Pressure dispersion type slope anchor cable and parameter design method thereof

Abstract

The application discloses a pressure dispersion type slope anchor cable and a parameter design method thereof, and belongs to the technical field of anchor cables, to solve the problem that traditional steel strand anchor cables need to be tensioned for multiple times when tensioning the anchor cable, resulting in low construction efficiency, the application comprises a cable body, a non-gap anchoring section and n gap anchoring sections are sequentially arranged along the tension direction of the cable body, wherein n is greater than or equal to 1, a compression gap is reserved between an anchor device and a pressure bearing plate in each gap anchoring section, and the gap amount of the n compression gaps gradually increases along the tension direction, by reasonably designing the gap amount in the gap anchoring section, the load bearing body pressure on each anchoring section can be uniformly distributed by only uniform tensioning, stress equality is achieved, the anchor cable does not need to be uniformly tensioned after multiple supplemental tensioning, and the construction efficiency is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of anchor cable, more particularly relates to a pressure dispersion type slope anchor cable and a parameter design method thereof. BACKGROUND

[0002] The traditional tension type anchor cable relies on the adhesion between the cable body and the grouting body to work, but the tensile resistance of the grouting body is low, so the designed tonnage is relatively low. The pressure type anchor cable effectively utilizes the characteristics that the compressive resistance of the grouting body and the rock-soil body is obviously better than the tensile resistance, improves the stress environment of the anchor cable, and thus improves the durability and anchoring effect of the anchor cable.

[0003] The existing pressure dispersion type anchor cable has the following characteristics: the cable body adopts unbonded steel strand, a plurality of load carriers are arranged on the anchor cable to form a plurality of anchoring segments, and the pressure dispersion is realized by gradually reducing the number of steel strands on the load carriers. For example, the Chinese patent with the publication number CN113356197A uses the reverse stress provided by the load carrier to extrude the front grouting body when the steel strand is tensioned, and the pressure-shear stress formed by the grouting body and the hole wall matches the prestress of the anchor cable, so that the tension tonnage is higher than that of the tension type anchor cable. However, there are two shortcomings: 1. Since the lengths of each group of steel strands of the pressure dispersion type anchor cable are inconsistent, the tension of the anchor cable should be performed on the unit body with a longer steel strand first, that is, different degrees of compensation tension are adopted for unit bodies with different lengths. After the compensation tension is in place, simultaneous tension can be performed, so as to ensure that the forces of steel strands with different lengths are the same, which requires repeated tensioning for multiple times, thereby causing low construction efficiency. 2. The anchor cable is a steel anchor cable, which is prone to corrosion. In the rock-soil environment, water and corrosive media can cause corrosion failure of the anchor cable, and the service life is short. SUMMARY

[0004] In view of the shortcomings of the prior art, the present application provides a pressure dispersion type slope anchor cable and a parameter design method thereof. A plurality of gap anchoring segments are arranged in sequence along the tension direction of the cable body. By reasonably designing the gap amount of the gap anchoring segments, pressure dispersion force transmission can be achieved during tensioning, and the effect of completing the construction in one tensioning can be achieved, so as to solve the technical problem of low construction efficiency caused by the need for multiple tensioning of the traditional steel strand anchor cable when tensioning the anchor cable.

[0005] To achieve the above purpose, the present application is implemented by the following technical scheme: a pressure dispersion type slope anchor cable, comprising a cable body, the key lies in: one non-gap anchoring segment and n gap anchoring segments are arranged in sequence along the tension direction of the cable body, wherein n≥1, a compression gap is reserved between the anchor and the load carrier in each gap anchoring segment, and the gap amounts of the n compression gaps gradually increase along the tension direction.

[0006] Further, the compression gap is filled with elastic components, and the stiffness coefficients of the n elastic components gradually decrease along the tension direction.

[0007] Further, the cable body is a multi-layer FRP plate cable, and the anchor is a wave-shaped anchor.

[0008] Further, the number of FRP plate layers of the multi-layer FRP plate cable gradually increases along the tension direction.

[0009] Further, the cable body is provided with a protective sleeve, and the protective sleeve is coated with lubricating grease.

[0010] Further, the anchor is provided with a protective cover, and the protective cover is filled with epoxy resin.

[0011] Based on a pressure dispersion type slope anchor cable, the application further provides a parameter design method of the pressure dispersion type slope anchor cable, and the key lies in comprising the following steps:

[0012] S1: according to the cable body length and the required tension, the number of gap anchoring sections is determined, and is sequentially marked as 1-n along the tension direction;

[0013] S2: through the first section cable force size is calculated, wherein F is the tension;

[0014] S3: according to the gap amount Δ of each compression gap is calculated, wherein L is the length of each anchoring section, A is the cross-sectional area of the cable body, E is the elastic modulus of the cable body material, and j is an arbitrary gap anchoring section, and 1≤j≤n.

[0015] Further, the compression gap is filled with elastic components, and according to the stiffness coefficient k of each elastic component is calculated.

