Grouting anchor cable for oppositely penetrating and reinforcing narrow coal pillar and using method of grouting anchor cable

Abstract

The invention relates to a grouting anchor cable for oppositely penetrating and reinforcing a narrow coal pillar and a using method thereof.The grouting anchor cable comprises a hollow anchor cable body, the tail end of the anchor cable body is provided with a rotating part and a grouting opening, the head end of the anchor cable body is provided with a jacking part, and the hollow part of the anchor cable body is provided with a hard grout outlet pipe with a grout overflow hole in the length direction of the anchor cable body; a bracket is arranged between the slurry outlet pipe and the steel strand; plugging trays are coaxially arranged at the head end and the tail end of the anchor cable body and extend towards the periphery in the radial direction to form a tray shape, and protruding thorns are arranged on the edges of the plugging trays. The jacking part and the rotating part are provided with locking parts used for locking the plugging tray to the wall of the coal pillar, and the locking parts are in threaded connection with the jacking part and the rotating part. Compared with the prior art, under the condition that the density and continuity of the steel strands are not affected, whole-section grouting can be achieved, the anchor cable strength and grout outlet uniformity are guaranteed, cracks in the coal pillar can be fully filled, and the bearing capacity of the narrow coal pillar in the section can be improved.

Description

Technical Field

[0001] The invention relates to the field of support and reinforcement of narrow coal pillars in a mining face section, support and reinforcement technology for mine lanes, tunnels and the like, and in particular to a grouting anchor cable for penetrating and reinforcing narrow coal pillars and a method of using the same. Background Art

[0002] When a mine adopts the "double excavation and double mining" method (i.e., two tunnels are excavated simultaneously and narrow coal pillars are left to protect the tunnels) to recover coal, the air intake tunnel (cable) below the upper section mining face must be retained and used as the return air tunnel (cable) for the lower section mining face. Under this condition, the deformation of the section coal pillar affected by mining will be relatively large; at the same time, with the increase in demand for coal resources and mining intensity, most mines have reduced the width of the section coal pillar in order to increase production and recovery rate as much as possible, making it very important to study and analyze the width of the narrow coal pillar and its stable control.

[0003] In view of the above problems, it is often difficult to achieve grouting for the cross-anchor cables used for double tunnel excavation in existing engineering practices, and the use of grouting anchor cables still remains at the stage of reinforcing from one side of the coal pillar, which cannot maximize the overall grouting anchoring. In addition, in order to achieve grouting of the coal pillar, the existing invention mainly focuses on setting an assembly or bonding structure in the middle of the anchor cable body for grouting. When the coal pillar swells and the anchor cable is subjected to axial tension, such a structure is prone to loosening and the anchor cable fails.

[0004] Therefore, it is urgent to develop a grouting anchor cable for penetrating and reinforcing narrow coal pillars, so as to realize grouting of the entire coal pillar section without changing the anchor cable body structure and affecting the anchor cable body strength, so as to improve the bearing capacity of the coal pillar and close the coal pillar cracks. Summary of the invention

[0005] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a grouting anchor cable for penetrating and reinforcing narrow coal pillars and a method of using the same, which can realize full-section grouting without affecting the density and continuity of the steel strands, ensure the strength of the anchor cable and the uniformity of the slurry discharge, fully fill the cracks in the coal pillar, and improve the bearing capacity of the narrow coal pillar section.

