Tower section grouting-free connecting method and device based on prefabricated ring pieces

Abstract

The invention relates to the technical field of wind power generation, in particular to a tower section grouting-free connecting method and device based on prefabricated ring pieces, the device comprises at least one group of prefabricated concrete tower sections, and each group of prefabricated concrete tower sections is formed by annularly splicing a plurality of prefabricated ring pieces; the upper end of the prefabricated ring piece is provided with a first convex tooth and a tooth groove, and the lower end of the prefabricated ring piece is provided with a second convex tooth and a tooth groove; a metal corrugated pipe is pre-buried in the first convex teeth, and a through hole in the metal corrugated pipe serves as a steel strand hole; anchoring mounting grooves are formed in the second convex teeth, and the two ends of the steel strand are arranged in the anchoring mounting grooves and penetrate through the steel strand holes. The method comprises the following steps: designing a plurality of prefabricated ring pieces; a plurality of prefabricated ring pieces are annularly spliced to form a plurality of prefabricated concrete tower sections; pulling and tensioning the prestressed steel strand; and the multiple concrete tower sections are spliced and assembled up and down to form the tower section grouting-free connecting device. Precise butt joint of the prefabricated parts is achieved, on-site grouting is not needed, the construction period is shortened, and the construction cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation technology, specifically relating to a method and device for grout-free connection of tower sections based on prefabricated ring plates. Background Technology

[0002] With the trend towards grid parity for wind power, technologies such as long blades, large-megawatt turbines, and lightweight towers are constantly being innovated. Especially in low-wind-speed areas, 120-140 meter high all-steel flexible towers dominate due to their economic efficiency, well-established supply chain, and shorter installation cycle. However, with the increase in tower height and the pursuit of grid parity for wind power, the reliability issues of flexible towers are becoming increasingly prominent. Pure steel towers experience a significant decrease in stiffness in high-tower applications and are prone to adverse vibration problems. Therefore, steel-concrete composite towers (hybrid towers) are increasingly becoming the mainstream choice for heights exceeding 100 meters due to their structural performance and material cost advantages.

[0003] However, during construction, wind turbine hybrid towers face severe challenges such as low construction efficiency, high transportation costs, and quality control difficulties. Traditional wet connection methods (prefabricated sections with embedded steel bars, grouting connection on-site) are time-consuming and labor-intensive, resulting in high transportation costs for large components and significant difficulties in on-site quality control, severely restricting the large-scale application and market expansion of tall wind turbine units. This method has a long construction cycle, high transportation and hoisting costs, and stringent requirements for the site environment. Furthermore, the quality control of grouting greatly affects the overall strength and reliability of the tower, posing potential safety hazards. In addition, the flatness and precision requirements of prefabricated components are extremely high, and on-site leveling work is cumbersome, increasing construction difficulty and costs.

[0004] Therefore, there is a need to design a grout-free connection method and device for tower sections based on prefabricated ring plates that can solve the existing problems.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by providing a method and apparatus for grout-free connection of tower sections based on prefabricated ring plates.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A grout-free tower segment connection device based on precast ring plates includes at least one set of precast concrete tower segments, each set of precast concrete tower segments being formed by circumferential splicing of several precast ring plates; wherein, the upper end of the precast ring plate is provided with a first protruding tooth and a tooth groove, and the lower end of the precast ring plate is provided with a second protruding tooth and a tooth groove; a metal corrugated pipe is pre-embedded inside the first protruding tooth, and the through hole inside the metal corrugated pipe serves as a steel strand hole; an anchoring installation groove is provided on the second protruding tooth, and both ends of the steel strand are located in the anchoring installation groove and pass through the steel strand hole.

[0008] Based on the above technical solution, further, the root radius of the first convex tooth and the tooth groove and the root radius of the second convex tooth and the tooth groove are both not less than 5mm.

[0009] A method for grout-free connection of tower sections based on precast ring plates includes the following steps: designing several precast ring plates; splicing several precast ring plates circumferentially to form several precast concrete tower sections; threading and tensioning prestressed steel strands; and assembling several concrete tower sections vertically to form a grout-free connection device for tower sections.

[0010] Based on the above technical solution, the circumferential splicing process further includes splicing in the horizontal direction and the vertical direction; wherein, the horizontal splicing is the vertical splicing between precast ring pieces within the same precast concrete tower segment; the vertical splicing is the horizontal splicing between the upper precast concrete tower segment and the lower precast concrete tower segment.

[0011] Based on the above technical solution, further, before assembly, a two-component epoxy resin structural adhesive is evenly applied to the surface of the vertical seam, and the adhesive layer thickness is preferably 2-3mm.

