A coal mine gob retaining support wall with self-repairing function and method

Abstract

The present invention discloses a supporting wall and method for a coal mine gob-side lane retaining with a self-repairing function, comprising a supporting wall body; the supporting wall body comprises a frame and a flexible template, the frame is a rectangular box body with a hollow interior; a grouting hole is provided on the frame, and the flexible template wraps the frame as a whole; the interior of the frame is filled with a closed filling material, and a plurality of repair balls are evenly distributed in the closed filling material; the repair balls are brittle spheres, and the internal cavity thereof is a three-layer structure, the middle layer is an interlayer, the interlayer is filled with water, and the remaining two layers are filled with a polymer composite swelling colloid material; the frame and the flexible template are fixed to the surrounding rock of the lane through a plurality of anchor bolts and a supporting plate, so that the supporting wall body supports the lane. The present invention can ensure that the lane and the supporting wall are closely connected, and the cracks generated can be automatically repaired in the shortest possible time, thereby extending the service life of the supporting wall.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine gob-side lane retaining without coal pillar mining, and in particular to a coal mine gob-side lane retaining supporting wall with self-repairing function and a method thereof. Background Art

[0002] Leaving lanes along the goaf is a major reform in coal mining technology. It eliminates the need for supporting coal pillars and achieves continuous mining without coal pillars. It can not only reduce the amount of tunnel excavation work, lower excavation costs, ease the tense situation of mining and excavation succession, and improve the coal resource recovery rate and mine economic benefits, but also avoid coal seam disasters caused by coal pillars left in the goaf, which is of great significance to mine safety.

[0003] At present, the main method of supporting the tunnel along the goaf is concrete pouring. Practice has proved that the current concrete partition wall method is better than other methods. This method has wide adaptability and high bearing capacity, but it uses a large amount of valuable materials, has high engineering costs and construction complexity, and the strength increase rate is slow, which cannot adapt to high-yield and high-efficiency mine working faces. The existing improved method is the flexible formwork pumping concrete support technology. This method has the characteristics of good fluidity, strong expansibility, and strong plasticity. However, after the tunnel is excavated and mined twice, it will crack under the action of dynamic pressure in the later stage. This problem has not been effectively solved, and it is extremely difficult to repair it manually after cracking, which may also affect the inside of the wall. If the flexible formwork wall is not connected to the top or is locally fractured, it may cause large air leakage. In addition, the coal seam has a high tendency to spontaneous combustion, which is very likely to cause spontaneous combustion in the area with more coal residue in the goaf. Therefore, during the mining process, how to ensure a close connection between the tunnel and the support wall while automatically repairing the cracks in the shortest possible time, thereby extending the service life of the support wall, is the research direction of this industry. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art, the present invention provides a coal mine goaf-retaining lane support wall and method with self-repairing function, which can ensure the close connection between the lane and the support wall while automatically repairing the generated cracks in the shortest possible time, thereby extending the service life of the support wall.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a coal mine gob-side lane retaining support wall with self-repairing function, comprising a support wall main body;

[0006] The supporting wall body includes a frame and a flexible formwork. The frame is a rectangular box with a hollow interior and is made of a reinforced fiber composite board. Grouting holes are provided on the frame, and the flexible formwork wraps the frame as a whole.

[0007] The frame is filled with a sealed filling material, and a plurality of repair balls are evenly distributed in the sealed filling material;

[0008] The repair ball is a brittle sphere, and its internal cavity is a three-layer structure, the middle layer is an interlayer filled with water, and the other two layers are filled with polymer composite swelling colloid materials;

[0009] The frame and the flexible formwork are fixed on the surrounding rock of the tunnel through a plurality of anchor bolts and supporting plates, so that the supporting wall body supports the tunnel.

[0010] Furthermore, the flexible template is made of double-layer high-strength fiber cloth. The use of this material can improve the stress deformation effect of the flexible template.

[0011] Furthermore, the enclosed filling material is one of HBMD12 / 4-22S type mining concrete, high-performance self-compacting concrete or polymer foam material.

