Anchoring anchor cable and method of manufacturing the same

Abstract

The present application relates to a kind of anchor injection anchor cable and its manufacturing method, wherein anchor injection anchor cable includes cable body and core pipe, the cable body includes hollow section, grout section and solid section arranged in order from back to front, the outer diameter of the solid section is less than the outer diameter of hollow section, the core pipe is located in the inner hole of hollow section, and extend to grout section, and the cable body wire between grout section forms grout seam.The cable body of the present application adopts variable diameter structure, hollow section is used for passing grout, grout section of variable diameter area is used for grout, solid section is used for shell expansion anchoring, the strength of each cable body wire remains consistent, realizes the pre-stress in small diameter drilling, and carries out grouting whole anchor.Grouting connector is connected with external grouting device using external thread, increases the grouting area, reduces grouting resistance, and is more beneficial to the application of organic material and inorganic thick grout.Through setting grouting column in core pipe, it is beneficial to the application of two-component reinforcing material, improves stirring effect and construction speed.

Description

Technical Field

[0001] This invention relates to the field of anchor cable technology for support or reinforcement in mining and geotechnical engineering, and particularly to an anchor cable for injection and its manufacturing method. Background Technology

[0002] Anchor cables are widely used in geotechnical engineering projects such as mine shafts and tunnels to support or reinforce surrounding rock. Due to the complex geological conditions in my country, various types of anchor cables are used in mines, mainly two categories: resin-end anchor cables and grouting anchor cables. Extensive engineering practice has proven that prestressed grouting anchor cables are more effective in controlling the surrounding rock in soft and fractured roadways.

[0003] Currently, hollow grouting anchor cables are commonly used in coal mines. The method involves first anchoring the cable end with resin anchoring agent within the borehole, then installing a tray and anchor at the tail end for tensioning and prestressing. Grouting is then performed through the hollow structure of the anchor cable, achieving full-length anchoring and grout diffusion to reinforce the surrounding rock. This type of anchor cable has achieved excellent rock control in soft rock tunnels and has been widely adopted. However, under certain geological conditions, such as borehole collapse, water ingress, or the presence of fissures or karst caves within the borehole, the resin anchoring agent cannot be installed, preventing the resin anchoring end from applying prestress to the anchor cable and limiting the application of hollow grouting anchor cables.

[0004] Another method is to use a mechanically expanded shell for end anchoring of the anchor cable, apply prestress, and then grout. For example, the patent for a large-diameter prestressed full-length anchor cable (application number: 202222836934.1) discloses a technique that uses a mechanically expanded shell end anchor to apply prestress to the anchor cable, and then uses a hollow cable body to grout and fill the drilled hole to achieve full-length anchoring. Because the mechanically expanded shell in this patent is set on a hollow cable body, it is suitable for anchor hole diameters greater than 40mm, but cannot be applied to anchor hole diameters less than 40mm. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing an anchor cable that can be used with small-diameter anchor holes, thus overcoming the deficiencies of existing technologies.

[0006] The present invention is achieved through the following technical solution: providing an anchor cable for grouting, comprising a cable body and a core tube. The cable body comprises a hollow section, a grout outlet section and a solid section arranged sequentially from back to front. The outer diameter of the solid section is smaller than the outer diameter of the hollow section. The core tube is located at the center of the hollow section and extends to the grout outlet section. A grout outlet gap is formed between the steel wires of the cable body in the grout outlet section.

[0007] The anchor cable setup in this scheme enables its use in small-diameter drilling by installing an expansion shell suspension assembly in the solid section. The grout enters the grout outlet section through the core tube, and the grout outlet gap is formed to allow the grout to flow out. The hollow section, grout outlet section, and solid section are different parts of the cable body, ensuring the integrity of the cable body.

[0008] As an optimization, a supporting guide cone is fixed inside the slurry outlet section. The front diameter of the supporting guide cone is smaller than the rear diameter, and the cable wires of the slurry outlet section press against the surface of the supporting guide cone. This optimized solution, by setting the supporting guide cone, supports the cable wires, better realizing the gradual and slow change of the cable diameter and avoiding shearing action on the cable wires in the diameter change zone.

[0009] As an optimization, the support guide cone includes a cylindrical section and a tapered section extending forward from the cylindrical section. The diameter of the cylindrical section is the same as the diameter of the rear end of the tapered section, and the cylindrical section and the tapered section are coaxial. This optimized design provides smoother support for the variable diameter of the cable wire and also facilitates the improvement of the stability of fixing the support guide cone, thereby ensuring that the support guide cone is coaxial with the cable.