[0012] Based on the above technical solution, the performance requirements of the two-component epoxy resin structural adhesive are: compressive strength ≥90MPa, tensile strength ≥20MPa, and initial setting time set to 45–60 minutes.

[0013] Based on the above technical solution, the initial installation angle of the toothed groove on the precast ring piece is pre-deflected by 11.25°, so that the vertical joint between the upper precast concrete tower section and the lower precast concrete tower section is staggered by 45°.

[0014] Based on the above technical solution, furthermore, the steel strands are low-relaxation epoxy-coated steel strands, and each strand is threaded into a pre-embedded metal corrugated pipe.

[0015] Based on the above technical solution, the tensioning loading process is further divided into three levels: the first level is loaded to 30% of the design tension, synchronously loaded at a rate of 5 MPa / min, and held for 5 minutes. The prestressed intelligent synchronous tensioning system samples and monitors the pressure at 10 times / second, automatically compensating for and controlling fluctuations within ±1%. The second level is loaded to 60% of the design tension, also held for 5 minutes. The prestressed intelligent synchronous tensioning system records the elongation in real time and plots the force-displacement curve. The third level is loaded to 100% of the design tension. The prestressed intelligent synchronous tensioning system compares the actual elongation value with the theoretical value in real time, implementing dual control. If the deviation exceeds the range of -5% to +10%, the prestressed intelligent synchronous tensioning system automatically alarms and pauses.

[0016] Based on the above technical solution, furthermore, after tensioning is completed, the prestressed intelligent synchronous tensioning system slowly depressurizes at a rate of 3MPa / min, and the data throughout the process is automatically recorded and stored; finally, a tensioning report is generated and uploaded to the cloud platform via the network.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adopts geometric interlocking dry prefabricated tower segment splicing technology to provide an efficient, economical and reliable solution for the construction of wind power hybrid towers, realizes the precise docking of prefabricated components, eliminates the need for on-site grouting, thereby greatly shortening the construction cycle, reducing the requirements for the on-site environment, and reducing the demand for construction personnel and training costs.

[0018] (2) This invention utilizes prestressed steel strands, ensuring the strength and reliability of the connection, effectively dispersing stress, improving the fatigue resistance of the tower, and extending the service life of the tower. Simultaneously, this geometric interlocking technology makes the transportation process simpler and more efficient, reducing the cost and risk of transporting large components and improving the transportation efficiency of prefabricated parts. The grout-free design completely solves the problem of excessively long traditional grouting and curing cycles, greatly improving construction efficiency, reducing project costs, and significantly enhancing construction quality; it breaks through the bottleneck of traditional wet connection technology and is expected to lead the wind power industry towards a new model of efficient, economical, and safe construction of tall wind turbine towers, meeting the growing demands of the wind power market.

[0019] (3) This invention systematically solves the inherent problems of traditional wet grouting connections, such as long construction period, high quality affected by environmental factors, and difficult maintenance, through a series of precise designs and processes. Its fundamental principle is to utilize the high-precision first convex tooth, second convex tooth, and groove assembly structure pre-formed on the prefabricated components to automatically achieve fitting during hoisting, forming preliminary mechanical shear resistance; then, by applying external prestress, a huge normal pressure is generated at the joint interface, thereby binding multiple ring pieces into a tower structure with extremely high integrity and rigidity. The entire connection process does not require any on-site concrete pouring or grouting operations, realizing a true "dry" assembly. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the assembly of precast concrete tower sections in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a single prefabricated ring sheet in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure after two precast concrete tower sections are assembled vertically in an embodiment of the present invention; Figure 4 This is a side view of two precast concrete tower sections assembled with staggered joints in an embodiment of the present invention. Figure 5 This is a schematic diagram of the installation process of the entire device in an embodiment of the present invention.

[0021] Figure label: 1-Precast ring; 2-Anchoring installation groove; 3-Steel strand hole; 4-Horizontal joint; 5-Vertical joint; 6-Steel strand; 7-Steel strand anchor; 101-First tooth; 102-Second tooth. Detailed Implementation

[0022] The technical solution of the present invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0023] It should be noted that, unless otherwise specifically stated, the relative arrangement and numerical expressions of the components and steps described in these embodiments should not be construed as limiting the scope of the invention.

[0024] The following description of exemplary embodiments is merely illustrative and is not intended to limit the invention or its application or use in any way. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail herein, but where applicable, such techniques, methods, and apparatus should be considered part of this specification.

