A novel application method for pressure-relief anchor bolts

Abstract

This application discloses a novel method for applying a pressure-yielding anchor bolt, comprising the following steps: fabricating the pressure-yielding anchor bolt; the pressure-yielding anchor bolt includes an outer sleeve and an inner sleeve; the inner sleeve is disposed inside the outer sleeve; the outer wall surface of the inner sleeve has a protrusion; the wall surface of the outer sleeve has a first opening, and the protrusion passes through the first opening; the axial length of the first opening is greater than the axial length of the outer wall surface of the inner sleeve where the protrusion is located; drilling a hole and cleaning the hole; installing a cement cartridge at the tail end of the outer sleeve; pushing the pressure-yielding anchor bolt into the drilled hole until it reaches the designed position; inserting a grouting pipe from the inner sleeve to perform grouting, and using the grouting pressure to push the protrusion into the surrounding rock for anchoring; installing a connecting mechanism at the head end of the outer sleeve to fix the pressure-yielding anchor bolt to the surrounding rock. This novel method for applying a pressure-yielding anchor bolt not only provides prestress and anchoring performance, but also allows the pressure-yielding anchor bolt to slide and yield pressure, releasing pressure in a timely manner.

Description

Technical Field

[0001] This manual relates to the field of anchor bolt support technology, and in particular to a novel method for applying a pressure-yielding anchor bolt. Background Technology

[0002] When constructing tunnels in areas with high ground stress, significant deformation of the surrounding rock can cause anchor bolts to bear excessive deformation pressure, greatly increasing the risk of anchor bolt failure. Currently, the most effective solution is for the anchor bolts to maintain high resistance while possessing corresponding deformation capacity to deform synchronously with the surrounding rock, thereby releasing some of the deformation pressure. Therefore, the strength, resistance, and "pressure-yielding" function of the anchor bolts are extremely important for controlling large deformation surrounding rock.

[0003] "Pressure yielding" refers to allowing the surrounding rock to contract to a certain extent, releasing some energy and improving the stability and safety of the support structure, while maintaining the anchor bolt itself without serious damage, using appropriate support methods. However, traditional anchor bolts are usually designed with high rigidity and strength to ensure they are firmly anchored in the soil and rock mass. However, this high-strength design makes it difficult for the anchor bolt to deform sufficiently under large tensile forces to absorb and release energy, leading to anchor bolt failure. This limits its ability to continuously suppress surrounding rock deformation and release surrounding rock energy, posing significant safety risks and economic challenges to construction. Therefore, there is an urgent need for an anchor bolt with certain anchoring resistance and slip yielding characteristics to quickly solve the current problem of support failure caused by surrounding rock compression deformation. Summary of the Invention

[0004] In view of the shortcomings of the prior art, one of the objectives of this specification is to provide a novel method for applying a pressure-yielding anchor bolt, which not only provides prestress and anchoring performance, but also allows the pressure-yielding anchor bolt to slide and yield, releasing pressure in a timely manner.

[0005] To achieve the above objectives, this specification provides a novel method for applying a pressure-relief anchor bolt, comprising the following steps:

[0006] Fabricate a pressure-relief anchor bolt; the pressure-relief anchor bolt includes an outer sleeve and an inner sleeve; the inner sleeve is disposed inside the outer sleeve; the outer wall surface of the inner sleeve is provided with a protrusion; the wall surface of the outer sleeve is provided with a first opening, and the protrusion passes through the first opening; the axial length of the first opening is greater than the axial length of the outer wall surface of the inner sleeve where the protrusion is disposed;

[0007] Drill holes and clean the inside of the holes;

[0008] A cement cartridge is installed at the tail end of the outer sleeve;

[0009] Push the pressure-relief anchor rod into the borehole until it reaches the designed position;

[0010] The grouting pipe is inserted into the inner sleeve for grouting, and the protrusion is pushed into the surrounding rock for anchoring by the grouting pressure.

[0011] A connecting mechanism is installed at the first end of the outer sleeve to fix the pressure-relief anchor rod to the surrounding rock.

[0012] In a preferred embodiment, the formula for calculating the resistance of the pressure-relief anchor bolt in the step of manufacturing the pressure-relief anchor bolt is as follows:

[0013]

[0014] Among them, F k τ is the resistance of the anchor bolt; τ is the shear strength of the surrounding rock; L c σ is the length of the protrusion; μ is the coefficient of friction between the protrusion and the surrounding rock; σ s d represents the compressive strength of the surrounding rock. c The diameter of the protrusion is given.

