A method for composite reinforcement of a bonding adhesive failure at a tower connection of a wind turbine tower

Abstract

The application discloses a kind of mixed tower wind turbine tower drum connecting place bonding glue failure composite reinforcement methods, belong to wind power structure repair technical field, first determine reinforcement scheme, then the pretreatment of failure area, further inject structural glue in the upper and lower concrete tower drum connecting place failure glue joint, restore interface bonding performance;Outer constraint layer is wrapped by prestressed carbon fiber cloth, and the shear resistance and fatigue resistance are improved;Synchronous paste fiber Bragg grating sensor, real-time monitoring prestressed force and reinforcement effect;Then spray polyurea elastomer protective layer, further prevent carbon fiber cloth from falling off;Mechanical reinforcement layer installation adjustable split steel hoop and apply radial pre-tightening force are carried out in outermost layer.This application can improve the strength and fatigue life of the upper and lower concrete tower drum connecting place, reduce the operation and maintenance cost, and is especially suitable for mixed tower repair in high humidity and high salt fog environment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of wind turbine tower structure reinforcement, and particularly relates to a composite reinforcement method for bonding glue failure at the connection of a mixed tower wind turbine tower. BACKGROUND

[0002] A mixed tower wind turbine is a structure that combines a concrete tower with a steel tower or a tower of other materials. This structure takes full advantage of the good compressive performance, relatively low cost of concrete materials, and good tensile performance, easy processing of steel materials, and can adapt to different wind resource conditions and site requirements, and has been widely used in modern wind power field. For example, in some low wind speed areas, the use of concrete tower can increase the height of the tower, improve the wind power capacity of the wind turbine, and thus improve the power generation efficiency. In the mixed tower wind turbine, the connection between the upper and lower concrete towers is usually connected by bonding glue. The bonding glue plays a crucial role in firmly bonding different parts of the tower together, transferring loads, and ensuring the integrity and stability of the structure. Through the action of the bonding glue, the sections of the concrete tower can effectively work together to withstand wind loads, self-weight of the unit and other external forces. However, in actual operation, due to various factors, the bonding glue at the connection may fail. For example, long-term exposure to complex environmental conditions such as high temperature, high humidity, strong ultraviolet radiation, etc. can accelerate the aging of the bonding glue; the frequent vibration of the wind turbine can also cause fatigue of the bonding glue, causing its bonding performance to gradually decrease; in addition, improper quality control during construction, such as unclean bonding surface treatment, uneven glue layer thickness, etc. may also cause the bonding glue to fail prematurely during use. Bonding glue failure can seriously endanger the safe operation of the wind turbine. It can cause cracks at the tower connection, reduce the overall stiffness of the tower, produce greater deformation and vibration under wind load, and thus affect the normal power generation of the unit, and even cause serious safety accidents such as tower collapse, causing huge economic losses and casualties. For the problem of bonding glue failure, there are currently some traditional reinforcement methods, such as using external wrapping steel plates, increasing bolt connections, etc. However, these methods often have some limitations. For example, external wrapping steel plates require a large construction space, and the welding process may have a thermal effect on the tower structure; increasing bolt connections may damage the original structure of the concrete tower, and the tightening force of the bolts is difficult to control uniformly, which can easily cause local stress concentration. Therefore, a more effective reinforcement method is needed to solve the problem of bonding glue failure at the connection of the mixed tower wind turbine concrete tower, to improve the safety and reliability of the wind turbine. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a composite reinforcement method for the bonding glue failure at the connection of the tower drum of a hybrid tower wind turbine in view of the above-mentioned existing problems.

