Lattice tower prestressed cable penetrating method

Abstract

The invention belongs to the field of lattice tower prestressed cable construction, and particularly relates to a lattice tower prestressed cable penetrating method which is characterized in that an anchorage device support is arranged on a construction platform at the top of a lattice tower, an anchor ring, a backing ring and a steering wheel are sequentially arranged on the anchorage device support from top to bottom, and through holes in one-to-one correspondence with cable penetrating holes in the anchor ring are formed in the steering wheel; the through hole is a variable-diameter hole with the two ends large in hole diameter and the middle small in hole diameter, the inner hole wall of the through hole smoothly extends in the hole core direction, the first steel wire rope is restrained at the tower top and slowly droops, and a worker at the tower top pulls the first steel wire rope to control the steering wheel to move downwards to the corner position of the latticed column in a pipe cavity of the latticed column. The steel strand is matched with the hole wall or the hole edge of the through hole in the steering wheel in a surface contact mode, the situation that protruding radial shear force point positions exist due to point contact or line contact between the steel strand and the steering wheel is effectively avoided, and the steel strand is prevented from being fractured due to the influence of radial shear force.

Description

Technical Field

[0001] The invention patent relates to the construction of prestressed cables for lattice towers, and specifically to a method for threading prestressed cables through lattice towers. Background Art

[0002] Under the development background of the enlargement and high altitude of wind turbines, the application of lattice-type wind turbine towers has begun to increase. A prestressed cable bundle composed of multiple steel strands is threaded through a lattice column composed of hollow steel pipe concrete to improve the bending resistance and bearing capacity of the entire tower. Among them, Figure 1 As shown in Fig. 1, it is the general structure of lattice tower A. The lattice section of lattice tower A usually includes a lower section and an upper section. The lower section is usually a tapered foundation section A1 with a smaller top and a larger bottom, and the upper section is a straight section A2. The top of the straight section A2 can be further equipped with a steel tower barrel through the setting of a transition section, so as to install a wind turbine at the top of the steel tower barrel. In this tower structure, the column of lattice column a is not a regular straight pipe shape but is bent as a whole. On the one hand, it is to meet the clearance distance limit of the blade tips of the generator blades, so that the blades can rotate normally without interfering with the tower body. On the other hand, it is beneficial to improve the stability of the tower body. Based on the above situation, in the prior art, in the cable threading construction operation of the lattice column, it is first necessary to thread the steel strands into the lumen of the lattice column one by one, and then tension and pre-tighten the steel strands. However, due to the tube shape limitation of the lattice column, after the steel strands are tensioned and pre-tightened, the steel strands will have point and line contact with the corner points at the corners of the inner wall of the tube cavity, thus forming a large radial shear force, which easily causes the steel strands to break and has a non-negligible negative impact on the normal service life of the steel strands.

[0003] The patent document with the name "A Method for Prestressed Cable Threading Construction of Lattice Tower and Lattice Tower" (publication number: CN119373315A, hereinafter referred to as Document 1) discloses a method for prestressed cable threading construction of lattice tower, including steps of installing a support, installing a cable threading ring plate, arranging a traction mechanism, performing cable threading work, and adjusting the cable threading ring plate. In this construction method, by using the traction mechanism to traction the cable threading ring plate to drive one end of the prestressed cable to move, it can ensure the normal lifting of the prestressed cable. And because one end of the prestressed cable is connected to the cable threading ring plate in advance, during the lifting process of the prestressed cable, they will not tangle with each other, which is beneficial to improving the cable threading construction efficiency of the prestressed cable. And by fixing the cable threading ring plate at the corner position of the lattice tower, it can effectively reduce the friction between the prestressed cable and the corner position.

[0004] In the above technical solution, by arranging the cable-passing ring plate at the corner position of the lattice tower, the cable-passing ring plate is used to prevent the prestressed cable from directly contacting the corner point in the lumen of the lattice column and generating friction, thereby preventing the prestressed cable from being frictionally fractured at the corner point of the lattice tower. However, after the prestressed cable is tensioned, even if the prestressed cable does not make point or line contact with the corner point or line of the lattice column, the point and line contact formed by the prestressed cable at the corner cannot be avoided, and the larger the angle at the corner position of the lattice column, the more obvious this is, because the same problem also exists between the prestressed cable and the orifice of the cable-passing ring plate. Secondly, the cable-passing scheme provided in Document 1 is that the traction mechanism is connected to the cable-passing ring plate through a traction cable, and the traction mechanism repeatedly pulls the cable-passing ring plate to move up and down in the lumen of the lattice column to carry the prestressed cable for threading. For this scheme, on the one hand, the cable-passing ring plate only carries and threads a single prestressed cable for one up and down round trip. There are many prestressed cables to be threaded in the lumen of the lattice column, and the up and down round trip operation of the cable-passing ring plate is cumbersome and seriously affects the efficiency. On the other hand, during the up and down movement of the cable-passing ring plate, it not only has to overcome the relative friction with the prestressed cable and the friction with the lumen of the lattice column, but also has to overcome the self-weight of the prestressed cable. This process is repeated many times, the load of the traction mechanism is greatly increased, the energy consumption is significantly increased, and the cable-passing ring plate is easily damaged by repeated friction, resulting in abnormal use. Summary of the Invention

[0005] The present invention provides a method for threading prestressed cables of a lattice tower, which solves the problem that the prestressed cable only has point and line contact with the corner of the lattice tower after being tensioned, resulting in the prestressed cable being easily fractured due to the radial shear force, and at the same time optimizes the overall construction plan of the cable-passing operation, improves the overall cable-passing efficiency of the lattice tower and reduces the energy consumption during the cable-passing process of the equipment.

