Reconstruction structure and method for old wind power plant fan foundation

Abstract

The invention provides an old wind power plant fan foundation reconstruction structure and method, and relates to the technical field of new energy wind power generation, the old wind power plant fan foundation reconstruction structure comprises an existing fan foundation, a first section of tower drum is arranged in the center of the top surface of the existing fan foundation, a reinforcing member is arranged on the first section of tower drum, and a supporting column is radially arranged around the side surface of the reinforcing member; pile foundations are arranged at the ends, away from the reinforcing components, of the supporting columns. The bottom of the first tower drum is tightly matched with the original foundation, the top of the first tower drum is connected with the new tower drum, the first tower drum, the supporting columns and the existing fan foundation are cooperatively stressed to form a new bearing structure, the load of the original foundation can be reduced, and the overall stability of the fan structure is achieved; the bearing capacity is further improved by arranging the reinforcing components and the stiffening ribs, the stability is enhanced, the transformation effect and the operation reliability are comprehensively improved, and a new thought is provided for efficient, economical and safe transformation of the old wind power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy wind power generation, and in particular to a structure and method for rebuilding a wind turbine foundation in an old wind farm. Background Art

[0002] In the field of wind power generation, the renovation of wind turbine foundations at older wind farms has become a critical issue that needs to be addressed. Due to technical limitations, wind turbines in older wind farms suffer from numerous deficiencies. On the one hand, power generation efficiency is low, and aging equipment and foundations lead to frequent failures, increased safety risks, and high operation and maintenance costs. These factors also hinder the efficient utilization of clean energy and the transformation of the energy structure. On the other hand, land resources are scarce, and the construction or large-scale renovation of foundations can easily lead to wasteful use of resources, drastically increased costs, and land acquisition disputes. Therefore, the search for cost-effective, efficient, and minimally disruptive renovation solutions for existing foundations is of great significance.

[0003] Song Yixiang and others invented a method for increasing the capacity of existing wind turbine foundations (application number 202410558403.1). This method involves installing a new foundation ring, inner ring anchor bolts, and strain sensors on the existing wind turbine foundation's center pier, and reinforcing it with variable-section piles and anchor rods. While this method improves foundation performance and enables remote monitoring, it requires deep destruction of the existing foundation, making it difficult and time-consuming to construct. The densely packed steel reinforcement in the wind turbine foundation presents significant obstacles to deep-level work.

[0004] Wang Fei et al. proposed a "Renovation Method and Application for Existing Wind Turbine Foundations in Existing Wind Farms" (Application No. 202210352531.1). This method utilizes the existing structure to install two rings of inner and outer anchor bolts and pour concrete to form an expanded center pier. This method utilizes the existing structure to save land and reduce costs, avoid land acquisition disputes, and is easy to operate, making it applicable to a variety of tower structures. However, localized grooving and drilling of the existing foundation may affect overall stability in complex geological conditions or weak foundations, and the long-term performance of the new wind turbine under high loads and its response to complex operating conditions are not fully considered. Summary of the Invention

[0005] This invention aims to provide an innovative connection structure that effectively adapts the small-sized wind turbine foundations of older wind farms to the towers of larger megawatt wind turbines. Through careful design and optimization of the connection structure, while meeting the stringent foundation load-bearing capacity and stability requirements of larger megawatt wind turbines, it significantly reduces the difficulty and cost of retrofitting projects and minimizes any adverse impacts on normal wind farm operations, providing a practical, efficient, and cost-effective solution for upgrading older wind farms.