[0004] To achieve the above technical purposes, the technical solution adopted by the present application is:

[0005] A composite reinforcement method for the bonding glue failure at the connection of the tower drum of a hybrid tower wind turbine, comprising the following steps:

[0006] Step 1: Determine the severity of the defect at the connection of the upper and lower concrete tower drums of the hybrid tower wind turbine according to the length, width and depth of the bonding glue failure at the connection, and determine the prestressed carbon fiber cloth reinforcement scheme according to the severity of the defect;

[0007] Step 2: Position the deglued area using an ultrasonic flaw detector, remove the failed glue and polish the substrate surface to form a reinforcement area;

[0008] Step 3: Open a U-shaped groove along the bonding joint, high-pressure inject modified epoxy resin glue containing carbon fiber short cut and nano-silica toughening agent, and form an embedded repair layer in the reinforcement area after heat curing;

[0009] Step 4: Brush epoxy resin glue on the outside of the embedded repair layer, then alternately lay horizontal carbon fiber cloth and vertical prestressed carbon fiber cloth on the outside of the embedded repair layer, install prestressed anchors on the surface of the tower drum concrete, tension the prestressed carbon fiber cloth with the prestressed anchors, and bond the carbon fiber cloth using vacuum-assisted resin infusion process to form a composite constraint layer;

[0010] Step 5: Pre-bury an optical fiber grating sensor in the composite constraint layer, connect the optical fiber grating sensor with an intelligent monitoring module, coat a polyurea elastomer protective layer on the surface of the outermost prestressed carbon fiber cloth and the surface of the prestressed anchor, and the intelligent monitoring module assesses the reinforcement effect and the prestressed state of the prestressed carbon fiber cloth according to the real-time monitoring of the deformation of the carbon fiber cloth by the optical fiber grating sensor.

[0011] Step 6: Install a split ring steel hoop on the outside of the connection of the upper and lower concrete tower drums, and apply radial pre-tightening force to the split ring steel hoop to make the split ring steel hoop tightly hold the composite constraint layer.

[0012] To optimize the above technical solution, the specific measures adopted include:

[0013] In step 1, the prestressed carbon fiber cloth reinforcing scheme is as follows: two layers of carbon fiber cloth are arranged transversely to cover the damaged part for reinforcing the bonding glue failure part at the connection between the upper and lower concrete tower cylinders, and a plurality of prestressed carbon fiber cloths are arranged vertically to reinforce the damaged part, and the carbon fiber cloth arrangement mode is: two layers of transversely arranged carbon fiber cloth and vertically arranged prestressed carbon fiber cloth are arranged alternately from inside to outside.

[0014] The thickness of the single layer of carbon fiber cloth is 0.2-0.3mm, the tensile strength is ≥4000MPa, the transversely arranged carbon fiber cloth is not prestressed, the vertically arranged carbon fiber cloth is prestressed, the length of the carbon fiber cloth is determined by the prestressed carbon fiber cloth reinforcing scheme: the first layer of transversely arranged carbon fiber cloth is arranged from inside to outside: the carbon fiber cloth is pasted along the direction of the concrete tower cylinder joint, the width of the carbon fiber cloth exceeds the width of the joint by 150mm on both sides, and the length of the carbon fiber cloth is adapted to the length of the bonding glue failure at the tower cylinder joint; the second layer of vertically arranged prestressed carbon fiber cloth: the vertically arranged prestressed carbon fiber cloth is pasted on the first layer of transversely arranged carbon fiber cloth in a plurality of densely arranged ways, the vertically arranged prestressed carbon fiber cloth has a spacing of 200mm, the number of the vertically arranged prestressed carbon fiber cloth is determined according to the length of the bonding glue failure, and the length of the vertically arranged prestressed carbon fiber cloth exceeds the width of the concrete tower cylinder joint by 330mm on both sides; the third layer of transversely arranged carbon fiber cloth: the same as the first layer of transversely arranged carbon fiber cloth, the reinforcing mode is a transversely arranged overall cladding mode, and the cladding height is the same as that of the first layer of transversely arranged carbon fiber cloth.

[0015] In step 3, the tensile strength of the modified epoxy resin glue is ≥60MPa, the elongation rate is ≥8%, and the addition amount of nano silicon dioxide is 3%-5% of the total mass of the glue; the depth of the U-shaped groove is 10-20mm, and the width is 15-25mm.

[0016] The heat curing condition of step 3 is: the temperature is increased in steps to 60-80℃, the holding time is ≥4 hours, and the heating rate is ≤5℃ / min.

[0017] In step 4, the prestressed anchor is a wedge-shaped anchor with an anchor ring and a wedge-shaped clamping piece, the wall thickness of the anchor ring is ≥10mm, the clamping force is ≥50kN, the slip amount is ≤0.05mm, the length of the wedge-shaped anchor is 20mm longer than the length of the carbon fiber cloth, the width is 40mm, and the wedge angle is 12°.

