Stay cable narrow space self-adaptive variable speed traction device and rapid construction method

Abstract

The invention discloses a stay cable narrow space self-adaptive variable-speed traction device and a rapid construction method. The stay cable narrow space self-adaptive variable-speed traction device comprises an anchor backing plate, an anchor cup nut, a supporting foot and a jack which are arranged in a steel anchor box. One end of the supporting leg is arranged on the anchor backing plate in the steel anchor box; the anchor cup nut is arranged on the inner side of the supporting leg on the anchor backing plate; a base of the jack is mounted at the other end of the supporting leg; steel strands penetrate through the interiors of the anchor bearing plate, the anchor cup nut, the supporting feet and the jack, one ends of the multiple steel strands are fixed in preset hole positions of the steel strand anchor plate, and the steel strand anchor plate is connected into the stay cable anchor cup through threads. The steel strand sequentially penetrates through the preset hole sites of the two automatic tool anchor assemblies; the two automatic tool anchor assemblies are arranged on a piston of the jack and the base plate respectively, and the base plate is centered and positioned through the positioning pressing plate. According to the invention, the technical problem of traction of the steel strand of the stay cable in a narrow operation space is efficiently and accurately solved, the operation safety of stay cable steel strand soft traction construction is guaranteed, and the construction efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of cable-stayed bridge construction, and particularly relates to a narrow space adaptive speed-changing traction device for a cable-stayed cable and a rapid construction method. Background Art

[0002] As my country's strategy of building a strong transportation nation deepens, kilometer-long cable-stayed bridges, with their ultra-long spans and technological breakthroughs, are becoming a key solution for modern bridge engineering in complex terrain scenarios such as cross-river and cross-sea passages, canyons, and bays. As bridge spans increase, the length and specifications of the cables also increase, which brings new challenges to construction technology. In particular, during the installation of extremely long and heavy cables, multiple parallel steel strands must be used, with the alternating action of two sets of tool anchors to pull the cables to the desired position. This construction technique is known as soft strand traction. Traditional soft strand traction devices have encountered multiple technical bottlenecks and have become a key problem restricting the technological progress of ultra-long span cable-stayed bridge construction, urgently requiring breakthrough technological innovation.

[0003] 1. Spatial adaptability

[0004] The overall size of a traditional soft strand traction device (including jacks, legs, strands, tool anchors, and the supporting hydraulic system) is directly proportional to the traction force. Increased traction force requires more strands, which in turn increases the size of the jacks and tool anchors, and in turn, the overall size of the soft strand traction device. This increased size makes installation more difficult, and within the anchorage space of the stay cable, the soft strand traction device is prone to interference between equipment and limited operating space. Consequently, during construction, the soft strand traction operation often needs to be suspended to cut the strands, seriously impacting construction continuity.

[0005] 2. Construction safety

[0006] As traction increases, the demand for steel strands also increases. When threading the strands through the tool anchors, it's crucial to ensure that the holes in both tool anchors perfectly match the holes in the strand anchor plates. As the number of strands increases, the risk of misaligned holes increases. Once misaligned holes occur, multiple strands can become entangled, altering the stress distribution of the strands. The shear forces generated by this entanglement at the anchor joint can easily cause the strands to break, leading to major accidents and seriously threatening the safety of the stay cable installation operation.

[0007] Furthermore, after the stay cable wires are twisted 3° counterclockwise, they rotate clockwise along their axis when subjected to axial tension, resulting in detwisting. During installation, this detwisting of the cable body causes the previously parallel traction strands to twist as a whole, changing the stress distribution of the strands and potentially preventing them from smoothly threading through the holes at the anchor joints, generating shear forces. As the twist angle of the stay cable increases, the shear forces also increase accordingly, which can easily lead to strand breakage, causing major or catastrophic accidents and seriously threatening the safety of the stay cable installation operation. To address this detwisting issue, existing patented technologies have proposed a solution: the introduction of thrust roller bearings in the strand traction device. However, this approach increases the assembly height of the strand traction device, limiting its applicability in confined spaces. During construction, if the thrust roller bearings are used continuously for long periods of time, they often lack effective maintenance, making it difficult to fully function.

