High-strength stable-resistance energy-absorbing anchor cable and supporting method thereof

Abstract

The invention relates to a high-strength stable-resistance energy-absorbing anchor cable and a supporting method thereof, and belongs to the technical field of mine and tunnel engineering supporting. The anchor cable comprises an anchor cable body, a steel sleeve, an anchorage device arranged in an inner cavity of the steel sleeve in a sliding mode, a steel ball located between the inner wall of the steel sleeve and the outer wall of the anchorage device, and an anchorage device ring located at the tail end of the steel sleeve. When the anchor cable is pulled to reach set stress, the anchorage device extrudes the steel balls to move in the axial direction of the steel sleeve until the steel balls are embedded into the anchorage device ring, and the constant-resistance yielding function is achieved. The steel balls are divided into two rows, the diameter of the front row is large, the diameter of the rear row is small, and annular grooves are formed in the outer wall of the anchorage device to stabilize the steel balls. The steel balls are higher than the steel sleeve and the anchorage device in hardness, so that stable work under high stress is ensured. The anchor cable enables the anchorage device to compress the steel balls to generate constant resistance through initial pre-tightening force, the steel balls are driven by the anchorage device to slide to absorb energy when surrounding rock deforms, and finally a rigid supporting state is locked. The problems that a traditional anchor cable is prone to brittle fracture under the high stress condition and lacks constant supporting resistance are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of support for mine and tunnel engineering, and particularly to a high-strength, stable-resistance, energy-absorbing anchor cable and its support method. Background Art

[0002] With the gradual depletion of shallow resources, the development of deep mineral resources has become an important direction of the national energy strategy. However, the high in-situ stress environment faced in deep mining leads to severe deformation of the surrounding rock of roadways, and the existing support technologies are difficult to adapt to such complex working conditions. The elongation rate of traditional anchor cables is usually only 3.5%-7%, and they are prone to brittle fracture under the continuous action of high stress. Even if the total elongation rate of the new high-elongation anchor cable is increased to 8.1%, it still cannot meet the large deformation requirements of more than 10% in deep roadways. Conventional anchor cables have a sudden drop in bearing capacity after reaching the peak strength, and lack the ability to maintain a constant support resistance under geological tectonic activities or mining-induced stress disturbances, resulting in low efficiency of the collaborative deformation between the surrounding rock and the support system. Existing yielding devices mostly rely on a single energy-absorbing element (such as a plastic deformation structure or a friction pair), with low energy dissipation efficiency and easy failure due to coal and rock debris pollution or cumulative damage. For example, the friction resistance of a conical friction type constant resistor is significantly unstable due to environmental influence, and although the shear pin type energy-absorbing device can accurately control the yielding threshold, it cannot be reused. In addition, traditional constant-resistance structures generally lack an intelligent conversion mechanism from "flexible yielding" to "rigid bearing", and it is difficult to form a high-strength anchoring system after the yielding stage ends. How to achieve collaborative control between high pre-tightening force application and large deformation adaptation has become a technical problem that urgently needs to be solved in the field of deep roadway support. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a high-strength, stable-resistance, energy-absorbing anchor cable and its support method. By installing a steel sleeve at the end of the anchor cable and arranging a movable anchor and steel balls therein, an effective constant-resistance yielding function is realized under high-stress and large-deformation conditions, improving the safety and stability of roadway support.

[0004] To achieve the above purpose, in the first aspect, the present invention provides a high-strength, stable-resistance, energy-absorbing anchor cable, comprising:

[0005] An anchor cable body;

[0006] A steel sleeve, sleeved on the outside of the end of the anchor cable body, and the steel sleeve has an inner cavity;

[0007] An anchor, slidably arranged in the inner cavity of the steel sleeve, and the anchor is connected to the end of the anchor cable body;

[0008] Steel balls, arranged in the annular space between the inner wall of the steel sleeve and the outer wall of the anchor;

[0009] The anchor ring is located at the end of the steel sleeve, and the other end is fixed to the surrounding rock.

[0010] When the tension of the cable anchor body reaches the set stress, the anchor squeezes the steel balls to move axially along the steel sleeve until the anchor is embedded into the anchor ring.

[0011] Beneficial effects: By the anchor sliding in the steel sleeve and squeezing the steel balls, the constant-resistance yielding function of the cable anchor under high stress is realized, effectively absorbing the deformation energy of the surrounding rock, and converting into rigid support after the anchor is embedded into the anchor ring, improving the adaptability and safety of the support structure. This structural design enables the cable anchor to achieve the constant-resistance yielding function in the high-stress and large-deformation environment, effectively absorbing and releasing the surrounding rock pressure, protecting the main body from damage. At the same time, after the anchor is embedded into the anchor ring, it can be transformed into a conventional cable anchor to continue to play the support role, improving the adaptability and reliability of the cable anchor.

