Anchorage traction device for cable-stayed bridge with large span and traction construction method thereof

Abstract

The present invention relates to an anchoring and traction device for the cable of a long-span cable-stayed bridge and a traction construction method thereof, comprising an anchor box, a cable guide tube, a traction device and a back-pressure device. The anchor box is provided with a cable guide tube, one end of the cable guide tube is located in the anchor box, and the other end passes through the box wall of the anchor box and is located outside the anchor box. The anchor box is provided with a traction device, and the anchor box is provided with a back-pressure device. The present invention combines two methods, namely, soft traction of steel strands of the traction device and back-pressure of the beam end of the back-pressure device. The traction device is used to penetrate the anchor cup of the cable from the outer end of the cable guide tube of the anchor box into the cable guide tube of the anchor box, and then the back-pressure device is used to press the anchor cup along the cable guide tube into the anchor box and lock it, so as to realize the installation and fixation of the cable of the cable-stayed bridge.

Description

Technical Field

[0001] The invention belongs to the technical field of cable-stayed bridge construction, and in particular relates to a cable-stayed cable anchoring and traction device for a large-span cable-stayed bridge and a traction construction method thereof. Background Art

[0002] With the continuous development of road and bridge technology, cable-stayed bridges are widely used as one of the main types of large-span bridges. At present, the common cable-beam anchoring types in large-span cable-stayed bridges are: anchor box connection, ear plate connection, anchor pipe connection and anchor plate connection. The anchor box cable-beam anchoring method is a combined structure composed of two different materials, steel and concrete, which jointly bears tension. It has the characteristics of high structural strength, strong tensile resistance, convenient construction and high construction efficiency. Therefore, the existing large-span cable-stayed bridges generally adopt the anchor box cable-beam anchoring method.

[0003] For cable-stayed bridges, the larger the span of the bridge, the longer the cable length and the larger the specification, and the greater the traction force at the beam end when the cable is installed. However, the internal space of the anchor box is small, the operation and construction space is limited, and it cannot meet the installation and operation requirements of larger traction equipment. Therefore, during the construction of existing large-span cable-stayed bridges, the cable-beam anchoring construction is a difficult problem affecting the construction of cable-stayed bridges, seriously affecting the construction efficiency and construction period of cable-stayed bridges, and increasing construction costs. With the continuous development of road and bridge technology, cable-stayed bridges with a span greater than 1km have appeared. For example, the Hutong Yangtze River Bridge under construction has a main span of 1,092 meters, and its longest cable reaches 576.2 meters. The traction force at the beam end when the cable is installed reaches more than 300 tons. In this case, the traction method and traction equipment used in the existing anchor box cable-beam anchoring method can no longer meet the needs. Summary of the invention

[0004] In summary, in order to overcome the shortcomings of the prior art problems, the present invention provides a cable anchoring and traction device for a large-span cable-stayed bridge and a traction construction method thereof, which combines the soft traction of steel strands and the back pressure of beam ends. The soft traction of steel strands is used to pass the anchor cup of the cable from the outer end of the cable guide tube of the anchor box into the cable guide tube of the anchor box, and then the back pressure of the beam end is used to press the anchor cup along the cable guide tube into the anchor box and lock it, thereby realizing the installation and fixation of the cable of the cable-stayed bridge.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0006] A cable anchoring and traction device for a long-span cable-stayed bridge, comprising an anchor box, a cable guide tube, a traction device and a back pressure device, wherein the anchor box is provided with a cable guide tube, one end of the cable guide tube is located in the anchor box, and the other end passes through the box wall of the anchor box and is located outside the anchor box, the anchor box is provided with a traction device, the traction device comprises a safety tension rod, a steel strand connector, a traction steel strand, a traction pressure plate, a thrust roller bearing assembly and a traction jack assembly, the lower end of the anchor cup of the cable is connected to the upper end of the safety tension rod, the safety tension rod is a screw, and the lower end of the safety tension rod is connected to the upper end of the safety tension rod. The end of the cable guide tube is inserted into the cable guide tube from the end of the cable guide tube located outside the anchor box, the lower end of the safety tension rod is connected to the upper end of the traction steel strand through a steel strand connector, a traction pressure plate is arranged on the end surface of the end of the cable guide tube located in the anchor box, a through hole for passing the traction steel strand is arranged on the traction pressure plate, a traction jack assembly is mounted on the traction pressure plate, a thrust roller bearing assembly is arranged between the traction jack assembly and the traction pressure plate, the lower end of the traction steel strand passes through the through hole on the traction pressure plate and the inner hole of the thrust roller bearing assembly in sequence, and then is connected to the traction jack assembly.

