A variable displacement large deformation anchor rod

Abstract

The present invention discloses a variable displacement large deformation anchor rod, which belongs to underground engineering protection equipment. The present invention comprises an anchor rod body (1), a sleeve (2), a steel plate tray (3), a nut (4) and a limit buckle (5). The sleeve (2) has at least two rows of symmetrical reserved holes along the axial direction at the tail end. The limit buckle (5) is fixed to the tail end of the anchor rod body (1). The anchor rod body (1) passes through the sleeve. The sleeve (2) is sleeved on the outer periphery of the rear end of the anchor rod body (1). The limit buckle (5) is locked in the reserved hole at the tail end of the sleeve (2). The nut (4) is threadedly engaged with the outer wall of the sleeve to press the steel plate tray (3) to reinforce the surrounding rock. The technical effect of the present invention is that the anchor rod can provide reliable and stable supporting force, and at the same time can realize large displacement deformation of the anchor rod device, ensure the safety and stability of the surrounding rock of the underground engineering, and meet the protection requirements of large deformation of the surrounding rock of the engineering.

Description

Technical Field

[0001] The invention belongs to underground engineering protection equipment, and in particular relates to a variable displacement and large deformation anchor rod. Background Art

[0002] As the country's resources are directed towards deep earth, deep sea, deep space and deep blue, the efficient utilization and development of deep resources have brought huge opportunities and challenges to the development of earth science. Studies have shown that if the depth of mineral development in my country reaches more than 2,000 meters, the proven reserves of mineral resources in my country can achieve a significant increase on the existing basis. In addition, there is still a large gap between the development level of urban underground space in my country and that of foreign countries. However, the mining of deep resources and the construction of deep underground projects are often affected by high ground stress, high permeability pressure, high ground temperature and strong mining disturbances. Therefore, the problem of large deformation of surrounding rock is the main problem that plagues the construction of deep rock engineering. The use of anchor support to solve the problem of large deformation of surrounding rock is a relatively common method in current deep rock engineering. However, the elongation of traditional anchors is low, and they cannot solve the problem of large deformation in deep rock engineering well.

[0003] Chinese patent document CN114542142A discloses a self-locking large deformation energy-absorbing anchor rod and anchor rod device, including a casing reserved hole and an arc-shaped self-locking clip. The patent uses the anchor rod body, clip and casing reserved hole to achieve large deformation of the anchor rod and absorb the energy generated by the deformation of the surrounding rock. However, this type of anchor rod has two disadvantages: 1. The anchor rod body has a variable cross-section (paragraph

[0014] records: the anchor rod body 7 is provided with a convex and concave compression and shearing section 6; paragraph

[0015] records: the closing inner diameter of the front end of the closing sleeve 1 is 0.5 mm larger than the diameter of the anchor rod body 7, and the maximum outer diameter of the compression and shearing section 6 is 2.5~4.5 mm larger than the closing inner diameter of the closing sleeve 1). According to the working principle of the invention, (paragraph

[0019] records: the closing sleeve 1 will continuously shear the raised part of the compression and shearing section 6 during the movement), the raised part of the compression and shearing section will be sheared during the displacement of the anchor rod, because there are more arc-shaped clips in the sleeve of the invention, and these damaged raised parts will remain in the sleeve and clamp the arc-shaped clips, making it difficult for the anchor rod body to produce further displacement.

[0004] 2. The anchor rod will shear off the compression shear section during the displacement process (recorded in

[0019] : the closing sleeve 1 will continuously shear off the protruding part of the compression shear section 6 during the movement). The compression shear section is part of the anchor rod body. The closing sleeve will cause local damage to the rod body during the process of destroying the compression shear section, causing stress concentration in the local area of ​​the rod body, leading to the destruction of the anchor rod body, which will greatly weaken the anchoring effect of this type of anchor rod.

[0005] Large deformation refers to deformation that is not negligible compared to the geometric dimensions of the anchor rod, and after the anchor rod is deformed, the deformation cannot be restored, and the anchoring force changes with the deformation of the anchor rod.