[0018] In step 4, in the vacuum-assisted resin infusion process, the resin curing temperature is 60-80℃, the vacuum degree is ≤-0.09MPa, and the fiber volume content is ≥60%.

[0019] In step 5, the fiber Bragg grating sensor is arranged at the middle part of the bottom layer of transversely arranged carbon fiber cloth, the length is 100mm, and the upper and lower tower cylinder joints are taken as the center, and the length on both sides is 50mm.

[0020] In step 6, the material of the split annular steel ring is Q345D steel, the radial pre-tightening force design value is 150-250 kN / m, and the number of split rings of the steel ring is 2.

[0021] The inner surface of the split annular steel ring is provided with a rubber buffer layer, and the rubber hardness is 60-80 Shore A.

[0022] Compared with the prior art, the beneficial effects of the present application are as follows:

[0023] Compared with the carbon fiber cloth reinforced concrete structure flat surface technology, the present application breaks through the single technical bottleneck of traditional reinforcement methods in detection, materials, process, monitoring and other links. First, the bonding scheme is determined according to the severity of the bonding glue failure at the connection between the upper and lower concrete tower drums, then the bonding glue and base surface are pretreated, and the tower drum connection joint is processed into a U-shaped mouth shape to improve the bonding of the epoxy resin glue and the concrete at the crack; the carbon fiber cloth is pasted by orthogonal pasting, and the vertical carbon fiber cloth is prestressed to improve the reinforcement effect of the carbon fiber cloth; the optical fiber grating sensor is pasted at the same time as the first layer of horizontal carbon fiber cloth is pasted, and the prestress application and reinforcement effect are monitored in real time; the outer layer is sprayed with a polyurea elastomer protective layer to further prevent the carbon fiber cloth from falling off, and the outermost side is installed with a split annular steel ring, and the radial pre-tightening force is applied through a hydraulic tensioning device to further improve the defect reinforcement effect. Another aspect of the application realizes the application of the prestress of the large curved surface carbon fiber cloth through the wedge-shaped anchor plate and the anchor ring, thereby improving the reinforcement effect of the carbon fiber cloth. The application of the prestress of the carbon fiber cloth and the anchoring fundamentally ensure the reinforcement effect of the carbon fiber cloth reinforcement of the bonding glue failure at the connection between the concrete tower drums of the wind turbine tower. The safety, reliability and service life of the connection between the concrete tower drums of the wind turbine generator are significantly improved, and the present application has significant engineering application value and economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of the bonding glue failure composite reinforcement method of the tower drum connection of the wind turbine generator of the present application;

[0025] Figure 2 It is a schematic diagram of the bonding glue failure at the tower drum connection;

[0026] Figure 3 It is a schematic diagram of the carbon fiber cloth pasting scheme;

[0027] Figure 4 It is a schematic diagram of the slot expansion treatment of the concrete tower drum connection;

[0028] Figure 5 It is a schematic diagram of the optical fiber grating sensor pasted in the middle region of the carbon fiber cloth with epoxy resin glue;

[0029] Figure 6 It is a vertical carbon fiber cloth prestress anchor arrangement diagram;

[0030] Figure 7 Schematic diagram of fixed wedge anchor for prestressing;

[0031] Figure 8 Sectional view of reinforcing area for tower drum connection;

[0032] Figure 9 Schematic diagram of split ring;

[0033] Figure 10 Schematic diagram of split ring installation. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and explained below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0035] Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those of ordinary skill in the art, the present application can be applied to other similar scenarios without creative labor on the basis of these drawings. In addition, it can be understood that although the efforts made in this development process can be complex and lengthy, for those of ordinary skill in the art related to the content disclosed in the present application, some design, manufacture or production changes on the basis of the technical content disclosed in the present application are only routine technical means, and should not be understood as insufficient disclosure of the present application.

[0036] In the present application, "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment that is not mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in the present application can be combined with other embodiments without conflict.

