Main cable anchoring system and installation method

Abstract

The present invention discloses a main cable anchoring system and installation method. The main cable anchoring system includes a main cable, a loose cable sleeve and an anchor plug body. After the main cable is connected to the main span section of the bridge, the main cable extends straightly in the direction close to the vertical steep wall; the loose cable sleeve is installed at the tail end of the main cable to disperse the main cable into multiple cable strands; the anchor plug body is installed and fixed in the vertical steep wall, the anchor plug body is located on the axis of the main cable, the anchor plug body includes a relatively large plug end and a small plug end, the small plug end is located on the side close to the edge of the vertical steep wall, and the height of the small plug end relative to the ground is less than the height of the large plug end relative to the ground, and the small plug end is connected to the dispersed multiple cable strands. By adopting the main cable anchoring system and installation method, the entire system does not need a composite cable saddle and a cable tower, the structural design is simplified, the manufacturing and installation costs are saved, and the force-bearing mode effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, and in particular to a main cable anchoring system and an installation method. Background Art

[0002] With the construction of more and more steep slope V-shaped canyon suspension bridges, it has become necessary to set up a main cable 3 anchoring system on a vertical steep wall 4. The most existing design method is to set up a composite cable saddle 5 on the steep wall to replace the cable tower. The main cable 3 passes through the composite cable saddle 5, completes the turning and cable strand 6 at one time, and is finally anchored on the anchor plug 7' of the tunnel anchor ( Figure 1 ), such as the Jinsha River Bridge in Tiger Leaping Gorge on the Xiangli Expressway and the Jinsha River Bridge.

[0003] In the prior art, the force transmission path of the anchoring system of the suspension bridge is: main beam 1->suspender rod 2->main cable 3->composite cable saddle 5 (steering)->upright anchor plug 7' (such as Figure 1 The reason for this arrangement is that the anchor plug body 7' must be set underground to provide boundary force for the structure through the earth, and the main tower and the composite cable saddle 5 are used for steering to convert the upward lifting force into the downward anchoring force. At the same time, the horizontal forces on both sides of the main tower and the composite cable saddle 5 can be balanced.

[0004] This design method has several problems:

[0005] (1) The axial force P1 of the main cable 3 of the main span of the suspension bridge is inclined downward, and the vertical component is roughly half the weight of the main span; the axial force P2 of the cable strand 6 is also inclined downward, and the vertical component is also roughly half the weight of the main span. The composite cable saddle 5, like the conventional main cable saddle, will bear a downward pressure of the entire main span bridge weight equal to the vertical component of P1 + the vertical component of P2 ( Figure 2 ), which requires the saddle foundation 51 of the composite saddle 5 to have a strong bearing capacity, and when the composite saddle 5 foundation is adjacent to the edge of the vertical wall, its foundation needs to be strengthened;

[0006] (2) When the live load on the main span of the suspension bridge changes, the horizontal forces on both sides of the composite saddle 5 will no longer be balanced ( Figure 3 ), it is necessary to set a roller under the composite cable saddle 5 to allow the composite cable saddle 5 to slide to adjust the balanced horizontal force. The roller system is complex and expensive: Assuming that the horizontal component of the axial force of the main cable 3 is P11, the horizontal component of the axial force of the cable strand 6 is P21, the original vertical axis of the composite cable saddle 5 is L1, and the vertical axis of the composite cable saddle 5 after movement is L2, when a car goes on the bridge, the horizontal component of the axial force of the main cable 3 P11 will increase, and the composite cable saddle 5 will move toward the main cable 3, and the vertical axis after movement is L2;

[0007] (3) The composite cable saddle 5 takes into account the functions of steering and spreading the main cable 3. The saddle groove is designed as a spatial curve, which has high processing requirements and high cost. Summary of the invention

[0008] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a main cable anchoring system and installation method, which does not require composite saddles and cable towers, simplifies the structural design, saves the production and installation costs of saddles, and has a good force-bearing effect.

[0009] In order to achieve the above object, the present invention is implemented through the following technical solution: a main cable anchoring system, comprising:

[0010] A main cable, after connecting the main span of the bridge, extends straight toward the vertical steep wall;

[0011] A cable-dispersing sleeve installed at the tail end of the main cable to disperse the main cable into multiple cable strands;

[0012] An anchor plug body is installed and fixed in the vertical steep wall. The anchor plug body is located on the axis of the main cable. The anchor plug body includes a relatively large plug end and a small plug end. The small plug end is located on the side close to the edge of the vertical steep wall, and the height of the small plug end relative to the ground is smaller than the height of the large plug end relative to the ground. The small plug end is connected to the dispersed multiple strands of the cable.