[0006] The present invention provides a grouting anchor cable for penetrating and reinforcing a narrow coal pillar, comprising a hollow anchor cable body, a rotating portion and a grouting port being provided at the end of the anchor cable body, a jacking portion being provided at the head end of the anchor cable body, a hard grouting pipe with a grouting hole being provided at the hollow portion of the anchor cable body along the length direction of the anchor cable body, and a bracket being provided between the grouting pipe and the steel strand;

[0007] A plugging tray is coaxially arranged at the head and the end of the anchor cable body, and the plugging tray extends in all directions along its radial direction to form a tray shape, and a spur is arranged on the edge of the plugging tray; a locking part for locking the plugging tray on the coal pillar wall is arranged on the jacking part and the rotating part, and the locking part is threadedly connected with the jacking part and the rotating part;

[0008] During grouting, the jacking part and the anchor body are inserted into the coal pillar borehole in sequence, the slurry is injected into the anchor body through the grouting port and overflows from the overflow hole and the gap between the steel strands into the coal pillar borehole, and the rotating part at the end of the anchor body is rotated to tighten the steel strand before the slurry solidifies, forming a cross-reinforcement support for the narrow coal pillar.

[0009] Furthermore, the rotating part includes a hollow straight tube body, the hollow straight tube body is rigidly coaxially connected to the anchor cable body, the steel strand is embedded in the hollow straight tube body, and the rotating part can drive the steel strand to rotate along the length direction of the anchor cable body to tighten the steel strand.

[0010] Furthermore, a grouting hole is axially provided in the middle of the rotating part, and the grouting hole is coaxially bonded with the slurry outlet pipe, and the two are separated after the rotating part is rotated to prevent the slurry outlet pipe and the jacking part from axially rotating.

[0011] Furthermore, the outer layers of the rotating part and the pushing part are both provided with threads, and the plugging tray can be movably installed on the rotating part and the pushing part. When the anchor cable is installed, the plugging tray is tightly attached to the coal pillar wall and locked by the locking part, so that there is no gap between the plugging tray and the coal pillar wall, and the rock and slurry on the coal pillar wall are sealed on the coal pillar wall. After the slurry mixed with the rock and soil solidifies, the strength of the coal pillar support can be significantly enhanced.

[0012] Furthermore, the jacking part includes a solid straight tube body, one end of which is rigidly coaxially connected to the anchor cable body, the steel strand is embedded in the solid straight tube body, and a drill bit is provided at the other end of the solid straight tube body. The drill bit can effectively reduce the pressure of driving, especially when encountering hard stones, the drill bit can easily break up or pass through the stones, effectively improving the speed of anchor cable construction jacking and improving work efficiency.

[0013] Furthermore, the overflow holes are evenly distributed in a plum blossom shape on the slurry outlet pipe, and the hole positions are 90 degrees to each other. The overflow holes are evenly distributed, so that the slurry can be fully injected into the coal pillar through the overflow holes, ensuring that the coal pillar is evenly stressed, thereby effectively avoiding stress concentration.

[0014] Furthermore, the edge of the plugging tray has a sharp blade angle that is axially inclined toward the anchor cable body. The plugging tray is struck so that the blade angle of its edge is pushed into the coal pillar in a manner of cutting and eating the soil, so that the plugging tray is closely attached to the wall of the coal pillar to prevent the rock and soil in the tunnel from falling off and the slurry in the coal pillar from seeping out, effectively improving the support strength. The edge of the plugging tray is provided with a spur that is higher than the blade angle. The plugging tray is struck so that the edge spur is pushed deeply into the coal pillar, thereby fixing the position of the plugging tray to prevent the axial rotation of the pushing part and the plugging tray when the steel strand is rotated.

[0015] Furthermore, a plurality of the brackets are arranged equidistantly along the length direction of the anchor cable to maintain the steel strand in a relaxed state and to build a gap between the slurry outlet pipe and the steel strand. During grouting, the slurry overflows from the overflow hole and fully enters the cracks in the coal pillar through the gap.

[0016] Furthermore, the bracket is made of thin grey cast iron and is provided with a pre-crack line. After the grouting is completed and the steel strands are tightened, the bracket is broken and shattered due to the pressure of the steel strands.