[0010] As an optimization, a fixing hoop I is provided at the end of the solid section near the supporting guide cone, and a fixing hoop II is provided at the end of the hollow section near the supporting guide cone. This optimized solution tightens the steel wire of the solid section by setting the fixing hoop I, preventing loosening, and has a simple structure. The fixing hoop II tightens the hollow section and, in conjunction with the fixing hoop I, provides a more reliable fixation to the supporting guide cone.

[0011] As an optimization, the distance between the support guide cone and the core tube is 10mm~30mm. The position setting of the support guide cone in this optimized scheme ensures sufficient outflow space for the slurry, while avoiding an excessively large distance between the support guide cone and the core tube, which would affect the fixing effect of the support guide cone.

[0012] As an optimization, the solid section and the slurry outlet section have 2-5 fewer cable wires than the hollow section. This optimized solution achieves the solid section and slurry outlet section by reducing the number of cable wires by 2-5 compared to the hollow section, ensuring the integrity of the cable and maximizing its structural strength.

[0013] As an optimization, a mixing column assembly is installed inside the core tube. The mixing column assembly includes a mixing column, an elastic positioning clamp I located in front of the mixing column, and an elastic positioning clamp II located behind the mixing column. Both elastic positioning clamps I and II are fixed relative to the inner wall of the core tube by elastic force. This optimized solution uses elastic positioning clamps I and II to secure the mixing column. The elastic positioning clamps I and II are fixed to the inner wall of the core tube by elastic force, preventing the mixing column from moving when the two-component materials pass through, thus ensuring thorough mixing of the two-component materials.

[0014] As an optimization, a mixing column is installed inside the core tube, and a positioning clamp III is provided on the outer wall of the core tube, the position of which corresponds to the front end of the mixing column. This optimized solution uses the variability of the core tube by setting the positioning clamp III on the outside of the core tube to fix the mixing column inside, making installation more convenient. When the two-component material passes through, it prevents the mixing column from moving, ensuring thorough mixing of the two-component material.

[0015] As an optimization, a grouting connector is fixedly connected to the rear end of the hollow section. The grouting connector is sealed to the core tube, and its rear end has an external thread. The inner hole of the grouting connector forms a grouting port that communicates with the inner hole of the core tube. This optimization scheme facilitates grouting operations by setting up the grouting connector, and the external thread on the grouting connector facilitates connection with external grouting devices and better ensures the grouting passage area.

[0016] This solution also provides a method for manufacturing the above-mentioned anchor cable, including the following steps: a. Insert a core tube into the hollow section of the hollow cable body, and make the front end of the core tube flush with the front end of the hollow section. Use a fixing hoop to tighten and fix the front end of the hollow section of the cable body. b. Remove 2-5 steel wires from the front of the hollow section, and place a support guide cone in the inner hole of the cable corresponding to the slurry outlet section, with the small diameter end of the support guide cone facing the solid section. The steel wires of the slurry outlet section clamp the support guide cone, and a slurry outlet gap is formed between adjacent steel wires of the slurry outlet section. c. Gather the steel wires of the cable body located in front of the support guide cone and tighten them with a fixing hoop to form a solid cable body. Install the expansion shell suspension assembly on the solid cable body.

[0017] The beneficial effects of this invention are as follows: 1. The cable adopts a variable diameter structure. The hollow section is used for grouting, the grout outlet section in the variable diameter zone is used for grouting, and the solid section is used for expansion shell anchoring. The steel wire strength of each section of the cable is consistent, which realizes the application of prestress in small diameter boreholes before grouting and full anchoring.

[0018] 2. The grouting connector uses external threads to connect with the external grouting device, increasing the grouting area, reducing grouting resistance, and facilitating the injection of organic materials and inorganic slurries. The inclusion of a mixing column within the core tube facilitates the application of two-component reinforcement materials, improving mixing efficiency and construction speed.