[0037] Unless otherwise defined, technical terms and scientific terms used in the present application shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terms "a", "an", "one", "this", and similar referents in the context of describing the application are to be construed to be inclusive, both singular and plural, unless otherwise indicated. The terms "comprising", "comprises" and "comprised of" as well as conjugations thereof, are used herein to mean that the process, method, system, product or apparatus that includes, but is not limited to, as elements the listed steps or units, and further include any additional step or unit that is inherent in such process, method, product or apparatus. The term "connected" and / or "coupled" to as used herein, is defined as connected, whether directly or indirectly through intervening components, unless otherwise indicated. The term "plurality" refers to two or more. The term "and / or" describes associated objects in association with the associated objects, which means that there are three relationships, for example, "A and / or B" can mean that A exists alone, A and B exist together, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects. The terms "first", "second", "third", and the like, merely distinguish similar objects, and do not represent a specific order.

[0038] The embodiment of the application provides a kind of tower wind turbine tower section connection bonding glue failure composite reinforcement method, as shown in Figure Figure 1 The repair method includes determining reinforcement scheme according to bonding glue failure severity, surface pretreatment, embedded repair layer construction, external constraint layer construction, burying fiber grating sensor, mechanical reinforcement layer installation, reinforcement quality detection and the like.

[0039] The reinforcement method includes the following steps:

[0040] Step 1: determine the bonding glue failure reinforcement scheme of the tower connection

[0041] According to the bonding glue failure length, width and depth of the upper concrete tower and the lower concrete tower connection of the tower wind turbine, the severity of the defect of the concrete tower connection is determined, and the corresponding prestressed carbon fiber cloth reinforcement scheme is selected according to the severity of the defect;

[0042] Step 2: failure area diagnosis and pretreatment

[0043] The degumming area is located using an ultrasonic flaw detector, the failed glue is removed, and the substrate surface is polished to a roughness Ra≥50 μm to form a reinforcement area;

[0044] Step 3: embedded repair layer construction

[0045] U-shaped grooves are formed along the bonding seam, modified epoxy resin glue containing carbon fiber short cut and nano-silica toughening agent is injected at high pressure, and an inlaid repair layer is formed through thermal curing;

[0046] Step 4: External constraint layer construction

[0047] Lay the horizontal carbon fiber cloth and vertical prestressed carbon fiber cloth alternately on the outer wall of the tower drum, brush epoxy resin glue on the area where the carbon fiber cloth is pasted, install prestressed anchors on the surface of the tower drum concrete according to the prestressed carbon fiber cloth reinforcement scheme, and use the vacuum-assisted resin infusion process to form the composite constraint layer;

[0048] Step 5: Deployment of monitoring system

[0049] Embed the fiber grating sensor in the reinforcement layer, connect the fiber grating sensor with the intelligent monitoring module, coat the polyurea elastomer protective layer on the surface of the prestressed carbon fiber cloth and the prestressed anchor, and the intelligent monitoring module monitors the deformation of the prestressed carbon fiber cloth in real time according to the fiber grating sensor, so as to evaluate the reinforcement effect and the prestressed state of the prestressed carbon fiber cloth.

[0050] Step 6: Installation of mechanical reinforcement layer

[0051] Install the split ring steel hoop on the outside of the upper and lower concrete tower drum connecting flanges, apply radial pretensioning force through the hydraulic tensioning device, and calibrate the bolt torque to the design value.

[0052] The embodiments of the present application are further described in detail below with reference to the accompanying drawings.

[0053] First, determine the area and range that need to be reinforced according to the bonding glue detection results at the connection of the upper and lower concrete tower drums, then determine the carbon fiber cloth pasting scheme according to the length of the bonding glue failure, as shown in Figure 2 , the pasting scheme is as shown in Figure 3 , specifically, the horizontally laid carbon fiber cloth is not prestressed, the vertically laid carbon fiber cloth is prestressed, and the length of the carbon fiber cloth is determined by the prestressed carbon fiber cloth reinforcement scheme: ① the first layer of horizontally laid carbon fiber cloth: paste the carbon fiber cloth along the direction of the concrete tower drum connecting seam, the width of the carbon fiber cloth exceeds 150mm on both sides of the connecting seam, and the length of the carbon fiber cloth is adapted to the length of the bonding glue failure at the tower drum connection. ② The second layer of vertically laid prestressed carbon fiber cloth: paste the vertically laid prestressed carbon fiber cloth on the first layer of horizontally laid fiber cloth in a densely packed manner, the vertically laid prestressed carbon fiber cloth has a spacing of 200mm, the number of vertically laid prestressed carbon fiber cloth is determined according to the length of the bonding glue failure, and the length of the vertically laid prestressed carbon fiber cloth exceeds 330mm on both sides of the concrete tower drum connecting seam. ③ The third layer of horizontally laid carbon fiber cloth: same as the first layer of horizontally laid carbon fiber cloth, using the reinforcement method of horizontal overall wrapping, the wrapping height is the same as that of the first layer of horizontally laid carbon fiber cloth.