[0015] In a preferred embodiment, in the step of manufacturing the pressure-relief anchor bolt, the inner sleeve includes two semi-circular steel pipes of the same size, and the protrusion is welded to the outer wall of the semi-circular steel pipes.

[0016] In a preferred embodiment, in the step of manufacturing the pressure-relief anchor rod, the number of protrusions provided on each semi-circular steel pipe is 2 to 5.

[0017] In a preferred embodiment, in the step of manufacturing the pressure-relief anchor bolt, the protrusion is cylindrical and extends radially, and the end of the protrusion is conical.

[0018] In a preferred embodiment, in the step of manufacturing the pressure-relief anchor bolt, the outer sleeve is set to be in the shape of a circular tube, and the outer wall of the outer sleeve is covered with threads.

[0019] In a preferred embodiment, in the step of manufacturing the pressure relief anchor, the first opening is located at the axial center of the outer sleeve; the circumferential dimension of the first opening is equal to the circumferential dimension of the protrusion.

[0020] In a preferred embodiment, during the step of inserting the grouting pipe from the inner sleeve for grouting, the formula for calculating the grouting pressure is:

[0021]

[0022] Among them, F c σ is the force σ exerted by the protrusion into the surrounding rock. s d represents the compressive strength of the surrounding rock. cP is the diameter of the protrusion; z The grouting pressure is L; k is an adjustment coefficient, which is related to the length of the protrusion and the integrity of the surrounding rock, and is taken as 1.5 to 2. n B is the length of the inner sleeve; n The width of the inner sleeve.

[0023] In a preferred embodiment, the connecting mechanism includes a bolt, a washer, and a nut; the washer has a second opening through which the first end of the outer sleeve passes; the step of installing the connecting mechanism at the first end of the outer sleeve includes: first fixing the washer to the surrounding rock with the bolt, and then installing the nut at the first end of the outer sleeve that passes through the second opening.

[0024] In a preferred embodiment, the nut is hollow inside to accommodate part of the inner sleeve.

[0025] Beneficial effects:

[0026] The novel pressure-relief anchor bolt application method provided in this embodiment features a pressure-relief anchor bolt with a protrusion on the outer wall of the inner sleeve, increasing the anchoring area. The outer sleeve has a first opening on its wall for the protrusion to pass through, and the axial length of the first opening is greater than the axial length of the outer wall with the protrusion. Thus, when the surrounding rock deforms, the inner sleeve can slide within the outer sleeve within a certain range, releasing some of the deformation pressure of the surrounding rock, reducing the stress on the support structure, and solving the problem that traditional anchor bolts may be damaged or fail due to the inability to release pressure in time when the rock and soil are subjected to large pressure.

[0027] Furthermore, installing a cement cartridge at the end of the outer sleeve allows cement to flow out and solidify rapidly, thus enhancing the anchoring performance of the anchor bolt.

[0028] In addition, grouting pipes are inserted into the inner sleeve for grouting. The grouting pressure opens the inner sleeve, allowing the protrusion to be inserted into the surrounding rock for anchoring, thus achieving anchor resistance. Pressure relief is achieved through the slippage of the inner and outer sleeves, which not only has prestressing and anchoring performance, but also allows for sliding pressure relief and timely pressure release.

[0029] Specific embodiments of the present invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the present invention are not limited in scope as a result.

[0030] Features described and / or illustrated for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

[0031] It should be emphasized that the term "including / comprises" as used herein refers to the presence of a feature, whole, step, or component, but does not exclude the presence or addition of one or more other features, wholes, steps, or components. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart illustrating the steps of an application method for a novel pressure-relief anchor bolt provided in this embodiment.

[0034] Figure 2 for Figure 1 A schematic diagram of the structure of the pressure-relief anchor bolt made in step S10;

[0035] Figure 3 Figure 2 A schematic diagram of the inner sleeve.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Pad; 11. Second opening; 2. Bolt; 3. Nut; 4. Outer sleeve; 41. First opening; 5. Inner sleeve; 51. Semicircular steel pipe; 52. Protrusion; 6. Cement cartridge. Detailed Implementation

[0038] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0039] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or may be interposed with another element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or may be interposed with another element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0041] Please see Figure 1 This application provides a novel method for applying a pressure-relief anchor bolt, comprising the following steps:

[0042] Step S10: Make the pressure relief anchor bolt.