[0017] After grouting is completed, the rotating part is rotated to tighten the steel strands to form a dense anchor cable body structure. Due to the friction between the tightened steel strands, the single steel strand with small tensile strain and other single steel strands with large tensile strain achieve deformation coordination through friction during the stretching process to increase the tensile strength of the steel strands. At the same time, after grouting is completed, the slurry fills the grouting pipe to form a solid anchor cable body, which can significantly enhance the strength of the coal pillar support after the rock and soil mixed with the slurry solidify.

[0018] The present invention also provides a method for using a grouting anchor cable, comprising the following steps:

[0019] S1: Simultaneously with the excavation work of the double tunnels, determine the construction point on one side of the coal pillar in the section where the excavation has been carried out but the support work has not yet been carried out, and mark multiple control points on the radial section of the tunnel where the construction point is located;

[0020] S2: drilling a hole at the control point and penetrating the coal pillar, and then inserting the anchor cable body;

[0021] S3: On the opposite side of the coal pillar at the construction point, the jacking part of the anchor cable body is passed through the plugging tray and the locking part in sequence, and the plugging tray is knocked along the length direction of the anchor cable to drive it into the coal pillar;

[0022] S4: Screw the locking part on the jacking part to lock the blocking tray and the jacking part on the coal pillar wall;

[0023] S5: preparing slurry, injecting the slurry into the anchor cable from the grouting port, the slurry is injected into the anchor cable body through the grouting port, and overflows from the overflow hole and the gap between the steel strands into the coal pillar borehole;

[0024] S6: After the grouting is completed, the grouting port is sealed, the rotating part is rotated to tighten the steel strand, and then the locking part is screwed to lock the sealing tray and the rotating part on the tunnel wall;

[0025] S7: Maintain for a certain period of time until the slurry in the coal pillar solidifies, thus forming a reinforcement support for the narrow coal pillar.

[0026] The slurry is polymer cement mortar, which is made by mixing cement and water in a certain proportion. The proportion of cement and water is determined based on experiments to ensure that the slurry has a certain fluidity after being made.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] The present invention can realize full-section grouting without affecting the density and continuity of the steel strands, ensure the strength of the anchor cable and the uniformity of the grouting, fully fill the cracks in the coal pillar, and improve the bearing capacity of the narrow coal pillar in the section. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The axial schematic diagram of the grouting anchor cable structure for penetrating and reinforcing a narrow coal pillar;

[0030] Figure 2 This is a schematic diagram of the relative positions of the slurry pipe, bracket and steel strand;

[0031] Figure 3 It is a schematic diagram of the blocking tray structure;

[0032] Figure 4 is a schematic diagram of the support structure;

[0033] Figure 5 Schematic diagram of the anchor cable structure before tightening the steel strand;

[0034] Figure 6 Schematic diagram of the anchor cable structure after tightening the steel strand;

[0035] Figure 7 This is a schematic diagram of the anchor cable arrangement position;

[0036] Figure 8 This is a schematic diagram of the layout of the "double excavation and double mining" tunnels and working faces.

[0037] Figure numerals: 1-anchor cable body; 2-pushing part; 3-rotating part; 4-grouting port; 5-locking part; 6-sealing tray; 7-steel strand; 8-bracket; 9-slurry outlet pipe; 10-slurry overflow hole; 11-blade angle; 12-thorn; 13-pre-splitting line. DETAILED DESCRIPTION

[0038] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all considered to be common technical features disclosed in the prior art.

[0039] Example 1

[0040] This embodiment provides a grouting anchor cable for penetrating and reinforcing a narrow coal pillar. Figure 1 , Attachment Figure 2 As shown, it comprises a hollow anchor cable body 1, a rotating part 3 and a grouting port 4 are provided at the end of the anchor cable body 1, a jacking part 2 is provided at the head end of the anchor cable body 1, a hard slurry outlet pipe 9 with a slurry overflow hole 10 is provided in the hollow part of the anchor cable body 1 along the length direction of the anchor cable body 1, and a bracket 8 is provided between the slurry outlet pipe 9 and the steel strand 7;

[0041] A plugging tray 6 is coaxially arranged at the head and the end of the anchor cable body 1. The plugging tray 6 extends in all directions along its radial direction to form a tray shape. A spur 12 is arranged on the edge of the plugging tray 6. A locking part 5 for locking the plugging tray 6 on the coal pillar wall is arranged on the jacking part 2 and the rotating part 3. The locking part 5 is threadedly connected with the jacking part 2 and the rotating part 3.