[0007] The anchor box is provided with a back-pressure device, which includes a back-pressure support frame, a back-pressure movable beam, a back-pressure cylinder, a back-pressure jack assembly and a back-pressure steel strand. The back-pressure support frame is mounted on the anchor box, and the cable guide tube on the anchor box is arranged in the middle of the back-pressure support frame. The outer sleeve of the inclined cable is provided with a back-pressure cylinder, and the lower end of the back-pressure cylinder contacts the upper end surface of the anchor cup of the inclined cable, and the upper end of the back-pressure cylinder is connected to the back-pressure movable beam. A group of back-pressure steel strands are respectively arranged on both sides of the back-pressure support frame, and the two groups of back-pressure steel strands are symmetrically arranged with the cable guide tube as the center. One end of the back-pressure steel strand is connected to the back-pressure support frame, and the other end of the back-pressure steel strand passes through the back-pressure movable beam and is connected to the back-pressure jack assembly arranged on the back-pressure movable beam. The two groups of back-pressure steel strands are respectively connected to two back-pressure jack assemblies.

[0008] The technical solution of the present invention can also be implemented as follows: the upper end of the safety tension rod is connected to the lower end of the anchor cup of the inclined cable through a traction connector, a threaded hole is provided on the lower end surface of the anchor cup of the inclined cable, the traction connector is a connecting sleeve provided with external threads and internal threaded holes, the connecting sleeve is connected to the threaded hole of the anchor cup through the external thread, and the internal threaded hole of the connecting sleeve is threadedly connected to the upper end of the safety tension rod.

[0009] The technical solution of the present invention can also be implemented as follows: the back-pressure support frame includes a lower back-pressure beam, a connecting screw, an upper back-pressure beam and a locking nut, the lower back-pressure beam and the upper back-pressure beam are connected by a connecting screw, the lower back-pressure beam and the upper back-pressure beam are clamped on the anchor box, and are locked by a locking nut cooperating with the connecting screw.

[0010] The technical solution of the present invention can also be implemented as follows: the traction jack assembly and the back pressure jack assembly have the same structure, both including a jack, a small support foot, an inner tool anchor assembly and an outer tool anchor assembly. The jack is a through-type jack, and the piston of the through-type jack is connected to the inner tool anchor assembly through a small support foot. The cylinder body of the through-type jack is provided with an outer tool anchor assembly.

[0011] The technical solution of the present invention can also be implemented as follows: the lower end of the traction steel strand passes through the inner tool anchor assembly, the small support leg, and the inner hole of the through-type jack of the traction jack assembly in sequence, and is then connected to the outer tool anchor assembly.

[0012] The technical solution of the present invention can also be implemented as follows: one end of the back-pressure steel strand is connected to the back-pressure support frame through a connector, and the other end of the back-pressure steel strand passes through the back-pressure movable beam, and then passes through the inner tool anchor assembly, the small support foot, and the inner hole of the through-type jack of the back-pressure jack assembly in sequence, and finally is connected to the outer tool anchor assembly.

[0013] A traction construction method for a traction device for anchoring a stay cable of a large-span cable-stayed bridge, comprising the following steps:

[0014] a. Connect one end of the safety tension rod to the anchor cup of the inclined cable through a traction connector, and install one end of the traction steel strand on the other end of the safety tension rod through a steel strand connector;

[0015] b. Install the traction pressure plate and the thrust roller bearing assembly on the end surface of the cable guide tube in the anchor box, insert the other end of the traction steel strand into the cable guide tube from the end of the cable guide tube outside the anchor box, and then pass through the inner hole of the traction pressure plate and the inner hole of the thrust roller bearing assembly in sequence, and then pass through the inner tool anchor assembly, the small support foot, and the through-type jack of the traction jack assembly in sequence, and finally clamp it through the outer tool anchor assembly;

[0016] c. Use the oil pump to feed oil into the through-type jack of the traction jack assembly, and the cylinder of the through-type jack extends, driving the outer tool anchor assembly to clamp the traction steel strand and stretch it. At this time, the clip of the inner tool anchor assembly is in a loose state. When the cylinder of the through-type jack reaches the maximum stroke, the piston of the through-type jack moves to push the clip of the inner tool anchor assembly to clamp the traction steel strand. After that, the through-type jack returns oil, and the cylinder of the through-type jack drives the outer tool anchor assembly to reset. At this time, the clip of the outer tool anchor assembly is in a loose state, and this cycle repeats;

