Arc-shaped cable strand embedded pipe structure and its manufacturing and installation method for suspension bridge anchorage system

Abstract

The present invention discloses a structure and manufacturing and installation method for an arc-shaped cable strand embedded pipe of a suspension bridge anchoring system; the corresponding anchoring system comprises a straight segment L1, a circular segment L2 and a straight segment L3; a portion of the embedded pipe at the front end of the straight segment L1, the circular segment L2 and the straight segment L3 is designed as a branching pipe composed of multiple small steel pipes, while the embedded pipe at the rear end of the straight segment L3 is a single straight steel pipe. A rectangular branching plate is inserted 10 cm from the rear end of the branching pipe, and the 10 cm pipe body is inserted into the straight embedded pipe, and a circular branching plate and a 20 cm long circular connecting pipe are inserted 10 cm from the front end, with the branching pipe being perpendicular to the branching plate and the connecting pipe being parallel to the axis of the branching pipe. After installation is completed, the lower end branching plate is welded to the straight embedded pipe opening. The present invention has the following advantages: it avoids the problem of uneven force caused by multiple cable strands contacting, squeezing and entangled with each other in the circular segment embedded pipe; it solves the installation problem of circular cross-section and arc-shaped embedded pipes; and it is easy to operate.

Description

Technical Field

[0001] The invention relates to the field of suspension bridge anchorage and anchoring, in particular to a curved cable strand pre-buried pipe structure of a suspension bridge anchorage and anchoring system and a manufacturing and installation method thereof. Background Art

[0002] The pre-buried cable pipe in a suspension bridge anchorage system is a tubular structure embedded in the anchor concrete during the anchorage pouring process, forming a mounting channel for the anchor cable. Currently, most suspension bridge anchorage systems utilize linear cables, and the pre-buried pipe is a single, straight steel tube, making it extremely simple to manufacture and install. Installation requires only measuring the coordinates of two front and rear sections to determine the pre-buried pipe's position.

[0003] In recent years, the anchoring system of suspension bridges (see Figure 1 、 Figure 2 、 Figure 3 Curved strands have been used in the past. They are generally designed with three segments: a straight segment L1, a circular segment L2, and a straight segment L3. L1 is located near the front anchor surface and diverges from the front end, intersecting the IP point of the saddle. The rear end is a parallel straight segment parallel to the main cable centerline. The circular segment L2 transforms the diverging straight line at the front end into a parallel straight line at the rear end. Accordingly, the embedded pipe for the curved strand adopts the same linear combination.

[0004] The main problems of the arc-shaped cable strand embedded pipe are as follows: (1) multiple cable strands will come into contact, squeeze and entangle with each other in an arc segment, which easily leads to uneven force; (2) the arc-shaped cable strand embedded pipe is made of round steel pipe, and the linear shape is a circular arc spatial linear shape, which makes it difficult to find at least enough (≥3) feature points for measurement and positioning. Summary of the Invention

[0005] Therefore, in order to solve the above-mentioned deficiencies, the present invention provides a structure and manufacturing and installation method of an arc-shaped cable strand pre-buried pipe for a suspension bridge anchorage system. The main problems solved are as follows: (1) A structure of an arc-shaped cable strand pre-buried pipe for a suspension bridge anchorage is proposed, which avoids the problem of uneven force caused by multiple cables contacting, squeezing, and entanglement in the arc-shaped pre-buried pipe; (see Figure 13 ). (2) The method of making and installing arc-shaped embedded pipes was proposed.

[0006] The present invention is implemented by constructing an arcuate cable strand embedded pipe structure for a suspension bridge anchoring system, characterized in that: the corresponding anchoring system comprises a straight segment L1, a circular segment L2, and a straight segment L3; a portion of the embedded pipe at the front end of the straight segment L1, the circular segment L2, and the straight segment L3 is designed as a branching pipe composed of multiple small steel pipes, while the embedded pipe at the rear end of the straight segment L3 is a single straight steel pipe. A rectangular branching plate is inserted 10 cm from the rear end of the branching pipe, and the 10 cm pipe body is inserted into the straight embedded pipe. A circular branching plate and a 20 cm long circular connecting pipe are inserted 10 cm from the front end, with the branching pipe being perpendicular to the branching plate and the connecting pipe being parallel to the axis of the branching pipe. After installation is complete, the lower end branching plate is welded to the straight embedded pipe opening.