[0006] Compared with the existing anchor rods that are deformed by tension alone, the anchor rod body of the present invention not only deforms by tension, but also causes the sleeve to be damaged, causing the anchor rod body to slip. The anchor rod displacement in the present invention includes two parts: the tensile deformation displacement of the rod body and the sliding displacement of the anchor rod body, and is a large deformation anchor rod. Summary of the Invention

[0007] In response to the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a variable displacement large deformation anchor rod, which can realize large displacement deformation of the anchor rod device and provide reliable support force to ensure the safety and stability of the surrounding rock of underground engineering.

[0008] The technical problem to be solved by the present invention is achieved through such a technical solution, which includes an anchor rod body, a sleeve, a steel plate tray, a nut and a limit clip; the tail section of the sleeve is axially opened with at least two rows of symmetrical reserved holes, the tail of the anchor rod body is fixed with a limit clip, the anchor rod body passes through the sleeve, the sleeve is sleeved on the outer periphery of the rear section of the anchor rod body, the limit clip is locked in the reserved hole of the sleeve, and the nut cooperates with the thread of the outer wall of the sleeve to press the steel plate tray to reinforce the surrounding rock.

[0009] The sleeve has a series of pre-set holes arranged symmetrically according to a specific pattern. When the anchor rod body acts on the sleeve through the limit clip, the sleeve presses against the limit clip, generating an anchoring force in the surrounding rock. When the surrounding rock undergoes significant deformation, the limit clip will destroy the pre-set holes in the sleeve, causing the sleeve to move. As the surrounding rock deformation continues, the pre-set holes on both sides of the sleeve are gradually destroyed by the limit clip, achieving a large displacement of the anchor device.

[0010] The limit buckle will cause the reserved hole in the sleeve to be damaged, thereby causing the anchor rod device to have a large displacement. By reasonably setting the spacing between the reserved holes in the casing, the anchor rod can still provide sufficient anchoring force during the large displacement process.

[0011] Compared with the prior art, the technical effects of the present invention are:

[0012] 1. The present invention has a simple structure and high applicability. It can generate a large displacement while ensuring the stable and reliable anchor support force.

[0013] 2. The large displacement produced by the present invention is controllable;

[0014] 3. A series of pre-set holes are arranged in the casing of the present invention. The process of large displacement of the anchor rod is caused by the destruction of the pre-set holes one by one. Therefore, under the action of dynamic load, the anchor rod of the present invention can have a longer response time, avoid instantaneous destruction of the anchor rod, and can resist the explosion impact load to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings of the present invention are as follows:

[0016] Figure 1 It is a structural schematic diagram of the present invention;

[0017] (a), axial cross-section; (b), radial cross-section;

[0018] Figure 2 for Figure 1 Structural details of the middle sleeve;

[0019] (a) Radial cross-section; (b) Circumferential surface development; (c) Partial magnified view of the reserved hole;

[0020] Figure 3 for Figure 2 The shape of the reserved hole on the middle sleeve;

[0021] (a) I reserved hole; (b) II reserved hole; (c) III reserved hole;

[0022] Figure 4 for Figure 1 Schematic diagram of the structure of the middle limit buckle;

[0023] (a) Stereoscopic view; (b) Front view; (c) Top view;

[0024] Figure 5 (a) is a schematic diagram showing the force applied to the sleeve of the present invention by the limit buckle at the reserved hole;

[0025] Figure 5 (b) is a schematic diagram showing the reserved hole being damaged by the limiting buckle of the present invention.

[0026] In the figure: 1. Anchor rod body; 2. Sleeve; 3. Steel plate tray; 4. Nut; 5. Limit buckle; 6. Surrounding rock; 7. Ith reserved hole; 8. IIth reserved hole; 9. IIIth reserved hole; 10. Round steel cylinder; 11. Steel plate. Implementation Method

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0028] In order to clearly describe the content of the invention, this patent application uses the directional words "front end" and "tail end" to distinguish. The "front end" and "tail end" are based on the attached Figure 1 The placement method of the anchor rod is that the end of the anchor rod inserted into the surrounding rock is called the "front end", and the part close to the grouting port is called the "tail" of the anchor rod. The directional name cannot be regarded as a limitation on the scope of patent protection.