[0006] In order to achieve the above object, the technical solution adopted is: a method for threading prestressed cables of a lattice tower, comprising the following steps:

[0007] Step 1: An anchor support is arranged on the construction platform at the top of the lattice tower. An anchor ring, a spacer ring and a steering disc are arranged on the anchor support from top to bottom in sequence. The steering disc has through holes corresponding one by one to the cable-passing holes on the anchor ring. The through holes are variable-diameter holes with larger diameters at both ends and a smaller diameter in the middle, and the inner hole wall of the through holes is smoothly extended in the direction of the hole core;

[0008] Step 2: A cable-passing machine is arranged on the construction platform. The steel strand is pulled from the bottom of the tower to the construction platform by the shuttle machine, and the cable-passing machine drives the steel strand to pass through the cable-passing hole on the anchor ring, the spacer ring and the corresponding through hole on the steering disc from top to bottom, and controls the free end of the steel strand to be lowered along the lumen of the lattice column to the bottom of the tower until the steel strand passes through to the bottom of the tower. The steel strand is locked with the anchor ring through the wedge-shaped clamp, and the steel strand above the wedge-shaped clamp is cut off;

[0009] Step 3: Control the lower end of the steel strand to pass from top to bottom through the cable hole on the tensioning end anchor set in the tower bottom foundation;

[0010] Step 4: Repeat the above steps 2 and 3 until the threading of the steel strands through all the cable holes on the anchor ring is completed;

[0011] Step 5: A first steel wire rope is pre-connected to the upper end of the steering wheel and the free end of the first steel wire rope is controlled by a person at the top of the tower. After step 4 is completed, the constraint on the steering wheel on the anchor bracket is released, and the first steel wire rope is constrained at the top of the tower and slowly lowered. The person at the top of the tower pulls the first steel wire rope to control the steering wheel to move down in the lumen of the lattice column to the corner position of the lattice column, and then the falling movement of the steering wheel is restricted by the positioning member;

[0012] Step 6: Install the clips in the cable holes on the tensioning end anchor, and then tension and pre-tighten each steel strand.

[0013] Compared with the prior art, the technical effect of the present invention is as follows: through the steering wheel and the hole type setting thereon, the steering wheel is placed at the corner position of the lattice tower tube cavity. After the steel strand is pre-tensioned, since the through hole is a variable diameter hole with a large aperture at both ends and a small aperture in the middle, and the inner hole wall of the through hole is smooth and extended in the direction of the hole core, the steel strand and the hole wall or hole edge of the through hole on the steering wheel form a surface contact fit, which effectively avoids the occurrence of point and line contact between the steel strand and the steering wheel, resulting in prominent radial shear force points, and prevents the steel strand from being broken due to the influence of radial shear force. In addition, the steel strands are inserted one by one from top to bottom by the shuttle, and there is no need for the steering wheel to move back and forth between the bottom and the top of the tower to pull the steel strand. On the one hand, it avoids the problem of repeated displacement of the steering wheel causing wear and tear and being unusable, and on the other hand, it is also conducive to improving the overall cable threading efficiency and reducing the energy consumption of the cable threading operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the lattice tower structure;

[0015] Figure 2 This is a schematic diagram of the construction platform on the top of the tower;

[0016] Figure 3 It is a schematic diagram of the components on the anchor bracket during the cable threading process;

[0017] Figure 4 This is a schematic diagram of the position of the anchor ring after the cable is threaded;

[0018] Figure 5 is a schematic diagram of the angular position of the steering wheel in the tube cavity of the lattice column;

[0019] Figure 6 This is a schematic diagram of the tower bottom foundation;

[0020] Figure 7 It is a schematic diagram of the tension end anchor

[0021] Figure 8 It is a top view of the cross-section of the positioning member on the lattice column

[0022] Figure 9 It is a schematic diagram of the shuttling sequence

[0023] Figure 10 It is a schematic diagram of the tensioning sequence

[0024] Figure 11 It is a schematic diagram of the cross-sectional structure of the steering wheel

[0025] Figure 12 It is a schematic diagram of the cable threading through the variable-diameter hole steering wheel Figure 1 ;

[0026] Figure 13 It is a schematic diagram of the cable threading through the variable-diameter hole steering wheel Figure 2 ;

[0027] Figure 14a It is a schematic diagram of the shear force point of the straight-hole steering wheel Figure 1 ;

[0028] Figure 14b It is a schematic diagram of the shear force point of the straight-hole steering wheel Figure 2 ;

[0029] Figure 15 It is a comparison diagram of the steel strand orientations with different cable threading sequences Specific implementation manners

[0030] Next, in combination with the attached Figure 1-15 and related content, the present invention will be further described in detail as follows:

[0031] A method for threading prestressed cables of a lattice tower includes the following steps:

[0032] Step 1: An anchor support 10 is arranged on the construction platform 1 at the top of the lattice tower A. An anchor ring 11, a spacer ring 13, and a steering wheel 12 are arranged on the anchor support 10 from top to bottom in sequence. The steering wheel 12 has through holes 121 that correspond one-to-one with the cable threading holes on the anchor ring 11. The through holes 121 are variable-diameter holes with larger diameters at both ends and a smaller diameter in the middle, and the inner hole wall of the through holes 121 is smoothly extended in the hole core direction;

[0033] Step 2: A cable threading machine 20 is arranged on the construction platform 1. The steel strand B is towed from the tower bottom to the construction platform 1 by the shuttle machine 20, and the cable threading machine 20 drives the steel strand B to pass through the cable threading holes on the anchor ring 11, the spacer ring 13, and the corresponding through holes 121 on the steering wheel 12 from top to bottom, and controls the free end of the steel strand B to be lowered along the lumen a1 of the lattice column a to the tower bottom until the steel strand B penetrates out to the tower bottom. The steel strand B is locked with the anchor ring 11 through the wedge-shaped clamp, and the steel strand B above the wedge-shaped clamp is cut off;

[0034] Step 3: Control the lower end of the steel strand B to pass through the cable threading hole on the tensioning end anchor 70 arranged in the tower bottom foundation 60 from top to bottom;

[0035] Step 4: Repeat the above Step 2 and Step 3 until the threading operation of the steel strand B for all the cable threading holes on the anchor ring 11 is completed;

[0036] Step 5: Connect a first steel wire rope 122 to the upper end of the steering wheel 12 in advance, and the free end of the first steel wire rope 122 is controlled by the personnel at the tower top. After Step 4 is completed, at this time, the restraint on the steering wheel 12 on the anchor support 10 is released, the first steel wire rope 122 is restrained at the tower top and slowly lowered, and the personnel at the tower top pull the first steel wire rope 122 to control the steering wheel 12 to move down in the lumen a1 of the lattice column a to the corner position of the lattice column a, and then the falling movement of the steering wheel 12 is restricted by the positioning member 30;

[0037] Step 6: Install wedge-shaped clamps in the cable threading holes on the tensioning end anchor 70, and then perform tension pre-tightening on each steel strand B.

[0038] In the above cable threading scheme, by setting the steering wheel 12 and the hole patterns thereon, the steering wheel 12 is placed at the corner position of the lumen a1 of the lattice tower a. After the steel strand B is tension pre-tightened, as Figures 11-13 shown, since the through hole 121 is a variable diameter hole with large diameters at both ends and a small diameter in the middle, and the inner hole wall of the through hole 121 is smoothly extended in the hole core direction, the steel strand B and the hole wall or hole edge of the through hole 121 on the steering wheel 12 form a surface contact fit, effectively avoiding the occurrence of point and line contacts between the steel strand B and the steering wheel 12 and the existence of prominent radial shear force points, and preventing the steel strand B from breaking due to the influence of radial shear force. On the contrary, as Figure 14a 、 Figure 14b shown, if the through hole 121 is an ordinary straight hole, after the steel strand B turns at the corner, it will be squeezed against the mouth edge to generate prominent radial shear force points (the positions shown by the circular black dots), which is likely to cause the steel strand B to break.

[0039] It should be noted that according to the size of the corner of the lattice column a, the curvature of the inner wall surface of the through hole 121 on the steering wheel 12 is also different. For example, the larger the corner of the lattice column a, the curvature of the inner wall surface of the through hole 121 can be appropriately increased to avoid the point and line contact between the steel strand B and the edge of the through hole 121.

[0040] In addition, in the preliminary preparation work of the cable threading method provided by the present invention, the cable reel around which the steel strand B is wound is placed at the bottom of the tower, and the steel strand B is pulled to the top of the tower by a pulling rope machine, and the contact parts of the steel strand B along the way and with the lattice tower A are protected to prevent the PE layer of the steel strand B from being damaged. When threading the cable, the steel strand B is connected to the shuttle 20, and the free end of the steel strand B is driven by the shuttle 20 to be threaded into the cable threading hole on the anchor ring on the anchor support 10. The steel strand B is threaded one by one from top to bottom, and passes through the anchor ring 11, the spacer ring 13 and the steering wheel 12 in sequence, and is lowered into the tower bottom foundation 60 along the lumen a1 of the lattice column a. At the same time, the steel strand B is threaded through the cable threading hole on the tension end anchor 70 in the tower bottom foundation 60. In this way, the steel strand B is repeatedly threaded into the cable threading hole on the anchor ring 11, and finally the first steel wire rope 122 is pulled manually or by equipment to lower the steering wheel 12 to the corner position of the lattice column a. This solution does not require the steering wheel 12 to move back and forth between the bottom and the top of the tower to pull the steel strand B. On the one hand, it avoids the problem that the steering wheel 12 is worn out and cannot be used due to repeated displacement, and on the other hand, it is also beneficial to improve the overall cable threading efficiency.

[0041] Here, considering that the steel strand B has to pass through the cable threading hole on the tension end anchor 70 from the lumen a1 of the lattice column a, in order to avoid the tension end anchor 70 blocking the lower port of the lumen a1 and affecting the threading of the steel strand B, before all the steel strands B are threaded, the tension end anchor 70 is also separated from the lower port of the lumen a1 of the lattice column a by using the anchor support to leave space for the personnel at the bottom of the tower to control the steel strand B to pass through the cable threading hole on the tension end anchor 70. This is a well-known technology in the art and will not be elaborated here.