[0007] A method for manufacturing and installing a curved cable strand pre-buried pipe for a suspension bridge anchorage system is characterized in that: the manufacturing and installation method of the curved cable strand pre-buried pipe is as follows: since the length of the curved cable strand pre-buried pipe for a suspension bridge is generally over 30 meters, if it is manufactured and installed as a whole, it is easily deformed during transportation and installation. Therefore, a segmented manufacturing and installation method is adopted, that is, the straight pre-buried pipe and the branched pipe are manufactured separately, first manufacturing and installing the lower straight pre-buried pipe, and then manufacturing and installing the upper branched pipe;

[0008] Before installing the embedded pipe, use steel to build a bracket inside the anchor to support and fix the embedded pipe;

[0009] The straight embedded pipe is a whole steel pipe. During production, the pipe opening is controlled to be perpendicular to its own axis. During installation, it is only necessary to measure the center coordinates of the cross sections at both ends and adjust the pipe opening to the design allowable error.

[0010] The key to the installation of the wire splitter is the measurement of its posture and position, which can be measured and controlled from both the wire splitter plate and the connecting pipe; (1) the wire splitter plate connected to the straight pre-buried pipe is designed to be rectangular, and the projection angle α of the wire splitter in the front anchor surface is reflected by the rotation angle of the rectangular wire splitter plate, thereby adjusting the posture of the wire splitter; (2) the position of the wire splitter in the front anchor surface is controlled by the center coordinates of the connecting pipe mouth.

[0011] According to the production and installation method described in the present invention, it is characterized in that: the production of the wire dividing tube: ① first use a pipe bending machine to make a single small steel tube into an arc shape; ② place several arc-shaped small steel tubes on the tire frame, keep the arc segment naturally drooping to form a bundle, and determine a cross-section for every 1m, and weld and fix the small steel tubes of the cross-section; ③ both ends of the wire dividing tube are inserted into the wire dividing plate, and the rectangular edge of the top of the rectangular wire dividing plate at the rear end is adjusted to a horizontal state using a level (this is very important), and then use an angle ruler to control the vertical relationship between the wire dividing plate and the wire dividing tube, and weld the two to fix; ④ A 20cm straight steel pipe is inserted into the front end as a connecting tube, which is perpendicular to the wire dividing plate, and the wire dividing tube is centered inside the connecting tube and the axes of the two are parallel, and the connecting tube is welded to the wire dividing plate.

[0012] The manufacturing and installation method according to the present invention is characterized in that: the wire branching pipe is installed: ① before installation, a straight angle steel is installed above the top pipe mouth of the straight pre-buried pipe to ensure that one surface of the angle steel is coplanar with the pipe mouth cross section, the top edge of the angle steel is adjusted to a level with a level ruler, and is spot welded to the straight pre-buried pipe.

[0013] ② The wire distribution pipe is transported by crane, and the lower end of the wire distribution pipe is inserted into the straight pre-buried pipe and pressed against the angle steel. At this time, the arc section of the wire distribution pipe still droops naturally, the axis of the entire wire distribution pipe is in the vertical plane, and the top edge of the rectangular wire distribution plate is horizontal.

[0014] ③ Install a hand chain hoist on the bracket, hang the middle and end of the wire distribution pipe, and rotate the wire distribution pipe by retracting and extending the hand chain hoist so that one side of the rectangular wire distribution plate and the angle steel rotate relative to each other. Use an electronic protractor to measure the angle between the top edge of the wire distribution plate and the angle steel and compare it with α. If the angle does not meet the error requirement, continue to rotate the wire distribution pipe and adjust it until the angle meets the allowable error and then stop rotating. Spot weld the wire distribution plate to the pipe opening of the straight pre-buried pipe;

[0015] ④Measure the absolute coordinates of the connecting pipe opening at the front end of the wire distribution pipe, keep the length and angle of the lower end inserted into the pipe opening unchanged, and translate the upper end of the pipe opening until the pipe opening coordinates are within the allowable error range;

[0016] ⑤ Weld the wire distribution pipe to the bracket system and fix it, and weld the lower wire distribution plate to the entire circumference of the straight pre-buried pipe opening.