[0017] d. When the anchor cup of the stay cable enters the cable guide tube under the traction of the traction steel strand, turn off the oil pump;

[0018] e. Assemble the back-pressure device on the anchor box. First, set the lower back-pressure beam and the upper back-pressure beam on the anchor box. Use the connecting screw and the locking nut to clamp the anchor box. Connect one end of the back-pressure steel strand to the upper back-pressure beam through the steel strand connector. Wrap the back-pressure cylinder outside the inclined cable. The lower end of the back-pressure cylinder bears against the upper end face of the anchor cup of the inclined cable. The upper end of the back-pressure cylinder is connected to the middle part of the back-pressure movable beam through bolts. After the other end of the back-pressure steel strand passes through both sides of the back-pressure movable beam, install the inner tool anchor assembly, small support foot, through-type jack and outer tool anchor assembly of the back-pressure jack assembly in sequence.

[0019] f. Use an oil pump to supply oil to the through-type jacks of the two counter-pressure jack assemblies at the same time. The cylinders of the two through-type jacks extend at the same time, driving their respective external tool anchor assemblies to clamp the counter-pressure steel strands and stretch them. Under the action of the tensile reaction force, the counter-pressure movable beam moves toward the anchor box, driving the counter-pressure cylinder to push the anchor cup of the inclined cable to move into the cable guide tube. When the counter-pressure steel strands are stretched, the clip of the inner tool anchor assembly is in a loose state. When the cylinder of the through-type jack reaches the maximum stroke, the piston of the through-type jack moves to push the clip of the inner tool anchor assembly to clamp the counter-pressure steel strand. After that, the through-type jack returns oil, and the cylinder of the through-type jack drives the outer tool anchor assembly to reset. At this time, the clip of the outer tool anchor assembly is in a loose state, and this cycle repeats;

[0020] g. The back pressure cylinder pushes the anchor cup of the inclined cable to move along the cable guide tube into the anchor box. When the steel strand connector connected to the anchor cup is pushed out of the cable guide tube, the end of the safety tension rod connected to the steel strand connector goes deep into the anchor box. At this time, the steel strand connector, traction steel strand, traction pressure plate, thrust roller bearing and traction jack assembly of the traction device in the anchor box are removed, and the safety tension rod of the traction device and the traction connector connecting the safety tension rod and the anchor cup are retained. The safety tension nut is installed at the end of the safety tension rod located in the anchor box;

[0021] h. Repeat step f. The back-pressure cylinder continues to push the anchor cup of the cable along the cable guide tube into the anchor box. At the same time, tighten the safety tensioning nut on the safety tensioning rod from the anchor box. When the back-pressure cylinder pushes the anchor cup of the cable out of the cable guide tube, remove the tensioning nut on the safety tensioning rod, and then install the anchor cup nut to the designed position. The anchoring and traction construction of the cable-stayed bridge with a large span is now completed. Beneficial Effects

[0022] 1. The present invention combines the two methods of soft traction of steel strands and back pressure at the beam ends. The steel strands are used to softly traction the anchor cup of the cable from the outer end of the cable guide tube of the anchor box into the cable guide tube of the anchor box. The back pressure at the beam ends is then used to press the anchor cup along the cable guide tube into the anchor box and lock it, thereby achieving installation and fixation of the cable of the cable-stayed bridge.

[0023] 2. The traction device of the present invention uses the traction pressure plate and thrust roller bearing assembly arranged on the cable guide tube as the support of the traction jack assembly, and there is no need to set up additional support equipment, thereby saving operating space in the anchor box. Moreover, the traction device of the present invention only needs to introduce the anchor cup of the inclined cable into the cable guide tube, and the anchor cup enters the anchor box from the cable guide tube through the back pressure device. The back pressure device is arranged outside the anchor box. This method also saves the anchor box space, and realizes the installation and fixation of the inclined cable of the cable-stayed bridge with a larger span without changing the volume of the existing anchor box structure.

[0024] 3. The present invention utilizes a traction device and a back-pressure device to carry out traction and anchoring construction on the cable-stayed bridge, and the back-pressure device is a back-pressure movable beam acting on two sets of back-pressure jack assemblies at the same time, which can provide a greater force for the traction and anchoring of the cable-stayed cable and can meet the traction force requirements for the anchoring of the cable-stayed cable of a large-span cable-stayed bridge.