[0008] 3. Hydraulic control

[0009] Traditional soft-tow systems for stay cables rely on manually operated oil pumps to control the oil supply and return to the jacks. This not only reduces construction efficiency but can also lead to excessive extension or retraction of the jack pistons due to operational delays, potentially damaging the jacks. A key feature of soft-tow systems for stay cables is the relatively low initial pulling force, making the pulling process relatively safe. However, as the pulling process progresses, the pulling force gradually increases, increasing the construction risk. Traditional soft-tow systems typically select the appropriate soft-tow equipment based on the final required pulling force and utilize a low-speed oil supply system to ensure safety during the pulling process. During the installation of extremely long and heavy stay cables, where the strands often extend for tens of meters, the soft-tow system can take 20 to 30 hours to complete, resulting in low efficiency. As the construction period lengthens, weather changes, such as strong winds and heavy rain, also increase the risks of soft-tow systems. Summary of the Invention

[0010] The purpose of this patent is to provide an adaptive speed-changing traction device and a rapid construction method for a cable-stayed cable in a narrow space, aiming to efficiently and accurately solve the technical problems of traction of the steel strands of the cable-stayed cable in a narrow working space, ensure the operational safety of the soft traction construction of the steel strands of the cable-stayed cable, and improve construction efficiency.

[0011] The technical solution adopted by the present invention is: an adaptive speed-changing traction device for a narrow space of an inclined cable, comprising an obliquely arranged steel anchor box, wherein a coaxial anchor plate, anchor cup nut, support foot and jack are arranged in the steel anchor box; one end of the support foot is arranged on the anchor plate; the anchor plate is arranged on the steel anchor box; the anchor cup nut is arranged on the inner side of the support foot on the anchor plate; the base of the jack is installed at the other end of the support foot; steel wire strands are passed through the interior of the anchor plate, anchor cup nut, support foot and jack, and one end of several of the steel wire strands is fixed in the preset hole position of the steel wire strand anchor plate, and the steel wire strand anchor plate is connected to the anchor cup of the inclined cable by threads; the steel wire strands also pass through the preset hole positions of the first automatic tool anchor assembly and the second automatic tool anchor assembly in sequence; the second automatic tool anchor assembly is arranged on the piston of the jack; the first automatic tool anchor assembly is fixed by a pad; the jack is connected to the hydraulic pump station through an oil pipe.

[0012] Furthermore, the layout structure of the preset hole positions of the steel strand anchor plate, the first automatic tool anchor assembly and the second automatic tool anchor assembly are the same.

[0013] Furthermore, the support leg includes a support leg top plate, a support leg bottom plate and four columns arranged therebetween; two baffles are provided in the middle of the columns, and a positioning pressure plate is rotatably connected to the column between the two baffles.

[0014] Furthermore, a first tool anchor positioning cover is provided on the outer side of the first automatic tool anchor assembly, and the first tool anchor positioning cover is fixed to the base plate by bolts; a second tool anchor positioning cover is provided on the outer side of the second automatic tool anchor assembly, and the second tool anchor positioning cover is fixed to the piston of the jack by bolts.

[0015] Furthermore, the backing plate, the first tool anchor positioning cover and the second tool anchor positioning cover adopt a symmetrical two-petal structure.

[0016] Furthermore, a displacement sensor is provided on the jack, and the displacement sensor sends a stroke signal of the jack to a PLC control system on the hydraulic pump station.