[0017] According to the manufacturing and installation method of the present invention, the feature is that the installation of the branching tube involves a parameter α which is the projection angle of the arc-shaped embedded tube in the front anchor surface and can be calculated and determined according to the following method:

[0018] The linear shape of a cable strand and its embedded pipe can be divided into three segments: L1, L2, and L3. L1 and L3 are straight line segments, and L2 is a circular arc segment. L3 is parallel to the main cable's force line and perpendicular to the front and rear anchor surfaces. The three segments are coplanar in space, and this plane is perpendicular to the front and rear anchor surfaces. Therefore, the projection of the cable strand on the front anchor surface is a straight line.

[0019] Establish a local coordinate system in the front anchor surface: take the intersection of the main cable force line and the front anchor surface as the origin, the direction of the main cable force line as the X axis, the horizontal axis as the Y axis, and the vertical axis as the Z axis;

[0020] Since L3 is perpendicular to the front anchor surface, its projection on the front anchor surface is a point. The rotation of L3 around its own center line will not change its shape in the front anchor surface. The projections of L2 and L3 on the front anchor surface are straight lines. When rotating around the center of the embedded pipe L3, the angle between the projection line on the front anchor surface and the X-axis will change. This angle is α.

[0021] Therefore, we only need to take the coordinates of any two points on L2 and L3 (y1, z1) and (y2, z2) to calculate the angle α;

[0022]

[0023] Method for measuring the coordinates of the connecting pipe opening at the front end of the wire distribution pipe:

[0024] Use an auxiliary disc for measurement. Create a disc with an inner diameter 2mm larger than the outer diameter of the connecting tube at the front of the split tube. Accurately locate the center point of the outer bottom of the disc and mark it. Place the disc over the connecting tube and measure the coordinates of the outer bottom center of the disc. This will give you the coordinates of the front end of the split tube.

[0025] The present invention has the following advantages: (1) It proposes a suspension bridge anchorage arc-shaped cable strand embedded pipe structure, which avoids the problem of uneven force caused by multiple cable strands contacting, squeezing, and entanglement in the arc segment embedded pipe; (See Figure 13 (2) A method for making and installing arc-shaped pre-buried pipes was proposed. This method solved the installation problem of circular cross-section and arc-shaped pre-buried pipes and was easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the facade line shape of the arc anchoring system;

[0027] Figure 2 It is the plane linear shape of the arc anchoring system;

[0028] Figure 3 It is the projection of the arc-shaped cable strand on the front anchor surface;

[0029] Figure 4 It is the elevation drawing of embedded pipe;

[0030] Figure 5 This is the posture cross-section diagram of the embedded pipe after installation;

[0031] Figure 6 This is the processing diagram of the wire tube;

[0032] Figure 7 It is the section of the processing posture of the wire tube;

[0033] Figure 8 It is a straight pre-buried pipe mouth welded horizontal angle steel;

[0034] Figure 9 The lower end of the wire distribution tube is inserted into the straight pre-buried tube;

[0035] Figure 10 It is the wire-distributing tube that adjusts its posture;

[0036] Figure 11 It is a schematic diagram of the local coordinate system of the segmented linear section of the embedded pipe;

[0037] Figure 12 This is a schematic diagram of the coordinate measurement of the connecting pipe mouth;

[0038] Figure 13 This is a cross-sectional diagram of the cable strands arranged in the embedded pipe;

[0039] Among them: front anchor surface 1, rear anchor surface 2, arc-shaped cable anchoring system 3, straight embedded pipe 4, wire dividing pipe 5, wire dividing plate 6, connecting pipe 7, tire frame 8, angle steel 9, auxiliary disc 10, prism 11, total station 12, anchor cable 13. DETAILED DESCRIPTION

[0040] The following will be combined with the Figures 1-13 The present invention is described in detail, and the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0041] The present invention provides a suspension bridge anchorage anchoring system arc-shaped cable strand pre-buried pipe structure and manufacturing and installation method through improvement, which mainly solves the following problems: (1) A suspension bridge anchorage arc-shaped cable strand pre-buried pipe structure is proposed, which avoids the problem of uneven force caused by multiple cable strands contacting, squeezing, and entangled with each other in the arc segment pre-buried pipe; (see Figure 13 ). (2) The method of making and installing arc-shaped embedded pipes was proposed.