[0019] 3. Easy to install; no need to mix resin and wait for it to solidify under an unsupported roof slab. It can bear load immediately upon installation, providing immediate support. Grouting can be scheduled according to the construction sequence and surrounding rock deformation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of an embodiment of the anchor cable of the present invention; Figure 2 for Figure 1 Enlarged view of a section of the slurry outlet; Figure 3 This is a schematic diagram of the installation of the slurry column according to Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the installation of the slurry column in Embodiment 2 of the present invention; As shown in the figure: 1. Expansion shell suspension assembly; 2. Fixing hoop I; 3. Support guide cone; 4. Grout outlet section; 5. Fixing hoop II; 6. Core tube; 7. Hollow section; 8. Solid section; 9. Tray; 10. Anchor; 11. Grouting connector; 12. Elastic positioning hoop I; 13. Grouting column; 14. Elastic positioning hoop II; 15. Protective cap; 16. Positioning hoop III. Detailed Implementation

[0021] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to describe the solution.

[0022] Example 1 like Figure 1 The illustrated anchor cable includes a cable body, a core tube 6, a tray 9, an anchor 10, and an expansion shell suspension assembly 1. The tray 9 and the anchor 10 are conventional components in the art, while the expansion shell suspension assembly 1 is prior art, disclosed in patent application number 2021231479164, and will not be described in detail here. For ease of description, in this embodiment, the side where the expansion shell suspension assembly is located is the cable head, and the side where the anchor and tray are located is the cable tail, with the cable head located in front of the cable tail.

[0023] The cable body comprises a hollow section 7, a slurry outlet section 4, and a solid section 8 arranged sequentially from back to front. The outer diameter of the solid section 8 is smaller than the outer diameter of the hollow section 7. The core tube 6 is located within the inner hole of the hollow section 7. In this embodiment, the core tube 6 is located at the center of the hollow section 7 and extends to the slurry outlet section 4. Slurry outlet slots are formed between the cable body wires in the slurry outlet section. The core tube 6 is a flexible tube, and its front end is flush with the front end of the hollow section.

[0024] A support guide cone 3 is fixedly installed inside the slurry outlet section, and the distance between the support guide cone 3 and the core tube 6 is 10mm~30mm. The front diameter of the support guide cone 3 is smaller than the rear diameter, and the cable wire of the slurry outlet section is pressed against the surface of the support guide cone. Specifically, the support guide cone in this embodiment includes a cylindrical section and a conical section extending forward from the cylindrical section. The diameter of the cylindrical section is the same as the rear diameter of the conical section. The cylindrical section and the conical section are coaxial, and the cable wire gradually shrinks along the surface of the support guide cone to form a solid section. A fixing hoop I2 is provided at one end of the solid section 8 near the support guide cone, and a fixing hoop II5 is provided at one end of the hollow section 7 near the support guide cone. The support guide cone causes the steel wire to slowly become a solid steel wire bundle along the outside of the cone, which is the solid section, preventing the steel wire from being sheared when the cable diameter decreases. The solid section (mostly a 1×7 steel wire bundle) is fastened together with two clamps at the front and back, with a diameter of 15~18mm. An expansion shell suspension assembly is installed on the solid section to achieve mechanical end anchoring in a small drill hole with a diameter of 30~40mm.

[0025] In this embodiment, the hollow section is formed by several outer steel wires wound around the core tube. No grout outlet is provided at any position on the tube wall within the length of the core tube. The rear end of the hollow section is connected to the grouting connector for connecting the grouting pipeline. The front end extends to the grout outlet section. The outer steel wires are clamped together with a fixing hoop II5. The diameter of the fixing hoop II5 is 1~4mm larger than the outer diameter of the cable body. The end of the flexible core tube is flush with the end of the fixing hoop II5.

[0026] The solid section and the grouting section have 2-5 fewer steel wires than the hollow section. That is, 2-5 steel wires are removed from the original number of steel wires. The gaps between the steel wires serve as grouting seams, which reduces the diameter of the cable and ensures the integrity of the cable. This provides sufficient installation space for the expansion shell suspension assembly to meet the requirements of small-diameter use, while maximizing the mechanical anchoring force of the cable. After grouting and anchoring, the overall bearing capacity of the cable is no less than that of a hollow grouting anchor cable of the same specification.

[0027] A grouting connector 11 is fixedly connected to the rear end of the hollow section. The grouting connector 11 is sealed to the core tube 6. The rear end of the grouting connector is provided with an external thread, and the inner hole of the grouting connector forms a grouting port that communicates with the inner hole of the core tube. The external thread on the grouting connector is used to connect to an external grouting device. When the external grouting device is not connected, the threaded connection to the protective cap 15 provides protection for the external thread.