[0006] The present invention provides the following technical solutions to achieve the above objectives:

[0007] A reconstruction structure for a wind turbine foundation of an old wind farm comprises an existing wind turbine foundation, a first tower section is arranged at the center of the top surface of the existing wind turbine foundation, a reinforcement member is arranged on the first tower section, a flange is arranged on the top of the reinforcement member, support columns are arranged radially around the side of the reinforcement member, and a pile foundation is arranged at one end of the support column away from the reinforcement member;

[0008] Furthermore, the bottom size of the first tower section is set to match the size of the existing wind turbine foundation, and the top size of the first tower section is set larger than the bottom size;

[0009] The inner circumference of the reinforcing member is provided with a plurality of vertical stiffening ribs and annular stiffening ribs;

[0010] Furthermore, the support columns are provided in three numbers and are arranged around the reinforcement member at an angle of 120 degrees;

[0011] Furthermore, the pile foundation and the support column are connected via an articulated seat;

[0012] A method for rebuilding wind turbine foundations in an old wind farm comprises the following steps:

[0013] S1. Inspect and evaluate the existing wind turbine foundation to obtain information on concrete strength, steel bar distribution, foundation dimensional accuracy, settlement and deformation, and surrounding geological conditions;

[0014] S2. Based on the obtained test and evaluation results and the parameters of the rebuilt wind turbine, design the structure of the first tower section, reinforcement components, support columns, and pile foundations, and perform mechanical calculations.

[0015] S3. Dismantle the existing wind turbine structure and carry out pile foundation construction;

[0016] S4. Install the first tower section on the existing wind turbine foundation and hoist the support columns to connect them with the reinforcement members and pile foundation;

[0017] S5. Install the upper tower structure in sequence until the entire wind turbine structure is installed.

[0018] Beneficial effects

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention arranges the bottom of the first section of the tower to fit closely with the original foundation and the top to connect to the new tower, and cooperates with the support column and the existing wind turbine foundation to form a new load-bearing structure, which can reduce the original foundation load and achieve the overall stability of the wind turbine structure; by arranging reinforcing components and stiffening ribs, the bearing capacity is further improved, the stability is enhanced, and the transformation effect and operational reliability are comprehensively improved, providing a new idea for the efficient, economical and safe transformation of old wind farms. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 It is a schematic diagram of the reconstruction structure of the present invention;

[0023] Figure 3 It is a top view schematic diagram of the reconstruction structure of the present invention;

[0024] Figure 4 is a schematic diagram of a reinforcing member of the present invention;

[0025] Figure 5 It is a hinge schematic diagram of the present invention;

[0026] Figure numbers: 1-existing wind turbine foundation; 2-first section of the tower; 3-pile foundation; 4-hinge seat; 5-support column; 6-reinforcement member; 7-flange; 8-weld between the support column and the reinforcement member; 9-vertical stiffening rib; 10-circumferential stiffening rib; 11-anti-pullout spherical bearing for bridge. DETAILED DESCRIPTION

[0027] To facilitate understanding of the present invention, the present application will be described more comprehensively below with reference to the relevant drawings; the drawings show preferred embodiments of the present invention, but the present invention can be implemented in many different forms and is not limited to the embodiments described herein; on the contrary, the purpose of providing these embodiments is to enable a more thorough and comprehensive understanding of the disclosed content of the present invention.

[0028] It should be noted that the terms “vertical”, “horizontal”, “up”, “down”, “left”, “right” and similar expressions used in this document are for illustrative purposes only and do not represent the only implementation method.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains; the terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0030] Example. A reconstruction structure of an old wind farm wind turbine foundation, the structure is as follows Figure 1 , comprising an existing wind turbine foundation 1, a first tower section 2 is provided at the center of the top surface of the existing wind turbine foundation 1, a reinforcement member 6 is provided on the first tower section 2, a flange 7 is provided on the top of the reinforcement member 6, support columns 5 are radially provided on the side surrounding the reinforcement member 6, and a pile foundation 3 is provided at one end of the support column 5 away from the reinforcement member 6; and it is connected to the superstructure of the newly built wind turbine through the flange 7;

[0031] The bottom size of the first tower section 2 is set to match the size of the existing wind turbine foundation 1, and the top size of the first tower section 2 is set to be larger than the bottom size. By matching the bottom size of the first tower section 2 with the size of the existing wind turbine foundation 1, it is convenient to firmly connect with the existing wind turbine foundation 1, reducing the need to modify the original foundation structure. The top size of the first tower section 2 is set to correspond to the tower size of the newly built wind turbine to meet the load transfer requirements of the newly built wind turbine.