[0012] Furthermore, the material of the repair ball is glass, ceramic or polymer material, with a wall thickness of 1 to 5 mm, wherein the wall thickness of both sides of the interlayer is 1 to 2 mm; the mass ratio of the polymer composite swellable colloid material to water in each repair ball is 1:3. With such parameter repair balls and the ratio of polymer composite swellable colloid material to water, the repair ball can be broken after being stressed, so that the water in the interlayer is mixed with the polymer composite swellable colloid material in the two side layers, thereby forming a polymer composite swellable colloid, which flows along the cracks to bond and reinforce them.

[0013] Furthermore, the reinforced fiber composite plate has a width of 200 to 300 mm and a thickness of 20 to 30 mm.

[0014] Furthermore, both sides of the frame and the flexible template are vertically fixed on the tunnel surrounding rock. This arrangement can ensure that the supporting wall and the tunnel surrounding rock are closely fitted, further improving the supporting effect of the supporting wall on the tunnel.

[0015] The method for using the above-mentioned coal mine gob-side lane retaining support wall with self-repairing function comprises the following specific steps:

[0016] A. Wrap the flexible formwork outside the frame. After completion, use anchor bolts and support plates to pass through the frame and the flexible formwork, and fix both sides of the two vertically on the surrounding rock of the tunnel;

[0017] B. Carry out reinforcing bar construction at the top and bottom of the flexible formwork to make the steel bars, wall support and surrounding rock form a whole;

[0018] C. Prepare multiple repair balls, and fill water in the interlayer of each repair ball, and fill the other two layers of the repair ball with a polymer composite swelling colloid material, then prepare a sealing filling material, put multiple repair balls into the sealing filling material and mix them, so that each repair ball is evenly distributed in the sealing filling material;

[0019] D. Connect the grouting hole of the frame to one end of the pipeline, and connect the other end of the pipeline to the grouting machine, put the sealing filling material and the repair ball mixture in step C into the grouting machine, start the grouting machine to fill the inside of the frame with the sealing filling material and the repair ball mixture, then disconnect the pipeline and seal the grouting hole. After the sealing filling material solidifies, apply pre-tightening force to the frame and the flexible formwork through the anchor bolts and the support plate to press and fix the supporting wall and the surrounding rock of the tunnel;

[0020] E. During the process of supporting the tunnel with the supporting wall, when the tunnel experiences excavation and multiple strong mining activities, the tunnel will deform and exert ground stress on the supporting wall to squeeze it. If the ground stress is small, the supporting wall can offset the ground stress exerted by the tunnel through the deformation of the flexible template. If the ground stress is large, the frame of the supporting wall and the solidified sealing filling material will directly bear the pressure. When the stress exceeds the limit value, the sealing filling material will be displaced due to the stress, and cracks will be generated. Since the repair balls are evenly distributed inside the sealing filling material, the repair balls at the cracks will be The ball is broken by the force, so that the water inside the interlayer and the high molecular weight mixed swelling colloid material in the other two layers flow out from the repair ball, and then the high molecular weight mixed swelling colloid material and water are mixed. After mixing, the high molecular weight mixed swelling colloid material absorbs water and swells to become a high molecular weight mixed swelling colloid, which is an elastic gel. Then, the high molecular weight mixed swelling colloid flows along the crack to fill and bind the crack. After the water content of the high molecular weight mixed swelling colloid evaporates and is oxidized by air, it solidifies into dry glue to bind and bind the crack, thus completing the repair work of the crack generated this time.

[0021] F. When the supporting wall is subjected to greater stress again and new cracks are generated, the repair balls around the cracks will break and the crack repair process in step E will be repeated, thereby effectively extending the service life of the supporting wall.

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] (1) The present invention eliminates the traditional brick wall structure and improves it into a composite board structure, which can reduce transportation pressure, simplify the transportation process, and save manpower and financial resources; by fixing the internal pre-set anchor bolts with the flexible formwork and surrounding rock, the cast wall can have higher strength and better sealing.

