Construction method for improving installation accuracy of pre-stressed anchor bolt assembly

Abstract

The invention relates to the technical field of wind power generation, in particular to a construction method for improving the installation accuracy of a pre-stressed anchor bolt assembly. S1, parts are counted and transported in a fragmented mode; s2, a foundation is cleaned, and a positioning formwork is installed; s3, the lower anchor plates are in butt joint in a segmented mode, and supporting bolt sets are installed; s4, a supporting bolt set is welded, and the lower anchor plate is leveled; s5, leveling anchor bolts are installed, and blackening nuts are fixed; s6, the upper anchor plate is in butt joint in a segmented mode, and the height is S7, the remaining anchor bolts are installed, and the levelness is finely adjusted; and S8, the concentricity is adjusted, and anti-corrosion sealing acceptance check is completed. Through the positioning template of an annular structure and the annular multi-circle bolt hole distribution, multi-layer reference positioning is provided for the fragmented anchor plate; the elevation of the lower anchor plate is adjusted through upper and lower nuts to ensure the concentricity of the upper and lower anchor plates; butt joints of the lower anchor plates are consistent with the main wind direction, butt joints of the upper anchor plates are distributed at 90 degrees, and the concentrated stress of alternating loads on the connecting joints is dispersed.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and specifically, it is a first construction method for improving the installation accuracy of prestressed anchor bolt assemblies. Background Art

[0002] With the transformation of the global energy structure towards cleaner and lower-carbon forms, wind power generation, as an important part of renewable energy, has shown a trend of large-scale and large-sized development in recent years. According to the statistics of the Global Wind Energy Council (GWEC), the newly installed wind power capacity globally reached 78 GW in 2022, with China accounting for more than 50%, becoming the core driving force for the growth of the global wind power market. To improve power generation efficiency, the single-unit capacity of mainstream wind turbines has leaped from the 3 MW level to the 6 MW - 15 MW level, the height of the wind turbine tower exceeds 150 meters, and the blade diameter has broken through 200 meters. This trend has put forward higher requirements for the stability of the wind turbine foundation structure. In particular, the installation accuracy of prestressed anchor bolt assemblies is directly related to the safety of the connection between the tower and the foundation and the reliability throughout the life cycle.

[0003] However, the large size of the wind turbines has led to a significant increase in the size and weight of the anchor bolt assemblies. Taking a 6 MW onshore wind turbine as an example, its foundation anchor bolt assembly usually contains 80 - 120 anchor bolts, the length of a single anchor bolt exceeds 4 meters, the overall diameter of the anchor plate reaches 8 - 12 meters, and the total weight exceeds 20 tons. The transportation, hoisting, and on-site installation of such super-large components face the following technical bottlenecks: ‌1. Difficulties in transportation and segmented assembly‌: The integral anchor plate cannot be transported through conventional roads due to its large size and requires a segmented design. However, cumulative errors are likely to occur during segmented docking, resulting in misalignment of the anchor bolt holes.

[0004] ‌2. Insufficient control of installation accuracy‌: Traditional construction relies on manual experience to adjust the verticality and horizontality of the anchor bolts, making it difficult to meet high-precision requirements; 3. Poor adaptability to dynamic loads‌: The alternating loads generated by the swinging of the tower during the operation of the wind turbine are likely to cause loss of the pre-tightening force of the anchor bolts and even lead to fatigue cracking of the connecting plate; ‌4. Defects in anti-corrosion and sealing‌: The exposed part of the anchor bolts is prone to corrosion after being eroded by rainwater and salt spray. The sealing life of traditional epoxy coatings or plastic caps is less than 10 years and cannot match the 25-year design life of the wind turbine. Summary of the Invention

[0005] The present invention aims to solve the above problems and thus provides a construction method for improving the installation accuracy of prestressed anchor bolt assemblies to ensure installation accuracy.

[0006] The technical solution adopted by the present invention to solve the above problems is: A construction method for improving the installation accuracy of prestressed anchor bolt assemblies, including a lower anchor plate, comprising the following steps: S1: Inventory components and transport in pieces: According to the prestressed anchor bolt foundation drawing, inventory the number of components of the anchor bolt assembly, transport the components to the construction site and place them on cork cushions, and slice the lower anchor plate and the upper anchor plate before transportation.

