Prestressed anchor bolt grouting construction method

Abstract

Disclosed in the present application is a prestressed anchor bolt grouting construction method, comprising the following steps: S100, performing measurement and positioning to determine a roughening area and a formwork mounting position; S200, performing roughening, and removing a floating slurry and a soft layer from a concrete surface of a bearing platform; S300, cleaning an operation surface; S400, performing wetting, and ensuring that the concrete surface of the bearing platform is wet; S500, performing leveling, spreading bedding mortar on the concrete surface of the bearing platform and leveling same, arranging a plurality of leveling shims between adjacent anchor bolts of an anchor bolt cage, and adjusting the levelness of the plurality of leveling shims; S600, mounting a bottom wind-turbine tower section; S700, mounting a formwork, and adjusting the position of the formwork on the basis of measurement and positioning marks, such that the formwork is equidistant from a flange of the bottom wind-turbine tower section; S800, performing grouting; and S900, removing the formwork. In the present application, by means of providing standard construction steps, the problems of non-standard prestressed anchor bolt grouting construction and the insufficient strength of hardened mortar are effectively solved; and the construction risk is effectively reduced, and the construction quality is ensured.

Description

A method for grouting prestressed anchor bolts Technical Field

[0001] This application belongs to the field of wind turbine foundation anchor bolt construction technology, specifically relating to a prestressed anchor bolt grouting construction method. Background Technology

[0002] Prestressed anchor bolt connection is currently the most commonly used connection method between wind turbine foundation and upper tower. The biggest difference between this method and the traditional foundation ring connection is that the prestressed anchor bolts are prestressed in advance, so that both the anchor bolt and the concrete foundation are under compression, thus effectively avoiding the stress concentration that is prone to occur in the traditional foundation ring connection.

[0003] For prestressed anchor grouting construction, common problems in existing construction methods include: inadequate roughening of the grouting area, poor sealing between the grouting formwork and the foundation or between formwork panels leading to grout leakage during grouting, insufficient strength of the hardened mortar, and cracks in the hardened mortar due to improper curing. These problems seriously affect the on-site construction progress and the subsequent installation of the wind turbine.

[0004] Therefore, there is an urgent need to propose a prestressed anchor grouting construction method. Summary of the Invention

[0005] In view of the shortcomings or deficiencies of the prior art, the technical problem to be solved by this application is to provide a prestressed anchor grouting construction method.

[0006] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0007] This application proposes a method for grouting prestressed anchor bolts, comprising the following steps:

[0008] S100. Measurement and positioning to determine the roughening area and template installation location;

[0009] S200, roughen the surface of the foundation concrete to remove laitance and soft layer;

[0010] S300, Clean the work surface;

[0011] S400, wetting, to ensure the concrete surface of the foundation cap is moist;

[0012] S500, leveling: lay grout on the concrete surface of the foundation for leveling, place multiple leveling shims between adjacent anchor bolts in the anchor cage, and level the horizontality of the multiple leveling shims.

[0013] S600, installation of the wind turbine base tower;

[0014] S700, Template installation: Set the position of the template according to the measurement and positioning marks so that the distance between the template and the flange of the wind turbine base tower is equal;

[0015] S800, grouting;

[0016] S900, Demolding.

[0017] Furthermore, the above-mentioned prestressed anchor grouting construction method also includes the following steps: S501, heat shrink tubing installation, using heat shrink tubing to protect the portion of the anchor cage between the bearing platform and the flange, so as to isolate the anchor bolt and the grouting material.

[0018] Furthermore, the above-mentioned prestressed anchor grouting construction method also includes the following steps: S701, formwork sealing, using polyurethane foam sealant to seal the gaps between the formwork and the foundation and between the formworks.

[0019] Furthermore, the above-mentioned prestressed anchor grouting construction method also includes the following steps: S801, curing, which involves curing the grouting area.

[0020] Furthermore, in the above-mentioned prestressed anchor grouting construction method, the curing is carried out by covering curing and / or spraying curing agent.

[0021] Furthermore, in the above-mentioned prestressed anchor grouting construction method, the leveling shim completes the leveling operation after coarse leveling and fine leveling.

[0022] Furthermore, in the above-mentioned prestressed anchor grouting construction method, the template includes: an inner ring template and an outer ring template, the inner ring template is set on the inner side of the flange, and the outer ring template is set on the outer side of the flange; both the inner ring template and the outer ring template include: multiple segment structures with arc cross-sections, the segment structures being connected end to end to form a ring structure with a circular cross-section.

[0023] Furthermore, in the above-mentioned prestressed anchor grouting construction method, the segment structure is also provided with ribs.

[0024] Furthermore, in the above-mentioned prestressed anchor grouting construction method, the template is coated with release oil before installation.