[0025] 4. The present invention has a simple structure, is easy to use, and has low cost. It utilizes the traction device and the back-pressure device to work together to achieve the installation and anchoring of the cable-stayed cable. The concept is novel and ingenious. The back-pressure jack assembly and the traction jack assembly are both commonly used equipment for anchoring existing cable-stayed cables. The operation is simple, and the installation and anchoring construction of the cable-stayed cables of large-span cable-stayed bridges can be achieved, effectively improving the construction efficiency of large-span cable-stayed bridges, reducing costs, and saving labor. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of the traction device of the present invention;

[0027] Figure 2 It is a structural schematic diagram of the back pressure device of the present invention;

[0028] Figure 3 It is a side structural schematic diagram of the back pressure device of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0030] like Figure 1 , Figure 2 , Figure 3As shown, a cable anchoring and traction device for a long-span cable-stayed bridge, which includes an anchor box 1, a cable guide tube 2, a traction device and a back pressure device. The anchor box 1 is provided with a cable guide tube 2, one end of the cable guide tube 2 is located in the anchor box 1, and the other end passes through the box wall of the anchor box 1 and is located outside the anchor box 1. The anchor box 1 is provided with a traction device, and the traction device includes a safety tension rod 3, a steel strand connector 4, a traction steel strand 5, a traction pressure plate 6, a thrust roller bearing assembly 7 and a traction jack. Component 8, the safety tension rod 3 is a screw rod, the upper end of the safety tension rod 3 is connected to the lower end of the anchor cup 10 of the inclined cable 9 through a traction connector 16, the lower end surface of the anchor cup 10 of the inclined cable 9 is provided with a threaded hole, the traction connector 16 is a connecting sleeve provided with an external thread and an internal threaded hole, the connecting sleeve is connected to the threaded hole of the anchor cup 10 through an external thread, the internal threaded hole of the connecting sleeve is threadedly connected to the upper end of the safety tension rod 3, and the lower end of the safety tension rod 3 is connected from the cable guide The end of the tube 2 located outside the anchor box 1 is inserted into the cable guide tube 2, the lower end of the safety tension rod 3 is connected to the upper end of the traction steel strand 5 through the steel strand connector 4, and a traction pressure plate 6 is arranged on the end surface of the end of the cable guide tube 2 located in the anchor box 1, and a through hole for passing the traction steel strand 5 is arranged on the traction pressure plate 6, and a traction jack assembly 8 is arranged on the traction pressure plate 6, and a thrust roller bearing assembly 7 is arranged between the traction jack assembly 8 and the traction pressure plate 6. The lower end of the traction steel strand 5 passes through the through hole on the traction pressure plate 6 and the inner hole of the thrust roller bearing assembly 7 in sequence, and then is connected to the traction jack assembly 8. The traction jack assembly 8 includes a jack 20, a small support foot 21, an inner tool anchor assembly 22 and an outer tool anchor assembly 23. The jack 20 is a through-type jack 20, and the piston of the through-type jack 20 is connected to the inner tool anchor assembly 22 through the small support foot 21. The cylinder body of the through-type jack 20 is provided with an outer tool anchor assembly 23. The inner tool anchor assembly 22 and the outer tool anchor assembly 23 have the same structure and both include a tool anchor plate and a clip. The tool anchor plate of the inner tool anchor assembly 22 is connected to the bearing seat of the thrust roller bearing assembly 7, and the clip of the inner tool anchor assembly 22 is connected to the piston of the through-type jack 20. The lower end of the traction steel strand 5 passes through the inner tool anchor assembly 22, the small support leg 21, and the inner hole of the through-type jack 20 of the traction jack assembly 8 in sequence, and is then connected to the outer tool anchor assembly 23.