[0013] Preferably, it further comprises a support column, wherein there are a plurality of the support columns, the plurality of the support columns are circumferentially spaced and arranged on the outside of the anchor plug body, and the support columns are fixed in the vertical steep wall.

[0014] Preferably, each of the support columns is inclined toward the outer side of the vertical steep wall.

[0015] A method for installing a main cable anchoring system, using the above main cable anchoring system, comprising:

[0016] A vertical shaft is excavated downward from the top of the vertical steep wall, and then an anchor chamber is opened inside the vertical steep wall, the anchor chamber is located in the straight extension direction of the main cable close to the vertical steep wall, the anchor chamber includes a large head end and a small head end opposite to each other, the small head end is located on the side close to the edge of the vertical steep wall, and the height of the small head end relative to the ground is less than the height of the large head end relative to the ground, and the vertical shaft is connected to the large head end of the anchor chamber;

[0017] Provide corresponding support to the anchor chamber;

[0018] A support chamber is excavated around the anchor chamber, and the support chamber is connected with the big end of the anchor chamber, and the support chamber is supported;

[0019] A guide hole is provided at the front end of the anchor chamber to connect the small end of the anchor chamber with the outside world, and the extension direction of the guide hole is consistent with the extension direction of the main cable;

[0020] Concrete is poured into the anchor chamber, the anchor plug body is cast in the big end, and the oblique support column is cast in the support chamber;

[0021] A loose rope sleeve is provided in the small end of the anchor chamber;

[0022] The tail end of the main cable is pulled into the steep wall through a guide hole, dispersed into multiple cable strands through a loose cable sleeve, and the multiple cable strands are fixed to the anchor plug body.

[0023] Preferably, the support of the anchor chamber is achieved by driving grouting anchor rods into the rock wall around the anchor chamber, setting up a grid steel frame on the inner wall of the anchor chamber, and spraying concrete to form support.

[0024] Preferably, the cross section of the pilot tunnel should be smaller than the cross section of the small end of the anchor chamber, and lining should be applied in the pilot tunnel.

[0025] Preferably, a steel frame needs to be installed in the anchor chamber, prestressed pipes need to be installed, cooling pipes need to be installed, steel bars need to be tied, and formwork needs to be set; then, concrete of the anchor body and the oblique support column is poured at one time to form the anchor body and the oblique support column.

[0026] The main cable anchoring system and installation method of the present invention have the following beneficial effects:

[0027] 1. This structure completely abandons the main cable steering design idea of ​​the composite saddle, directly extends the spatial axis of the main cable, and uses the location advantage of the vertical steep wall at a high place as the anchor point of the main cable according to the terrain conditions;

[0028] 2. The structure does not require a cable tower or a composite cable saddle, the structural design is simplified, and the structural force transmission path is clearer and more direct;

[0029] 3. This design does not use composite cable saddles, does not have side span main cables, does not require horizontal sliding of composite cable saddles, and adjusts the horizontal force balance. The main cable force is always self-balanced in the direction of its axis.

[0030] 4. The anchor body is inverted, with a smaller diameter at the lower end and a larger diameter at the upper end. When pulled out, it forms a clamping effect with the rock wall, and an inclined support column is set as an anti-pullout device, which has greater advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation of the present invention, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0032] Figure 1 The anchor structure and installation method of the main cable in the prior art;

[0033] Figure 2 Analysis diagram of vertical forces on both sides of composite cable saddle of suspension bridge in prior art;

[0034] Figure 3 Horizontal force analysis diagram on both sides of the middle composite saddle;

[0035] Figure 4 A main cable anchoring system and a schematic diagram after installation provided by an embodiment of the present invention;

[0036] Figure 5 A is a schematic diagram of the position of the support column on the inverted anchor plug body section, and B is a schematic diagram of the position of the support column on the upright anchor plug body section;

[0037] Figure 6 A schematic diagram of an installation method of a main cable anchoring system provided by an embodiment of the present invention;

[0038] Figure 7 A schematic diagram of a shaft and an anchor chamber in a method for installing a main cable anchoring system provided by an embodiment of the present invention;

[0039] Figure 8 A schematic diagram of a shaft, an anchor chamber and a guide hole in a method for installing a main cable anchoring system provided by an embodiment of the present invention;

[0040] Fig. 9 A schematic diagram of installing a prestressed pipe and an anchor plug body section in a method for installing a main cable anchoring system provided by an embodiment of the present invention;

[0041] Fig.10 A schematic diagram of a method for installing a main cable anchoring system provided by an embodiment of the present invention after installing a traction winch and a temporary bracket for a loose cable sleeve;

[0042] Fig.11 A schematic diagram of a main cable anchoring system installation method provided by an embodiment of the present invention after the cable strands are installed;

[0043] Fig.12 A schematic diagram of a main cable anchoring system installation method provided by an embodiment of the present invention after installing a loose cable sleeve.