[0016] The application provides a pressure dispersion type slope anchor cable and a parameter design method thereof, and has the following beneficial effects:

[0017] 1. A plurality of gap anchoring sections are sequentially arranged along the tension direction of the cable body, the gap amount in the gap anchoring section is reasonably designed, the load on each anchoring section is uniformly distributed by only uniformly tensioning, the stress is equal, the anchoring section does not need to be tensioned multiple times and then uniformly tensioned, and the construction efficiency is greatly improved.

[0018] 2. The cable body adopts FRP plate material, has strong corrosion resistance, and has a long service life under the premise of good protection of the anchor.

[0019] 3. The application adopts FRP plate material, has high tensile strength, and the combination of the two can make the design tonnage higher. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the pressure-dispersing slope anchor cable provided in this embodiment;

[0021] Figure 2 This is a schematic diagram of the gapless anchoring section provided in this embodiment;

[0022] Figure 3 This is a schematic diagram of the structure of the gap anchoring section provided in this embodiment;

[0023] Figure 4 A simplified calculation diagram for setting up a reserved compression gap is provided in this embodiment;

[0024] Figure 5 This is a simplified calculation diagram for setting up the elastic component in this embodiment.

[0025] In the diagram: 1. Cable body; 2. Anchorage; 3. Bearing body; 4. Elastic component; 5. Protective cover; 6. Tensioning device. Detailed Implementation

[0026] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0027] The invention provides the following technical solution:

[0028] Example 1:

[0029] like Figures 1-3 As shown, a pressure-dispersing slope anchor cable includes a cable body 1, characterized in that: a gapless anchoring section and n gap anchoring sections are sequentially arranged along the tensioning direction of the cable body 1, wherein n≥1, a compression gap is reserved between the anchor 2 and the bearing body 3 in each gap anchoring section, and the gap amount of the n compression gaps increases stepwise along the tensioning direction, wherein the bearing body 3 can be a pressure plate or other components.

[0030] In the specific implementation, the anchorage 2 is moved to the tensioning direction through the compression gap reserved between the anchorage 2 and the bearing body 3, and the compression gap is compressed under the force, at this time, the movement of the anchorage 2 at this position can be equivalent to pulling the anchoring segment cable body 1 behind. Similarly, the anchorage 2 on the rear anchoring segment is pulled to compress the corresponding compression gap, and then moves again to pull the anchoring segment cable body 1 behind. When the compression gap on each anchoring segment no longer compresses, at this time, the bearing body 3 on each anchoring segment reaches a stable force and transmits the pressure to the corresponding grouting body. In this way, the tensioning force distribution of the anchor cable can be proportionally distributed according to the compression amount of the compression gap, and only uniform tensioning is required to uniformly distribute the pressure of the bearing body on each anchoring segment, so that the force is equal, and multiple tensioning is not required, which greatly improves the construction efficiency. At the same time, through the pressure dispersion effect, each anchoring segment is uniformly stressed, so that the anchor cable can withstand stronger tensioning force.

[0031] In the tensioning, the tensioning device 6 is used for tensioning, and the tensioning device 6 includes an anchoring component, a pad plate, a hollow jack, and a tensioning screw rod. The end of the cable body 1 is anchored by the anchoring component, the hollow jack is used for stretching and tensioning, and then the tensioning screw rod is used for locking and fixing.

[0032] As shown in Figure 2 Figure 3 As shown in the drawings, regarding the cable body 1, the cable body 1 is a multi-layer FRP plate cable, which is formed by parallel stacking of multiple FRP plates, and the anchorage 2 is a wave-shaped anchorage. The wave-shaped anchorage works by adhesion and friction, fully utilizes the bending effect to further improve the anchoring effect of adhesion and friction, can fully clamp the FRP plate, and plays the high-strength performance of the FRP material.

[0033] Since the tensioning force of the anchor cable is stronger as it is closer to the tensioning position, the number of layers of the FRP plate of the multi-layer FRP plate cable is gradually increased along the tensioning direction, and the number of layers of the FRP plate behind is relatively small. This setting can reduce the amount of FRP plate, ensure that the cable body 1 can withstand the same tensioning force, and save materials.

[0034] In order to ensure that the cable body 1 can move freely after grouting in the hole, a protective sleeve is provided outside the cable body 1, and lubricating grease is brushed in the protective sleeve, so as to ensure that the FRP plate cable can be freely stretched.

[0035] In addition, as shown in Figure 2 Figure 3 As shown in the drawings, considering that the grouting hole will be affected by water and corrosive media in the rock-soil environment, the anchorage 2 is provided with a protective cover 5, and the protective cover 5 is filled with epoxy resin. In this way, the anchorage 2 is protected, and the service life of the anchorage 2 is longer.

[0036] Example two:

[0037] Considering that the compression gap is filled with cement mortar when grouting, the elastic component 4 is filled in the compression gap, and the elastic component 4 is attached to the anchor 2 and the bearing body 3 respectively, the stiffness coefficient of the n elastic components 4 gradually decreases along the tension direction, and the elastic component 4 can be selected from materials such as rubber pads.

[0038] In actual use, the working principle is similar to that of the first embodiment, except that the compression amount of the elastic component 4 is related to the stiffness coefficient k itself, so that the effect of uniform stress of the grouting body is achieved by selecting elastic components 4 with different stiffness coefficients k.