[0024] (2) A flexible formwork is used to completely cover the wrapping frame with some space left. In the subsequent support process, the flexible formwork can be changed with the change of the tunnel shape, which has a certain buffering effect. In addition, the internal cavity of the repair ball is a three-layer structure, the middle layer is an interlayer filled with water, and the other two layers are filled with polymer composite swellable colloid materials. In this way, before the repair ball breaks, the polymer composite swellable colloid materials are not only isolated from the water in the interlayer, but also from the outside air, thereby ensuring that the polymer composite swellable colloid materials will not absorb water, expand, or oxidize. In this way, after the subsequent rupture, they can be mixed with water to form an elastic colloid, thereby achieving the effect of subsequent bonding and reinforcement of cracks.

[0025] (3) The supporting wall of the gob-side tunnel retaining of the present invention contains repair balls. When the tunnel is excavated and subjected to multiple strong mining activities, cracks are likely to appear in the wall under the action of the mine pressure. Some of the repair balls will break under the stress (because they are brittle spheres, they will break after being subjected to a large force), releasing the polymer composite swellable colloid material and water inside. Then, the polymer composite swellable colloid material and water are mixed. After mixing, the polymer composite swellable colloid material absorbs water and expands to become a polymer composite swellable colloid, which is an elastic gel. Then, the polymer composite swellable colloid flows along the cracks. , fill and bond the cracks, and after the water in the polymer composite swellable colloid evaporates and is oxidized by the air, it solidifies into dry glue to achieve bonding and reinforcement of the cracks, and quickly repair the wall cracks. As the repair process proceeds, the other part of the repair balls will be retained as the stress decreases, so that they can be used next time or even multiple times when the wall cracks. It has better achieved the goal of using as much as is lacking, avoiding material waste to a large extent, and can greatly make up for the defects of slow and difficult manual repair. It is safe, efficient, fast, convenient, and can be used multiple times, and also achieves the goal of self-repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0027] Figure 2 for Figure 1 A longitudinal internal section of

[0028] Figure 3 It is a schematic diagram of the structure of the repair ball in the present invention.

[0029] In the figure: 1-flexible formwork, 2-frame, 3-grouting hole, 4-anchor bolt, 5-reinforcement bar, 6-support plate, 7-repair ball, 8-interlayer, 9-water, 10-polymer composite swelling colloid material. DETAILED DESCRIPTION

[0030] The present invention will be further described below.

[0031] like Figure 1 and2 As shown, a coal mine gob-side lane retaining support wall with self-repairing function comprises a support wall main body;

[0032] The supporting wall body includes a frame 2 and a flexible formwork 1. The frame 2 is a rectangular box with a hollow interior and is made of a reinforced fiber composite board. The width of the reinforced fiber composite board is 200-300 mm and the thickness is 20-30 mm. Grouting holes 3 are provided on the frame 2. The flexible formwork 1 wraps the frame 2 as a whole. The flexible formwork 1 is made of double-layer high-strength fiber cloth. The use of this material can improve the stress deformation effect of the flexible formwork 1.

[0033] The frame 2 is filled with a sealed filling material, which is one of HBMD12 / 4-22S mining concrete, high-performance self-compacting concrete or polymer foam material; multiple repair balls 7 are evenly distributed in the sealed filling material; the repair balls 7 are made of glass, ceramic or polymer material, with a wall thickness of 1 to 5 mm, wherein the wall thickness of both sides of the interlayer 8 is 1 to 2 mm; the mass ratio of the polymer mixed swelling colloid material to water in each repair ball 7 is 1:3;

[0034] like Figure 3 As shown, the repair ball 7 is a brittle sphere, and its internal cavity is a three-layer structure, the middle layer is an interlayer 8, the interlayer 8 is filled with water, and the other two layers are filled with polymer composite swelling colloid materials;

[0035] The frame 2 and the two sides of the flexible formwork 1 are vertically fixed to the tunnel surrounding rock through multiple anchor bolts 4 and support plates 6, so that the supporting wall body supports the tunnel. This arrangement can ensure that the supporting wall and the tunnel surrounding rock are closely fitted, further improving the supporting effect of the supporting wall on the tunnel.