[0042] It should be noted that in the above solution, the aperture of the through hole 121 on the steering wheel 12 is larger than the wire diameter of the steel strand B. In the case where the steering wheel 12 itself is heavy, under the influence of gravity, lowering the first steel wire rope 122 can control the steering wheel 12 to naturally fall to the corner position of the lattice column a.

[0043] Furthermore, in order to ensure that the steel strand B can be threaded straight up and down through the cable threading hole on the anchor ring 11 and the through hole 121 on the steering wheel 12, in step one, the hole area of the through hole 121 on the steering wheel 12 and the hole area of the cable threading hole on the anchor ring 11 are arranged vertically opposite to each other, so that the steel strand B is more convenient to thread and will not be inconvenient to thread due to the misalignment of the hole areas.

[0044] As a preferred solution, in step five, a second steel wire rope 123 is pre-connected to the lower end of the steering wheel 12. The free end of the second steel wire rope 123 is lowered along the lumen a1 of the lattice column a to the tower bottom and is controlled by the personnel or equipment at the tower bottom. The personnel at the tower top and the personnel at the tower bottom respectively pull the first steel wire rope 122 and the second steel wire rope 123 to jointly control the steering wheel 12 to move down in the lumen a1 of the lattice column a to the corner position of the lattice column a. This solution is aimed at the situation where the steering wheel 12 itself is relatively light in weight (plastic part) or the aperture of the through hole 121 and the wire diameter of the steel strand B have a small difference, resulting in relatively large friction. In order to ensure that the steering wheel 12 can move down smoothly in the lumen a1 without being affected by the friction between the steering wheel 12 and the steel strand B, by adding the second steel wire rope 123 at the lower end of the steering wheel 12, when the personnel at the tower top loosen the first steel wire rope 122, the personnel at the tower bottom pull down the second steel wire rope 123, so as to ensure that the steering wheel 12 can be pulled down to the corner position of the lattice column a. Among them, under the traction control of the personnel at the tower top, the first steel wire rope 122 can ensure that the steering wheel 12 will not fall.

[0045] As a preferred solution, in step one, columnar wire dividing rings 40 are arranged at intervals below the steering wheel 12, and the wire dividing rings 40 are connected to the steering wheel 12 through connecting ropes 14. The wire dividing rings 40 are provided with through holes for the steel strand B to pass through, and the hole areas of the through holes correspond one by one to the cable passing holes on the anchor ring 11 and the through holes 121 on the steering wheel 12. The wire dividing rings 40 are short columnar with multiple holes. Because they are connected to the steering wheel 12 through the connecting ropes 14 to form an integral structure, they can move down into the lumen a1 of the lattice column a together with the steering wheel 12. The function of the wire dividing rings 40 is to comb the line segments of the steel strand B at the corner position to prevent the steel strand B from being entangled with each other.

[0046] Furthermore, when a wire dividing ring 40 is connected below the steering wheel 12, in step five, the second steel wire rope 123 is not directly connected to the steering wheel 12. Instead, the second steel wire rope 123 is pre-connected to the lower end of the wire dividing ring 40. The free end of the second steel wire rope 123 is lowered along the lumen a1 of the lattice column a to the tower bottom and is controlled by the personnel at the tower bottom. The personnel at the tower top and the personnel at the tower bottom respectively pull the first steel wire rope 122 and the second steel wire rope 123 to jointly control the steering wheel 12 to move down in the lumen a1 of the lattice column a to the corner position of the lattice column a. On the one hand, this can pull the wire dividing ring 40 through the second steel wire rope 123 and drive the steering wheel 12 to displace towards the corner position of the lattice column a. On the other hand, it can also fully separate the wire dividing ring 40 and the steering wheel 12 from each other at the corner position. The wire dividing ring 40 is located in the lumen a1 of the lattice column a below the corner position and will not be present at the corner position to generate an outstanding radial shearing force on the steel strand B.

[0047] It should be noted that the solution of adding the second steel wire rope 123 is applicable to the situation where the self-weight of the steering wheel 12 is relatively light or the aperture of the through hole 121 and the wire diameter of the steel strand B have a small difference, resulting in a large friction. Among them, the steering wheel 12 and the wire dividing ring 40 are connected by a connecting rope 14. The connecting rope 14 is preferably a steel wire rope and is not easily broken. Furthermore, when the fixing constraints of the wire dividing ring 40 and the steering wheel 12 on the anchor support 10 are released, the wire dividing ring 40 can be manually controlled to slowly drop until the connecting rope 14 is straightened, and then the personnel at the tower bottom pull the second steel wire rope 123 to prevent the wire dividing ring 40 from falling after the fixing constraint is cancelled and causing the connecting rope 14 to be broken by the fall.