[0039] In addition, based on a pressure dispersion type slope anchor cable, the application also provides a parameter design method of the pressure dispersion type slope anchor cable, comprising the following steps:

[0040] S1: According to the length of the cable body 1 and the required tension, the number of gap anchoring sections is determined, and is marked as 1-n along the tension direction;

[0041] S2: Through the first section cable force is calculated, wherein F is the tension;

[0042] S3: According to the gap amount Δ of each compression gap is calculated, wherein L is the length of each anchoring section, A is the cross-sectional area of the cable body 1, E is the elastic modulus of the material of the cable body 1, and j is any one gap anchoring section, and 1≤j≤n.

[0043] The derivation of the above formula is as follows:

[0044] As shown in Figure 4 , it is assumed that the anchor cable has n gap anchoring sections, plus the last gap anchoring section (the bearing body 3 directly contacts the anchor 2), a total of n+1 anchoring sections. In order to make the bearing body 3 on each anchoring section bear uniformly, each bearing body 3 bears F / (n+1), and each cable force size is reduced in proportion, and each cable force size is

[0045] The gap amount Δ is Δ, according to Hooke's law, under the condition of meeting the deformation coordination:

[0046]

[0047] Therefore, the gap amount Δ of each gap can be obtained:

[0048]

[0049] …

[0050]

[0051] If Δ1 is known, the void volume Δj of any one reserved compression void anchoring segment j j is:

[0052]

[0053] In summary, the void volume is set according to the above relationship, which can achieve equal stress of each carrier 3 and the effect of uniform pressure dispersion.

[0054] In addition, considering that the reserved compression void will be filled with cement mortar when grouting, further fill elastic components 4 in the compression void, and according to Calculate the stiffness coefficient k of each elastic component 4, where j is any one void anchoring segment, and 1≤j≤n.

[0055] The derivation of the above formula is as follows:

[0056] As shown in Figure 5 , it is assumed that the anchor cable has n elastic component 4 anchoring segments, plus the last anchoring segment without elastic component 4 (carrier 3 directly contacts with anchor 2), a total of n+1 anchoring segments. In order to make the elastic component 4 on each anchoring segment bear uniform stress, each elastic component 4 bears F / (n+1), and the size of each segment cable force decreases by equal proportion.

[0057] The size of each segment cable force is:

[0058]

[0059] The pressure borne by the elastic component 4 is:

[0060]

[0061] The stiffness coefficient of the elastic component 4 is k, according to Hooke's law, under the condition of meeting the deformation coordination:

[0062]

[0063]

[0064] …

[0065]

[0066]

[0067] Therefore, the stiffness coefficient k of each elastic component 4 can be obtained:

[0068]

[0069] It can be seen that the stiffness coefficient k of each elastic component 4 can be represented by k1, and thus:

[0070]

[0071] If k1 is known, the stiffness coefficient k of any elastic component 4 is j :

[0072]

[0073] In summary, the stiffness coefficient of the elastic component 4 can be set according to the above relationship to achieve equal stress on each carrier and uniform dispersion of pressure.

[0074] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can make equivalent replacements or changes within the technical range disclosed by the present application according to the technical solution and inventive concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A parameter design method of a pressure-dispersive slope anchor cable, characterized in that: The pressure-dispersing slope anchor cable includes a cable body (1), and along the tensioning direction of the cable body (1), there is a gapless anchoring section and n gap anchoring sections, where n≥1. In each gap anchoring section, a compression gap is reserved between the anchor (2) and the bearing body (3), and the amount of the n compression gaps increases step by step along the tensioning direction. Elastic components (4) are filled in the compression gaps, and the stiffness coefficient of the n elastic components (4) decreases step by step along the tensioning direction. Parameter design includes the following steps: S1: Determine the number of gap anchorage sections according to the length of the cable (1) and the required tension, and mark them sequentially as 1~n along the tensioning direction; S2: Through Calculate the magnitude of the tension in the first cable segment, where F is the tension force; S3: According to , Calculate the void amount Δ for each compression void, where L is the length of each anchoring segment, A is the cross-sectional area of ​​the cable (1), E is the elastic modulus of the cable (1) material, j is any void anchoring segment, and 1≤j≤n; according to , The stiffness coefficient k of each elastic component (4) is calculated.

2. The parameter design method for pressure-dispersing slope anchor cables according to claim 1, characterized in that: The cable body (1) is a multi-layer FRP plate cable, and the anchor (2) is a corrugated anchor.

3. The parameter design method for pressure-dispersing slope anchor cables according to claim 2, characterized in that: The number of FRP layers in the multi-layer FRP cable increases progressively along the tensioning direction.

4. The parameter design method for pressure-dispersing slope anchor cables according to claim 1, characterized in that: The cable body (1) is covered with a protective sleeve, and the inside of the protective sleeve is coated with lubricating grease.

5. The parameter design method for pressure-dispersing slope anchor cables according to claim 1, characterized in that: The anchor (2) is covered with a protective cover (5), and epoxy resin is filled into the protective cover (5).

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