[0007] S2: Clean the foundation and install the positioning template: Clean the surface of the foundation cushion layer and lay out the cross reference lines. Prepare the positioning template for the ring structure and hoist it to the installation position. There are multiple circles of bolt holes circumferentially arranged along the upper edge of the positioning template. After adjusting the levelness of the positioning template to align with the reference lines, fix it on the cushion layer.

[0008] S3: Piecewise butt joint the lower anchor plate and install the support bolt group: Use the connecting plate and connecting bolts to piecewise butt joint and assemble the lower anchor plate. According to the distribution of the bolt holes on the positioning template, equidistantly install the support bolt group on the lower anchor plate. Each group of support bolts includes upper and lower nuts and a lower washer.

[0009] S4: Weld the support bolt group and level the lower anchor plate: Weld the support bolt group to the center line of the embedded part, with the weld leg height not less than 6 mm. Adjust the upper and lower nuts of the support bolts to make the lower anchor plate reach the design elevation, and tighten the nuts so that the butt joint seam of the lower anchor plate is in the same direction as the main wind direction.

[0010] S5: Install the leveling anchor bolts and fix the blackened nuts: Based on the positions of the bolt holes on the positioning template, install the leveling anchor bolts with nylon nuts at the top at the corresponding positions of the support bolt group. Some of the leveling anchor bolts are marked with yellow tape and installed at the connecting plate of the lower anchor plate, and blackened nuts and washers are screwed into the lower part of the lower anchor plate.

[0011] S6: Piecewise butt joint the upper anchor plate and adjust the height: Use the connecting plate and connecting bolts to piecewise butt joint and assemble the upper anchor plate. The connecting plate is located on the upper side of the upper anchor plate. Hoist the upper anchor plate onto the leveling anchor bolts and use the adjusting nylon nuts to adjust the height. The connecting seam of the upper anchor plate and the connecting seam of the lower anchor plate are distributed at 90°.

[0012] S7: Install the remaining anchor bolts and finely adjust the levelness: Sequentially install the remaining anchor bolts and adjust the verticality, levelness and exposed length. Tighten the blackened nuts under the lower anchor plate. After adjusting the nylon nuts so that the levelness of the upper anchor plate ≤ 1.5 mm, install and tighten the dacromet nuts above the nylon nuts.

[0013] S8: Adjust the concentricity and complete the anti-corrosion and sealing acceptance: Set up four-way adjusting piles outside the fan foundation, adjust the concentricity of the upper and lower anchor plates through turnbuckles and theodolite. Sleeve PVC sleeves on the exposed parts of the anchor bolts, heat-seal the ports of the PVC sleeves with heat-shrinkable tubes, and accept the anti-corrosion, concentricity, levelness and bolt torque of the anchor bolts.

[0014] The present invention adopting the above technical solution, compared with the prior art, its prominent features are: Through the positioning template of the ring structure and the circumferential multi - turn bolt hole distribution, multi - layer reference positioning is provided for the segmented anchor plate to ensure that the hole position deviation is ≤1.2 mm during segmented butt - joint. At the same time, the elevation of the lower anchor plate is adjusted by the upper and lower nuts, the levelness of the anchor plate is adjusted by the nylon nut, and real - time calibration is carried out through the turnbuckle and the theodolite to ensure the concentricity of the upper and lower anchor plates. In addition, the butt - joint seam of the lower anchor plate is in the same direction as the main wind direction, and is distributed at 90° to the butt - joint seam of the upper anchor plate to disperse the concentrated stress of the alternating load on the connection seam. A Dacromet nut is installed above the nylon nut, and its corrosion resistance and anti - loosening characteristics ensure long - term load stability. The PVC sleeve is sleeved on the exposed part of the anchor bolt to prevent rainwater from directly contacting. After heating, the heat - shrinkable tube fits tightly with the port of the PVC sleeve without gaps to block the water seepage path. The blackened nut of the lower anchor plate and the Dacromet nut form a double anti - corrosion barrier.