[0025] Furthermore, in the above-mentioned prestressed anchor grouting construction method, the grouting first involves lubricating the pipe, and then pumping the grouting material to the design elevation.

[0026] Compared with the prior art, this application has the following technical effects:

[0027] This application effectively solves the problems of non-standard prestressed anchor bolt grouting construction and insufficient strength of hardened mortar by proposing standardized construction procedures. It effectively reduces construction risks and ensures construction quality. Attached Figure Description

[0028] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0029] Figure 1: Schematic diagram of the construction process of a prestressed anchor bolt connection according to an embodiment of this application;

[0030] Figure 2: A schematic diagram of the construction process according to an embodiment of this application;

[0031] Figure 3: Top view of an embodiment of this application;

[0032] Figure 4: Cross-sectional view of the structure shown in Figure 3;

[0033] Figure 5: Schematic diagram of the middle section structure in one embodiment of this application;

[0034] In the diagram: 1. Anchor cage; 2. Bolt; 3. Nut; 4. Protective sleeve; 5. Grouting area; 6. Foundation; 7. Section structure; 8. Rib plate; 9. Support block; 10. Outer ring template; 11. Inner ring template; 12. Flange; 13. Wind turbine base tower. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] As shown in Figure 1, this application provides a detailed design for the grouting steps in the construction process of prestressed anchor bolt connections. Specifically, the construction process for prestressed anchor bolt connections includes the following steps: pile driving, cofferdam installation, foundation concrete pouring, anchor bolt cage 1 assembly and transportation, anchor bolt cage 1 hoisting, rebar tying, secondary concrete pouring, prestressed anchor bolt grouting, prestressing tensioning, and fan installation.

[0037] Prestressed anchor grouting is carried out on the second-phase concrete foundation 6, below the flange 12 of the wind turbine base tower 13, using high-strength grout. The high-strength grout bears the pressure during the prestressing tensioning process, avoiding problems such as cracks in the foundation 6, unstable anchor pretension, and large changes in the horizontality of the flange 12 caused by insufficient concrete strength below the flange 12.

[0038] As shown in Figure 2, one embodiment of this application discloses a prestressed anchor bolt grouting construction method, which includes the following steps:

[0039] S100. Measurement and positioning: Determine the roughening area and the installation position of the template. Specifically, measure and position the construction area according to the design drawings and mark the lines with a paint pen.

[0040] The roughened area is a ring with the same center as the anchor cage 1, and its width is generally wider than the ring of the anchor cage 1; the template is installed close to the roughened area and is set at the inner and outer edges of the ring of the roughened area.

[0041] S200. Roughening: Remove the laitance and soft layer from the concrete surface of the foundation 6. Specifically, roughen the designated area according to the measurement and positioning marks. The roughening depth can be controlled at about 10mm to expose the coarse aggregate. The roughening marks should be staggered to avoid being in one direction, which will increase the bonding strength. The roughening should be light and meticulous to avoid loosening the coarse aggregate.

[0042] S300. Clean the work surface. Specifically, use a rotating wire brush to clean the roughened surface, and then use a blower or vacuum cleaner to remove fine particles and dust to avoid loosening problems caused by loose particles after grouting.

[0043] S400, wetting: Ensure that the concrete surface of the foundation 6 is moist. Specifically, ensure that the concrete surface of the foundation 6 is fully moistened 8 to 12 hours before the grouting construction, and that there is no standing water on the surface 1 hour before the grouting construction.

[0044] S500, Leveling: Lay grout on the concrete surface of the foundation 6 for leveling, place multiple leveling shims between adjacent anchor bolts of the anchor cage 1, and level the horizontality of the multiple leveling shims; specifically, arrange leveling shims at intervals in the circumferential direction between the inner ring bolt 2 and the outer ring bolt 2 of the anchor cage 1. The construction sequence is to first lay grout to level the concrete foundation, place the bottom metal plate and level and compact it, place fiberboard on the leveled metal plate, and finally place leveling shims on the fiberboard.

[0045] Optionally, the bolt 2 is equipped with a connecting nut 3 to ensure a stable connection, and the nut 3 is provided with a protective sleeve 4 to prevent the nut 3 from being damaged.

[0046] Optionally, the thickness of the grout is 8mm to 12mm. In this embodiment, the thickness of the grout is set to 10mm.

[0047] S600, wind turbine base tower 13 installation: When the grout strength reaches 30MPa or above, the wind turbine base tower 13 is hoisted, so that the bolts 2 of the anchor cage 1 are inserted into the two pre-drilled bolt holes on the flange 12 of the wind turbine base tower 13. The pre-placed nuts 3 and washers are installed and pre-tightened using a quick electric wrench. The nuts 3 should be pre-tightened in sequence, with the inner and outer rings being pre-tightened simultaneously. After the entire circumference is pre-tightened, the main lifting tool is removed.