[0042] During implementation, the structure of the arc-shaped cable strand embedded pipe is as follows: Figure 4 、 Figure 5 In order to prevent the cables from contacting, squeezing and entangled with each other in the arc section, part of the embedded pipe at the front end of the straight section L1, arc section L2 and straight section L3 is designed as a branching pipe composed of multiple small steel pipes, and the embedded pipe at the rear end of the straight section L3 is a straight steel pipe. A rectangular branching plate is inserted 10 cm from the rear end of the branching pipe, and the 10 cm pipe body is inserted into the straight embedded pipe. A circular branching plate and a 20 cm long circular connecting pipe are inserted 10 cm from the front end. The branching pipe is perpendicular to the branching plate, and the connecting pipe is parallel to the axis of the branching pipe. After installation is completed, the lower end branching plate is welded to the straight embedded pipe opening.

[0043] The manufacturing and installation method of the arc-shaped cable strand embedded pipe of this application is as follows:

[0044] Since the length of the embedded pipe of the curved cable strand of the suspension bridge is generally more than 30m, if the whole pipe is manufactured and installed, it is easy to deform during transportation and installation. Therefore, the segmented manufacturing and installation method is adopted, that is, the straight embedded pipe and the branch pipe are manufactured separately, and the lower straight embedded pipe is manufactured and installed first, and then the upper branch pipe is manufactured and installed.

[0045] Before installing the embedded pipe, use steel sections to set up brackets inside the anchor to support and fix the embedded pipe.

[0046] The straight embedded pipe is a whole steel pipe. During production, the pipe mouth is controlled to be perpendicular to its own axis. During installation, it is only necessary to measure the center coordinates of the cross sections at both ends and adjust the pipe mouth to the error allowed by the design.

[0047] The key to installing the wire splitter is measuring its posture and position, which can be controlled from both the wire splitter plate and the connecting pipe. (1) The wire splitter plate connected to the straight pre-buried pipe is designed to be rectangular. The rotation angle of the rectangular wire splitter plate reflects the projection angle α of the wire splitter on the front anchor surface, thereby adjusting the posture of the wire splitter. (2) The position of the wire splitter on the front anchor surface is controlled by the center coordinates of the connecting pipe opening.

[0048] Production of wire-dividing tubes: ① First, use a pipe bending machine to make a single small steel pipe into an arc shape; ② Place several arc-shaped small steel pipes on the tire frame, keep the arc section naturally drooping, and form a bundle. According to the cross-section of each meter, weld and fix the small steel pipes of the cross-section; ③ Insert the two ends of the wire-dividing tube into the wire-dividing plate, and use a level to adjust the rectangular edge of the top of the rectangular wire-dividing plate at the rear end to a horizontal state (this is very important), and then use a square to control the vertical relationship between the wire-dividing plate and the wire-dividing tube, and weld the two together; ④ Insert a 20cm straight steel pipe at the front end as a connecting pipe, perpendicular to the wire-dividing plate, and make the wire-dividing tube centered inside the connecting pipe and the axes of the two parallel, and weld the connecting pipe to the wire-dividing plate. Figure 6 、 Figure 7 .

[0049] Installation of branch pipe: ① Before installation, install a straight angle steel above the top of the straight pre-buried pipe to ensure that one side of the angle steel is coplanar with the cross section of the pipe mouth. Use a level to adjust the level of the top edge of the angle steel and spot weld it to the straight pre-buried pipe. Figure 8 ② The wire pipe is transported by crane, and the lower end of the wire pipe is inserted into the straight pre-buried pipe and pressed against the angle steel. Figure 9 . At this time, the arc section of the wire-dividing tube still droops naturally, the axis of the entire wire-dividing tube is in the vertical plane, and the top edge of the rectangular wire-dividing plate is in a horizontal position. ③Install a hand chain hoist on the bracket, hang the middle and end of the wire-dividing tube, and rotate the wire-dividing tube by retracting and extending the hand chain hoist, so that one side of the rectangular wire-dividing plate rotates relative to the angle steel. Use an electronic protractor to measure the angle between the top edge of the wire-dividing plate and the angle steel, and compare it with α. When the angle does not meet the error requirement, continue to rotate the wire-dividing tube and adjust it until the angle meets the allowable error and then stop rotating. Spot weld the wire-dividing plate to the pipe mouth of the straight pre-buried pipe. See Figure 10 ④Measure the absolute coordinates of the pipe opening at the front end of the wire distribution pipe, keep the length and angle of the lower end inserted into the pipe opening unchanged, and translate the upper end of the pipe opening until the pipe opening coordinates are within the allowable error range. Figure 12⑤ Weld the wire distribution pipe to the bracket system and weld the lower wire distribution plate to the entire circumference of the straight pre-buried pipe opening.