[0015] As a preferred embodiment, a further technical solution of the present invention is: Furthermore, the inner diameter deviation of the positioning template in S2 is ≤2 mm, the adjacent hole spacing error of each circle of bolt holes is ≤0.5 mm, and the fit tolerance between the bolt hole diameter and the anchor bolt diameter is H8 / h7. Controlling the inner diameter deviation of the positioning template and the bolt hole spacing error ensures the hole position consistency during the butt - joint of the segmented anchor plate, optimizing the fit tolerance to ensure the gap - free fit between the anchor bolt and the bolt hole, reducing the fretting wear during the installation process, and improving the stability of the anchor bolt pre - tightening force.

[0016] Furthermore, the installation position of the support bolt group in S3 is calibrated by a laser locator. During the calibration process, the center of the bolt hole of the positioning template is used as the reference to ensure that the deviation between the axis of the support bolt group and the center line of the embedded part is ≤1 mm, providing a high - precision basis for the subsequent installation of the leveling anchor bolt. The real - time calibration function reduces the manual adjustment time, avoids the problem of over - tolerance of the anchor plate levelness caused by the installation deviation of the support bolt group, and reduces the rework rate.

[0017] Furthermore, the surface of the nylon nut in S5 is coated with a polytetrafluoroethylene anti - slip coating, the width of the yellow tape marking is 10 mm ± 0.2 mm, and the installation position of the leveling anchor bolt corresponds one - to - one with the bolt hole position of the positioning template. The polytetrafluoroethylene coating significantly reduces the loosening risk of the nylon nut under alternating loads, while improving the corrosion resistance. The yellow tape marking ensures the visualization and accuracy of the installation position of the leveling anchor bolt, reducing installation errors. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the construction process of the embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be further described below in conjunction with embodiments, and the purpose is only to better understand the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0020] A construction method for improving the installation accuracy of a prestressed anchor bolt assembly, including a lower anchor plate, comprising the following steps: S1: Inventory components and transport them in pieces: According to the prestressed anchor bolt foundation drawing, inventory the number of components of the anchor bolt assembly, transport the components to the construction site and place them on cork pads. Before transportation, the lower anchor plate and the upper anchor plate are sliced.

[0021] S2: Clean the foundation and install the positioning template: Clean the surface of the foundation cushion and lay out the cross-reference line. Prepare the positioning template in a circular structure and hoist it to the installation position. There are multiple circles of bolt holes circumferentially along the upper edge of the positioning template. After adjusting the level of the positioning template to align with the reference line, fix it to the cushion.

[0022] S3: Piecewise butt joint the lower anchor plate and install the support bolt group: Use connecting plates and connecting bolts to piecewise butt joint and assemble the lower anchor plate. According to the bolt hole distribution of the positioning template, install the support bolt group equidistantly on the lower anchor plate. Each group of support bolts includes upper and lower nuts and a lower washer.

[0023] S4: Weld the support bolt group and level the lower anchor plate: Weld the support bolt group to the center line of the embedded part, with the weld leg height not less than 6 mm. Adjust the upper and lower nuts of the support bolts to make the lower anchor plate reach the design elevation and the levelness ≤ 3 mm. Tighten the nuts so that the butt joint of the lower anchor plate is consistent with the main wind direction.

[0024] S5: Install the leveling anchor bolts and fix the blackened nuts: Based on the bolt hole positions of the positioning template, install the leveling anchor bolts with nylon nuts at the top at the corresponding positions of the support bolt group. Among them, some leveling anchor bolts are marked with yellow tape and installed at the connecting plate of the lower anchor plate, and blackened nuts and washers are screwed into the lower part of the lower anchor plate.

[0025] S6: Piecewise butt joint the upper anchor plate and adjust the height: Use connecting plates and connecting bolts to piecewise butt joint and assemble the upper anchor plate. The connecting plate is located on the upper side of the upper anchor plate. Hoist the upper anchor plate onto the leveling anchor bolts and use the adjusting nylon nuts to adjust the height. The connection seam of the upper anchor plate and the connection seam of the lower anchor plate are distributed at 90°.