[0032] The inner circumference of the reinforcing member 6 is provided with a plurality of vertical reinforcing ribs 9 and annular reinforcing ribs 10; by providing the vertical reinforcing ribs 9 and annular reinforcing ribs 10, the bearing capacity and structural rigidity of the reinforcing member 6 are improved to ensure the stability of the overall structure;

[0033] The three support columns 5 are arranged at an angle of 120° around the reinforcement member 6. By arranging the three support columns 5 at an even interval of 120° around the first tower section 2, the gravity of the newly built wind turbine structure on the upper part is shared, and the wind load during the operation of the new wind turbine is also shared, thereby improving the stability of the overall structure.

[0034] The pile foundation 3 and the support column 5 are connected via an articulated seat 4; the reinforcing member 6 and the support column 5 are connected by welding; the articulated seat 4 is a spherical support 11 for bridges; by connecting the pile foundation 3 and the support column 5 with the articulated seat 4, the bending moment generated at the connection can be released, thereby avoiding rigid damage at the connection;

[0035] The first tower section 2, the reinforcement member 6 and the support column 5 are made of high-quality alloy steel with high strength and corrosion resistance;

[0036] A method for rebuilding wind turbine foundations in an old wind farm, characterized by comprising the following steps:

[0037] S1. Inspect and evaluate the existing wind turbine foundation 1 to obtain information on concrete strength, steel bar distribution, foundation dimensional accuracy, settlement and deformation, and surrounding geological conditions;

[0038] Comprehensive and detailed inspection and evaluation of existing wind turbine foundations at older wind farms1 included precise measurement of various parameters, including concrete strength, reinforcement distribution, foundation dimensional accuracy, settlement and deformation, and surrounding geological conditions. Based on these inspection results, a precise mechanical model of the foundation was constructed, providing a detailed and reliable data foundation for the subsequent optimization of the connecting structure.

[0039] S2. Based on the obtained test and evaluation results and in combination with the parameters of the rebuilt wind turbine, design the structure of the first tower section 2, reinforcement member 6, support column 5, and pile foundation 3, and perform mechanical calculations;

[0040] Based on the detailed technical parameters of the rebuilt wind turbine, such as wind turbine weight, hub height, rotor diameter, rated power, and other key indicators, combined with the test data of the existing wind turbine foundation 1, professional mechanical analysis software (such as ANSYS, ABAQUS, etc.) is used to conduct in-depth and systematic design calculations for the customized first tower section 2 and support columns 5. The material specifications of the first tower section 2, the dimensions and shapes of the bottom and top (especially the detailed structure of the top reinforcement), the layout of the vertical stiffeners 9 and circumferential stiffeners 10, as well as the diameter, wall thickness, length of the support columns 5 and the type, depth, and diameter of the pile foundation 3 are determined to ensure that the entire connection structure meets all the requirements of wind turbine operation in terms of theoretical design.

[0041] S3. Dismantle the existing wind turbine structure and construct the pile foundation 3; thoroughly clean and fine-tune the surface of the existing wind turbine foundation 1, completely remove debris, dust, and any damaged parts on the surface, and ensure that the foundation surface is flat and clean and meets the installation requirements;

[0042] During the construction of pile foundation 3, a rotary drilling rig or other equipment is used to dig a concrete pile hole, lower the steel skeleton and pour concrete, and place the hinge seat 4 before the pile foundation concrete begins to set;

[0043] S4. Install the first tower section 2 on the existing wind turbine foundation 1, and hoist the support column 5 to connect it with the reinforcement member 6 and the pile foundation 3;

[0044] The first tower section 2 is hoisted steadily and slowly lowered above the foundation. A high-precision positioning device is used to ensure that the bottom of the first tower section 2 is accurately aligned with the connection interface of the existing wind turbine foundation 1, with deviations controlled within a very small range. High-strength bolts are used to tightly connect the first tower section 2 to the existing wind turbine foundation 1 according to the specified torque value, and sealant is injected into the connection to form a reliable sealing layer, effectively preventing moisture, dust and impurities from invading the connection, ensuring the long-term stability and durability of the connection.