[0054] Take the tower drum joint as the center, and use a small cutting machine to expand the crack on both sides to form a U-shaped opening as shown in Figure 4 The concrete surface within a certain range on both sides of the concrete tower drum joint is cleaned to remove dust, oil stains, loose concrete and other impurities on the surface, and then the concrete base surface is polished along the joint on both sides to expose the fresh aggregate, making it flat and rough, to enhance the bonding force between the carbon fiber cloth and the concrete. Finally, the surface is cleaned with a high-pressure water gun and dried completely.

[0055] The fiber Bragg grating sensor is pasted in the middle area of the carbon fiber cloth. As shown in Figure 5 The fiber Bragg grating sensor is arranged in the middle part of the bottom layer of prestressed carbon fiber cloth with a length of 100mm, taking the vertical crack as the center, and 50mm on both sides.

[0056] Before pasting, the carbon fiber cloth is first pretreated and the appropriate impregnating agent is applied on its surface. The fiber Bragg grating sensor is arranged in the middle of the carbon fiber cloth and is firmly pasted with nano-level modified epoxy resin glue. The impregnating glue for the carbon fiber cloth and the fiber Bragg grating sensor is modified epoxy resin glue with a viscosity of 2500-3000mPa·s, a shear strength after curing not less than 15MPa, a bonding strength loss rate not more than 5% in-40 degree environment, and a epoxy resin glue layer thickness of 2.0-2.5mm.

[0057] A prestressed fixed wedge-shaped anchor is installed on the surface of the tower drum, as shown in Figure 6 The wedge-shaped anchor is a steel structure, which is divided into an anchor ring and a wedge-shaped clamping piece. The wall thickness of the anchor ring is ≥10mm, the clamping force is ≥50kN, and the slip amount is ≤0.05mm. After 2 million cycle load tests, the wedge-shaped anchor has no cracks and no slip, as shown in Figure 7 The length of the wedge-shaped clamping piece is the width of the carbon fiber cloth + 20mm, the width is 40mm, and the wedge angle is 12°. For the scheme of pasting multiple layers of prestressed carbon fiber cloth, there is one group of anchors per layer. The bottom layer is on the outermost side of the crack, and the top layer is in the innermost part. Before pasting the anchor, the concrete surface is polished and cleaned, and the pasting glue is nano-level modified epoxy resin glue with a viscosity of 3000-3500mPa·s and a shear strength not less than 20Mpa. The glue layer thickness is 2.0-2.5mm, and the bonding strength loss rate is not more than 5% in-40 degree environment.

[0058] The surface is brushed with a clean small brush to remove the dust again. The bonding glue failure area is repaired by pressure grouting method with a grouting pressure of 0.3-0.6MPa. The repair slurry is epoxy resin glue to ensure that the crack gap and the wedge gap are filled, and then the epoxy resin glue is brushed on the carbon fiber cloth pasting area with a brush. The shear strength of the epoxy resin glue after curing is not less than 15MPa, and the adhesive curing time at 20℃ is less than or equal to 4 hours.

[0059] The pasting area is brushed with epoxy resin glue, and then another clean brush is filled with epoxy resin glue to brush the pasting surface, with a thickness of 2.0-2.5mm for the bottom glue layer and 1.5-2.0mm for the middle layer.