[0025] Example Combination Figures 1-5 As shown, this embodiment provides a tower segment grout-free connection device based on precast ring plates 1, which includes at least one set of precast concrete tower segments, each set of precast concrete tower segments being formed by circumferential splicing of several precast ring plates 1.

[0026] Specifically, refer to Figure 1As shown, taking four precast ring segments 1 as an example, the four precast ring segments 1 are spliced ​​together circumferentially to form a set of precast concrete tower segments. All precast ring segments 1 are designed to meet the size requirements of highway or railway transportation clearance. Preferably, the weight of a single precast ring segment 1 generally does not exceed 40 tons and the width does not exceed 4.5 meters. Furthermore, the precast ring segments 1 are precast in a factory with strictly controlled environment using high-performance concrete (C60-C80). In addition, the concrete mix proportion incorporates silica fume and polycarboxylate-based high-efficiency water-reducing agent, and the water-cement ratio is not higher than 0.30 to ensure the high fluidity, high strength and low shrinkage characteristics of the concrete. Furthermore, the cross-sectional flatness of the precast ring piece 1 is preferably controlled within 2mm. The edge groove is formed by high-precision steel mold. The mold is made of Q345B alloy steel by CNC machining. The working surface is hard chrome plated and polished to a roughness Ra≤0.4μm to ensure that the concrete surface is smooth and the dimensions are accurate after demolding. The mold design rigidity must ensure that the deformation does not exceed 0.2mm during the concrete pouring and vibration process. In this embodiment, all prefabricated ring pieces 1 have the same structure. Taking one prefabricated ring piece 1 as an example, refer to... Figure 2 As shown, the upper end of the precast ring 1 is provided with a first protruding tooth 101 and a tooth groove, and the lower end of the precast ring 1 is provided with a second protruding tooth 102 and a tooth groove. Preferably, the tooth height difference between the upper end face of the first protruding tooth 101 and the end face of the tooth groove is 60mm, the tooth height difference between the lower end face of the second protruding tooth 102 and the end face of the tooth groove is 60mm, and the root radius of the tooth arc between the first protruding tooth 101 and the tooth groove and the root radius of the tooth arc between the second protruding tooth 102 and the tooth groove are both not less than 5mm, so as to optimize stress distribution. Furthermore, a galvanized metal corrugated pipe is pre-embedded inside the first protrusion 101. The through hole inside the metal corrugated pipe serves as the steel strand hole 3, and steel strand anchors 7 are provided at both ends of the steel strand hole 3. The steel strand anchors 7 are installed on both sides of the first protrusion 101. It should be noted that the diameter of the through hole is determined according to the specifications of the steel strand 6, usually 60-80mm. The port of the metal corrugated pipe is preferably installed using three-dimensional laser positioning technology, and its centerline deviation is controlled within 1mm. It is fixed to the main reinforcement in the precast ring 1 by anti-pull clamp welding to prevent displacement during concrete pouring. Furthermore, an anchoring groove 2 is provided on the second protruding tooth 102. Anchor plates and spiral reinforcements are pre-embedded in the anchoring groove 2 to enhance the local bearing capacity. After each precast ring piece 1 is demolded, strict quality inspection is required. Specifically, a total station and a 3D laser scanner are preferably used to measure the dimensions of each tooth groove, the position of the pre-embedded components, and the overall outline of the precast concrete tower section. Point cloud data is generated and compared with the design model. The dimensional tolerances after comparison must meet the following requirements: the position deviation of each tooth groove is ±1.2mm, the center deviation of each pre-embedded component is ±1.0mm, and the overall outline deviation is ±2mm. Only after passing the test can the material proceed to the next process and be marked.

[0027] In other embodiments, based on the structure of the aforementioned connecting device, a grout-free connection method for tower sections based on prefabricated ring plates 1 is also provided, comprising the following steps: Step 1: Design several prefabricated ring pieces 1; Specifically, after the precast ring sheet 1 has been cured to reach its design strength, it is vertically loaded onto a truck using existing transport frames, with rubber corner protectors installed on each toothed area to prevent impact. Once transported to the site, it is stored on a flat area and covered with a tarpaulin for dust and moisture protection. Before hoisting, all joint surfaces (including horizontal joint 4 and vertical joint 5) must be surface treated; preferably, the concrete surface is treated by sandblasting or milling to remove laitance, expose fresh aggregate, and achieve a certain roughness. After treatment, it is thoroughly cleaned with high-pressure air to ensure that there is no oil or dust.