[0048] Specifically, when the wind turbine base tower 13 is hoisted to the flange 12 through the foundation anchor bolts, it is important to ensure that the hoisting is stable. Manpower can be arranged around the perimeter to assist in positioning, and the coaxiality of the flange hole and bolt 2 should be ensured to avoid the flange hitting the bolt 2 and causing damage to the bolt 2.

[0049] Optionally, the preload torque is 300-500 Nm, and in this embodiment, the preload torque is 400 Nm.

[0050] S700, Template installation: The position of the template is set according to the measurement and positioning marks. The template is specifically set with an inner ring template 11 and an outer ring template 10. The distance between the inner ring template 11, the outer ring template 10 and the flange 12 of the wind turbine base tower 13 is equal and meets the design requirements.

[0051] S800, grouting.

[0052] S900, after grouting, the inner and outer ring formwork can be removed 1-3 days after the formwork is removed, depending on the site conditions. When removing the formwork, care should be taken to avoid collisions and damage to the hardened mortar surface.

[0053] This application effectively solves the problems of non-standard prestressed anchor bolt grouting construction and insufficient strength of hardened mortar by proposing standardized construction procedures. It effectively reduces construction risks and ensures construction quality.

[0054] Specifically, the leveling shims complete the leveling operation after coarse leveling and fine leveling.

[0055] In this embodiment, the coarse leveling is achieved by using a spirit level to adjust adjacent leveling shims until they are flush; the fine leveling is achieved by using a laser level to measure the levelness of the leveling shims around the entire circumference to meet the design requirements.

[0056] Specifically, the fine leveling process requires randomly selecting one of the leveling shims as a reference point to place the laser emitter, taking multiple leveling shims other than the reference point to measure their height deviation values, recording the data, and analyzing the deviation data to determine whether it meets the design requirements.

[0057] Specifically, the leveling process should control the overall height of the leveling shims to ensure that after the flange 12 of the wind turbine base tower 13 is installed, the exposed thread length of the bolt 2 meets the requirements of the tensioner.

[0058] Specifically, the prestressed anchor grouting construction method also includes the following steps: S501, heat shrink tubing installation, using heat shrink tubing to protect the portion of the anchor cage 1 between the foundation 6 and the flange 12 to isolate the bolt 2 and the grouting material.

[0059] Optionally, the height of the heat shrink tubing protection is 15-30mm, and in this embodiment, the specific protection height is 20mm.

[0060] Specifically, the prestressed anchor grouting construction method also includes the following steps: S701, formwork sealing, using polyurethane foam sealant to seal the gaps between the formwork and the foundation 6 and between the formworks to avoid missing gaps that could lead to grout leakage during grouting. For areas with larger or more gaps, polyurethane foam sealant should be used to seal both the inner and outer sides of the formwork.

[0061] Specifically, the prestressed anchor grouting construction method also includes the following steps: S801, curing, curing the grouting area 5 by covering the entire grouting area 5 with straw mats or blankets, and sprinkling water intermittently to keep the straw mats or blankets moist. When covering the grouting area 5, the straw mats or blankets should be draped over the top of the bolts of the anchor cage 1, and fixed to the formwork with ropes and wood clamps to avoid contact with the grout.

[0062] Specifically, the prestressed anchor grouting construction method also includes the following steps: S901, spraying curing agent. After demolding, a concrete curing agent is evenly sprayed or brushed onto the hardened mortar surface to form a protective film on the hardened surface, which plays a curing role.

[0063] As shown in Figures 3 to 5, the template includes an inner ring template 11 and an outer ring template 10. The inner ring template 11 is disposed on the inner side of the flange 12, and the outer ring template 10 is disposed on the outer side of the flange 12. Both the inner ring template 11 and the outer ring template 10 include multiple segment structures 7 with arc cross-sections. The segment structures 7 are connected end to end to form a ring structure with a circular cross-section.

[0064] In this embodiment, the inner ring template 11 is a ring structure formed by the segment structure 7, and the outer ring template 10 is a ring structure formed by the segment structure 7. The inner ring template 11 and the outer ring template 10 are concentric circles, and the radius of the inner ring template 11 is smaller than that of the outer ring template 10.

[0065] Optionally, the segment structure 7 is made of channel steel.

[0066] Specifically, the segment structure 7 is also provided with a rib plate 8, which has a reinforcing function.

[0067] Optionally, in this embodiment, for ease of handling and demolding, the inner ring template 11 and the outer ring template 10 are each divided into four equal-length arcs, which are connected by screws during installation.