[0036] The method for using the above-mentioned coal mine gob-side lane retaining support wall with self-repairing function comprises the following specific steps:

[0037] A. Wrap the flexible formwork 1 outside the frame 2. After completion, use anchor bolts 4 and support plates 6 to pass through the frame 2 and the flexible formwork 1, and vertically fix both sides of the two on the surrounding rock of the tunnel;

[0038] B. Plant reinforcement at the top and bottom of the flexible formwork 1 so that the reinforcement 5, the wall support and the surrounding rock form a whole;

[0039] C. Prepare a plurality of repair balls 7, and fill water in the interlayer 8 of each repair ball 7, and fill the other two layers of the repair ball 7 with a polymer composite swelling colloid material 10, and then prepare a sealing filling material, put a plurality of repair balls 7 into the sealing filling material and mix them, so that each repair ball 7 is evenly distributed in the sealing filling material;

[0040] D. Connect the grouting hole 3 of the frame 2 to one end of the pipeline, and connect the other end of the pipeline to the grouting machine, put the sealing filling material and the repair ball 7 mixture in step C into the grouting machine, start the grouting machine to fill the inside of the frame 2 with the sealing filling material and the repair ball 7 mixture, then disconnect the pipeline and seal the grouting hole. After the sealing filling material solidifies, apply pre-tightening force to the frame 2 and the flexible formwork 1 through the anchor bolt 4 and the support plate 6, so that the supporting wall and the surrounding rock of the tunnel are pressed and fixed;

[0041] E. During the process of supporting the tunnel by the supporting wall, when the tunnel experiences excavation and multiple strong mining activities, the tunnel will deform and exert ground stress on the supporting wall to squeeze it. If the ground stress is small, the supporting wall can offset the ground stress exerted by the tunnel through the deformation of the flexible template 1. If the ground stress is large, the frame 2 of the supporting wall and the solidified sealing filling material will directly bear the pressure. When the stress exceeds the limit value, the sealing filling material will be displaced due to the stress, and cracks will be generated. Since the repair balls are evenly distributed inside the sealing filling material, the repair balls 7 at the cracks are affected. The force causes the crack to break, so that the water inside the interlayer 8 and the polymer composite swellable colloid material 10 in the other two layers flow out from the repair ball 7, and then the polymer composite swellable colloid material 10 and water are mixed. After mixing, the polymer composite swellable colloid material 10 absorbs water and swells to become a polymer composite swellable colloid, which is an elastic gel. Then the polymer composite swellable colloid flows along the crack to fill and bind the crack. After the water in the polymer composite swellable colloid evaporates and is oxidized by air, it solidifies into dry glue to achieve bonding and reinforcement of the crack, completing the repair work of the crack generated this time;

[0042] F. When the supporting wall is subjected to greater stress again and new cracks are generated, the repair balls around the cracks will break and the crack repair process in step E will be repeated, thereby effectively extending the service life of the supporting wall.

[0043] The above-mentioned anchor bolts 4, support plates 6, steel bars 5 and grouting machines are all existing equipment or components, and the reinforced fiber composite plates, high-strength fiber cloths, and polymer composite swellable colloid materials 10 are all existing materials. Among them, the polymer composite swellable colloid materials 10 are currently commonly used in the prevention and control of spontaneous combustion of coal underground, mainly including comprehensive fire prevention and extinguishing technologies and measures such as blocking air leakage along goafs, spraying to cover coal residues in goafs, and closing connecting tunnels.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A coal mine gob retaining wall with self-repairing function, characterized in that: Including the main body of the retaining wall; The supporting wall body includes a frame and a flexible formwork. The frame is a rectangular box with a hollow interior and is made of a reinforced fiber composite board. Grouting holes are provided on the frame, and the flexible formwork wraps the frame as a whole. The frame is filled with a sealed filling material, and a plurality of repair balls are evenly distributed in the sealed filling material; The repair ball is a brittle sphere, and its internal cavity is a three-layer structure, the middle layer is an interlayer filled with water, and the other two layers are filled with polymer composite swelling colloid materials; The frame and the flexible formwork are fixed on the surrounding rock of the tunnel through a plurality of anchor bolts and supporting plates, so that the supporting wall body supports the tunnel.