[0028] Step 2: Several precast ring pieces 1 are joined together circumferentially to form several precast concrete tower segments; Specifically, the circumferential assembly process of the precast ring piece 1 includes splicing / butt jointing in the horizontal direction (vertical joint 5 between precast ring pieces 1 within the same precast concrete tower segment) and vertical direction (horizontal joint 4 between upper and lower precast concrete tower segments). Furthermore, regarding horizontal docking, such as Figure 3 As shown, several precast ring pieces 1 within the same precast concrete tower section are connected by vertical joints 5. Before assembly, a two-component epoxy resin structural adhesive is evenly applied to the surface of the vertical joints 5, with the adhesive layer thickness controlled at 2-3 mm. Preferably, the performance requirements of this two-component epoxy resin structural adhesive are: compressive strength ≥90 MPa, tensile strength ≥20 MPa, initial setting time approximately 45-60 minutes, and a 7-day strength exceeding that of C80 concrete. After applying the adhesive, a crane is used to slowly bring the precast ring pieces 1 together, using the guiding effect of each tooth groove for initial alignment. Subsequently, hydraulic jacks are used for fine-tuning to ensure uniform joint gaps. Once the precast ring pieces 1 are in place, circumferential prestressed bolts are immediately installed. The bolt strength grade is preferably 8.8 or higher, and the torque is applied according to the design value to ensure tight fit and temporary fixation between each precast ring piece 1. Furthermore, regarding vertical connections, such as... Figure 4 As shown, the upper and lower precast concrete tower sections are connected by horizontal joint 4. The joint surfaces of the upper surface (already installed) of the lower precast concrete tower section and the lower surface of the upper precast concrete tower section both require sandblasting cleaning. A two-component epoxy structural adhesive is evenly applied to the upper surface of the lower precast concrete tower section, with the adhesive width slightly larger than the groove width. During the hoisting of the precast concrete tower section above, self-alignment is achieved by relying on the complementary shapes of the first protrusion 101 and the second protrusion 102; and by pre-deflecting the initial installation angle of the tooth groove on the precast ring piece 1 by 11.25° (for 4 precast ring pieces 1) during the design stage, the vertical joints 5 of the upper and lower precast concrete tower sections can be naturally staggered by 45° without additional adjustment, which significantly enhances the integrity and torsional resistance of the tower.

[0029] Step 3: After all the precast ring pieces 1 are assembled, the prestressed steel strands 6 are threaded and tensioned. Specifically, firstly, a high-pressure air pump is used to clean the corrugated metal pipe to ensure it is unobstructed. The steel strands 6 are low-relaxation epoxy-coated steel strands 6, which are inserted one by one into the pre-embedded corrugated metal pipe. A guide is used during threading to prevent twisting. The ends of the steel strands 6 are reserved with a tensioning length of not less than 800mm within the anchoring groove 2, and they pass through the steel strand holes 3. During tensioning, a prestressed intelligent synchronous tensioning system is used. Each bundle of steel strands 6 is loaded in three stages according to the design tension force: 30%, 60%, and 100%, with each stage held for 5 minutes. Elongation values ​​are measured for dual control (stress and elongation). In this embodiment, the prestressed intelligent synchronous tensioning system uses a PLC as the core control unit and communicates with multiple tensioning devices in real time via industrial Ethernet. It mainly consists of jacks, hydraulic sensors, displacement sensors, solenoid valves and controllers, etc. This is an existing structure and will not be described in detail. Specifically, the implementation process is as follows: The prestressed intelligent synchronous tensioning system is equipped with a high-precision hydraulic servo device and sensors to form a closed-loop control, with a synchronization accuracy of ±2%. During the initialization of the prestressed intelligent synchronous tensioning system, technicians input the design parameters of the steel strand 6 through the human-machine interface, and the system automatically calculates the target value and completes the equipment self-check. The tensioning process is divided into three stages: The first stage loads to 30% of the design tension at a synchronous loading rate of 5 MPa / min, held for 5 minutes. The intelligent synchronous tensioning system samples and monitors the pressure at 10 times / second, automatically compensating for fluctuations within ±1%. The second stage loads to 60% of the design tension, also held for 5 minutes. The intelligent synchronous tensioning system records the elongation in real time and plots the force-displacement curve. The third stage loads to 100% of the design tension. The intelligent synchronous tensioning system compares the actual elongation with the theoretical value in real time, implementing dual control. If the deviation exceeds the range of -5% to +10%, the intelligent synchronous tensioning system automatically alarms and pauses. After tensioning is completed, the prestressed intelligent synchronous tensioning system slowly depressurizes at a rate of 3 MPa / min, with all data automatically recorded and stored. A tensioning report is then generated and uploaded to an external cloud platform for quality traceability and remote monitoring. Vacuum-assisted grouting is performed within 48 hours of tensioning. The grout uses non-shrink cement-based material with a water-cement ratio of 0.28, incorporating expanding and water-reducing agents, and has a flowability of at least 300 mm. During grouting, a negative pressure of -0.08 MPa is maintained at the vacuum end, and the grouting end pressure is controlled between 0.5 and 0.7 MPa to ensure the ducts are dense. After grouting, a special protective cover is installed to cover the anchorage area, and the outside of the anchorage is filled with anti-corrosion grease to form permanent protection.