[0031] A back-pressure device is provided on the anchor box 1, and the back-pressure device includes a back-pressure support frame 11, a back-pressure movable beam 12, a back-pressure cylinder 13, a back-pressure jack assembly 15 and a back-pressure steel strand 14. The back-pressure support frame 11 includes a lower back-pressure beam 17, a connecting screw 18, an upper back-pressure beam 19 and a locking nut. The lower back-pressure beam 17 and the upper back-pressure beam 19 are connected by the connecting screw 18. The lower back-pressure beam 17 and the upper back-pressure beam 19 are clamped on the anchor box 1 and locked by a locking nut cooperating with the connecting screw 18. The cable guide tube 2 on the anchor box 1 is arranged in the middle part of the back-pressure support frame 11, and the oblique cable 9 is sheathed with a back-pressure cylinder 13. The lower end of the back-pressure cylinder 13 contacts the upper end surface of the anchor cup 10 of the oblique cable 9, and the upper end of the back-pressure cylinder 13 is connected to the back-pressure movable beam 12. A group of back-pressure steel strands 14 are respectively arranged on both sides of the back-pressure support frame 11, and the two groups of back-pressure steel strands 14 are symmetrically arranged with the cable guide tube 2 as the center. One end of the back-pressure steel strand 14 is connected to the back-pressure support frame 11 through a steel strand connector 4, and the other end of the back-pressure steel strand 14 passes through the back-pressure movable beam 12 and is connected to the back-pressure jack assembly 15 arranged on the back-pressure movable beam 12, and the two groups of back-pressure steel strands 14 are respectively connected to the two back-pressure jack assemblies 15. The counter-pressure jack assembly 15 has the same structure and includes a jack 20, a small support leg 21, an inner tool anchor assembly 22 and an outer tool anchor assembly 23. The jack 20 is a through-type jack 20. The piston of the through-type jack 20 is connected to the inner tool anchor assembly 22 through the small support leg 21. The cylinder of the through-type jack 20 is provided with an outer tool anchor assembly 23. One end of the counter-pressure steel strand 14 is connected to the counter-pressure support frame 11 through a connector. The other end of the counter-pressure steel strand 14 passes through the counter-pressure movable beam 12, and then passes through the inner tool anchor assembly 22, the small support leg 21, and the inner hole of the through-type jack 20 of the counter-pressure jack assembly 15 in sequence, and finally connected to the outer tool anchor assembly 23.

[0032] A traction construction method for an anchoring traction device of a cable-stayed bridge with a long span, comprising the following steps:

[0033] a. Connect one end of the safety tension rod 3 to the anchor cup 10 of the inclined cable 9 through the traction connector 16, and install one end of the traction steel strand 5 on the other end of the safety tension rod 3 through the steel strand connector 4;

[0034] b. Install the traction pressure plate 6 and the thrust roller bearing assembly 7 on the end surface of the cable guide tube 2 in the anchor box 1, and insert the other end of the traction steel strand 5 into the cable guide tube 2 from the end of the cable guide tube 2 outside the anchor box 1, and then pass through the inner hole of the traction pressure plate 6 and the inner hole of the thrust roller bearing assembly 7 in sequence, and then pass through the inner tool anchor assembly 22, the small support leg 21, and the through-type jack 20 of the traction jack assembly 8 in sequence, and finally clamp it through the outer tool anchor assembly 23;

[0035] c. Use an oil pump to feed oil into the through-type jack 20 of the traction jack assembly 8, and the cylinder of the through-type jack 20 extends, driving the outer tool anchor assembly 23 to clamp the traction steel strand 5 and stretch it. At this time, the clip of the inner tool anchor assembly 22 is in a loose state. When the cylinder of the through-type jack 20 reaches the maximum stroke, the piston of the through-type jack 20 moves to push the clip of the inner tool anchor assembly 22 to clamp the traction steel strand 5. After that, the through-type jack 20 returns oil, and the cylinder of the through-type jack 20 drives the outer tool anchor assembly 23 to reset. At this time, the clip of the outer tool anchor assembly 23 is in a loose state, and this cycle repeats;

[0036] d. When the anchor cup 10 of the stay cable 9 enters the cable guide tube under the traction of the traction steel strand 5, the oil pump is turned off;

[0037] e. Assemble the back-pressure device on the anchor box 1. First, set the lower back-pressure beam 17 and the upper back-pressure beam 19 on the anchor box 1. Use the connecting screw 18 and the locking nut to clamp the anchor box 1 with the upper back-pressure beam 19 and the lower back-pressure beam 17. Connect one end of the back-pressure steel strand 14 to the upper back-pressure beam 19 through the steel strand connector 4. Wrap the back-pressure cylinder 13 outside the inclined cable 9. The lower end of the back-pressure cylinder 13 bears against the upper end surface of the anchor cup 10 of the inclined cable 9. The upper end of the back-pressure cylinder 13 is connected to the middle part of the back-pressure movable beam 12 through bolts. After the other end of the back-pressure steel strand 14 passes through both sides of the back-pressure movable beam 12, the inner tool anchor assembly 22, the small support foot 21, the through-type jack 20 and the outer tool anchor assembly 23 of the back-pressure jack assembly 15 are installed in sequence.