[0017] The present invention also discloses a rapid construction method using the above device, comprising the following steps:

[0018] Step 1: First squeeze one end of the steel strand into the P anchor, then pass the other end of the steel strand through the preset holes of the anchor plate, the first automatic tool anchor assembly, and the second automatic tool anchor assembly in sequence;

[0019] Step 2: Screw the steel strand anchor plate into the internal thread of the stay cable anchor cup, and adjust the positions of the first automatic tool anchor assembly and the second automatic tool anchor assembly on the steel strand so that they are spaced apart;

[0020] Step 3: Fix the support legs, jacks and anchor cup nuts in sequence to form a traction base;

[0021] Step 4: Pass the steel strand with the first automatic tool anchor assembly and the second automatic tool anchor assembly through the support leg; after the first automatic tool anchor assembly passes through the anchor cup nut, install a backing plate on the first automatic tool anchor assembly and secure it with a positioning pressure plate;

[0022] Step 5: Install the first automatic tool anchor assembly into the first tool anchor positioning cover, and use high-strength bolts to fix the first tool anchor positioning cover to the backing plate; after the second automatic tool anchor assembly passes through the jack, install the second automatic tool anchor assembly into the second tool anchor positioning cover, and use high-strength bolts to fix the second tool anchor positioning cover to the piston of the jack;

[0023] Step 6: Start the hydraulic pump station, and the PLC control system controls the extension and retraction of the jack piston according to the stroke size of the jack piston.

[0024] Furthermore, when the cable body is twisted back, causing the originally parallel traction steel strands to twist as a whole, during the oil return process of the jack, the construction personnel rotate the second automatic tool anchor assembly in the opposite direction, and then fill the jack with oil to make the second automatic tool anchor assembly subject to force. At this time, the first automatic tool anchor assembly will rotate in the first tool anchor positioning cover, thereby restoring the steel strands to a parallel state.

[0025] Furthermore, there are two oil pipes between the jack and the hydraulic pump station, namely an oil inlet pipe and an oil return pipe, and the high pressure and low pressure in the oil inlet pipe and the oil return pipe are switched by a handwheel control valve.

[0026] The beneficial effects of the present invention are:

[0027] 1. The tool anchor is set inside the support leg, which reduces the assembly height of the entire steel strand soft traction device and enhances the adaptability of the steel strand soft traction device to operations in narrow anchoring spaces;

[0028] 2. The assembly process of the steel strand soft traction device is simple and quick. During construction, you only need to use the positioning cover to lock the two sets of tool anchors to easily complete the assembly of the entire soft traction device;

[0029] 3. Before assembling the steel strand soft traction device, ensure that the steel strands are accurately passed through the holes of the soft traction anchor plate and the tool anchor, effectively avoiding the problem of misalignment of the steel strand holes; this not only improves construction efficiency but also ensures construction safety;

[0030] 4. Without raising the assembly height of the steel strand soft traction device, the problem of steel strand twisting during soft traction construction was successfully solved, making the construction process simpler and eliminating the twisting of steel strands.

[0031] 5. The hydraulic pump station achieves continuous traction of the stay cables through the PLC control system, significantly improving construction efficiency and effectively avoiding damage to the soft traction equipment caused by manual operation delays;

[0032] 6. The hydraulic pump station adopts a variable speed oil circuit design to ensure that under low pressure conditions, when the traction force is small, the traction speed can reach a higher level; and when the traction force increases, the low-pressure oil circuit valve can be manually closed and the high-pressure oil circuit valve can be opened at any time, thereby ensuring the safety and stability of traction construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the structure of the support leg in the present invention;

[0035] Figure 3 This is a construction method diagram for step 1 of the present invention;

[0036] Figure 4 This is a construction method diagram for step 2 of the present invention;

[0037] Figure 5 This is a construction method diagram for step 3 of the present invention;

[0038] Figure 6 This is a construction method diagram for step 4 of the present invention;

[0039] Figure 7 This is a construction method diagram for step 5 of the present invention;

[0040] In the figure: 1-stayed cable anchor cup, 2-steel strand anchor plate, 3-steel strand, 4-anchor pad, 5-anchor cup nut, 6-pad, 7-positioning pressure plate, 8-first tool anchor positioning cover, 9-first automatic tool anchor assembly, 10-support foot, 101-support foot top plate, 102-support foot bottom plate, 103-column, 104-baffle, 11-jack, 12-steel anchor box, 13-second tool anchor positioning cover, 14-second automatic tool anchor assembly, 15-oil pipe, 16-hydraulic pump station. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to the accompanying drawings.

