adhesive before it dries to ensure a tight fit. Pre-tensioning the adhesive before it fully solidifies (to a stress less than the design stress) eliminates any gaps in the adhesive and ensures a tighter fit.

[0030] Step 4: After the wind turbine foundation structure is spliced, the post-cast strip 104 is poured. After the strength of the post-cast strip 104 reaches the required value, the prestressed anchor cable 106 is tensioned again to the design value.

[0031] Step 5: Check the connection strength between the anchor rod 201 and the anchor rod mechanical connection joint 205 . If the connection strength meets the design requirements, grouting is performed in the annular groove 204 .

[0032] Step 6: Backfill the foundation pit. The backfill soil uses the wing plate 102 as the bearing surface and is filled between the trapezoidal main beams 101. The backfill height reaches the top of the trapezoidal main beam 101. Then, the entire wind turbine foundation area is backfilled with a gravel layer except for the core tube. For foundations with waterproofing requirements, geotextiles and geomembranes or waterproof membranes should also be laid, and then sand layers and graded gravel layers should be paved in sequence.

[0033] Step 7: Then hoist the first section of the tower 300. Pass the anchor rod 201 through the reserved hole of the flange at the bottom of the first section of the tower. Use the tensioner to tension the anchor rod, tighten the nut, and then over-tension it to the design value to complete the installation of the wind turbine foundation and the first section of the tower 300.

[0034] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the ideas and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An inverted conical prefabricated beam-slab fan foundation, characterized in that: The invention relates to a wind turbine comprising a plurality of ladder beams (1) with wing plates, prestressed anchor cables (106), and a core tube (2) arranged at the center of a wind turbine foundation; the ladder beams (1) with wing plates and the core tube (2) are reinforced concrete prefabricated components; the plurality of ladder beams (1) with wing plates are arranged around the side of the core tube (2) to form an inverted cone structure, wherein the ladder beam (1) is a concrete prefabricated component consisting of a ladder main beam (101), a wing plate (102), and a secondary beam (103); the ladder main beam (101) of each ladder beam (1) is arranged radially, and the ladder main beam (101) of each ladder beam (1) is arranged radially. The secondary beam is located at the outer end of the trapezoidal main beam (101) and is arranged in a T-shape with the trapezoidal main beam (101). The wing plate (102) is connected to the trapezoidal main beam (101) and the secondary beam (103). The top of the trapezoidal beam (1) is provided with a first horizontal reserved channel (105) and is horizontally connected to the core tube (2) through a prestressed anchor cable (106). The bottom of the trapezoidal beam (1) is fixedly connected to the core tube (2) through a post-casting strip (104). The core tube (2) is provided with an anchor hole (206) and is connected to the first section of the tower tube using the anchor (201).

2. The inverted tapered prefabricated beam-slab fan foundation according to claim 1, characterized in that: The wing plate (102) is located at the bottom of the hypotenuse of the trapezoidal main beam (101) and is connected to the secondary beam (103) at the outer end; the wing plates of adjacent trapezoidal beams (1) are connected to each other by structural adhesive to form the bottom surface of the wind turbine foundation, and the secondary beams of adjacent trapezoidal beams (1) are connected to each other by structural adhesive to form a whole.

3. The inverted tapered prefabricated beam-slab fan foundation according to claim 1, characterized in that: A second post-casting strip steel bar (1042) is provided at the inner end of the wing plate (102); a first post-casting strip steel bar (1041) is provided at a position corresponding to the post-casting strip of the trapezoidal main beam (101); a third post-casting strip steel bar (1043) is provided at an outer side surface of the core tube corresponding to the position of the post-casting strip; the first post-casting strip steel bar (1041), the second post-casting strip steel bar (1042), and the third post-casting strip steel bar (1043) are all multi-layer U-shaped structures and are plugged together; the first post-casting strip steel bar (1041), the second post-casting strip steel bar (1042), and the third post-casting strip steel bar (1043) are respectively connected to the steel bars inside the trapezoidal main beam (101), the core tube (2), and the wing plate (102).

4. The inverted tapered prefabricated beam-slab fan foundation according to claim 1, characterized in that: The outer side surface of the core tube (2) is a polyhedron, and each side corresponds to a trapezoidal beam (1) with a wing plate.