[0050] The installation of the branch pipe involves the parameter α, which is the projection angle of the arc-shaped embedded pipe in the front anchor surface. It can be calculated and determined according to the following method:

[0051] like Figure 11 As shown in the figure, the linear shape of a cable strand and its embedded pipe can be divided into three segments: L1, L2, and L3, where L1 and L3 are straight line segments and L2 is a circular arc segment. L3 is parallel to the main cable force line and perpendicular to the front and rear anchor surfaces. The three segments are coplanar in space, and this plane is perpendicular to the front and rear anchor surfaces. Therefore, the projection of the cable strand on the front anchor surface is a straight line.

[0052] A local coordinate system is established within the front anchor surface: the intersection of the main cable resultant line and the front anchor surface is taken as the origin, the direction of the main cable resultant line is the X-axis, the horizontal axis is the Y-axis, and the vertical axis is the Z-axis.

[0053] Since L3 is perpendicular to the front anchor surface, its projection on the front anchor surface is 1 point. The rotation of L3 around its own center line will not change its shape in the front anchor surface. The projections of L2 and L3 on the front anchor surface are straight lines. When rotating around the center of the L3 embedded pipe, the angle between the projection line on the front anchor surface and the X-axis will change. This angle is α.

[0054] Therefore, we only need to take the coordinates of any two points (y1, z1) and (y2, z2) on L2 and L3 to calculate the angle α.

[0055]

[0056] Method for measuring the coordinates of the connecting pipe opening at the front end of the wire distribution pipe:

[0057] Use an auxiliary disc for measurement. Create a disc with an inner diameter 2mm larger than the outer diameter of the connecting tube at the front of the split tube. Accurately locate the center point of the outer bottom of the disc and mark it. Place the disc over the connecting tube and measure the coordinates of the outer bottom center of the disc. This will give you the coordinates of the front end of the split tube.

[0058] The advantages of this patent are as follows:

[0059] (1) A suspension bridge anchorage arc-shaped cable strand embedded pipe structure was proposed to avoid the problem of uneven force caused by multiple cable strands contacting, squeezing, and entanglement in the arc-shaped embedded pipe; (see Figure 13 )

[0060] (2) A method for making and installing arc-shaped pre-buried pipes was proposed. This method solved the installation problem of circular cross-section and arc-shaped pre-buried pipes and was easy to operate.

[0061] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for manufacturing and installing a curved cable strand embedded pipe for a suspension bridge anchorage system, characterized in that ； The corresponding anchoring system has a straight section L1, an arc section L2, and a straight section L3; a portion of the embedded pipe at the front end of the straight section L1, the arc section L2, and the straight section L3 is designed as a branching pipe composed of multiple small steel pipes, and the embedded pipe at the rear end of the straight section L3 is a straight steel pipe; a rectangular branching plate is inserted 10 cm from the rear end of the branching pipe, and the 10 cm pipe body is inserted into the straight embedded pipe, and a circular branching plate and a 20 cm long circular connecting pipe are inserted 10 cm from the front end, with the branching pipe perpendicular to the branching plate and the connecting pipe parallel to the axis of the branching pipe; after installation is completed, the lower end branching plate is welded to the straight embedded pipe opening; The production and installation methods for the curved cable strand embedded pipe are as follows: Since the length of the embedded pipe for the curved cable strand of a suspension bridge is generally over 30 meters, if it is manufactured and installed as a whole, it is easy to deform during transportation and installation. Therefore, the segmented production and installation method is adopted. That is, the straight embedded pipe and the branch pipe are manufactured and installed separately. The lower straight embedded pipe is manufactured and installed first, and then the upper branch pipe is manufactured and installed. Before installing the embedded pipe, use steel to build a bracket inside the anchor to support and fix the embedded pipe; The straight embedded pipe is a whole steel pipe. During production, the pipe opening is controlled to be perpendicular to its own axis. During installation, it is only necessary to measure the center coordinates of the cross sections at both ends and adjust the pipe opening to the design allowable error. The key to installing the wire splitter is to measure its posture and position, which is controlled by measuring the wire splitter plate and the connecting pipe. (1) The wire splitter plate connected to the straight pre-buried pipe is designed to be rectangular. The rotation angle of the rectangular wire splitter plate reflects the projection angle α of the wire splitter on the front anchor surface, thereby adjusting the posture of the wire splitter. (2) The position of the wire splitter on the front anchor surface is controlled by the center coordinates of the connecting pipe opening. Installation of the branch pipe: ① Before installation, install a straight angle steel above the top of the straight pre-buried pipe, ensuring that one surface of the angle steel is coplanar with the cross section of the pipe mouth. Use a level to adjust the level of the top edge of the angle steel and spot weld it to the straight pre-buried pipe. ② The branching pipe is transported by crane, and the lower end of the branching pipe is inserted into the straight pre-buried pipe and pressed against the angle steel; At this time, the arc section of the wire-dividing tube still droops naturally, the axis of the entire wire-dividing tube is in the vertical plane, and the top edge of the rectangular wire-dividing plate is in a horizontal posture; ③ Install a hand chain hoist on the bracket, hang the middle and end of the wire distribution pipe, and rotate the wire distribution pipe by retracting and extending the hand chain hoist so that one side of the rectangular wire distribution plate and the angle steel rotate relative to each other. Use an electronic protractor to measure the angle between the top edge of the wire distribution plate and the angle steel, and compare it with α. If the angle does not meet the error requirement, continue to rotate the wire distribution pipe and adjust it until the angle meets the allowable error and then stop rotating; fix the wire distribution plate and the straight pre-buried pipe by spot welding; ④Measure the absolute coordinates of the connecting pipe opening at the front end of the wire distribution pipe, keep the length and angle of the lower end inserted into the pipe opening unchanged, and translate the upper end of the pipe opening until the pipe opening coordinates are within the allowable error range; ⑤ Weld the wire distribution pipe to the bracket system and fix it, and weld the lower wire distribution plate to the entire circumference of the straight pre-buried pipe opening.