[0042] like Figure 1As shown, the present invention is an adaptive speed-changing traction device for a cable-stayed cable in a narrow space, comprising an obliquely arranged steel anchor box 12, within which are arranged a coaxial anchor plate 4, an anchor cup nut 5, a support leg 10 and a jack 11; one end of the support leg 10 is arranged on the anchor plate 4; the anchor plate 4 is arranged on the steel anchor box 12; the anchor cup nut 5 is arranged on the inner side of the support leg 10 on the anchor plate 4; and the base of the jack 11 is installed on the other end of the support leg 10.

[0043] like Figure 2 As shown, the support leg 10 includes a support leg top plate 101, a support leg bottom plate 102 and four columns 103 arranged therebetween; two baffles 104 are provided in the middle of each column 103, and a positioning pressure plate 7 is rotatably connected to the column 103 between the two baffles 104.

[0044] The anchor plate 4, anchor cup nut 5, support leg 10, and jack 11 are internally threaded with steel strands 3. One end of several steel strands 3 is fixed in the preset hole of the steel strand anchor plate 2, which is threadedly connected to the inclined cable anchor cup 1. The steel strands 3 also sequentially pass through the preset holes of the first automatic tool anchor assembly 9 and the second automatic tool anchor assembly 14. Since the layout structure of the preset holes of the steel strand anchor plate 2, the first automatic tool anchor assembly 9, and the second automatic tool anchor assembly 14 is the same, the several steel strands 3 are all parallel to each other. The second automatic tool anchor assembly 14 is set on the piston of the jack 11. The first automatic tool anchor assembly 9 is fixed by the pad 6, which is centered and positioned by the positioning pressure plate 7 to prevent the first automatic tool anchor assembly 9 from moving freely during the traction process. After the pad 6 is subjected to force, it is transmitted to the anchor cup nut 5, which transmits the bearing pressure to the anchor plate 4. The jack 11 is connected to the hydraulic pump station 16 via the oil pipe 15. Since the first automatic tool anchor assembly 9 is arranged inside the support leg 10, the assembly height of the entire set of soft traction equipment is greatly reduced, making the soft traction equipment more adaptable to construction requirements in narrow spaces.

[0045] A first tool anchor positioning cover 8 is provided on the outside of the first automatic tool anchor assembly 9 and is bolted to the backing plate 6. A second tool anchor positioning cover 13 is provided on the outside of the second automatic tool anchor assembly 14 and is bolted to the piston of the jack 11. The backing plate 6, the first tool anchor positioning cover 8, and the second tool anchor positioning cover 13 are symmetrically arranged in two parts.

[0046] The jack 11 is provided with a displacement sensor, which sends a stroke signal of the jack 11 to a PLC control system on the hydraulic pump station 16 .

[0047] The present invention also includes a rapid construction method using the above device, comprising the following steps:

[0048] Step 1: If Figure 3As shown, one end of the steel strand 3 is first squeezed into the P anchor, and then the other end of the steel strand 3 is passed through the preset holes of the anchor plate 2, the first automatic tool anchor assembly 9, and the second automatic tool anchor assembly 14 in sequence.

[0049] Putting the steel strand anchor plate 2, the first automatic tool anchor assembly 9 and the second automatic tool anchor assembly 14 together to thread the steel strand fundamentally solves the problem of misalignment of the steel strand punching.

[0050] Step 2: If Figure 4 As shown, the steel strand anchor plate 2 is screwed into the internal thread of the stay cable anchor cup 1, and the positions of the first automatic tool anchor assembly 9 and the second automatic tool anchor assembly 14 on the steel strand 3 are adjusted so that they are spaced apart.