[0030] Step 3: Assemble several concrete tower sections by splicing them together into a tower section grout-free connection device. Reference Figure 5 As shown, after assembly, the precast concrete tower sections undergo overall inspection; the verticality of the tower sections is measured using a total station, and the deviation should be less than H / 2000 (H is the height of the tower section). The joints are then inspected for sealing and appearance; if necessary, ultrasonic or impact-echo methods are used to test the bonding quality. All data are recorded and archived to ensure quality traceability.

[0031] The above specific embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A precast segmental ring based tower segment grout free connection device, characterized in that, The precast concrete tower section comprises at least one set of precast concrete tower sections, and each set of precast concrete tower sections is formed by a plurality of precast segments through ring-wise splicing. The upper end of the precast segment is provided with a first protruding tooth and a tooth groove, and the lower end of the precast segment is provided with a second protruding tooth and a tooth groove. A metal bellows is embedded in the first protruding tooth, and a through hole in the metal bellows serves as a steel strand hole. An anchoring installation groove is arranged on the second protruding tooth, and the two ends of the steel strand are arranged in the anchoring installation groove and pass through the steel strand hole.

2. A pre-fabricated ring segment based tower segment grout free connection device according to claim 1, characterized in that, The tooth root circular arc radius between the first protruding tooth and the tooth groove and the tooth root circular arc radius between the second protruding tooth and the tooth groove are both not less than 5 mm.

3. A method for precast segmental tower section grout-free connection, characterized in that, The precast segment grouting-free connecting device based on the precast segment according to any one of claims 1-2 comprises the following steps: A plurality of precast segments are designed. The plurality of precast segments are spliced to form a plurality of precast concrete tower sections. The pre-tensioned steel strand is threaded and tensioned. The plurality of precast concrete tower sections are spliced and assembled into a precast segment grouting-free connecting device.

4. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 3, wherein, The splicing process includes horizontal and vertical splicing. The horizontal splicing is the vertical joint splicing between the precast segments in the same precast concrete tower section, and the vertical splicing is the horizontal joint splicing between the upper precast concrete tower section and the lower precast concrete tower section.

5. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 4, wherein, Before assembly, a two-component epoxy structural adhesive is uniformly applied on the surface of the vertical joint, and the adhesive layer has a thickness of 2-3 mm.

6. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 5, wherein, The two-component epoxy structural adhesive has a performance requirement that the compressive strength is greater than or equal to 90 MPa, the tensile strength is greater than or equal to 20 MPa, and the initial setting time is 45-60 minutes.

7. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 3, wherein, The initial installation angle of the upper tooth groove of the precast segment is pre-deflected by 11.25°, so that the vertical joint between the upper precast concrete tower section and the lower precast concrete tower section is staggered by 45°.

8. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 3, wherein, The steel strand is a low-relaxation epoxy-coated steel strand, and is threaded into the embedded metal bellows one by one.

9. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 3, wherein, The tensioning loading process is divided into three stages: The first stage is loaded to 30% of the design tension, and a synchronous loading at a rate of 5 MPa / min is adopted, and the pre-tensioned intelligent synchronous tensioning system is sampled at 10 times per second to monitor the pressure, and the automatic compensation control fluctuation is within ±1%; The second stage is loaded to 60% of the design tension, and the same holding time is 5 minutes; the pre-tensioned intelligent synchronous tensioning system records the elongation in real time, and draws a force-displacement curve; The third stage is loaded to 100% of the design tension, and the pre-tensioned intelligent synchronous tensioning system compares the actual elongation value with the theoretical value in real time, and implements double control; If the deviation exceeds the range of -5% to +10%, the pre-tensioned intelligent synchronous tensioning system automatically alarms and pauses.

10. A pre-fabricated ring segment based tower section grout free connection method as claimed in claim 9, wherein, After the tensioning is completed, the pre-tensioned intelligent synchronous tensioning system slowly releases the pressure at a rate of 3 MPa / min, and the data is automatically recorded and stored throughout the process; finally, a tensioning report is generated and uploaded to the cloud platform through the network.

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