[0045] After the pile foundation reaches the designed strength, the three support columns 5 are hoisted in sequence, and one end of the support column 5 is precisely connected to the corresponding connection part on the reinforcement member 6 of the first section of the tower 2, and the welding is carried out using a full penetration welding process. During the welding process, professional welders strictly follow the welding process regulations to control parameters such as welding current, voltage, and welding speed to ensure that the weld quality meets the relevant standard requirements, and the weld appearance is smooth and free of defects such as undercuts, pores, and cracks. After welding is completed, the weld is inspected using advanced non-destructive testing equipment (such as ultrasonic flaw detectors, radiographic flaw detectors, etc.) to ensure reliable welding quality. Then, the other end of the support column 5 is connected to the articulated seat 4 and ensures that the connection is tight, ensuring the safe and stable operation of the entire connection structure system.

[0046] After the installation of the entire remodeled structure is completed, professional personnel will be organized to conduct a comprehensive and in-depth quality inspection and strict acceptance. The inspection content includes but is not limited to the firmness of each connection part, the overall stability of the structure, the verticality of the tower, and the performance of the shock-absorbing buffer device. After the wind turbine is installed, professional monitoring equipment will be used to monitor the key parameters such as the stress, vibration, deformation, etc. of the connection structure during the operation of the wind turbine in real time during operation, and the monitoring data will be recorded in detail. Based on the monitoring results, the connection structure will be further optimized and adjusted to ensure that it always maintains a good performance state during long-term operation, meets the safe and stable operation requirements of large-megawatt wind turbines, and provides a solid guarantee for the efficient upgrade and sustainable operation of old wind farms;

[0047] S5. Install the upper tower structure in sequence until the entire wind turbine structure is installed.

[0048] The design principle of the support column 5 of the present invention is as follows: When accurately analyzing the joint stress conditions of the three support columns 5 and the original foundation, the consideration of the influence of bending moment is particularly critical, which is related to the safety and stability of the entire connection structure under complex working conditions.

[0049] Assume that the total vertical downward load generated by the large megawatt wind turbine during operation is F total (including wind turbine deadweight, vertical component of wind load, etc.), the total horizontal load is F h (mainly due to the horizontal action of wind load), the height of wind load is H (the distance from the top of the foundation to the center of the wind turbine rotor).

[0050] The original foundation bearing capacity was confirmed to be P after preliminary testing and evaluation. base , whose area is A base , the maximum pressure that can be tolerated is P max-base , so the actual vertical load F base-vert Must meet F base-vert ≤P max-base ×A base , thereby ensuring the vertical stability of the foundation and preventing excessive pressure from causing structural damage or uneven settlement.

[0051] For the three support columns 5, the maximum axial force that each column can withstand is set to F max-pipe According to the principle of material mechanics, it is related to the cross-sectional area A of the steel pipe. pipe , material yield strength σ yirld It is closely related to the safety factor n, that is, F max-pipe =σ yirld ×A pipe / n, which is the core calculation basis for the axial bearing capacity of the steel pipe support, ensuring that it can safely bear the load under extreme working conditions.

[0052] Horizontally, the three support columns 5 work together with the original foundation to resist the horizontal load F h Given that they are evenly distributed around the original wind turbine foundation, similar to the synergistic mechanism of the bridge pile structure, assuming that the angle between the steel pipe support and the horizontal direction is θ, each steel pipe support has a horizontal resistance F h-pipe F max-pipe =F h / (3cosθ). This distribution method is based on the principle of force balance and structural symmetry, ensuring that the horizontal load is evenly distributed to each supporting component and foundation, avoiding local overload that may cause structural instability.

[0053] Vertical direction, total vertical load F total The load is borne by the original foundation and the three support columns 5. Assume that the vertical load borne by the three support columns 5 is F pipe-vert , then the original foundation bears F base-vert =F total -F pipe-vert .

[0054] Considering the bending moment, the bending moment caused by wind load is M=F h ×H. This bending moment is resisted by the original foundation and three supporting columns 5, forming a balanced structure similar to a spatial force system. The original foundation's ability to resist bending moment is set to M base , according to the mechanical characteristics of the foundation structure, it is related to the foundation section inertia moment I base , material elastic modulus E base And basic length L base It is accurately calculated through specific formulas to provide quantitative indicators for evaluating the bending performance of the foundation.