[0038] f. Use an oil pump to supply oil to the through-type jacks 20 of the two counter-pressure jack assemblies 15 at the same time. The cylinders of the two through-type jacks 20 extend at the same time, driving their respective outer tool anchor assemblies 23 to clamp the counter-pressure steel strand 14 and stretch it. Under the action of the tensile reaction force, the counter-pressure movable beam 12 moves toward the anchor box 1, driving the counter-pressure cylinder 13 to push the anchor cup 10 of the inclined cable 9 to move into the cable guide tube 2. When the counter-pressure steel strand 14 is stretched, the clip of the inner tool anchor assembly 22 is in a loose state. When the cylinder of the through-type jack 20 reaches the maximum stroke, the piston of the through-type jack 20 moves to push the clip of the inner tool anchor assembly 22 to clamp the counter-pressure steel strand 14. After that, the through-type jack 20 returns oil, and the cylinder of the through-type jack 20 drives the outer tool anchor assembly 23 to reset. At this time, the clip of the outer tool anchor assembly 23 is in a loose state, and this cycle repeats;

[0039] g. The back pressure cylinder 13 pushes the anchor cup 10 of the inclined cable 9 to move along the cable guide tube 2 into the anchor box 1. When the steel strand connector 4 connected to the anchor cup 10 is pushed out of the cable guide tube 2, the end of the safety tension rod 3 connected to the steel strand connector 4 is deeply inserted into the anchor box 1. At this time, the steel strand connector 4, the traction steel strand 5, the traction pressure plate 6, the thrust roller bearing and the traction jack assembly 8 of the traction device in the anchor box 1 are removed, and the safety tension rod 3 of the traction device and the traction connector 16 connecting the safety tension rod 3 and the anchor cup 10 are retained. The safety tension nut is installed at the end of the safety tension rod 3 located in the anchor box 1;

[0040] h. Repeat step f. The back-pressure cylinder 13 continues to push the anchor cup 10 of the inclined cable 9 along the cable guide tube 2 into the anchor box 1. At the same time, tighten the safety tensioning nut on the safety tensioning rod 3 from the anchor box 1. When the back-pressure cylinder 13 pushes the anchor cup 10 of the inclined cable 9 out of the cable guide tube 2, remove the tensioning nut on the safety tensioning rod 3, and then install the nut of the anchor cup 10 to the designed position. At this point, the anchoring and traction construction of the inclined cable 9 of the large-span cable-stayed bridge is completed.

[0041] It should be noted that the above embodiments are illustrative of the technical solution of the present invention rather than limiting. Equivalent substitutions made by ordinary technicians in the relevant technical field or other modifications made according to the prior art should be included in the scope of rights required by the present invention as long as they do not exceed the concept and scope of the technical solution of the present invention.