[0051] Step 3: If Figure 5 As shown, the support leg 10, the jack 11 and the anchor cup nut 5 are fixed in sequence to form a traction base.

[0052] Step 4: If Figure 6 As shown, the steel wire rope 3 with the first automatic tool anchor assembly 9 and the second automatic tool anchor assembly 14 is passed through the support leg 10; after the first automatic tool anchor assembly 9 passes through the anchor cup nut 5, a pad 6 is installed on the first automatic tool anchor assembly 9 and fixed with a positioning pressure plate 7.

[0053] Step 5: Figure 7 As shown, the first automatic tool anchor assembly 9 is installed into the first tool anchor positioning cover 8, and the first tool anchor positioning cover 8 is fixed to the base plate 6 with high-strength bolts; after the second automatic tool anchor assembly 14 passes through the jack 11, the second automatic tool anchor assembly 14 is installed into the second tool anchor positioning cover 13, and the second tool anchor positioning cover 13 is fixed to the piston of the jack 11 with high-strength bolts; at this point, the rapid assembly of the steel strand soft traction device is completed.

[0054] Step 6: Start the hydraulic pump station 16. The PLC control system, based on the displacement sensor on the jack 11, sends a signal to the PLC control system. After reaching the final stroke, the hydraulic pump station 16 retracts and then extends again after returning to zero stroke, repeatedly controlling the jack. Two oil pipes 15 run between the jack 11 and the hydraulic pump station 16: an inlet and a return pipe. These pipes are shared by both high-pressure and low-pressure systems, and are switched between high- and low-pressure operation using a handwheel control valve. At low pressure, the oil circuit uses a 22kW motor driving a 37L / min pump head. Once the system reaches a high pressure of 31 MPa, the handwheel control valve switches to a 5.5kW motor driving an 8L / min pump head. The operator makes the necessary switch based on comprehensive assessments of the on-site traction conditions and operating conditions. This ensures that when low pressure is used, the traction speed is high. When the traction force is high, the oil circuit switches to the high-pressure circuit, ensuring a slower speed and safe and stable traction operation.

[0055] When the cable body is twisted back, causing the originally parallel traction steel strands 3 to twist as a whole, and the jack 11 returns oil, the second tool anchor assembly 14 is in a free state; at this time, the construction personnel rotate the second automatic tool anchor assembly 14 in the opposite direction, and then the jack 11 adds oil to make the second automatic tool anchor assembly 14 subject to force, and at this time the first automatic tool anchor assembly 9 will rotate in the first tool anchor positioning cover 8, thereby restoring the steel strands to a parallel state.

Claims

1. An adaptive speed-changing traction device for a stay cable in a narrow space, characterized by: The invention comprises a steel anchor box (12) arranged obliquely, wherein a coaxial anchor plate (4), an anchor cup nut (5), a support leg (10) and a jack (11) are arranged in the steel anchor box (12); one end of the support leg (10) is arranged on the anchor plate (4); the anchor plate (4) is arranged on the steel anchor box (12); the anchor cup nut (5) is arranged on the inner side of the support leg (10) on the anchor plate (4); the base of the jack (11) is installed on the other end of the support leg (10); the interior of the anchor plate (4), the anchor cup nut (5), the support leg (10) and the jack (11) is penetrated There are steel strands (3), one end of a plurality of the steel strands (3) is fixed in a preset hole position of a steel strand anchor plate (2), and the steel strand anchor plate (2) is connected to the inclined cable anchor cup (1) through a thread; the steel strands (3) also pass through the preset holes of a first automatic tool anchor assembly (9) and a second automatic tool anchor assembly (14) in sequence; the second automatic tool anchor assembly (14) is arranged on the piston of the jack (11); the first automatic tool anchor assembly (9) is fixed by a pad (6); and the jack (11) is connected to a hydraulic pump station (16) through an oil pipe (15).