[0029] like Figure 1 As shown, the present invention includes an anchor rod body 1, a sleeve 2, a steel plate tray 3, a nut 4 and a limiting buckle 5; the tail section of the sleeve 2 is provided with at least two rows of symmetrical reserved holes along the axial direction, the tail of the anchor rod body 1 is fixed with a limiting buckle 5, the anchor rod body 1 passes through the sleeve, the sleeve 2 is sleeved on the outer periphery of the rear section of the anchor rod body 1, the limiting buckle 5 is locked in the first reserved hole at the tail end of the sleeve 2, and the nut 4 cooperates with the outer wall thread of the sleeve to press the steel plate tray 3 to reinforce the surrounding rock.

[0030] like Figure 2 As shown, the wall of the sleeve 2 is provided with upper and lower symmetrical reserved holes along the axial direction; the I reserved hole 7, the II reserved hole 8, and the III reserved hole 9 are arranged in sequence from the rear edge of the sleeve, and a spacing D is left between each reserved hole.

[0031] The arrangement of the reserved holes of the sleeve takes into account the way in which the limiting buckle destroys the sleeve, and also takes into account the maximum support force of the anchor rod design. There are three types of reserved holes on the sleeve 2, namely: the I reserved hole 7, the II reserved hole 8 and the III reserved hole 9. The I reserved hole 7 is located at the edge of the sleeve, the III reserved hole 9 is located at the end of the reserved hole queue, and the II reserved holes 8 are arranged at equal intervals between the I reserved hole 7 and the III reserved hole 9. In addition, the width and depth of the I reserved hole 7 should be such that the steel plate 11 of the limiting buckle 5 can be placed therein, and the II reserved hole 8 is diamond-shaped. The distance D between the holes should be selected so that the anchor rod will not be damaged before the designed support force is reached. In addition, in order to enable the anchor rod of the present invention to provide a relatively constant support force when a large displacement occurs, such as Figure 2 As shown in (c), the distance D between all reserved holes is equal.

[0032] like Figure 3 As shown, Figure 3 (a) shows that the first reserved hole 7 is a straight mouth with a pointed mouth; Figure 3 (b) shows that the second reserved hole 8 is a diamond-shaped opening. Figure 3 (c) shows that the third reserved hole 9 is a triangular opening. Figure 3 In the equation, β represents the angle of the V-shaped opening, and l represents the side length of the V-shaped opening. In order to ensure that the force in the anchor rod body 1 is approximately the same when the limit buckle 5 destroys the reserved hole, Figure 3 V-shaped opening angle of the reserved hole β Same, the side length of the reserved V-shaped hole l same.

[0033] The first reserved hole 7 is used to form the initial anchor support force; the second reserved hole 8 is a diamond hole, which is used to control the way in which the sleeve is damaged by the limiting buckle during the large displacement of the anchor, and the distance between the diamond holes is used to control the constant support force that the anchor can provide during the large displacement process; the third reserved hole 9 is used to limit the maximum displacement of the large deformation anchor device and provide the final support force for the anchor device after the large displacement.

[0034] like Figure 4 As shown, the limit buckle 5 is composed of a circular steel cylinder 10 and a steel plate 11. In this embodiment, the two steel plates 11 are symmetrically fixed to the outer wall of the circular steel cylinder 10. The limit buckle 5 is connected to the anchor rod body 1 through threads, and the two steel plates 11 are inserted into two symmetrical rows of reserved holes in the sleeve 2.

[0035] When assembling the anchor rod, first, the limiting buckle 5 is firmly connected to the anchor rod body 1 through the circular steel cylinder 10 by means of a threaded connection. Then, the assembled anchor rod body is passed through the sleeve 2 and the steel plate 11 on the limiting buckle 5 is pressed against the first reserved hole 7 on the sleeve. Then, the assembled anchor rod is embedded in the surrounding rock 6 that needs to be reinforced, and the anchor rod grouting treatment is performed. Finally, the nut 4 is screwed in from the tail end of the sleeve 2, and the nut 4 presses the steel plate tray 3 to reinforce the surrounding rock.

[0036] The principle behind the large displacement of the anchor rod in this invention is that the limiting clips cause the pre-set holes in the sleeve to be broken one by one, causing the sleeve to slide. As the anchor rod's support force increases, exceeding the designed support force of the anchor rod, the limiting clips 5 cause the pre-set holes in the sleeve 2 to break, causing the sleeve 2 to slide in the direction of the pre-set holes' destruction, causing the sleeve 2 to move. Because the sleeve 2 can be provided with multiple pre-set holes, the gradual destruction of these holes can cause large displacement of the sleeve 2.