[0055] The axial force F generated by the bending moment on each of the three support columns 5 is m-pipe According to the formula Calculate d pipe I is the distance from the steel pipe support to the center axis of the foundation, pipe is the moment of inertia of the cross section of a single steel tube support. This formula, based on the bending theory of material mechanics, accurately quantifies the force contribution of the steel tube support under bending moment, ensuring that each support reasonably shares the bending moment and collaboratively maintains structural balance.

[0056] According to the structural mechanics deformation coordination principle, the vertical deformation of the steel pipe support and the original foundation must be coordinated, that is, Δ base =Δ pipe For the original foundation, its vertical deformation is based on the foundation elastic modulus E base , height h base The vertical load and bending moment effects are accurately calculated with the help of complex structural mechanics deformation formulas, taking into account the coupling effect of foundation compression and bending deformation. The vertical deformation of the steel pipe support is based on the elastic modulus E of the material. base , length L base, vertical and bending moment axial forces, and accurately solve them using the combined deformation formula of tension, compression and bending in material mechanics, fully reflecting its deformation characteristics under complex forces.

[0057] By combining the above series of equations and applying professional numerical calculation methods and software tools, we can accurately solve the load-bearing and deformation parameters of each component under different working conditions, provide solid theoretical support for the design of connection structures, ensure accuracy and science in all links from material selection and size determination to process formulation, and guarantee stable and efficient operation of the wind turbine throughout its life cycle.

[0058] Obviously, the above is only a partial embodiment of the present invention, not all embodiments. The above embodiments are not intended to limit the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any combination, modification, equivalent replacement, improvement, and other embodiments that can be made by those of ordinary skill in the art within the spirit and principles of the present invention shall be within the scope of protection of the present invention.

Claims

1. A wind turbine foundation reconstruction structure for an old wind farm, characterized by: The invention comprises an existing wind turbine foundation (1), a first tower section (2) is arranged at the center of the top surface of the existing wind turbine foundation (1), a reinforcing member (6) is arranged on the first tower section (2), a flange (7) is arranged on the top of the reinforcing member (6), a support column (5) is radially arranged around the side of the reinforcing member (6), and a pile foundation (3) is arranged at one end of the support column (5) away from the reinforcing member (6).

2. The old wind farm wind turbine foundation reconstruction structure according to claim 1 is characterized by: The bottom size of the first tower section (2) is set to match and correspond to the size of the existing wind turbine foundation (1), and the top size of the first tower section (2) is set to be larger than the bottom size.

3. The old wind farm wind turbine foundation reconstruction structure according to claim 1 is characterized by: A plurality of vertical stiffening ribs (9) and annular stiffening ribs (10) are arranged in the inner circumferential direction of the reinforcing member (6).

4. The old wind farm wind turbine foundation reconstruction structure according to claim 1 is characterized by: The support columns (5) are provided in three numbers and are arranged around the reinforcing member (6) at an angle of 120°.

5. The old wind farm wind turbine foundation reconstruction structure according to claim 1 is characterized by: The pile foundation (3) and the support column (5) are connected via a hinged seat (4).

6. The method for rebuilding wind turbine foundations in an old wind farm according to claim 1, characterized in that: The following steps are involved: S1. Conduct inspection and evaluation of the existing wind turbine foundation (1) to obtain information on concrete strength, steel bar distribution, foundation dimensional accuracy, settlement and deformation, and surrounding geological conditions; S2. Based on the obtained test and evaluation results and in combination with the parameters of the rebuilt wind turbine, the structure of the first tower section (2), the reinforcement member (6), the support column (5) and the pile foundation (3) is designed, and mechanical calculations are performed; S3, dismantling the existing wind turbine structure and carrying out the construction of pile foundation (3); S4, installing the first tower section (2) on the existing wind turbine foundation (1), and hoisting the support column (5) to connect it with the reinforcement member (6) and the pile foundation (3); S5. Install the upper tower structure in sequence until the entire wind turbine structure is installed.

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