2. The narrow space adaptive speed-changing traction device for a stay cable according to claim 1, characterized in that: The layout structure of the preset hole positions of the steel strand anchor plate (2), the first automatic tool anchor assembly (9), and the second automatic tool anchor assembly (14) is the same.

3. The narrow space adaptive speed-changing traction device for a stay cable according to claim 1, characterized in that: The support leg (10) comprises a support leg top plate (101), a support leg bottom plate (102) and four columns (103) arranged therebetween; two baffles (104) are provided in the middle of the columns (103); a positioning pressure plate (7) is rotatably connected to the column (103) between the two baffles (104).

4. The narrow space adaptive speed-changing traction device for a stay cable according to claim 1, characterized in that: A first tool anchor positioning cover (8) is provided on the outer side of the first automatic tool anchor assembly (9), and the first tool anchor positioning cover (8) is fixed to the backing plate (6) by bolts; a second tool anchor positioning cover (13) is provided on the outer side of the second automatic tool anchor assembly (14), and the second tool anchor positioning cover (13) is fixed to the piston of the jack (11) by bolts.

5. The narrow space adaptive speed-changing traction device for a stay cable according to claim 4, characterized in that: The backing plate (6), the first tool anchor positioning cover (8) and the second tool anchor positioning cover (13) adopt a symmetrical two-petal structure.

6. The narrow space adaptive speed-changing traction device for a stay cable according to claim 1, characterized in that: The jack (11) is provided with a displacement sensor, which sends a stroke signal of the jack (11) to a PLC control system on a hydraulic pump station (16).

7. The rapid construction method of the device according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: First squeeze one end of the steel strand (3) into the P anchor, and then pass the other end of the steel strand (3) through the preset holes of the anchor plate (2), the first automatic tool anchor assembly (9), and the second automatic tool anchor assembly (14) in sequence; Step 2: Screw the steel strand anchor plate (2) into the internal thread of the inclined cable anchor cup (1), and adjust the positions of the first automatic tool anchor assembly (9) and the second automatic tool anchor assembly (14) on the steel strand (3) so that they are spaced apart; Step 3: Fix the support leg (10), the jack (11) and the anchor cup nut (5) in sequence to form a traction base; Step 4: Pass the steel strand (3) with the first automatic tool anchor assembly (9) and the second automatic tool anchor assembly (14) through the support leg (10); after the first automatic tool anchor assembly (9) passes through the anchor cup nut (5), install the backing plate (6) on the first automatic tool anchor assembly (9) and fix it with a positioning pressure plate (7); Step 5: Install the first automatic tool anchor assembly (9) into the first tool anchor positioning cover (8), and use high-strength bolts to fix the first tool anchor positioning cover (8) to the backing plate (6); after the second automatic tool anchor assembly (14) passes through the jack (11), install the second automatic tool anchor assembly (14) into the second tool anchor positioning cover (13), and use high-strength bolts to fix the second tool anchor positioning cover (13) to the piston of the jack (11); Step 6: Start the hydraulic pump station (16), and the PLC control system controls the extension and contraction of the jack (11) piston according to the stroke size of the jack (11) piston.

8. The rapid construction method according to claim 7, characterized in that: When the cable body is twisted back, causing the originally parallel traction steel strands to twist as a whole, after the jack returns oil, the construction personnel rotate the second automatic tool anchor assembly (14) in the opposite direction, and then the jack (11) is filled with oil to make the second automatic tool anchor assembly (14) bear force. At this time, the first automatic tool anchor assembly (9) will rotate in the first tool anchor positioning cover (8), thereby restoring the steel strands to a parallel state.

9. The rapid construction method according to claim 7, characterized in that: There are two oil pipes (15) between the jack (11) and the hydraulic pump station (16), namely an oil inlet pipe and an oil return pipe, and a hand wheel control valve is used to switch the high pressure and low pressure in the oil inlet pipe and the oil return pipe.

Images