[0044] Reference numerals:

[0045] 1. Main beam; 2. Hanging rod; 3. Main cable; 4. Vertical steep wall; 5. Composite saddle; 51. Saddle foundation; 6. Cable strand; 7. Anchor plug; 71. Support column; 8. Loose rope sleeve; 9. Anchor chamber; 91. Big head end; 92. Small head end; 10. Guide tunnel; 11. Vertical shaft; 12. Support chamber; 13. Temporary support; 14. Winch; 15. Grouting anchor rod; 16. Prestressed pipe. DETAILED DESCRIPTION

[0046] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0047] See also Figures 4 to 11 The present invention provides a main cable anchoring system, including a main cable 3, a loose cable sleeve 8 and an anchor plug body 7.

[0048] Specifically, after the main cable 3 is connected to the main span section of the bridge, the main cable 3 extends straight toward the vertical steep wall 4. The loose cable sleeve 8 is installed at the tail end of the main cable 3 to disperse the main cable 3 into multiple cable strands 6; the anchor plug body 7 is installed and fixed in the vertical steep wall 4, and the anchor plug body 7 is located on the axis of the main cable 3. The anchor plug body 7 includes a relatively large plug body end and a small plug body end. The small plug body end is located on the side close to the edge of the vertical steep wall 4, and the height of the small plug body end relative to the ground is less than the height of the large plug body end relative to the ground. The small plug body end is connected to the dispersed multiple cable strands 6.

[0049] When in use, the anchor plug body 7 is first installed and fixed on the vertical steep wall 4, and the main cable 3 is connected to the main span section of the bridge and is directly connected to the anchor plug body 7 without turning.

[0050] It should be noted that, in the specific implementation, the average diameter of the anchor plug 7 should be controlled according to the dispersion angle factor of the cable strand 6, and the minimum value should be selected; at the same time, in order to enhance the anchoring effect, the length of the anchor plug can be appropriately lengthened to obtain the anchoring effect. In addition, after the excavation is completed, the rock wall should be inspected, and the cracks and cavities in the rock wall should be grouted and filled to strengthen the

[0051] The use of this structure to fix the main cable 3 has the following advantages:

[0052] 1. This structure completely abandons the design idea of ​​turning the main cable 3 of the composite saddle 5, directly extends the spatial axis of the main cable 3, and uses the location advantage of the vertical steep wall 4 at a high place as the anchor point of the main cable 3 according to the terrain conditions;

[0053] 2. The structure does not require a cable tower or a composite cable saddle 5, the structural design is simplified, and the structural force transmission path is clearer and more direct;

[0054] 3. This design does not use the composite saddle 5, does not have a side span main cable, does not require the composite saddle 5 to slide horizontally, and does not require the horizontal force balance to be adjusted. The main cable 3 force is always self-balanced in the direction of its axis.

[0055] 4. The anchor plug body 7 is inverted, with a smaller diameter at the lower end and a larger diameter at the upper end. When pulled out, it forms a clamping effect with the rock wall, and an oblique support column is provided as an anti-pullout device, which has greater advantages.

[0056] Further preferably, the main cable anchoring system further comprises a supporting column 71. There are a plurality of supporting columns 71, and the plurality of supporting columns 71 are arranged at intervals in the circumferential direction on the outside of the anchor plug body 7, and the supporting columns 71 are fixed in the vertical steep wall 4.

[0057] The support column 71 can increase the anchoring force between the anchor plug body 7 and the vertical steep wall 4. In specific implementation, the number and size of the support column 71 can be determined according to the site conditions.

[0058] See also Figure 5 In addition, each support column 71 should be inclined toward the vertical steep wall 4, that is, the angle between the support column 71 and the small end of the plug body is less than 90°. In this way, the anchoring effect can be further improved. At the same time, since the anchor plug body 7 is inverted, the end position a of the support column 71 can be slightly lower than the intersection position b of the support column 71 and the anchor plug body 7, which is conducive to the compaction of the concrete at the end of the support column 71; when the anchor plug body 7 is upright, the end position c of the support column 71 is slightly higher than the intersection position b of the support column 71 and the anchor plug body 7, and the concrete at the end of the support column 71 is difficult to be compacted. When the force is pulled out, the entire anchor plug body 7 may be displaced due to the compression of the gap.