[0028] Specifically, after one end of the grouting connector is sealed to the core tube, the steel wire is welded around the end of the core tube and then wound around the grouting connector. Because this hollow anchor cable does not undergo resin mixing during installation, the grouting connector is circular (lower cost than hexagonal or octagonal designs), with a diameter not exceeding the diameter of the hollow section of the cable. To ensure the grouting area, the thread connecting the grouting connector to the external grouting device is set as an external thread, and the area of ​​the central hole is equivalent to the grouting area of ​​the core tube.

[0029] To ensure the grouting of the two-component material, a grout mixing column assembly is installed inside the core tube in this embodiment. The grout mixing column assembly includes a grout mixing column 13, an elastic positioning hoop I 12 located in front of the grout mixing column, and an elastic positioning hoop II 14 located behind the grout mixing column. Both elastic positioning hoop I and elastic positioning hoop II are fixed relative to the inner wall of the core tube by elastic force. Both elastic positioning hoop I and elastic positioning hoop II are elastic elements, fixed to the inner wall of the core tube by elastic force, firmly clamping the grout mixing column and preventing it from moving or rotating. When the two-component material passes through the grout mixing column, it forms a thorough mixture. The overall position of the grout mixing column assembly is offset from the position where the anchor is applied to the cable body to prevent damage to the grout mixing column caused by compression of the cable body when the anchor tightens. At the same time, the grout mixing column assembly will not slip out of the core tube during cable transportation, affecting the material's performance. The grout mixing column is existing technology, and its structure will not be described in detail.

[0030] The method for manufacturing anchor cables in this embodiment includes the following steps: a. Insert a core tube into the hollow section of the hollow cable body, and make the front end of the core tube flush with the front end of the hollow section. Use a fixing hoop to tighten and fix the front end of the hollow section of the cable body. b. Remove 2-5 steel wires from the front of the hollow section, and place a support guide cone in the inner hole of the cable corresponding to the slurry outlet section, with the small diameter end of the support guide cone facing the solid section. The steel wires of the slurry outlet section clamp the support guide cone, and a slurry outlet gap is formed between adjacent steel wires of the slurry outlet section. c. Gather the steel wires of the cable body located in front of the support guide cone and tighten them with a fixing hoop to form a solid cable body. Install the expansion shell suspension assembly on the solid cable body.

[0031] When installing the grout mixing column assembly, first insert the elastic positioning hoop I12 into the core tube from the grouting connector end, ensuring the insertion depth is greater than the total length of the grout mixing column and the elastic positioning hoop II14. Then, insert the grout mixing column and the elastic positioning hoop II14 in sequence. Placing the grout mixing column assembly inside the core tube ensures effective mixing of the two-component materials during grouting. The two-component materials can be fully mixed through the grout mixing column after injection into the core tube, greatly reducing the requirements on the pump during the mixing process.

[0032] In cases where there is no requirement for anchor cable preload, the expansion shell suspension structure can be simplified. Two to four barbed steel wires are installed at the solid cable section to replace the expansion shell suspension assembly, preventing the anchor cable from being easily pulled out after installation in the hole. Then, grouting is performed for full-length anchoring. After the grout solidifies, the anchor is tensioned and tightened.

[0033] Specifically, the hollow cable has an outer diameter of 22mm. A flexible core tube is inserted axially within the hollow section of the cable. Several steel wires are wrapped around the flexible core tube to form the hollow cable. The end of the core tube in the hollow cable is tightened and fixed with a round tube. After fixing, several steel wires are removed from the outer gap, leaving 7 steel wires. A support guide cone 3 is placed coaxially with the cable and surrounded by the remaining steel wires, with the small end of the cone facing the solid cable end and the large end 20-30mm from the end of the core tube. The steel wires are then bundled into a 1×7 steel wire bundle along the support guide cone 3 and tightened and fixed with a round tube, thus transforming the cable into a solid cable with a diameter of 15mm. An expansion shell suspension assembly is installed on the solid cable, suitable for a drilling diameter of 32mm. The total length of the anchor cable is 10300mm.

[0034] During construction, a 32mm borehole is first drilled using an anchor drilling rig, with a drilling depth of 10200mm. The expansion shell component of the hollow anchor cable is assembled, and the head is slowly pushed into the borehole until it reaches the bottom. Suddenly, the tail section of the cable is pulled forcefully, fixing the expansion shell to the bottom of the borehole. The tray and anchor are then installed, and pre-tensioning is performed. Tensioning is stopped when the pre-tensioning force reaches 150kN. The grouting connector is then connected to the grouting device for grouting inside the borehole.