[0060] The vertical prestressed carbon fiber cloth is tensioned by using a tensioning device, and a prestress of 5%-10% of the ultimate tensile strength is slowly applied by the tensioning device. When the preset value is reached, the tensioning is stopped, the nanoscale modified epoxy resin glue is injected at the gap, the carbon fiber cloth is pasted on the surface of the tower drum, and then anchoring is performed.

[0061] The first layer of transverse carbon fiber cloth is pasted.

[0062] Then the second layer of vertical prestressed carbon fiber cloth is tensioned, pasted, and anchored.

[0063] The third layer of transverse carbon fiber cloth is further pasted.

[0064] The bonding quality of the carbon fiber cloth and the concrete is detected by using an ultrasonic detector, and the bubble area should not exceed 1% of the pasting area; at the same time, the prestress loss of the prestressed carbon fiber cloth after pasting for 4 hours should not exceed 5%.

[0065] A polyurea elastomer protective layer is coated on the surface of the carbon fiber cloth and the prestressed wedge-shaped anchor, the thickness of the polyurea elastomer protective coating is 1.5-2.0mm, the weather resistance grade is not less than ASTM G154 standard, the tensile strength is ≥25MPa, the elongation is ≥400%, the tear strength is ≥50MPa, there is no peeling and cracking when bending at -40 degrees, the surface drying time is less than 120s, the water absorption rate is ≤5%, as shown in Figure 8 .

[0066] After the above steps are completed, the mechanical reinforcement layer is installed, and the split ring steel hoop as shown in Figure 9 is installed to the repair area. The material of the split ring steel hoop is Q345D steel, the radial pre-tightening force design value is 150-250kN / m, the number of split rings of the steel hoop is 2, an independent hydraulic tensioning device is provided, the inner surface of the split ring steel hoop is provided with a rubber buffer layer, the rubber hardness is 60-80Shore A, and the installation of the split ring steel hoop is as shown in Figure 10 .

[0067] The fiber grating sensor is connected with the intelligent monitoring module, the intelligent monitoring module monitors the deformation of the prestressed carbon fiber cloth in real time according to the fiber grating sensor, so as to evaluate the reinforcement effect and the prestressed state of the prestressed carbon fiber cloth. The intelligent monitoring module deeply analyzes and calculates the data transmitted by the fiber grating sensor. The actual stress value borne by the carbon fiber cloth is accurately calculated, and then compared with the initial set prestress value, the deviation degree of the prestressed state of the prestressed carbon fiber cloth is clearly presented. Through the above method, the fiber grating sensor can realize the fine evaluation of the whole life cycle of the carbon fiber cloth repairing concrete effect, and provide the safety guarantee of "from details to whole" for the wind power tower.

[0068] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application shall be equivalent replacement methods, and shall be included in the protection scope of the present application.

Claims

1. A method for composite reinforcement of the joint adhesive failure at the tower connection of a hybrid tower wind turbine, characterized in that, The method comprises the following steps: Step 1: According to the length, width and depth of the bonding glue failure of the upper concrete tower and the lower concrete tower of the mixing tower wind turbine, the severity of the defect of the concrete tower connection is determined, and the prestressed carbon fiber cloth reinforcing reinforcement scheme is determined according to the severity of the defect; Step 2: Use an ultrasonic flaw detector to locate the degummed area, remove the failed glue and polish the substrate surface to form a reinforcing and reinforcing area; Step 3: A U-shaped groove is opened along the bonding joint, and a modified epoxy resin glue containing carbon fiber short cut and nano silica toughening agent is injected at high pressure to form an embedded repair layer in the reinforcing and reinforcing area after heat curing; Step 4: Brush epoxy resin glue outside the embedded repair layer, then alternately lay horizontal carbon fiber cloth and vertical prestressed carbon fiber cloth outside the embedded repair layer, install prestressed anchors on the surface of the tower concrete, prestressed anchors tension the vertical prestressed carbon fiber cloth, and bond the carbon fiber cloth by using vacuum assisted resin infusion process to form a composite constraint layer; Step 5: Embed an optical fiber grating sensor in the composite constraint layer, connect the optical fiber grating sensor with an intelligent monitoring module, coat a polyurea elastomer protective layer on the surface of the outermost prestressed carbon fiber cloth and the surface of the prestressed anchor, and the intelligent monitoring module monitors the deformation of the carbon fiber cloth in real time according to the optical fiber grating sensor, so as to evaluate the reinforcement effect and the prestressed state of the prestressed carbon fiber cloth; Step 6: Install a split ring steel hoop outside the connection between the upper and lower concrete towers, and apply radial pre-tightening force to the split ring steel hoop to make the split ring steel hoop tightly hold the composite constraint layer.