[0042] During grouting, the jacking part 2 and the anchor body 1 are inserted into the coal pillar borehole in sequence, the slurry is injected into the anchor body 1 through the grouting port 4 and overflows from the overflow hole 10 and the gap between the steel strands 7 into the coal pillar borehole, and the rotating part 3 at the end of the anchor body 1 is rotated to tighten the steel strands 7 before the slurry solidifies, thereby forming a cross-penetration reinforcement support for the narrow coal pillar.

[0043] In a specific embodiment, the rotating part 3 includes a hollow straight tube body, which is rigidly coaxially connected to the anchor body 1, and the steel strand 7 is embedded in the hollow straight tube body. The rotating part 3 can drive the steel strand 7 to rotate along the length direction of the anchor body 1 to tighten the steel strand 7.

[0044] In a specific embodiment, a grouting hole is axially provided in the middle of the rotating part 3, and the grouting hole is coaxially bonded with the slurry outlet pipe 9, and the two are separated after the rotating part 3 is rotated to prevent the slurry outlet pipe 9 and the jacking part 2 from axial rotation.

[0045] In a specific embodiment, the outer layers of the rotating part 3 and the pushing part 2 are both provided with threads, and the plugging tray 6 can be movably installed on the rotating part 3 and the pushing part 2. After the anchor cable is installed, the plugging tray 6 is tightly attached to the coal pillar wall and locked by the locking part 5, so that there is no gap between the plugging tray 6 and the coal pillar wall, and the rock and slurry on the coal pillar wall are sealed on the coal pillar wall. After the slurry mixed with the rock and soil solidifies, the strength of the coal pillar support can be significantly enhanced.

[0046] In a specific embodiment, the jacking part 2 includes a solid straight tube body, one end of which is rigidly coaxially connected to the anchor cable body 1, the steel strand 7 is embedded in the solid straight tube body, and a drill bit is provided at the other end of the solid straight tube body. The drill bit can effectively reduce the pressure of driving, especially when encountering hard stones, the drill bit can easily break up or pass through the stones, effectively improving the speed of anchor cable construction jacking and improving work efficiency.

[0047] In the specific implementation mode, see the attached Figure 2 As shown, the overflow holes 10 are evenly distributed in a plum blossom shape on the slurry outlet pipe 9, and the hole positions are 90° to each other. The overflow holes 10 are evenly distributed, so that the slurry can be fully injected into the coal pillar through the overflow holes 10, ensuring that the coal pillar is evenly stressed, thereby effectively avoiding stress concentration. In this embodiment, the slurry outlet pipe 9 is a high-strength steel pipe. In other embodiments, the specific positions of the overflow holes 10 on the slurry outlet pipe 9 and the specific materials of the slurry outlet pipe 9 are not limited to the above description or the methods given in the figures.

[0048] In the specific implementation mode, see the attached Figure 3 As shown, the edge of the plugging tray 6 has a sharp blade corner 11 that is axially inclined toward the anchor cable body 1. The plugging tray 6 is struck so that the blade corner 11 of its edge is pushed into the coal pillar in a manner of cutting and eating the soil, so that the plugging tray 6 is close to the wall of the coal pillar to prevent the rock and soil in the tunnel from falling off and the slurry in the coal pillar from seeping out, effectively improving the support strength. The edge of the plugging tray 6 is provided with a spur 12 that is higher than the blade corner 11. The plugging tray 6 is struck so that the edge spur 12 is pushed deeply into the coal pillar, thereby fixing the position of the plugging tray 6 to prevent the axial rotation of the pushing part 2 and the plugging tray 6 when the steel strand 7 is rotated.