2. The manufacturing and installation method according to claim 1, characterized in that; Production of wire-dividing tubes: ① First, use a pipe bending machine to make a single small steel tube into an arc shape; ② Place several arc-shaped small steel tubes on the tire frame, keep the arc segment drooping naturally, to form a bundle, and determine one section per 1m, and weld and fix the small steel tubes of this section; ③ Insert the two ends of the wire-dividing tube into the wire-dividing plate, and use a level to adjust the rectangular edge of the top of the rectangular wire-dividing plate at the rear end to a horizontal state, and then use a square to control the vertical relationship between the wire-dividing plate and the wire-dividing tube, and weld the two to fix; ④ Insert a 20cm straight steel pipe at the front end as a connecting pipe, perpendicular to the wire-dividing plate, and make the wire-dividing tube centered inside the connecting pipe and the axes of the two parallel, and weld the connecting pipe to the wire-dividing plate.

3. The manufacturing and installation method according to claim 1, characterized in that; The installation of the branch pipe involves the parameter α, which is the projection angle of the arc-shaped embedded pipe in the front anchor surface. It is calculated and determined according to the following method: The line shape of a cable strand and its embedded pipe can be divided into three segments: L1, L2, and L3. L1 and L3 are straight line segments, and L2 is a circular arc segment. L3 is parallel to the main cable's force line and perpendicular to the front and rear anchor surfaces. The three segments are coplanar in space, and this plane is perpendicular to the front and rear anchor surfaces. Therefore, the projection of the cable strand on the front anchor surface is a straight line. Establish a local coordinate system in the front anchor surface: take the intersection of the main cable force line and the front anchor surface as the origin, the direction of the main cable force line as the X axis, the horizontal axis as the Y axis, and the vertical axis as the Z axis; Since L3 is perpendicular to the front anchor surface, its projection on the front anchor surface is a point. The rotation of L3 around its own center line will not change its shape in the front anchor surface. The projections of L2 and L3 on the front anchor surface are straight lines. When rotating around the center of the embedded pipe L3, the angle between the projection line on the front anchor surface and the X-axis will change. This angle is α. Therefore, we only need to take the coordinates of any two points on L2 and L3 (y1, z1) and (y2, z2) to calculate the angle α; Method for measuring the coordinates of the connecting pipe opening at the front end of the wire distribution pipe; Use an auxiliary disc for measurement, that is, make a disc with an inner diameter 2mm larger than the outer diameter of the connecting tube at the front end of the wire-dividing tube, accurately determine the center point of the outer bottom of the disc, and mark it; when measuring, cover the disc on the connecting tube, measure the coordinates of the center of the outer bottom of the disc, and get the coordinates of the front end of the wire-dividing tube.

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