2. The method of claim 1, wherein the method further comprises: In step 1, the prestressed carbon fiber cloth reinforcing reinforcement scheme is as follows: two layers of horizontal carbon fiber cloth are used to cover the damaged part for reinforcement, and multiple vertical prestressed carbon fiber cloths are used to reinforce and reinforce the damaged part, and the carbon fiber cloth arrangement mode is: two horizontal carbon fiber cloths and vertical prestressed carbon fiber cloths are arranged alternately from inside to outside.

3. The method of claim 2, wherein the method further comprises: The thickness of the single layer of carbon fiber cloth is 0.2-0.3mm, the tensile strength is ≥4000MPa, the horizontally arranged carbon fiber cloth is not prestressed, the vertically arranged carbon fiber cloth is prestressed, and the length of the carbon fiber cloth is determined by the prestressed carbon fiber cloth reinforcing reinforcement scheme: the first layer of horizontal carbon fiber cloth is pasted along the direction of the concrete tower joint, the width of the carbon fiber cloth exceeds the width of the joint by 150mm on both sides, and the length of the carbon fiber cloth is adapted to the length of the bonding glue failure of the tower connection; the second layer of vertical prestressed carbon fiber cloth is pasted on the first layer of horizontal fiber cloth in a plurality of dense manner, the vertical prestressed carbon fiber cloth has a spacing of 200mm, the number of vertical prestressed carbon fiber cloths is determined according to the length of the bonding glue failure, and the length of the vertical prestressed carbon fiber cloth exceeds the length of the concrete tower joint by 330mm on both sides; the third layer of horizontal carbon fiber cloth is the same as the first layer of horizontal carbon fiber cloth, and the reinforcing mode is a horizontal overall wrapping mode, and the wrapping height is the same as that of the first layer of horizontal carbon fiber cloth.

4. The method of claim 1, wherein the method further comprises: In step 3, the tensile strength of the modified epoxy resin glue body is greater than or equal to 60 MPa, the elongation is greater than or equal to 8%, and the addition amount of nano-silicon dioxide is 3%-5% of the total mass of the glue body; the depth of the U-shaped groove is 10-20 mm, and the width is 15-25 mm.

5. The method of claim 1, wherein the method further comprises: The heat curing condition of step 3 is: stepwise heating to 60-80℃, holding time is greater than or equal to 4 hours, and the heating rate is less than or equal to 5℃ / min.

6. The method of claim 1, wherein the method further comprises: In step 4, the prestressed anchor is a wedge-shaped anchor with an anchor ring and a wedge-shaped clamping piece, the wall thickness of the anchor ring is greater than or equal to 10 mm, the clamping force is greater than or equal to 50 kN, the slip amount is less than or equal to 0.05 mm, the length of the wedge-shaped anchor is the length of the carbon fiber cloth plus 20 mm, the width is 40 mm, and the wedge angle is 12°.

7. The method of claim 1, wherein the method further comprises: In step 4, in the vacuum-assisted resin infusion process, the resin curing temperature is 60-80℃, the vacuum degree is less than or equal to -0.09 MPa, and the fiber volume content is greater than or equal to 60%.

8. The method of claim 1, wherein the method further comprises: In step 5, the fiber Bragg grating sensor is arranged at the middle part of the bottom layer transverse carbon fiber cloth, the length is 100 mm, and the center is the upper and lower tower drum connection joints, and each side is 50 mm.

9. The method of claim 1, wherein the method further comprises, In step 6, the material of the split ring-shaped steel hoop is Q345D steel, the radial pre-tightening force design value is 150-250 kN / m, and the number of split ring-shaped steel hoops is 2.

10. The method of claim 9, wherein the method further comprises, The inner surface of the split ring-shaped steel hoop is provided with a rubber buffer layer, and the rubber hardness is 60-80 Shore A.

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