[0059] In addition, the present invention also provides a method for installing a main cable anchoring system, which adopts the above main cable anchoring system and mainly includes the following steps:

[0060] S110: digging a vertical shaft 11 downward from the top of the vertical steep wall 4, and then opening an anchor chamber 9 inside the vertical steep wall 4, the anchor chamber 9 is located in the straight extension direction of the main cable 3 to the vertical steep wall 4, the anchor chamber 9 includes a large head end 91 and a small head end 92 opposite to each other, the small head end 92 is located on the side close to the edge of the vertical steep wall 4, and the height of the small head end 92 relative to the ground is less than the height of the large head end 91 relative to the ground, and the vertical shaft 11 is connected with the large head end 91 of the anchor chamber 9;

[0061] S120: Provide corresponding support to the anchor chamber 9;

[0062] Specifically, grouting anchor rods 15 are driven into the rock wall around the anchor chamber 9 , a grid steel frame is set up on the inner wall of the anchor chamber 9 , and concrete is sprayed to form a support, so as to reinforce the anchor chamber 9 .

[0063] S130: excavating a support chamber 12 around the anchor chamber 9, wherein the support chamber 12 is connected to the large end 91 of the anchor chamber 9, and supporting the support chamber 12;

[0064] Specifically, a support chamber 12 is first excavated around the anchor chamber 9, and the support chamber 12 is connected to the large end 91 of the anchor chamber 9, and each support column 71 is inclined toward the outside of the vertical steep wall 4. Grouting anchor rods 15 are driven around the support chamber 12, cement slurry is injected, and cracks are closed for reinforcement.

[0065] S140: A guide hole 10 is opened at the front end of the anchor chamber 9 to connect the small end 92 of the anchor chamber 9 with the outside, and the extension direction of the guide hole 10 is consistent with the extension direction of the main cable 3;

[0066] Specifically, a guide hole 10 is opened at the front end of the anchor chamber 9 to connect the small end 92 of the anchor chamber 9 with the outside world, and the extension direction of the guide hole 10 is consistent with the extension direction of the main cable 3. The cross-section of the guide hole 10 should be smaller than the cross-section of the small end 92 of the anchor chamber 9, and lining should be applied in the guide hole 10.

[0067] S150: injecting concrete into the anchor chamber 9, casting the anchor plug body 7 in the large end 91, and casting the oblique support column 71 in the support chamber 12;

[0068] Specifically: first, it is necessary to install a steel frame in the big head end 91 of the anchor body 7, install the prestressed pipe 16, install the cooling pipe, tie the steel bars, and set the formwork; then, pour the concrete of the anchor body 7 and the oblique support column 71 at one time to form the anchor body 7 and the oblique support column 71.

[0069] S160: Arrange a loose cable sleeve 8 in the small end 92 of the anchor chamber 9;

[0070] Specifically, a rope strand 6 traction winch 14 is installed in the front anchor chamber 9, and a temporary bracket 13 is set up at the preset position of the loose rope sleeve 8, the loose rope sleeve 8 is temporarily fixed on the bracket, and the bolts of the loose rope sleeve 8 are loosened to make the loose rope sleeve 8 in a relaxed state.

[0071] S170: The tail end of the main cable 3 is pulled into the steep wall through the guide hole 10, dispersed into a plurality of cable strands 6 through the cable sleeve 8, and the plurality of cable strands 6 are fixed to the anchor plug body 7.

[0072] The specific construction steps for installing the above main cable anchoring system are:

[0073] 1. Calculate the axial spatial position of the anchor plug 7, dig a vertical shaft 11 from the top of the mountain to the rear of the anchor chamber 9, and then dig the anchor chamber 9 horizontally, and make the anchor chamber 9 located in the axial direction of the main cable 3, even if the anchor chamber 9 is tilted and inverted;

[0074] 2. The anchor chamber 9 is divided into a large end 91 and a small end 92 from the back to the front. The shaft 11 is connected to the large end 91. The front anchor chamber 9 is located near the edge of the steep wall. During the excavation process, the axial direction of the entire anchor chamber 9 should be controlled, and grouting anchor rods 15 should be driven into the rock wall around the anchor chamber 9, and the cracks should be sealed by injecting cement slurry. In addition, a grid steel frame is set up on the inner wall of the anchor chamber 9, and concrete is sprayed to form a support (see Figure 7 ).

[0075] 3. Excavate the support chamber 12 around the anchor chamber 9. After the excavation is completed, the grouting anchor rods 15 should be driven around the support chamber 12, and cement slurry should be injected to close the cracks. At the same time, the front anchor chamber 9 section is excavated forward to connect the anchor chamber 9 with the outside world. The guide hole 10 is also located in the axial direction of the main cable 3. The diameter of the guide hole 10 is smaller than the diameter of the anchor chamber 9. At the same time, lining is applied in the guide hole 10 (see Figure 7 , 8 ).