Claims

1. A cable anchoring and traction device for a long-span cable-stayed bridge, characterized in that: The anchor box (1) comprises an anchor box (1), a cable guide tube (2), a traction device and a back pressure device. The anchor box (1) is provided with a cable guide tube (2). One end of the cable guide tube (2) is located inside the anchor box (1), and the other end passes through the wall of the anchor box (1) and is located outside the anchor box (1). The anchor box (1) is provided with a traction device. The traction device comprises a safety tension rod (3), a steel strand connector (4), a traction steel strand (5), a traction pressure plate (6), a thrust roller bearing assembly (7) and a traction jack assembly (8). The lower end of the anchor cup (10) of the inclined cable (9) is connected to the upper end of the safety tension rod (3). The safety tension rod (3) is a screw. The lower end of the safety tension rod (3) is extended from the position of the cable guide tube (2). One end outside the anchor box (1) is inserted into the cable guide tube (2), the lower end of the safety tension rod (3) is connected to the upper end of the traction steel strand (5) through the steel strand connector (4), a traction pressure plate (6) is provided on the end surface of the cable guide tube (2) located in the anchor box (1), the traction pressure plate (6) is provided with a through hole for inserting the traction steel strand (5), a traction jack assembly (8) is mounted on the traction pressure plate (6), a thrust roller bearing assembly (7) is provided between the traction jack assembly (8) and the traction pressure plate (6), the lower end of the traction steel strand (5) passes through the through hole on the traction pressure plate (6) and the inner hole of the thrust roller bearing assembly (7) in sequence, and then is connected to the traction jack assembly (8), The anchor box (1) is provided with a back-pressure device, and the back-pressure device comprises a back-pressure support frame (11), a back-pressure movable beam (12), a back-pressure cylinder (13), a back-pressure jack assembly (15) and a back-pressure steel strand (14). The back-pressure support frame (11) is erected on the anchor box (1), and the cable guide tube (2) on the anchor box (1) is arranged in the middle of the back-pressure support frame (11). The back-pressure cylinder (13) is sheathed on the inclined cable (9), and the lower end of the back-pressure cylinder (13) contacts the upper end face of the anchor cup (10) of the inclined cable (9). The upper end of the back-pressure cylinder (13) is connected to the back-pressure movable beam (12), and a group of back-pressure steel strands (14) are respectively arranged on both sides of the back-pressure support frame (11). The two groups of back-pressure steel strands (14) are symmetrically arranged with the cable guide tube (2) as the center. One end of the back-pressure steel strand (14) is connected to the back-pressure support frame (11), and the other end of the back-pressure steel strand (14) passes through the back-pressure movable beam (12) and is connected to a back-pressure jack assembly (15) arranged on the back-pressure movable beam (12). The two groups of back-pressure steel strands (14) are respectively connected to the two back-pressure jack assemblies (15). The upper end of the safety tension rod (3) is connected to the lower end of the anchor cup (10) of the inclined cable (9) through a traction connector (16); a threaded hole is provided on the lower end surface of the anchor cup (10) of the inclined cable (9); the traction connector (16) is a connecting sleeve provided with an external thread and an internal threaded hole; the connecting sleeve is connected to the threaded hole of the anchor cup (10) through an external thread; the internal threaded hole of the connecting sleeve is threadedly connected to the upper end of the safety tension rod (3); The counter-pressure support frame (11) comprises a lower counter-pressure beam (17), a connecting screw (18), an upper counter-pressure beam (19) and a locking nut. The lower counter-pressure beam (17) and the upper counter-pressure beam (19) are connected via the connecting screw (18). The lower counter-pressure beam (17) and the upper counter-pressure beam (19) are clamped on the anchor box (1) and locked via a locking nut that cooperates with the connecting screw (18).

2. The anchoring and traction device for the cable-stayed bridge of a long-span cable-stayed bridge according to claim 1 is characterized in that: The traction jack assembly (8) and the back pressure jack assembly (15) have the same structure, both comprising a jack (20), a small support foot (21), an inner tool anchor assembly (22) and an outer tool anchor assembly (23); the jack (20) is a through-type jack (20); the piston of the through-type jack (20) is connected to the inner tool anchor assembly (22) via the small support foot (21); and the cylinder body of the through-type jack (20) is provided with an outer tool anchor assembly (23).

3. The anchoring and traction device for the cable-stayed bridge of a long-span cable-stayed bridge according to claim 2 is characterized in that: The lower end of the traction steel strand (5) passes through the inner tool anchor assembly (22), the small support foot (21), and the inner hole of the through-type jack (20) of the traction jack assembly (8) in sequence, and is then connected to the outer tool anchor assembly (23).

4. The anchoring and traction device for the cable-stayed bridge of a long-span cable-stayed bridge according to claim 3 is characterized in that: One end of the counter-pressure steel strand (14) is connected to the counter-pressure support frame (11) through a connector, and the other end of the counter-pressure steel strand (14) passes through the counter-pressure movable beam (12), and then passes through the inner tool anchor assembly (22), the small support foot (21), and the inner hole of the through-type jack (20) of the counter-pressure jack assembly (15) in sequence, and finally is connected to the outer tool anchor assembly (23).