2. The coal mine gob-side entry retaining support wall with self-repairing function according to claim 1 is characterized in that: The flexible template is made of double-layer high-strength fiber cloth.

3. The coal mine gob-side entry retaining support wall with self-repairing function according to claim 1, characterized in that: The enclosed filling material is one of HBMD12 / 4-22S type mining concrete, high-performance self-compacting concrete or polymer foam material.

4. The coal mine gob-side entry retaining support wall with self-repairing function according to claim 1, characterized in that: The repair ball is made of glass, ceramic or polymer material, with a wall thickness of 1 to 5 mm, wherein the wall thickness on both sides of the interlayer is 1 to 2 mm; the mass ratio of the polymer composite swollen colloid material to water in each repair ball is 1:

3.

5. The coal mine gob-side entry retaining support wall with self-repairing function according to claim 1, characterized in that: The reinforced fiber composite plate has a width of 200 to 300 mm and a thickness of 20 to 30 mm.

6. The coal mine gob-side entry retaining support wall with self-repairing function according to claim 1, characterized in that: The frame and both sides of the flexible formwork are vertically fixed on the surrounding rock of the tunnel.

7. A method for using the coal mine gob-side entry retaining support wall with self-repairing function according to any one of claims 1 to 6, characterized in that: The specific steps are: A. Wrap the flexible formwork outside the frame. After completion, use anchor bolts and support plates to pass through the frame and the flexible formwork, and fix both sides of the two vertically on the surrounding rock of the tunnel; B. Carry out reinforcing bar construction at the top and bottom of the flexible formwork to make the steel bars, wall support and surrounding rock form a whole; C. Prepare multiple repair balls, and fill water in the interlayer of each repair ball, and fill the other two layers of the repair ball with a polymer composite swelling colloid material, then prepare a sealing filling material, put multiple repair balls into the sealing filling material and mix them, so that each repair ball is evenly distributed in the sealing filling material; D. Connect the grouting hole of the frame to one end of the pipeline, and connect the other end of the pipeline to the grouting machine, put the sealing filling material and the repair ball mixture in step C into the grouting machine, start the grouting machine to fill the inside of the frame with the sealing filling material and the repair ball mixture, then disconnect the pipeline and seal the grouting hole. After the sealing filling material solidifies, apply pre-tightening force to the frame and the flexible formwork through the anchor bolts and the support plate to press and fix the supporting wall and the surrounding rock of the tunnel; E. During the process of supporting the tunnel with the supporting wall, when the tunnel experiences excavation and multiple strong mining activities, the tunnel will deform and exert ground stress on the supporting wall to squeeze it. If the ground stress is small, the supporting wall can offset the ground stress exerted by the tunnel through the deformation of the flexible template. If the ground stress is large, the frame of the supporting wall and the solidified sealing filling material will directly bear the pressure. When the stress exceeds the limit value, the sealing filling material will be displaced due to the stress, and cracks will be generated. Since the repair balls are evenly distributed inside the sealing filling material, the repair balls at the cracks will be The ball is broken by the force, so that the water inside the interlayer and the high molecular weight mixed swelling colloid material in the other two layers flow out from the repair ball, and then the high molecular weight mixed swelling colloid material and water are mixed. After mixing, the high molecular weight mixed swelling colloid material absorbs water and swells to become a high molecular weight mixed swelling colloid, which is an elastic gel. Then, the high molecular weight mixed swelling colloid flows along the crack to fill and bind the crack. After the water content of the high molecular weight mixed swelling colloid evaporates and is oxidized by air, it solidifies into dry glue to bind and bind the crack, thus completing the repair work of the crack generated this time. F. When the supporting wall is subjected to greater stress again and new cracks are generated, the repair balls around the cracks will break and the crack repair process in step E will be repeated, thereby effectively extending the service life of the supporting wall.

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