5. The inverted tapered prefabricated beam-slab fan foundation according to claim 1, characterized in that: The core tube (2) is composed of multiple sections of tube bodies connected together, and each section of the tube body is provided with an anchor hole section that passes through from top to bottom to form an anchor hole. The bottom tube body end is pre-buried with an anchor mechanical connection joint (205) at the bottom end of the anchor hole. The top surface of the top tube body end is provided with an annular groove (204) for fixing and installing an anchor plate (202) and grouting to form an anchor plate support plane. The anchor rods (201) are used to fasten the sections of the tube body and the first section of the tower tube into a whole. A post-cast strip (104) is provided at the connection between the bottom tube body section and the wing plate. The top tube body section is provided with a second horizontal reserved channel (203) in the lower area of ​​the annular groove (204). The top tube body section is provided with a second horizontal reserved channel (203) corresponding to the first horizontal reserved channel (105) in the trapezoidal beam (1) in the lower area of ​​the annular groove (204) for the prestressed anchor cable (106) to pass through.

6. The inverted tapered prefabricated beam-slab fan foundation according to claim 1, characterized in that: The anchor rod passes through the anchor rod hole (206) of the core tube, and the bottom is anchored on the anchor rod mechanical connection joint (205) pre-buried in the bottom of the core tube. The upper part passes through the anchor plate (202) and is connected to the fan tower flange, and is fixed by applying prestress.

7. The inverted tapered prefabricated beam-slab fan foundation according to claim 1, characterized in that: The core tube is composed of multiple tube sections connected together, and each tube section is a prefabricated reinforced concrete part.

8. A construction method for an inverted tapered prefabricated beam-slab fan foundation, characterized by: For constructing the inverted tapered prefabricated beam-slab wind turbine foundation according to claim 1, the core tube is an integral section or is composed of multiple sections connected together, and the steps are as follows: Step 1: Excavate the foundation pit according to the design drawings, ensure that the foundation pit slope is consistent with the wing plate angle, perform surface hardening treatment on the soft soil foundation pit slope, and level the foundation pit bottom area; Step 2: After the excavation of the foundation pit and the pouring of the cushion layer, clean the surface of the cushion layer, start to locate the center of the wind turbine foundation circle, and stake out the foundation dimensions. Apply structural adhesive to the bottom of the core tube and then hoist it to the designated position. If the core tube is not segmented, install all anchor rods after hoisting. The anchor rods are anchored to the anchor rod mechanical connection joints at the bottom of the core tube through the anchor rod holes of the core tube. If the core tube is divided into multiple sections, first pre-install several anchor rods evenly at the bottom of the tube section through the anchor rod mechanical connection joints for vertical positioning, and then hoist each section of the tube in sequence. The contact surfaces between different sections of the tube need to be cleaned and coated with structural adhesive. After all sections of the tube are hoisted, install the remaining anchor rods. Step 3: Hoist the trapezoidal beams, mark the center lines of the main trapezoidal beams and the center lines of the corresponding mounting surfaces on the outer wall of the core tube, and position the trapezoidal beams according to the center lines; evenly apply structural adhesive on the contact surfaces between the core tube and the trapezoidal beams, as well as on the contact surfaces between adjacent trapezoidal beams, hoist the trapezoidal beams, and install prestressed anchor cables. Pre-tension the cables before the adhesive dries to ensure the structure fits together; Step 4: After the wind turbine foundation structure is spliced, cast the post-cast strip. When the strength of the post-cast strip reaches the required value, tension the prestressed anchor cable to the design value again. Step 5: Test the connection strength of the anchor rod and the anchor rod mechanical connection joint. If it meets the design requirements, grouting is performed in the annular groove; Step 6: Backfill the foundation pit. The backfill soil is filled between the trapezoidal main beams, using the wing plates as the bearing surface. The backfill height reaches the top of the trapezoidal main beam. Then, the entire wind turbine foundation area, except for the core tube, is backfilled with a gravel layer. For foundations with waterproofing requirements, geotextiles and geomembranes or waterproof membranes are also laid. Then, sand layers and graded gravel layers are laid in sequence. Step 7: Then, the first section of the tower is hoisted, and the first section of the tower and the core tube are connected as a whole using the anchor rods, and prestress is applied to the anchor rods to complete the installation of the wind turbine foundation and the first section of the tower.

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