[0048] As a preferred solution, during the process of the shuttle 20 controlling the steel strand B to pass through the cable downward, when the steel strand B reaches the base section A2 from the vertical section A2 in the pipe cavity a1, since the lattice columns a on the base section A2 are arranged obliquely outward from top to bottom, the free end of the steel strand B will first contact the inclined pipe wall of the lattice column a on the base section A2 close to the tower center, thus hindering the straight-up-and-down falling movement of the free end of the steel strand B. In addition, the free end of the steel strand B is not smooth, so when the free end of the steel strand B touches the inclined pipe wall, the wire segment is likely to curl and the steel strand B cannot fall normally along the pipe cavity a1. Therefore, in step two, when the steel strand B passes through the through hole 121 on the steering wheel 12, a guiding head 50 is connected to the free end of the steel strand B. Driven by the gravity of the guiding head 50, the guiding head 50 will surely slide down along the pipe cavity a1 of the lattice column a, thereby pulling the free end of the steel strand B to displace towards the tower bottom, ensuring that the steel strand B will not curl in the pipe cavity a1.

[0049] Furthermore, the overall shape of the guiding head 50 is bullet-shaped with the tip facing downwards, and the smooth bullet-shaped guiding head 50 slides more smoothly in the pipe cavity a1.

[0050] Considering that the second steel wire rope 123 is softer and lighter than the steel strand B, in order to avoid the situation where the free end of the second steel wire rope 123 stays in the pipe cavity a1 and cannot pass through the tower bottom, in step two, when the free end of the steel strand B passes through the through hole 121 on the steering wheel 12, the free end of the second steel wire rope 123 is connected to the free end of the steel strand B, and the free end of the second steel wire rope 123 is brought to the tower bottom by lowering the steel strand B. Utilizing the self-weight of the steel strand B to fall, the second steel wire rope 123 is led to pass through the tower top to the tower bottom together, so that the personnel at the tower bottom can pull the second steel wire rope 123.

[0051] Combined with Figure 8 and Figure 9As shown, there are multiple cable-passing holes on the anchor ring 11. The cable-passing method provided by the present invention does not simply involve randomly selecting a hole position to pass the steel strand B. In step four, when passing the steel strand B through the anchor ring 11, first pass through the cable-passing holes close to the tower center (such as the digital sequence shown in Figure 9 ), and pass the cables row by row from the tower center to the outside of the tower until the operation of passing the steel strand B through all the cable-passing holes on the anchor ring 11 is completed. Suppose the cable-passing holes close to the outside of the tower are passed first. After the first steel strand B1 passes through the corner position, the first steel strand B1 will be stacked on the inner cavity wall of the lumen a1 of the base section A1 close to the tower center. At this time, when passing through the cable-passing holes close to the tower center, there is a possibility that the free end of the subsequent steel strand B2 will be blocked by the first steel strand B1 and cannot fall normally (as shown in the left part of Figure 15 ); on the contrary, if the cable-passing holes close to the tower center are passed first, the above situation will not occur (as shown in the right part of Figure 15 ).

[0052] As a preferred solution, in step five, at least three first steel wires 122 are provided and are circumferentially equidistantly distributed at the connection positions on the steering wheel 12. A single first steel wire 122 easily causes the steering wheel 12 to be stressed unevenly, resulting in the possibility that the steering wheel 12 may tilt severely during the lowering process, and thus it cannot be normally lowered to the corner position of the lattice column a. For this reason, three first steel wires 122 are evenly distributed on the steering wheel 12 and are respectively pulled by different personnel at the top of the tower to control the stable downward movement of the steering wheel 12 in the lumen a1.

[0053] Combined with Figure 3 and Figure 5 shown, in step five, a fixed-length mark is made on the first steel wire 122. When controlling the downward movement of the steering wheel 12 in the lumen a1 of the lattice column a, with the top construction platform 1 as the reference, when the fixed-length mark on the first steel wire 122 approaches the reference position, an endoscope is used to observe the relative position of the steering wheel 12 in the lumen a1 at the corner position of the lattice column a to determine whether the steering wheel 12 has reached the corner position of the lattice column a. In this solution, during the downward movement of the steering wheel 12, through the fixed-length mark set on the first steel wire 122, it is generally possible to know whether the released length of the first steel wire 122 can meet the requirement for the steering wheel 12 to reach the corner position. The specific situation can be observed through an endoscope at the corner position of the lattice tower A to further precisely adjust the released length of the first steel wire 122 to ensure that the steering wheel 12 reaches the corner position.

[0054] Combined with Figure 5As shown in the figure, the positioning member 30 includes a positioning tube 31. The positioning tube 31 is pre-set at the corner position of the lattice column a. The core direction of the positioning tube 31 is arranged along the radial direction of the lattice column a, and the tube body of the positioning tube 31 avoids the falling path of the steering wheel 12. When judging whether the steering wheel 12 reaches the corner position of the lattice column a, the endoscope is inserted into the positioning tube 31 and extends into the tube cavity a1 of the lattice column a. When the steering wheel 12 moves down to the upper side of the position where the positioning tube 31 is located, a positioning rod 32 is inserted into the positioning tube 31, and the inner rod end of the positioning rod 32 supports the lower end face of the steering wheel 12.

[0055] In this solution, an endoscope is inserted into the pre-set positioning tube 31 at the corner position of the lattice column a to observe whether the steering wheel 12 reaches the specified position. When the steering wheel 12 has reached the upper side of the position where the positioning tube 31 is located, a positioning rod 32 is inserted into the positioning tube 31, so that the inner rod end of the positioning rod 32 supports the lower end face of the steering wheel 12, thereby restricting the falling movement of the steering wheel 12 and realizing the positioning of the steering wheel 12.