[0043] The pressure-relief anchor bolt includes an outer sleeve 4 and an inner sleeve 5. The inner sleeve 5 is disposed inside the outer sleeve 4. The outer wall surface of the inner sleeve 5 has a protrusion 52. The wall surface of the outer sleeve 4 has a first opening 41, through which the protrusion 52 passes. The axial length of the first opening 41 is greater than the axial length of the outer wall surface of the inner sleeve 5 where the protrusion 52 is located.

[0044] Step S20: Drill holes and clean the inside of the holes.

[0045] Step S30: Install cement cartridge 6 at the tail end of the outer sleeve 4.

[0046] Step S40: Push the pressure-relief anchor rod into the borehole until it reaches the designed position.

[0047] Step S50: Insert the grouting pipe into the inner sleeve 5 to perform grouting, and use the grouting pressure to push the protrusion 52 into the surrounding rock for anchoring.

[0048] Step S60: Install a connecting mechanism at the first end of the outer sleeve 4 to fix the pressure relief anchor rod to the surrounding rock.

[0049] The novel pressure-relief anchor bolt application method provided in this embodiment has a protrusion 52 on the outer wall of the inner sleeve 5, which expands the anchoring area; the outer sleeve 4 has a first opening 41 for the protrusion 52 to pass through, and the axial length of the first opening 41 is greater than the axial length of the outer wall with the protrusion 52. Thus, when the surrounding rock deforms, the inner sleeve 5 can slide within the outer sleeve 4 within a certain range, releasing part of the deformation pressure of the surrounding rock, reducing the stress on the support structure, and solving the problem that traditional anchor bolts may be damaged or fail due to the inability to release pressure in time when the rock and soil are subjected to large pressure.

[0050] Furthermore, a cement cartridge 6 is installed at the tail end of the outer sleeve 4. Piercing the cement cartridge 6 allows cement to flow out and solidify rapidly, which can enhance the anchoring performance of the anchor bolt.

[0051] In addition, the grouting pipe is inserted into the inner sleeve 5 for grouting. The grouting pressure opens the inner sleeve 5, and the protrusion 52 is inserted into the surrounding rock for anchoring, thus achieving anchor resistance. The pressure is released by the slippage of the inner and outer sleeves 4, so that it not only has prestress and anchoring performance, but also slips to release pressure in time.

[0052] In this embodiment, in the step of manufacturing the pressure-relief anchor bolt (i.e., step S10), the formula for calculating the resistance of the pressure-relief anchor bolt is:

[0053]

[0054] Among them, F k τ is the resistance of the pressure anchor bolt; τ is the shear strength of the surrounding rock; L c The length of the protrusion 52 is given by σ; μ is the coefficient of friction between the protrusion 52 and the surrounding rock; σ is the coefficient of friction between the protrusion 52 and the surrounding rock. s d represents the compressive strength of the surrounding rock. c The diameter of the protrusion 52.

[0055] Therefore, the resistance of the anchor bolt can be calculated by considering the shear strength, compressive strength, size and number of protrusions 52, and frictional resistance between the surrounding rock and the protrusions 52. This allows for the determination of the size and number of protrusions 52, and the relevant parameters for the yield anchor bolt, enabling its fabrication. Specifically, the resistance of the yield anchor bolt can be determined based on the on-site deformation suppression requirements, followed by the determination of its relevant parameters to ensure it meets the requirements and effectively performs its anchoring and slip-yielding functions.

[0056] Specifically, in step S10, such as Figure 2 and Figure 3 As shown, the inner sleeve 5 includes two semi-circular steel pipes 51 of the same size, and the protrusion 52 is welded to the outer wall of the semi-circular steel pipes 51. High-pressure grouting is performed inside the two semi-circular steel pipes 51. Through high-pressure grouting, the two semi-circular steel pipes 51 separate, allowing the protrusion 52 to be pushed out from the first opening 41 of the outer sleeve 4, so that the protrusion 52 can be inserted into the surrounding rock. Accordingly, there are two first openings 41 on the outer sleeve 4, and the two first openings 41 are arranged opposite to each other.

[0057] In step S10, the number of protrusions 52 provided on each semi-circular steel pipe 51 is preferably 2 to 5. The protrusions 52 are evenly spaced and aligned along the axial direction. The circumferential dimension of the first opening 41 is set equal to the circumferential dimension of the protrusions 52, so that the inner sleeve 5 can only move axially relative to the outer sleeve 4, and cannot move circumferentially. Alternatively, the circumferential dimension of the first opening 41 is slightly larger than the circumferential dimension of the protrusions 52, so that the circumferential movement of the inner sleeve 5 relative to the outer sleeve 4 is negligible.