[0026] S7: Install the remaining anchor bolts and fine-tune the levelness: Install the remaining anchor bolts in sequence and adjust the verticality, levelness and exposed length. Tighten the blackened nuts under the lower anchor plate. After adjusting the nylon nuts to make the levelness of the upper anchor plate ≤ 1.5 mm, install and tighten the dacromet nuts above the nylon nuts.

[0027] S8: Adjust the concentricity and complete the anti-corrosion and sealing acceptance: Set up four-way adjusting piles outside the fan foundation, adjust the concentricity of the upper and lower anchor plates through turnbuckles and theodolites. Sleeve the exposed part of the anchor bolts with PVC sleeves, heat-seal the ports of the PVC sleeves with heat-shrinkable tubes, and accept the anti-corrosion, concentricity, levelness and bolt torque of the anchor bolts.

[0028] Furthermore, the inner diameter deviation of the positioning template in S2 is ≤2 mm, the adjacent hole spacing error of each circle of bolt holes is ≤0.5 mm, and the fit tolerance between the bolt hole diameter and the anchor bolt diameter is H8 / h7. Controlling the inner diameter deviation of the positioning template and the bolt hole spacing error ensures the consistency of hole positions during the butt joint of the segmented anchor plates. Optimizing the fit tolerance ensures the clearance-free fit between the anchor bolts and the bolt holes, reduces fretting wear during installation, and improves the stability of the anchor bolt pre-tightening force.

[0029] Furthermore, the installation position of the support bolt group in S3 is calibrated by a laser locator. During the calibration process, the center of the bolt hole of the positioning template is used as the reference to ensure that the deviation between the axis of the support bolt group and the center line of the embedded part is ≤1 mm, providing a high-precision basis for the subsequent installation of the leveling anchor bolts. The real-time calibration function reduces the manual adjustment time and avoids the problem of out-of-tolerance levelness of the anchor plate caused by the installation deviation of the support bolt group, reducing the rework rate.

[0030] Furthermore, the surface of the nylon nut in S5 is coated with a polytetrafluoroethylene anti-slip coating, the width of the yellow tape marking is 10 mm ± 0.2 mm, and the installation positions of the leveling anchor bolts correspond one by one to the bolt hole positions of the positioning template. The polytetrafluoroethylene coating significantly reduces the loosening risk of the nylon nut under alternating loads and improves the corrosion resistance at the same time. The yellow tape marking ensures the visualization and accuracy of the installation positions of the leveling anchor bolts, reduces installation errors, and the leveling anchor bolts correspond one by one to the bolt holes of the positioning template, avoiding the problem of out-of-tolerance levelness of the anchor plate caused by misalignment installation.

[0031] Through the positioning template with a ring structure and the circumferential multi-circle bolt hole distribution, multi-layer reference positioning is provided for the segmented anchor plates to ensure that the hole position deviation during segmented butt joint is ≤1.2 mm. At the same time, the elevation of the lower anchor plate is adjusted by the upper and lower nuts, the levelness of the anchor plate is adjusted by the nylon nut, and real-time calibration is carried out through the turnbuckle and the theodolite to ensure the concentricity of the upper and lower anchor plates. In addition, the butt joint seam of the lower anchor plate is consistent with the main wind direction and is distributed at 90° to the butt joint seam of the upper anchor plate to disperse the concentrated stress of the alternating load on the connection seam. A dacromet nut is installed above the nylon nut, and its corrosion resistance and anti-loosening characteristics ensure long-term load stability. The PVC sleeve is sleeved on the exposed part of the anchor bolt to prevent direct contact with rainwater. The heat shrinkable tube is heated and fits tightly with the port of the PVC sleeve without clearance to block the water seepage path. The blackening nut of the lower anchor plate and the dacromet nut form a double anti-corrosion barrier.

[0032] The above are only the preferred and feasible embodiments of the present invention, and do not limit the scope of the rights of the present invention accordingly. All equivalent changes made by using the content of the specification and drawings of the present invention are included within the scope of the rights of the present invention.