[0056] Furthermore, as Figure 5 shown, two steering wheels 12 are arranged at intervals up and down in advance and are connected to each other by a connecting rope 14. Two positioning tubes 31 are arranged at intervals up and down in advance and are respectively located at the upper and lower positions near the corner point of the lattice column a. The distance between the two positioning tubes 31 is less than or equal to the length of the connecting rope 14 between the two steering wheels 12. When it is observed through the endoscope that the lower steering wheel 12 moves down to the upper side of the position where the lower positioning tube 31 is located, positioning rods 32 are inserted into the two positioning tubes 31 respectively, and the inner rod ends of the two positioning rods 32 respectively support the lower end faces of the two steering wheels 12.

[0057] This solution is for the case where two steering wheels 12 are arranged at intervals up and down. The positioning rod 32 in the upper positioning tube 31 and the positioning rod 32 in the lower positioning tube 31 respectively support the upper and lower two steering wheels 12, so as to ensure that both steering wheels 12 can reach the specified positions, that is, one steering wheel 12 is above the corner, and the other steering wheel 12 is below the corner and both steering wheels 12 are near the corner position, as Figure 5 shown.

[0058] As a preferred solution, at least three positioning tubes 31 are arranged equidistantly in the circumferential direction of the lattice column a to prevent the supporting force received by the steering wheel 12 in the tube cavity a1 from being unevenly distributed and causing the steering wheel 12 to tilt and affect the normal steering of the steel strand B at the corner position of the lattice column a.

[0059] Combined with Figure 4As shown, after the steering wheel 12 is positioned, that is, when the inner rod end of the positioning rod 32 is at the supporting position for supporting the lower end surface of the steering wheel 12, the free end of the first towing rope 122 is fixed. At the same time, the constraints of the anchor support 10 on the anchor ring 11 and the spacer ring 13 are released, and the anchor ring 11 and the spacer ring 13 are lowered to and fixed on the embedded anchor backing plate a2 at the upper port of the pipe cavity a1, so as to complete the fixed installation between the anchor ring 11 and the lattice tower A.

[0060] Combined with Figure 8 and Figure 10 As shown, in step six, the steel strand B in the cable-passing hole near the outside of the tower is first tensioned, and the steel strands B are tensioned row by row from the outside of the tower to the center of the tower. Among them, for the steel strands B in the same row of cable-passing holes on the anchor ring 11, the steel strand B in the middle cable-passing hole is first tensioned, and then, with the middle cable-passing hole as the symmetry point, the steel strands B in the symmetric cable-passing holes in the same row are successively and individually tensioned. For example, Figure 10 for the steel strands B in the columns where 14# - 22# are located in, the 14# is first tensioned, and then the 15# and 16# are tensioned, and so on, until all the steel strands B are tensioned and pre-tightened. In this scheme, the tensioning sequence of the steel strand B is limited. When the steel strand B is tensioned and pre-tightened, the steel strand B has a tendency to deflect towards the outside of the tower, thereby generating a pressure on the steering wheel 12 pointing towards the outside of the tower. If the steel strand B in the cable-passing hole near the outside of the tower is not tensioned and pre-tightened at the beginning, but the steel strand B in the cable-passing hole near the center or the side of the tower is selected, the part of the steering wheel 12 near the outside of the tower lacks positioning, and when the steel strand B is pre-tightened, it is easy to cause the steering wheel 12 to rotate in the pipe cavity a1 due to uneven force, resulting in the steel strands B being wound around each other in the pipe cavity a1 and unable to be used normally. Figure 10 What is shown is the tensioning sequence of the steel strand B in the cable-passing method provided by the present invention, that is, the numerical sequence in the figure.

[0061] It should be noted that Figure 9 and Figure 10 what is shown is a basic schematic diagram of the corresponding relationship between the steel strand B and the cable-passing hole from a top-down perspective, rather than directly pointing to the specific structure of the anchor ring 11 or the specific position of the steel strand B in the pipe cavity a1.

[0062] As a preferred solution, in the present invention, the pre-tightening force of each steel strand B is first uniformly tensioned to 30% of the standard pre-tightening force, and then the pre-tightening force of the steel strand B is tensioned to 100%-103% of the standard pre-tightening force according to the same tensioning sequence. In this solution, the first step of tensioning to 30% of the standard pre-tightening force is to achieve the basic positioning of each component, and also provides the stress required for the basic positioning of the steering wheel 12 in the lumen a1. Subsequently, the pre-tightening force is tensioned to 100%-103% of the standard pre-tightening force to complete the pre-tightening operation of the steel strand B. Compared with the form of directly tensioning the steel strand B to 100%-103% of the standard pre-tightening force at the beginning, it is more helpful to avoid the rotation of the steering wheel 12.

[0063] In addition, after the tensioning of each steel strand B is completed, the length of the steel strand B below the tensioning end anchor 70 is reserved at 980 mm - 1000 mm, and a cap 71 for accommodating the free section below the steel strand B is installed on the tensioning end anchor 70, and an outer cap 111 for accommodating the free section above the steel strand B is installed on the tower top anchor ring 11. The cap 71 and the outer cap 111 respectively protect the bottom exposed section and the top exposed section of the steel strand B, and at the same time apply anti-corrosion and sealing measures.