[0058] Preferably, the protrusion 52 is cylindrical and extends radially, allowing it to be pushed out from the first outlet after high-pressure grouting into the inner sleeve 5, inserting into the surrounding rock and enhancing the anchoring performance of the anchor bolt. Figure 3 As shown, the end of the protrusion 52 is conical, which facilitates insertion into the surrounding rock. In this specification, the length of the protrusion 52 is the radial length of the protrusion 52, and the diameter of the protrusion 52 is the diameter of the cylindrical protrusion 52.

[0059] like Figure 2 As shown, the outer sleeve 4 is configured as a cylindrical tube, and its outer wall is covered with threads to enhance the anchoring performance of the anchor rod. The first opening 41 is preferably located at the center of the outer sleeve 4 along the axial direction.

[0060] In this embodiment, in the step of inserting the grouting pipe from the inner sleeve 5 for grouting (i.e., step S50), the formula for calculating the grouting pressure is:

[0061]

[0062] Among them, F c σ is the force σ exerted by the protrusion 52 into the surrounding rock. s d represents the compressive strength of the surrounding rock. c P is the diameter of the protrusion 52; z The grouting pressure is L; k is an adjustment coefficient, which is related to the length of the protrusion 52 and the integrity of the surrounding rock, and is taken as 1.5 to 2. n B is the length of the inner sleeve 5; n The width of the inner sleeve 5.

[0063] That is, the pressure required for the protrusion 52 to be inserted into the surrounding rock can be calculated by considering the compressive strength of the surrounding rock, the size and number of the protrusions 52, and the size of the inner sleeve 5, thus determining the grouting pressure inside the anchor pipe. To improve construction efficiency, the calculation of the grouting pressure can also be performed in step S10, and grouting can be carried out in step S50 based on the calculated grouting pressure. This scheme can calculate the size of the pressure-yielding anchor rod and the grouting pressure based on field parameters such as the surrounding rock strength and pressure, so that the pressure-yielding anchor rod meets the design requirements and accordingly performs its anchoring performance and sliding pressure-yielding performance.

[0064] like Figure 2As shown, the connecting mechanism includes a bolt 2, a washer 1, and a nut 3. The washer 1 has a second opening 11 through which the first end of the outer sleeve 4 passes. After grouting is completed, step S60 is performed. Step S60 includes: first, fixing the washer 1 to the lining or surrounding rock with the bolt 2, and then installing the nut 3 on the first end of the outer sleeve 4 that passes through the second opening 11. The nut 3 can seal the first end of the outer sleeve 4, preventing the inner sleeve 5 from shifting and bringing out excess mortar.

[0065] Specifically, the nut 3 is hollow inside to accommodate part of the inner sleeve 5, which facilitates the inner sleeve 5 to slide within the outer sleeve 4 and release pressure in a timely manner.

[0066] In step S20, drilling operations can be performed using appropriate drilling equipment, and the borehole is cleaned after drilling. In step S40, the pressure-relief anchor rod is slowly pushed into the borehole manually or mechanically. In step S60, the pressure-relief anchor rod can be fixed to the surrounding rock or lining, and the pressure relief of the anchor rod is achieved by the deformation of the inner sleeve 5 of the pressure-relief anchor rod together with the surrounding rock or lining.

[0067] It should be noted that in the description of this specification, the terms "first," "second," etc., are used only for descriptive purposes and to distinguish similar objects; there is no order between them, nor should they be construed as indicating or implying relative importance. Furthermore, in the description of this specification, unless otherwise stated, "a plurality of" means two or more.

[0068] Any numerical values ​​cited herein include all values ​​ranging from a lower limit to an upper limit, increasing by one unit, with at least two units between any lower and any higher value. For example, if the quantity of a component or the value of a process variable (e.g., temperature, pressure, time, etc.) is described as being from 1 to 90, preferably from 20 to 80, more preferably from 30 to 70, the purpose is to illustrate that values ​​such as 15 to 85, 22 to 68, 43 to 51, 30 to 32 are also explicitly listed in this specification. For values ​​less than 1, a unit is appropriately considered to be 0.0001, 0.001, 0.01, 0.1, etc. These are merely examples intended for explicit expression, and it can be assumed that all possible combinations of values ​​listed between the minimum and maximum values ​​are similarly explicitly stated in this specification.

[0069] Unless otherwise stated, all ranges include the endpoints and all numbers between them. The terms "approximately" or "about" used with ranges apply to both endpoints of the range. Thus, "approximately 20 to 30" is intended to cover "approximately 20 to approximately 30," including at least the specified endpoints.