[0068] Optionally, the template is coated with release oil before installation to prevent the template from sticking to the concrete and damaging the concrete during demolding.

[0069] Optionally, a support block 9 of equal length is provided between the flange 12 and the inner ring template 11, so that the flange 12 is equidistant from the inner ring template 11; a support block 9 of equal length is provided between the flange 12 and the outer ring template 10, so that the flange 12 is equidistant from the outer ring template 10.

[0070] Specifically, the grouting process involves removing excess polyurethane foam sealant from the grouting area 5 after it has fully hardened, cleaning the area, and then commencing grouting. First, lubrication is performed by mixing lubricating material in a mixer and pumping it into the grouting pipeline system to lubricate the grouting pump and hoses. Next, the grouting material is mixed and pumped through the grouting pipeline until the grouting material reaches the design elevation. Once the design elevation is reached, pumping is stopped, the grout is allowed to stand, and the liquid level is observed to ensure it is above the lower surface of flange 12. After confirming that the requirements are met, grouting is completed. Excess grout in the grouting pump hopper is poured into the waste tank, and the mixer, grouting pump, and grouting pipeline are cleaned. The construction site is also cleaned.

[0071] Specifically, the lubricating material has high fluidity and resistance to water dispersion. Pumped into the grouting pipeline before the grouting material is pumped in, it effectively lubricates the grouting pump and grouting hose, preventing blockage in the grouting pipeline system. However, the strength of the lubricating material is lower than that of the grouting material; therefore, the lubricating material should be discharged from the grouting pipeline system before grouting area 5.

[0072] Specifically, the curing agent is a liquid film-forming compound. When sprayed onto the surface of concrete or mortar, it quickly forms a colorless, waterproof film as the moisture in the curing agent evaporates. This effectively prevents the evaporation of moisture from the concrete or mortar, reducing problems such as shrinkage and cracking of the concrete or mortar.

[0073] This application addresses the problem of cracks appearing in hardened mortar by proposing measures such as covering it with straw mats or bedding for curing and spraying a curing agent after demolding for long-term maintenance. These measures effectively reduce the risk of cracks appearing in hardened mortar when exposed to harsh environments such as sunlight and wind.

[0074] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. The preferred embodiments have been described in detail. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application, and all such modifications and substitutions should be covered within the scope of the claims of this application.

Claims

1. A method for grouting prestressed anchor bolts, characterized in that, Includes the following steps: S100. Measurement and positioning to determine the roughening area and template installation location; S200, roughen the surface of the foundation concrete to remove laitance and soft layer; S300, Clean the work surface; S400, wetting, to ensure the concrete surface of the foundation cap is moist; S500, leveling: lay grout on the concrete surface of the foundation for leveling, place multiple leveling shims between adjacent anchor bolts in the anchor cage, and level the horizontality of the multiple leveling shims. S600, installation of the wind turbine base tower; S700, Template installation: Set the position of the template according to the measurement and positioning marks so that the distance between the template and the flange of the wind turbine base tower is equal; S800, grouting; S900, Demolding.

2. The prestressed anchor grouting construction method according to claim 1, characterized in that, It also includes the following steps: S501, heat shrink tubing installation, using heat shrink tubing to protect the portion of the anchor cage between the bearing platform and the flange, in order to isolate the anchor bolt and the grout.

3. The prestressed anchor grouting construction method according to claim 1, characterized in that, It also includes the following steps: S701, template sealing, which involves sealing the gaps between the template and the foundation, as well as the gaps between templates, with polyurethane foam sealant.

4. The prestressed anchor grouting construction method according to claim 1, characterized in that, It also includes the following steps: S801, curing, which involves curing the grouting area.

5. The prestressed anchor grouting construction method according to claim 4, characterized in that, The maintenance is carried out by covering and / or spraying a maintenance agent.

6. The prestressed anchor grouting construction method according to any one of claims 1 to 5, characterized in that, The leveling shims complete the leveling operation after coarse and fine leveling.

7. The prestressed anchor grouting construction method according to any one of claims 1 to 5, characterized in that, The template includes an inner ring template and an outer ring template. The inner ring template is disposed on the inner side of the flange, and the outer ring template is disposed on the outer side of the flange. Both the inner ring template and the outer ring template include multiple segment structures with arc cross-sections. The segment structures are connected end to end to form a ring structure with a circular cross-section.

8. The prestressed anchor grouting construction method according to claim 7, characterized in that, The segment structure is also provided with ribs.

9. The prestressed anchor grouting construction method according to any one of claims 1 to 5, characterized in that, The template is coated with release oil before installation.

10. The prestressed anchor grouting construction method according to any one of claims 1 to 5, characterized in that, The grouting process begins with pipe lubrication, followed by pumping the grout material to the design elevation.

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