[0076] 4. Install the steel frame inside the anchor plug body 7, install the prestressed pipe 16, install the cooling pipe, tie the steel bars, set the formwork, and pay attention to reserving the pedestrian passage between the anchor plug body 7 and the front anchor chamber 9; then, pour the concrete of the anchor plug body 7 and the oblique support column 71 at one time. After the concrete reaches the strength, tension the anchor plug body 7 prestress, and install the cable strand 6 connection device on the anchor plug body 7 (see Fig. 9 ).

[0077] 5. Install the cable strand 6 traction winch 14 in the small end 92, and set up a temporary bracket 13 at the preset position of the loose cable sleeve 8, temporarily fix the loose cable sleeve 8 on the bracket, loosen the cable strand 6 set bolts, and make the cable strand 6 set in a relaxed state (see Fig.10 ).

[0078] 6. During the construction of the bridge main cable 3, the rope strands 6 of the main cable 3 are pulled one by one by the winch 14 through the loose rope sleeve 8, into the front anchor chamber 9, and finally connected to the anchor plug body 7 (see Fig.11 ).

[0079] 7. After all the cables 6 are connected to the anchor plug 7, the bolts of the loose cable sleeve 8 should be tightened to clamp the loose cable sleeve 8 on the cross section of the cable strand 6. 8. After the construction is completed, the winch 14 and the temporary support 13 are removed, and the loose cable sleeve 8 will be suspended at the designed position. At this point, the inverted tunnel anchor construction is completed (see Fig.12 ).

Claims

1. A main cable anchoring system, characterized in that: include: A main cable, after connecting the main span of the bridge, extends straight toward the vertical steep wall; A cable-dispersing sleeve installed at the tail end of the main cable to disperse the main cable into multiple cable strands; and An anchor plug body is installed and fixed in the vertical steep wall. The anchor plug body is located on the axis of the main cable. The anchor plug body includes a large plug end and a small plug end that are opposite to each other. The small plug end is located on the side close to the edge of the vertical steep wall. The height of the small plug end relative to the ground is smaller than the height of the large plug end relative to the ground. The small plug end is connected to the dispersed multiple strands of the cable. It also includes a plurality of support columns, wherein the plurality of support columns are arranged at circumferential intervals on the outside of the anchor plug body, and the support columns are fixed in the vertical steep wall; Each of the support columns is inclined toward the outer side of the vertical steep wall.

2. A method for installing a main cable anchoring system, characterized in that: The main cable anchoring system according to any one of claim 1 comprises: A vertical shaft is excavated downward from the top of the vertical steep wall, and then an anchor chamber is opened inside the vertical steep wall, the anchor chamber is located in the straight extension direction of the main cable close to the vertical steep wall, the anchor chamber includes a large head end and a small head end opposite to each other, the small head end is located on the side close to the edge of the vertical steep wall, and the height of the small head end relative to the ground is less than the height of the large head end relative to the ground, and the vertical shaft is connected to the large head end of the anchor chamber; Provide corresponding support to the anchor chamber; A support chamber is excavated around the anchor chamber, and the support chamber is connected with the big end of the anchor chamber, and the support chamber is supported; A guide hole is provided at the front end of the anchor chamber to connect the small end of the anchor chamber with the outside world, and the extension direction of the guide hole is consistent with the extension direction of the main cable; Concrete is poured into the anchor chamber, the anchor plug body is cast in the big end, and the oblique support column is cast in the support chamber; A loose rope sleeve is provided in the small end of the anchor chamber; The tail end of the main cable is pulled into the steep wall through the guide hole, dispersed into multiple cable strands through the loose cable sleeve, and the multiple cable strands are fixed to the anchor plug body.

3. The installation method of the main cable anchoring system according to claim 2, characterized in that: The anchor chamber is supported by driving grouting anchor rods into the rock wall around the anchor chamber, setting up a grid steel frame on the inner wall of the anchor chamber, and spraying concrete to form support.

4. The installation method of the main cable anchoring system according to claim 2, characterized in that: The cross section of the pilot tunnel should be smaller than that of the small end of the anchor chamber, and lining should be applied in the pilot tunnel.

5. The installation method of the main cable anchoring system according to claim 2, characterized in that: First, it is necessary to install a steel frame in the anchor chamber, install prestressed pipes, install cooling pipes, tie steel bars, and set up formwork; then, pour concrete for the anchor body and the oblique support column at one time to form the anchor body and the oblique support column.

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