[0070] All articles and references disclosed herein, including patent applications and publications, are incorporated herein by reference for various purposes. The term “substantially constitutes…” used to describe a combination should include the identified elements, components, parts, or steps, as well as other elements, components, parts, or steps that do not substantially affect the essential novelty of the combination. The use of the terms “comprising” or “including” to describe combinations of elements, components, parts, or steps herein also contemplates embodiments substantially constituted by such elements, components, parts, or steps. The use of the term “may” herein is intended to indicate that any described attribute included by “may” is optional.

[0071] Multiple elements, components, parts, or steps can be provided by a single integrated element, component, part, or step. Alternatively, a single integrated element, component, part, or step can be divided into multiple separate elements, components, parts, or steps. The use of "a" or "an" to describe an element, component, part, or step does not imply the exclusion of other elements, components, parts, or steps.

[0072] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this teaching should not be determined by reference to the above description, but rather by reference to the appended claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the preceding claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the inventors have not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. A novel method for applying a pressure-relief anchor bolt, characterized in that, Includes the following steps: Fabricate a pressure-relief anchor bolt; the pressure-relief anchor bolt includes an outer sleeve and an inner sleeve; the inner sleeve is disposed inside the outer sleeve; the outer wall surface of the inner sleeve is provided with a protrusion; the wall surface of the outer sleeve is provided with a first opening, and the protrusion passes through the first opening; the axial length of the first opening is greater than the axial length of the outer wall surface of the inner sleeve where the protrusion is disposed; Drill holes and clean the inside of the holes; A cement cartridge is installed at the tail end of the outer sleeve; Push the pressure-relief anchor rod into the borehole until it reaches the designed position; The grouting pipe is inserted into the inner sleeve for grouting, and the protrusion is pushed into the surrounding rock for anchoring by the grouting pressure. A connecting mechanism is installed at the first end of the outer sleeve to fix the pressure-relief anchor rod to the surrounding rock; In the step of manufacturing the pressure-relief anchor bolt, the formula for calculating the resistance of the pressure-relief anchor bolt is as follows: ； in, The resistance of the pressure anchor bolt; The shear strength of the surrounding rock; The length of the protrusion; The friction coefficient between the protrusion and the surrounding rock is denoted as . The compressive strength of the surrounding rock; The diameter of the protrusion is given.

2. The application method of the novel pressure-yielding anchor bolt according to claim 1, characterized in that, In the step of making the pressure relief anchor rod, the inner sleeve includes two semi-circular steel pipes of the same size, and the protrusion is welded to the outer wall of the semi-circular steel pipes.

3. The application method of the novel pressure-yielding anchor bolt according to claim 2, characterized in that, In the step of making the pressure-relief anchor rod, the number of protrusions on each semi-circular steel pipe is 2 to 5.

4. The application method of the novel pressure-yielding anchor bolt according to claim 3, characterized in that, In the step of making the pressure-relief anchor bolt, the protrusion is cylindrical and extends radially, and the end of the protrusion is conical.

5. The application method of the novel pressure-yielding anchor bolt according to claim 1, characterized in that, In the step of making the pressure-relief anchor bolt, the outer sleeve is set to be in the shape of a round tube, and the outer wall of the outer sleeve is covered with threads.

6. The application method of the novel pressure-yielding anchor bolt according to claim 5, characterized in that, In the step of manufacturing the pressure relief anchor, the first opening is located at the center of the outer sleeve along the axial direction; the circumferential dimension of the first opening is equal to the circumferential dimension of the protrusion.

7. The application method of the novel pressure-yielding anchor bolt according to claim 1, characterized in that, In the step of inserting the grouting pipe from the inner sleeve for grouting, the formula for calculating the grouting pressure is: ； in, The force by which the protrusion inserts into the surrounding rock. The compressive strength of the surrounding rock; The diameter of the protrusion; The grouting pressure is mentioned above; The adjustment coefficient is related to the length of the protrusion and the integrity of the surrounding rock, and is taken as 1.5~2; The length of the inner sleeve; The width of the inner sleeve.

8. The application method of the novel pressure-yielding anchor bolt according to claim 1, characterized in that, The connecting mechanism includes a bolt, a washer, and a nut; the washer has a second opening through which the first end of the outer sleeve passes; the step of installing the connecting mechanism at the first end of the outer sleeve includes: first fixing the washer to the surrounding rock with the bolt, and then installing the nut at the first end of the outer sleeve that passes through the second opening.

9. The application method of the novel pressure-yielding anchor bolt according to claim 8, characterized in that, The nut is hollow inside to accommodate part of the inner sleeve.

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