[0049] In the specific implementation mode, see the attached Figure 5 As shown, a plurality of brackets 8 are arranged equidistantly along the length direction of the anchor cable to maintain the relaxed state of the steel strand 7 and to build a gap between the slurry outlet pipe 9 and the steel strand 7. During grouting, the slurry overflows from the overflow hole 10 and fully enters the cracks in the coal pillar through the above gap.

[0050] In the specific implementation mode, see the attached Figure 4 As shown, the bracket 8 is made of thin gray cast iron and is provided with a pre-crack line 13. After the grouting is completed and the steel strand 7 is tightened, the bracket 8 is compressed by the steel strand 7 and breaks and shatters. Of course, in other embodiments, the specific material of the bracket 8 and the position of the pre-crack line 13 are not limited to the above description or the method given in the figure.

[0051] See attached Figure 6As shown, after grouting is completed, the rotating part 3 is rotated to tighten the steel strands 7 to form a dense anchor cable body 1 structure. Due to the friction between the tightened steel strands 7, during the stretching process, the single steel strand 7 with small tensile strain and the other single steel strands 7 with large tensile strain achieve deformation coordination through friction, so as to increase the tensile strength of the steel strand 7. At the same time, after grouting is completed, the slurry fills the grouting pipe to form a solid anchor cable body 1, which can significantly enhance the strength of the coal pillar support after the rock and soil mixed with the slurry solidify.

[0052] This embodiment also provides a method for using a grouting anchor cable, such as Figure 7 , 8 As shown, the following steps are included:

[0053] S1: See Appendix Figure 7 As shown, the excavation work of the two tunnels is carried out simultaneously, a construction point is determined on one side of the coal pillar of the section where the excavation work has been carried out but the support work has not been carried out, and a plurality of control points are marked on the radial section of the tunnel where the construction point is located;

[0054] S2: drilling a hole at the control point and penetrating the coal pillar, and then inserting the anchor cable body 1;

[0055] S3: On the opposite side of the coal pillar at the construction point, the jacking part 2 of the anchor cable body 1 passes through the blocking tray 6 and the locking part 5 in sequence, and the blocking tray 6 is knocked along the length direction of the anchor cable to drive it into the coal pillar;

[0056] S4: Screw the locking part 5 on the jacking part 2 to lock the blocking tray 6 and the jacking part 2 on the coal pillar wall;

[0057] S5: preparing slurry, injecting the slurry into the anchor cable from the grouting port 4, the slurry is injected into the anchor cable body 1 through the grouting port 4, and overflows from the overflow hole 10 and the gap between the steel strands 7 into the coal pillar borehole;

[0058] S6: After the grouting is completed, the grouting port 4 is blocked, the rotating part 3 is rotated to tighten the steel strand 7, and then the locking part 5 is screwed to lock the blocking tray 6 and the rotating part 3 on the tunnel wall;

[0059] S7: Maintain for a certain period of time until the slurry in the coal pillar solidifies, thus forming a reinforcement support for the narrow coal pillar.

[0060] The slurry is polymer cement mortar, which is made by mixing cement and water in a certain proportion. The proportion of cement and water is determined based on experiments to ensure that the slurry has a certain fluidity after being made.

[0061] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0062] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar. It is characterized in that The invention comprises a hollow anchor cable body (1), wherein the end of the anchor cable body (1) is provided with a rotating part (3) and a grouting port (4), the head end of the anchor cable body (1) is provided with a jacking part (2), the hollow part of the anchor cable body (1) is provided with a grouting pipe (9) with a grouting hole (10) along the length direction of the anchor cable body (1), and a bracket (8) is provided between the grouting pipe (9) and the steel strand (7); A blocking tray (6) is coaxially arranged at the head and the tail of the anchor cable body (1); the blocking tray (6) extends in all directions along its radial direction to form a tray shape; and a thorn (12) is arranged on the edge of the blocking tray (6); During grouting, the jacking part (2) and the anchor cable body (1) are sequentially inserted into the coal pillar borehole, the slurry is injected into the anchor cable body (1) through the grouting port (4) and overflows from the overflow hole (10) and the gap between the steel strands (7) into the coal pillar borehole, and before the slurry solidifies, the rotating part (3) at the end of the anchor cable body (1) is rotated to tighten the steel strands (7), thereby forming a cross-penetration reinforcement support for the narrow coal pillar.

2. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The rotating part (3) comprises a hollow straight tube body, the hollow straight tube body is rigidly coaxially connected to the anchor cable body (1), the steel strand (7) is embedded in the hollow straight tube body, and the rotating part (3) can drive the steel strand (7) to rotate along the length direction of the anchor cable body (1) to tighten the steel strand (7).

3. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that A grouting hole is axially arranged in the middle of the rotating part (3), and the grouting hole is coaxially bonded with the slurry outlet pipe (9). The two are separated after the rotating part (3) is rotated, so as to prevent the slurry outlet pipe (9) and the jacking part (2) from axially rotating.

4. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The outer layers of the rotating part (3) and the pushing part (2) are both provided with threads, and the blocking tray (6) can be movably mounted on the rotating part (3) and the pushing part (2).

5. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The jacking part (2) comprises a solid straight tube body, one end of which is rigidly coaxially connected to the anchor cable body (1), the steel strand (7) is embedded in the solid straight tube body, and the other end of which is provided with a drill bit.

6. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The overflow holes (10) are evenly distributed in a plum blossom shape on the slurry outlet pipe (9), and the hole positions are 90 degrees to each other.

7. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The edge of the blocking tray (6) has a blade angle (11) that is axially inclined toward the anchor cable body (1); and the edge of the blocking tray (6) is provided with a spur (12) that is higher than the blade angle (11).

8. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The plurality of brackets (8) are arranged at equal distances along the length direction of the anchor cable, and are used to maintain the steel strand (7) in a relaxed state and to build a gap between the slurry outlet pipe (9) and the steel strand (7).

9. A grouting anchor cable for penetrating and reinforcing a narrow coal pillar according to claim 1, It is characterized in that The support (8) is made of thin grey cast iron and is provided with a pre-crack line (13). After grouting is completed and the steel strand (7) is tightened, the support (8) is compressed by the steel strand (7) and breaks into pieces.

10. A method for using a grouting anchor cable according to any one of claims 1 to 9, It is characterized in that The steps include: S1: Simultaneously with the excavation work of the double tunnels, determine the construction point on one side of the coal pillar in the section where the excavation has been carried out but the support work has not yet been carried out, and mark multiple control points on the radial section of the tunnel where the construction point is located; S2: drilling a hole at the control point and penetrating the coal pillar, and then inserting the anchor cable body (1); S3: On the opposite side of the coal pillar at the construction point, the jacking portion (2) of the anchor cable body (1) is passed through the plugging tray (6) and the locking portion (5) in sequence, and the plugging tray (6) is struck along the length direction of the anchor cable to drive it into the coal pillar; S4: Screwing the locking part (5) on the jacking part (2) to lock the blocking tray (6) and the jacking part (2) on the coal pillar wall; S5: preparing slurry, and injecting the slurry into the anchor cable from the grouting port (4); the slurry is injected into the anchor cable body (1) through the grouting port (4) and overflows from the overflow hole (10) and the gap between the steel strands (7) into the coal pillar borehole; S6: After the grouting is completed, the grouting port (4) is sealed, the rotating part (3) is rotated to tighten the steel strand (7), and then the locking part (5) is rotated to lock the sealing tray (6) and the rotating part (3) on the tunnel wall; S7: Maintain for a certain period of time until the slurry in the coal pillar solidifies to form a reinforcement support for the narrow coal pillar.

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