[0012] Further, there are two rows of the steel balls, divided into the front-row steel balls and the rear-row steel balls. Among them, the diameter of the front-row steel balls is larger than that of the rear-row steel balls, and the two rows of steel balls are arranged in sequence along the moving direction of the anchor.

[0013] Beneficial effects: By setting two rows of steel balls with different diameters, the large-diameter front-row steel balls provide the initial resistance, and the small-diameter rear-row steel balls maintain the subsequent stability, realizing more precise resistance control and enhancing the constant-resistance effect.

[0014] Further, an annular groove is provided on the outer wall of the anchor. Part of the front-row steel balls are embedded into the annular groove, and the rear-row steel balls are in contact with the outer wall of the anchor.

[0015] Beneficial effects: The annular groove fixes the front-row steel balls to prevent them from falling off during the movement. The contact between the rear-row steel balls and the outer wall of the anchor increases the friction force, further improving the stability of the resistance.

[0016] Further, a through hole is provided at the center of the anchor ring, and one end of the cable anchor body passes through the through hole on the anchor ring. A gap is left between the through hole and the cable anchor body, and the outer contour of the anchor is adapted to the gap.

[0017] Beneficial effects: The through hole and gap design ensure that the anchor can be smoothly embedded into the anchor ring, realizing the locking function and completing the smooth transition from constant-resistance yielding to rigid support.

[0018] Further, the hardness of the steel balls is higher than that of the inner wall of the steel sleeve and the outer wall of the anchor.

[0019] Beneficial effects: The steel balls with a hardness higher than that of the inner wall of the steel sleeve and the outer wall of the anchor can cut or deform the inner wall of the sleeve during the movement, ensuring the constancy of the resistance and enhancing the energy absorption efficiency.

[0020] Furthermore, the outer diameter of the end of the steel sleeve is enlarged to form a flared section, and the flared section corresponds to the installation position of the anchor ring.

[0021] Beneficial effects: The stability between the steel sleeve and the anchor ring is improved.

[0022] Furthermore, the depth of the annular groove is 1 / 3 to 1 / 2 of the diameter of the front-row steel balls.

[0023] Beneficial effects: The appropriate groove depth not only ensures the stability of the steel balls but also allows necessary movement, ensuring the flexibility and stability of the anchor cable under high-stress conditions.

[0024] Furthermore, in a second aspect, the present invention also provides a support method for a high-strength, stable-resistance, energy-absorbing anchor cable according to any one of the first aspects, including the following steps:

[0025] S1. Drill a hole in the surrounding rock and insert the anchor cable body so that the steel sleeve is located at the hole opening;

[0026] S2. Apply an initial pre-tightening force to compress the steel balls by the anchor to generate a constant resistance;

[0027] S3. When the surrounding rock deforms and causes the anchor cable to be tensioned, the anchor drives the steel balls to slide along the steel sleeve to absorb energy;

[0028] S4. When the anchor moves to the position of the anchor ring, it is locked and converted into a rigid support state.

[0029] Beneficial effects: The support method provided by the present invention realizes the dynamic conversion of constant-resistance energy absorption and rigid support of the anchor cable in a high-stress and large-deformation environment, ensuring the stability and safety of the anchor cable. It not only simplifies the construction steps but also can effectively absorb energy in practical applications, protect the surrounding rock from damage, and improve the reliability and durability of the support.

[0030] Furthermore, in step S2, the initial pre-tightening force is 20%-30% of the breaking strength of the anchor cable, and the pre-tightening force error is controlled by a torque wrench ≤5%.

[0031] Beneficial effects: By precisely controlling the initial pre-tightening force, it is ensured that the anchor cable is in the best working state immediately after installation, improving the reliability and consistency of the support effect.

[0032] Furthermore, in step S3, the constant resistance F generated by the sliding of the steel balls satisfies:

[0033] F = n·μ·P

[0034] Wherein, n is the number of rows of steel balls, μ is the friction coefficient between the steel balls and the sleeve, and P is the normal pressure of a single row of steel balls.

[0035] Further, after the anchor is embedded in the anchor ring in step S4, the elongation rate of the anchor cable is increased to 8%-12%, and the residual support force ≥ 90% of the initial constant resistance.