[0037] When the limit buckle 5 acts on the sleeve 2, the sleeve 2 will be subjected to a force, such as Figure 5As shown in (a), the effect of the iron block 11 on the reserved hole can be simplified to two concentrated forces; then, when the reserved hole is damaged, according to the literature "Brittle fracture assessment of engineering components in the presence of notches: areview", Ayatollahi, MR, Torabi, AR, Rahimi, AS, Fatigue&Fracture ofEngineering Materials&Structures, 2016, 39(3), 267– 291, ("Brittle fracture assessment of engineering components in the presence of notches: areview", Ayatollahi, MR, Torabi, AR, Rahimi, AS, Fatigue & Fracture ofEngineering Materials&Structures, 2016, 39(3), 267– 291), the local damage of the sleeve caused by the limit buckle 5 is as follows Figure 5 (b) As shown, the limit buckle 5 will then slide to the next reserved hole. Due to the V-shaped opening of the reserved hole, the sleeve 2 will slide along the direction of the reserved hole, causing a large displacement of the anchor device without causing the entire sleeve to be damaged.

[0038] The setting of the third reserved hole 9 is determined by the maximum deformation of the anchor rod design. Figure 3 (a) Figure 3 (b) and Figure 3 (c) As can be seen, the force applied by the stopper 5 in the third reserved hole 9 is different from that in the first and second reserved holes 7 and 8. The force applied by the stopper 5 in the third reserved hole 9 must not damage the sleeve, preventing it from sliding. Therefore, if necessary, the third reserved hole 9 can be reinforced, such as by chamfering it, to avoid stress concentration.

[0039] Therefore, the arrangement of the sleeve pre-holes takes into account the way the limit buckle can damage the sleeve and the maximum support force of the anchor design. In actual use, the width of the limit buckle 5 after the combination of cylinder 10 and iron block 11 can be slightly larger than the diameter of sleeve 2 to prevent the limit buckle 5 from slipping into the sleeve 2 when the limit buckle 5 and sleeve 2 cooperate.

Claims

1. A variable displacement and large deformation anchor rod, comprising an anchor rod body (1), a sleeve (2), a steel plate tray (3) and a nut (4), characterized in that: It also includes a limit buckle (5), the tail section of the sleeve (2) is provided with at least two rows of symmetrical reserved holes along the axial direction, the tail of the anchor rod body (1) is fixed with the limit buckle (5), the anchor rod body (1) passes through the sleeve, the sleeve (2) is sleeved on the outer periphery of the rear section of the anchor rod body (1), the limit buckle (5) is locked in the reserved hole of the tail section of the sleeve (2), and the nut (4) cooperates with the outer wall thread of the sleeve to press the steel plate tray (3) to reinforce the surrounding rock; The reserved holes include a first reserved hole (7), a second reserved hole (8) and a third reserved hole (9); the first reserved hole (7) is a straight opening with a pointed mouth; the second reserved hole (8) is a diamond-shaped opening, and the third reserved hole (9) is a triangular opening; the V-shaped opening angles of all the reserved holes are β The same, the side length of the reserved V-shaped hole l are all the same, forming a preset fracture path; the limit buckle (5) is composed of a circular steel cylinder (10) and a steel plate (11), the two steel plates (11) are symmetrically fixed on the outer wall of the circular steel cylinder (10), the limit buckle (5) is connected to the anchor rod body (1), the steel plate (11) is inserted into the two rows of symmetrical reserved holes of the sleeve (2) and squeezes the V-shaped mouth, causing the brittle fracture of the sleeve material to achieve pressure displacement.

2. The variable displacement and large deformation anchor rod according to claim 1, characterized in that: The sleeve (2) is arranged in sequence along the axial direction from the tail edge to the first reserved hole (7), the second reserved hole (8), and the third reserved hole (9), with a spacing D between each reserved hole.

3. The variable displacement and large deformation anchor rod according to claim 2, characterized in that: The width of the circular steel cylinder (10) and the steel plate (11) after being combined is greater than the diameter of the sleeve (2).

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