[0064] Finally, after the cable-passing construction of the lattice tower A is completed, that is, after step six is completed, the tower top construction platform 1 and the cable-passing machine 20 are removed and lifted to the ground by the main crane, so as to install a steel tower barrel or a wind turbine unit on the vertical section A2 of the lattice tower A. It should be noted that for the construction platform 1 and various components to be arranged thereon, they can be assembled at the tower bottom first and then lifted to the tower top together by the main crane.

[0065] It should be added that in step two, when the steel strand B is inserted into the cable-passing hole on the anchor ring 11, grease is applied to the PE protective sleeve on the outer surface of the steel strand B to avoid excessive friction between the wire body of the steel strand B and the cable-passing hole on the anchor ring 11 or the through hole on the steering wheel 12 during the perforation, resulting in damage.

Claims

1. A method for threading prestressed cables of a lattice tower, characterized in that, It includes the following steps: Step 1: An anchor support (10) is arranged on the construction platform (1) at the top of the lattice tower (A). An anchor ring (11), a spacer ring (13), and a steering wheel (12) are arranged on the anchor support (10) from top to bottom in sequence. The steering wheel (12) has through holes (121) that correspond one by one to the cable-passing holes on the anchor ring (11). The through holes (121) are stepped holes with larger diameters at both ends and a smaller diameter in the middle, and the inner hole wall of the through holes (121) is smoothly extended in the direction of the hole core; Step 2: A cable passing machine (20) is arranged on the construction platform (1). The steel strand (B) is towed from the tower bottom to the construction platform (1) by the shuttle machine (20), and the cable passing machine (20) drives the steel strand (B) to pass through the cable-passing holes on the anchor ring (11), the spacer ring (13), and the corresponding through holes (121) on the steering wheel (12) from top to bottom, and controls the free end of the steel strand (B) to be lowered along the lumen (a1) of the lattice column (a) to the tower bottom until the steel strand (B) penetrates out to the tower bottom. The steel strand (B) is locked with the anchor ring (11) through wedge-shaped keys, and the steel strand (B) above the wedge-shaped keys is cut off; Step 3: Control the lower end of the steel strand (B) to pass through the cable-passing hole on the tensioning end anchor (70) arranged in the tower bottom foundation (60) from top to bottom; Step 4: Repeat Step 2 and Step 3 above until the threading operation of the steel strands (B) in all the cable-passing holes on the anchor ring (11) is completed; Step 5: Connect a first steel wire rope (122) to the upper end of the steering wheel (12) in advance, and the free end of the first steel wire rope (122) is controlled by the personnel at the tower top. After Step 4 is completed, at this time, the restraint on the steering wheel (12) on the anchor support (10) is released. The first steel wire rope (122) is restrained at the tower top and slowly lowered. The personnel at the tower top pull the first steel wire rope (122) to control the steering wheel (12) to move down in the lumen (a1) of the lattice column (a) to the corner position of the lattice column (a), and then the falling movement of the steering wheel (12) is restricted by the positioning member (30); Step 6: Install wedge-shaped keys in the cable-passing holes on the tensioning end anchor (70), and then perform tension pre-tightening on each steel strand (B).

2. The cable threading method for the lattice tower prestressed cable according to claim 1, characterized in that: In Step 1, the hole areas of the through holes (121) on the steering wheel (12) and the cable-passing holes on the anchor ring (11) are arranged vertically opposite to each other.

3. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: In Step 5, connect a second steel wire rope (123) to the lower end of the steering wheel (12) in advance. The free end of the second steel wire rope (123) is lowered along the lumen (a1) of the lattice column (a) to the tower bottom and is controlled by the personnel at the tower bottom. The personnel at the tower top and the personnel at the tower bottom pull the first steel wire rope (122) and the second steel wire rope (123) respectively to jointly control the steering wheel (12) to move down in the lumen (a1) of the lattice column (a) to the corner position of the lattice column (a).

4. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: In step one, column-shaped wire dividing rings (40) are arranged at intervals below the steering wheel (12), and the wire dividing rings (40) are connected to the steering wheel (12) through connecting ropes (14). The wire dividing rings (40) are provided with through holes for the steel strands (B) to pass through, and the hole areas of the through holes correspond one by one to the cable passing holes on the anchor ring (11) and the through holes (121) on the steering wheel (12).

5. The method for threading prestressed cables of a lattice tower according to claim 4, wherein: In step five, a second steel wire rope (123) is pre-connected to the lower end of the wire dividing ring (40). The free end of the second steel wire rope (123) is lowered along the lumen (a1) of the lattice column (a) to the tower bottom and is controlled by the personnel at the tower bottom. The personnel at the tower top and the personnel at the tower bottom respectively pull the first steel wire rope (122) and the second steel wire rope (123) to jointly control the steering wheel (12) to move downward in the lumen (a1) of the lattice column (a) to the corner position of the lattice column (a).

6. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: In step two, when the steel strand (B) passes through the through hole (121) on the steering wheel (12), a guiding head (50) is connected to the free end of the steel strand (B).

7. The method for threading prestressed cables of a lattice tower according to claim 6, characterized in that: The overall shape of the guiding head (50) is bullet-shaped with the tip facing downward.