[0036] In summary, compared with the prior art, the high-strength, stable resistance and energy-absorbing anchor cable of the present invention can achieve high-strength and stable constant resistance and energy-absorbing functions in a high-stress and large-deformation environment. Through the synergistic effect of the anchor cable body, steel sleeve, anchor, steel ball and anchor ring, the anchor cable can not only absorb the deformation energy of the surrounding rock, but also be converted into rigid support when necessary, significantly improving the safety and adaptability of deep roadway support. In addition, by adjusting the material and structural parameters, the customized requirements of different constant resistances can be realized, further serving the support work of high-stress and large-deformation roadways in deep resource mining. Description of the Drawings

[0037] Figure 1 is a schematic diagram of a high-strength, stable resistance and energy-absorbing anchor cable of the present invention;

[0038] Figure 2 is a schematic diagram of the cable anchor ring in a high-strength, stable resistance and energy-absorbing anchor cable of the present invention;

[0039] Figure 3 is a schematic diagram of the anchor and the steel sleeve in a high-strength, stable resistance and energy-absorbing anchor cable of the present invention;

[0040] Figure 4 is a schematic diagram of the anchor and the steel ball in a high-strength, stable resistance and energy-absorbing anchor cable of the present invention;

[0041] Label description: 1 - anchor cable, 2 - anchor ring, 3 - steel sleeve, 4 - steel ball, 5 - anchor, 6 - rock stratum. Detailed Embodiments

[0042] The present invention will be further described below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be used to limit the protection scope of the present invention.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "axial direction", "lateral direction", "upper", "lower", "inner", "outer", etc. is the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0044] In the description of the invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0045] As Figures 1-4 shown, an embodiment of the present invention provides a high-strength, stable-resistance and energy-absorbing anchor cable, including:

[0046] An anchor cable body 1;

[0047] A steel sleeve 4, sleeved on the outside of the end of the anchor cable body 1, and the steel sleeve 4 has an inner cavity;

[0048] An anchor 3, slidably disposed in the inner cavity of the steel sleeve 4, and the anchor 3 is connected to the end of the anchor cable body 1;

[0049] Steel balls 2, disposed in the annular space between the inner wall of the steel sleeve 4 and the outer wall of the anchor 3; the presence of the steel balls 2 can effectively disperse the pressure and reduce wear.

[0050] An anchor ring 5, located at the end of the steel sleeve 4, and the other end is fixed to the surrounding rock 6;

[0051] Then, when the tensile stress of the anchor cable 1 reaches the critical stress, the anchor 3 and the steel balls 2 move forward, so as to realize the constant-resistance yielding function of the anchor cable under high-stress and large-deformation disturbances; when the anchor 3 moves to the bottom rock layer 6 at the end, the anchor 3 is embedded in the anchor ring 5 and becomes a conventional anchor cable; after that, the tensile deformation characteristics of the anchor cable are mainly controlled by the structure and mechanical characteristics of the anchor cable itself. Through the movement of the steel balls 2 and the anchor 3 at the end of the anchor cable, the function of the constant-resistance yielding anchor cable under high stress is realized. The present invention can realize the constant-resistance yielding anchor cable for roadways with high stress and large deformation.

[0052] Specifically, two rows of steel balls 2 are provided, which are divided into the front-row steel balls and the rear-row steel balls. Among them, the diameter of the front-row steel balls is larger than that of the rear-row steel balls, and the two rows of steel balls are arranged in sequence along the moving direction of the anchor 3.

[0053] Furthermore, an annular groove is provided on the outer wall of the anchor 3. The front-row steel balls are partially embedded in the annular groove, and the rear-row steel balls are in contact with the outer wall of the anchor 3. The annular groove limits the steel balls in the anchor 3, ensuring that the steel balls 2 will not easily move out of position during the stress process.

[0054] Furthermore, a through hole is provided at the center of the anchor ring 5, and one end of the anchor cable body 1 passes through the through hole on the anchor ring 5. There is a gap between the through hole and the anchor cable body 1, and the outer contour of the anchor 3 is adapted to the gap.

[0055] Specifically, the hardness of the steel balls 2 is higher than the hardness of the inner wall of the steel sleeve 4 and the outer wall of the anchor 3.

[0056] Specifically, the outer diameter of the end of the steel sleeve 4 is enlarged to form a flared section, and the flared section corresponds to the installation position of the anchor ring 5.

[0057] Furthermore, the depth of the annular groove is 1 / 3 to 1 / 2 of the diameter of the front row of steel balls.

[0058] As an embodiment, a support method for a high-strength, stable-resistance and energy-absorbing anchor cable includes the following steps:

[0059] S1. Drill a hole in the surrounding rock and insert the anchor cable body 1 so that the steel sleeve 4 is located at the hole opening;

[0060] S2. Apply an initial pre-tightening force to compress the steel balls 2 by the anchor 3 to generate a constant resistance force;

[0061] S3. When the surrounding rock deforms and causes the anchor cable to be tensioned, the anchor 3 drives the steel balls 2 to slide along the steel sleeve 4 to absorb energy;

[0062] S4. When the anchor 3 moves to the position of the anchor ring 5, it is locked and converted into a rigid support state.