5. The traction construction method of the anchoring traction device of the cable of a long-span cable-stayed bridge according to any one of claims 1 to 4, characterized in that: The following steps are involved: a. Connect one end of the safety tension rod (3) to the anchor cup (10) of the inclined cable (9) through a traction connector (16), and install one end of the traction steel strand (5) on the other end of the safety tension rod (3) through a steel strand connector (4); b. Install a traction pressure plate (6) and a thrust roller bearing assembly (7) on the end surface of the cable guide tube (2) in the anchor box (1), and insert the other end of the traction steel strand (5) into the cable guide tube (2) from the end of the cable guide tube (2) outside the anchor box (1), and then pass through the inner hole of the traction pressure plate (6) and the inner hole of the thrust roller bearing assembly (7) in sequence, and then pass through the inner tool anchor assembly (22), the small support foot (21), and the through-type jack (20) of the traction jack assembly (8) in sequence, and finally clamp it through the outer tool anchor assembly (23); c. Using an oil pump to supply oil to the through-type jack (20) of the traction jack assembly (8), the cylinder of the through-type jack (20) extends, driving the outer tool anchor assembly (23) to clamp the traction steel strand (5) and stretch it. At this time, the clip of the inner tool anchor assembly (22) is in a loose state. When the cylinder of the through-type jack (20) reaches the maximum stroke, the piston of the through-type jack (20) moves to push the clip of the inner tool anchor assembly (22) to clamp the traction steel strand (5). After that, the through-type jack (20) returns oil, and the cylinder of the through-type jack (20) drives the outer tool anchor assembly (23) to reset. At this time, the clip of the outer tool anchor assembly (23) is in a loose state. This cycle repeats. d. When the anchor cup (10) of the stay cable (9) enters the cable guide tube under the traction of the traction steel strand (5), the oil pump is turned off; e. Assemble the back-pressure device on the anchor box (1), first set the lower back-pressure beam (17) and the upper back-pressure beam (19) on the anchor box (1), use the connecting screw (18) and the locking nut to clamp the upper back-pressure beam (19) and the lower back-pressure beam (17) to the anchor box (1), connect one end of the back-pressure steel strand (14) to the upper back-pressure beam (19) through the steel strand connector (4), wrap the back-pressure cylinder (13) outside the inclined cable (9), and then install the back-pressure device on the anchor box (1). The lower end of the cylinder (13) is pressed against the upper end surface of the anchor cup (10) of the inclined cable (9), and the upper end of the back-pressure cylinder (13) is connected to the middle part of the back-pressure movable beam (12) by bolts. After the other end of the back-pressure steel strand (14) passes through both sides of the back-pressure movable beam (12), the inner tool anchor assembly (22), the small support foot (21), the through-type jack (20) and the outer tool anchor assembly (23) of the back-pressure jack assembly (15) are installed in sequence; f. Use an oil pump to supply oil to the through-type jacks (20) of the two back-pressure jack assemblies (15) at the same time. The cylinders of the two through-type jacks (20) extend at the same time, driving their respective external tool anchor assemblies (23) to clamp the back-pressure steel strand (14) and stretch it. Under the action of the stretching reaction force, the back-pressure movable beam (12) moves toward the anchor box (1), driving the back-pressure cylinder (13) to push the anchor cup (10) of the inclined cable (9) to move into the cable guide tube (2), and the back-pressure steel strand (14) is stretched. When the inner tool anchor assembly (22) is in a loosened state, when the cylinder of the through-type jack (20) reaches the maximum stroke, the piston of the through-type jack (20) moves to push the clamp of the inner tool anchor assembly (22) to clamp the counter-pressure steel strand (14), and then the through-type jack (20) returns oil, and the cylinder of the through-type jack (20) drives the outer tool anchor assembly (23) to reset, at which time the clamp of the outer tool anchor assembly (23) is in a loosened state, and this cycle repeats; g. The back pressure cylinder (13) pushes the anchor cup (10) of the inclined cable (9) to move along the cable guide tube (2) into the anchor box (1). When the steel strand connector (4) connected to the anchor cup (10) is pushed out of the cable guide tube (2), the end of the safety tension rod (3) connected to the steel strand connector (4) is deeply inserted into the anchor box (1). At this time, the steel strand connector (4), the traction steel strand (5), the traction pressure plate (6), the thrust roller bearing and the traction jack assembly (8) of the traction device in the anchor box (1) are removed, and the safety tension rod (3) of the traction device and the traction connector (16) connecting the safety tension rod (3) and the anchor cup (10) are retained. The safety tension nut is installed on the end of the safety tension rod (3) located in the anchor box (1); h. Repeat step f, the back pressure cylinder (13) continues to push the anchor cup (10) of the inclined cable (9) along the cable guide tube (2) into the anchor box (1). At the same time, tighten the safety tensioning nut on the safety tensioning rod (3) from the anchor box (1). When the back pressure cylinder (13) pushes the anchor cup (10) of the inclined cable (9) out of the cable guide tube (2), remove the tensioning nut on the safety tensioning rod (3), and then install the nut of the anchor cup (10) to the designed position. At this point, the anchoring and traction construction of the inclined cable (9) of the long-span cable-stayed bridge is completed.

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