[0035] If the rock inside the borehole is loose and prestress cannot be applied, a simple suspension structure can be used instead. The anchor cable is suspended from the borehole and then injected with chemical grout or injectable resin anchoring agent. After solidification, pre-tightening is performed. Generally, chemical grout and injectable resin anchoring agents are two-component materials, and a single-mixing grout column assembly should be added to the core tube.

[0036] Example 2 The difference between this embodiment and Embodiment 1 is that a mixing column 13 is installed inside the core tube, and a positioning hoop Ⅲ16 is provided on the outer wall of the core tube, the position of which corresponds to the front end of the mixing column.

[0037] In this embodiment, a positioning hoop Ⅲ16 is set on the outer wall of the core tube. The positioning hoop Ⅲ16 is tightened at the corresponding mixing column of the core tube by auxiliary force, which firmly fixes the mixing column and saves the number of positioning hoops.

[0038] Of course, the above description is not limited to the examples above. Technical features not described in this invention can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solutions of this invention and are not intended to limit this invention. This invention has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention do not depart from the spirit of this invention and should also fall within the scope of protection of the claims of this invention.

Claims

1. An anchor cable, comprising a cable body and a core tube (6), characterized in that: The cable body includes a hollow section (7), a slurry outlet section (4), and a solid section (8) arranged sequentially from back to front. The outer diameter of the solid section (8) is smaller than the outer diameter of the hollow section (7). The core tube (6) is located in the inner hole of the hollow section (7) and extends to the slurry outlet section (4). A slurry outlet gap is formed between the cable body wires of the slurry outlet section.

2. The anchor cable according to claim 1, characterized in that: The discharge section is provided with a support guide cone (3), the front diameter of the support guide cone (3) is smaller than the rear diameter, and the steel wire of the discharge section is pressed against the surface of the support guide cone.

3. The anchor cable according to claim 2, characterized in that: The support guide cone includes a cylindrical section and a tapered section extending forward from the cylindrical section. The diameter of the cylindrical section is the same as the diameter of the rear end of the tapered section, and the cylindrical section and the tapered section are coaxial.

4. The anchor cable according to claim 2, characterized in that: The solid section (8) is fitted with a fixing hoop I (2) at one end near the supporting guide cone, and the hollow section (7) is fitted with a fixing hoop II (5) at one end near the supporting guide cone.

5. An anchor cable according to claim 2, characterized in that: The distance between the support guide cone (3) and the core tube (6) is 10mm~30mm.

6. The anchor cable according to claim 2, characterized in that: The solid section and the slurry outlet section have 2 to 5 fewer steel wires than the hollow section.

7. The anchor cable according to claim 1, characterized in that: The core tube is equipped with a mixing column assembly, which includes a mixing column (13), an elastic positioning hoop I (12) located on the front side of the mixing column, and an elastic positioning hoop II (14) located on the rear side of the mixing column. Both the elastic positioning hoop I and the elastic positioning hoop II are fixed relative to the inner wall of the core tube by elastic force.

8. The anchor cable according to claim 1, characterized in that: A mixing column (13) is installed inside the core tube, and a positioning hoop III (16) is provided on the outer wall of the core tube. The position of the positioning hoop III (16) corresponds to the front end of the mixing column.

9. An anchor cable according to claim 1, characterized in that: The rear end of the hollow section is fixedly connected to a grouting connector (11), which is sealed to the core tube (6). The rear end of the grouting connector is provided with an external thread, and the inner hole of the grouting connector forms a grouting port that communicates with the inner hole of the core tube.

10. A method for manufacturing an anchor cable according to claim 1, characterized in that, Includes the following steps: a. Insert a core tube into the hollow section of the hollow cable body, and make the front end of the core tube flush with the front end of the hollow section. Use a fixing hoop to tighten and fix the front end of the hollow section of the cable body. b. Remove 2-5 steel wires from the front of the hollow section, and place a support guide cone in the inner hole of the cable corresponding to the slurry outlet section, with the small diameter end of the support guide cone facing the solid section. The steel wires of the slurry outlet section clamp the support guide cone, and a slurry outlet gap is formed between adjacent steel wires of the slurry outlet section. c. Gather the steel wires of the cable body located in front of the support guide cone and tighten them with a fixing hoop to form a solid cable body. Install the expansion shell suspension assembly on the solid cable body.

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