Claims

1. A construction method for improving the installation accuracy of a prestressed anchor bolt assembly, including a lower anchor plate, characterized in that: It includes the following steps: S1: Inventory components and transport them in pieces: According to the prestressed anchor bolt foundation drawing, inventory the number of components of the anchor bolt assembly, transport the components to the construction site and place them on cork cushions. Before transportation, slice the lower anchor plate and the upper anchor plate; S2: Clean the foundation and install the positioning template: Clean the surface of the foundation cushion and lay out the cross reference lines. Prepare the positioning template for the ring structure and hoist it to the installation position. There are multiple circles of bolt holes circumferentially on the upper edge of the positioning template. After adjusting the levelness of the positioning template to align with the reference line, fix it on the cushion; S3: Piecewise butt joint the lower anchor plate and install the support bolt group: Use connecting plates and connecting bolts to piecewise butt joint and assemble the lower anchor plate. According to the distribution of the bolt holes of the positioning template, equidistantly install the support bolt group on the lower anchor plate. Each group of support bolts includes upper and lower nuts and a lower end washer; S4: Weld the support bolt group and level the lower anchor plate: Weld the support bolt group to the center line of the embedded part. The weld leg height is not less than 6 mm. Adjust the upper and lower nuts of the support bolts to make the lower anchor plate reach the design elevation, and tighten the nuts to make the butt joint seam of the lower anchor plate consistent with the main wind direction; S5: Install the leveling anchor bolts and fix the blackened nuts: Based on the bolt hole positions of the positioning template, install the leveling anchor bolts with nylon nuts at the top at the corresponding positions of the support bolt group. Some of the leveling anchor bolts are marked with yellow tape and installed at the connecting plate of the lower anchor plate, and blackened nuts and washers are screwed into the lower part of the lower anchor plate; S6: Piecewise butt joint the upper anchor plate and adjust the height: Use connecting plates and connecting bolts to piecewise butt joint and assemble the upper anchor plate. The connecting plate is located on the upper side of the upper anchor plate. Hoist the upper anchor plate onto the leveling anchor bolts and use the adjusting nylon nuts to adjust the height. The connection seam of the upper anchor plate and the connection seam of the lower anchor plate are distributed at 90°; S7: Install the remaining anchor bolts and fine-tune the levelness: Install the remaining anchor bolts in sequence and adjust the verticality, levelness and exposed length. Tighten the blackened nuts under the lower anchor plate. After adjusting the nylon nuts to make the levelness of the upper anchor plate ≤ 1.5 mm, install and tighten the dacromet nuts above the nylon nuts; S8: Adjust the concentricity and complete the anti-corrosion and sealing acceptance: Set up four-way adjusting piles outside the fan foundation. Adjust the concentricity of the upper and lower anchor plates through turnbuckles and theodolites. Sleeve PVC sleeves on the exposed parts of the anchor bolts, heat-seal the ports of the PVC sleeves with heat-shrinkable tubes, and accept the anti-corrosion, concentricity, levelness and bolt torque of the anchor bolts.

2. The construction method for improving the installation accuracy of the prestressed anchor bolt assembly according to claim 1, characterized in that: The inner diameter deviation of the positioning template in S2 ≤ 2 mm, the adjacent hole spacing error of each circle of bolt holes ≤ 0.5 mm, and the fit tolerance between the bolt hole diameter and the anchor bolt diameter is H8 / h7.

3. The construction method for improving the installation accuracy of the prestressed anchor bolt assembly according to claim 1, characterized in that: The installation position of the support bolt group in S3 is calibrated by a laser locator. During the calibration process, the center of the bolt hole of the positioning template is used as the reference to ensure that the deviation between the axis of the support bolt group and the center line of the embedded part ≤ 1 mm.

4. The construction method for improving the installation accuracy of the prestressed anchor bolt assembly according to claim 1, characterized in that: The surface of the nylon nut in S5 is coated with a polytetrafluoroethylene anti-slip coating. The width of the yellow tape marking is 10 mm ± 0.2 mm, and the installation positions of the leveling anchor bolts correspond one by one to the bolt hole positions of the positioning template.

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