8. The method for threading prestressed cables of a lattice tower according to claim 3 or 5, characterized in that: In step two, when the free end of the steel strand (B) passes through the through hole (121) on the steering wheel (12), the free end of the second steel wire rope (123) is connected to the free end of the steel strand (B), and the free end of the second steel wire rope (123) is brought to the tower bottom by lowering the steel strand (B).

9. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: In step four, when threading the steel strand (B) through the anchor ring (11), the cable passing holes near the tower center are threaded first, and the cables are threaded row by row from the tower center to the outside of the tower until the threading operation of the steel strand (B) in all the cable passing holes on the anchor ring (11) is completed.

10. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: In step five, at least three first steel wire ropes (122) are provided and are circumferentially equidistantly distributed at the connection positions on the steering wheel (12).

11. The method for threading prestressed cables of a lattice tower according to claim 1 or 10, characterized in that: In step five, a fixed-length mark is made on the first steel wire rope (122). During the process of controlling the downward movement of the steering wheel (12) in the lumen (a1) of the lattice column (a), with the tower top construction platform (1) as the reference, when the fixed-length mark on the first steel wire rope (122) approaches the reference position, an endoscope is used to observe the relative position of the steering wheel (12) in the lumen (a1) at the corner position of the lattice column (a) to judge whether the steering wheel (12) has reached the corner position of the lattice column (a).

12. The method for threading prestressed cables of a lattice tower according to claim 11, wherein: The positioning member (30) includes a positioning tube (31). The positioning tube (31) is pre-set at the corner position of the lattice column (a). The core direction of the positioning tube (31) is arranged along the radial direction of the lattice column (a), and the tube body of the positioning tube (31) avoids the falling path of the steering wheel (12). When judging whether the steering wheel (12) has reached the corner position of the lattice column (a), the endoscope is inserted into the positioning tube (31) and extends into the lumen (a1) of the lattice column (a). When the steering wheel (12) moves downward to a position above the position where the positioning tube (31) is located, a positioning rod (32) is inserted into the positioning tube (31), and the inner rod end of the positioning rod (32) supports the lower end face of the steering wheel (12).

13. The method for threading prestressed cables of a lattice tower according to claim 12, wherein: Two steering wheels (12) are arranged at intervals vertically in advance and are connected to each other by a connecting rope (14). Two positioning pipes (31) are arranged at intervals vertically in advance and are respectively located at the upper and lower positions adjacent to the corner point of the lattice column (a). The distance between the two positioning pipes (31) is less than or equal to the length of the connecting rope (14) between the two steering wheels (12). When it is observed through the endoscope that the lower steering wheel (12) moves down to a position above the position where the lower positioning pipe (31) is located, positioning rods (32) are respectively inserted into the two positioning pipes (31), and the inner rod ends of the two positioning rods (32) respectively support the lower end surfaces of the two steering wheels (12).

14. The method for threading prestressed cables of a lattice tower according to claim 12 or 13, characterized in that: When the inner rod ends of the positioning rods (32) are at the supporting positions for supporting the lower end surfaces of the steering wheels (12), the free ends of the first traction ropes (122) are fixed. At the same time, the constraints of the anchor support (10) on the anchor ring (11) and the spacer ring (13) are released, and the anchor ring (11) and the spacer ring (13) are lowered to and fixed on the embedded anchor backing plate (a2) at the upper port of the pipe cavity (a1).

15. The method for threading prestressed cables of a lattice tower according to claim 12 or 13, characterized in that: At least three positioning pipes (31) are arranged equidistantly in the circumferential direction of the lattice column (a).

16. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: In step six, the steel strands (B) in the cable-passing holes near the outside of the tower are first tensioned, and the steel strands (B) are tensioned row by row from the outside of the tower to the center of the tower. Among the steel strands (B) in the same row of cable-passing holes on the anchor ring (11), the steel strand (B) in the middle cable-passing hole is first tensioned, and then, with the middle cable-passing hole as the symmetry point, the steel strands (B) in the symmetric cable-passing holes in the same row are successively and individually tensioned until the tensioning and pre-tightening operation of all the steel strands (B) is completed.

17. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: After the pre-tightening force of each steel strand (B) is uniformly tensioned to 30% of the standard pre-tightening force, the pre-tightening force of the steel strands (B) is then tensioned to 100%-103% of the standard pre-tightening force according to the same tensioning sequence.

18. The method for threading prestressed cables of a lattice tower according to claim 1 or 17, characterized in that: After the tensioning of each steel strand (B) is completed, the length of the steel strand (B) below the tensioning end anchor (70) is reserved at 980 mm - 1000 mm, and a cap (71) for accommodating the free section below the steel strand (B) is installed on the tensioning end anchor (70), and an outer cap (111) for accommodating the free section above the steel strand (B) is installed on the tower top anchor ring (11).

19. The method for threading prestressed cables of a lattice tower according to claim 1, characterized in that: After step six is completed, the tower top construction platform (1) and the cable-passing machine (20) are removed and lifted to the ground by the main hoist.

20. The cable threading method for the lattice tower prestressed cable according to claim 1, characterized in that: In step two, when the steel strands (B) are inserted into the cable-passing holes on the anchor ring (11), grease is applied to the PE protective sleeve on the outer surface of the steel strands (B).

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