[0063] Furthermore, in step S2, the initial pre-tightening force is 20%-30% of the breaking strength of the anchor cable, and the pre-tightening force error is controlled by a torque wrench ≤5%.

[0064] Furthermore, in step S3, the constant resistance force F generated by the sliding of the steel balls satisfies:

[0065] F = n·μ·P

[0066] Wherein, n is the number of rows of steel balls, μ is the friction coefficient between the steel balls and the sleeve, and P is the normal pressure of a single row of steel balls.

[0067] Furthermore, after the anchor is embedded in the anchor ring in step S4, the elongation rate of the anchor cable is increased to 8%-12%, and the residual support force ≥90% of the initial constant resistance force.

[0068] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device.

[0069] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A high-strength, stable-resistance, energy-absorbing anchor cable, characterized in that: include: Anchor cable body(1); A steel sleeve (4) is sleeved on the outer side of the end of the anchor cable body (1), and the steel sleeve (4) has an inner cavity; An anchor (3) is slidably disposed in the inner cavity of the steel sleeve (4), and the anchor (3) is connected to the end of the anchor cable body (1); A steel ball (2) is arranged in an annular space between the inner wall of the steel sleeve (4) and the outer wall of the anchor (3); An anchor ring (5), located at the end of the steel sleeve (4), with the other end fixed to the surrounding rock (6); When the anchor cable body (1) is pulled to a set stress, the anchor (3) squeezes the steel ball (2) to move axially along the steel sleeve (4) until the anchor (3) is embedded in the anchor ring (5).

2. The high-strength, stable-resistance, energy-absorbing anchor cable according to claim 1 is characterized in that: The steel balls (2) are arranged in two rows, namely a front row of steel balls and a rear row of steel balls, wherein the diameter of the front row of steel balls is larger than the diameter of the rear row of steel balls, and the two rows of steel balls are arranged in sequence along the moving direction of the anchor (3).

3. The high-strength, stable-resistance, energy-absorbing anchor cable according to claim 2 is characterized in that: The outer wall of the anchor (3) is provided with an annular groove, the front row of steel balls are partially embedded in the annular groove, and the rear row of steel balls are in contact with the outer wall of the anchor (3).

4. The high-strength, stable-resistance, energy-absorbing anchor cable according to claim 1, characterized in that: The anchor ring (5) is provided with a through hole at its center, and one end of the anchor cable body (1) passes through the through hole on the anchor ring (5), a gap is left between the through hole and the anchor cable body (1), and the outer contour of the anchor (3) is adapted to the gap.

5. The high-strength, stable-resistance, energy-absorbing anchor cable according to claim 1 is characterized in that: The hardness of the steel ball (2) is higher than the hardness of the inner wall of the steel sleeve (4) and the outer wall of the anchor (3).

6. The high-strength, stable-resistance, energy-absorbing anchor cable according to claim 1 is characterized in that: The outer diameter of the end of the steel sleeve (4) is enlarged to form a flared section, and the flared section corresponds to the installation position of the anchor ring (5).

7. The high-strength, stable-resistance, energy-absorbing anchor cable according to claim 3 is characterized in that: The depth of the annular groove is 1 / 3 to 1 / 2 of the diameter of the front row of steel balls.

8. A support method based on the high-strength stable resistance energy-absorbing anchor cable according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Drill a hole in the surrounding rock and insert the anchor cable body (1) so that the steel sleeve (4) is located at the hole opening; S2, applying an initial pre-tightening force so that the anchor (3) compresses the steel ball (2) to generate a constant resistance; S3. When the surrounding rock deforms and the anchor cable is pulled, the anchor (3) drives the steel ball (2) to slide along the steel sleeve (4) to absorb energy; S4. When the anchor (3) moves to the position of the anchor ring (5), it is locked and turns into a rigid support state.

9. The method for supporting high-strength, stable-resistance, energy-absorbing anchor cable according to claim 8, characterized in that: In step S2, the initial preload force is 20%-30% of the breaking strength of the anchor cable, and the preload force error is controlled by a torque wrench to be ≤5%.

10. The method for supporting high-strength, stable-resistance, energy-absorbing anchor cable according to claim 8, characterized in that: The constant resistance F generated by the sliding of the steel ball in step S3 satisfies: F=n·μ·P Among them, n is the number of steel ball rows, μ is the friction coefficient between the steel ball and the sleeve, and P is the normal pressure of a single row of steel balls.

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