Coal pillar dam body reinforcing method

Abstract

The invention provides a coal pillar dam body reinforcing method. The coal pillar dam body reinforcing method comprises the steps that S1, drilling positioning is conducted on the to-be-reinforced surface of a coal pillar dam body, and drilling operation is conducted after drilling positioning is completed; s2, an anchor rod or an anchor cable is put into the drilled hole; s3, a plurality of lattice beams are poured on the surface to be reinforced, so that the two ends of each lattice beam extend to the two adjacent holes; s4, anchor heads are installed at the holes, grouting holes communicating with the holes are reserved in the anchor heads, and grouting is conducted in the holes through the grouting holes; and S5, net hanging and concrete spraying are conducted on the upstream face of the coal pillar dam body. The problem that in the prior art, a coal pillar dam body reinforcing method cannot meet the use requirement of a user is effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of coal pillar dam reinforcement of underground water reservoirs in coal mines, and in particular to a coal pillar dam reinforcement method. Background Art

[0002] At present, the coal pillar dam of underground reservoirs is not only the bearing body of the overlying rock strata, but also the water retaining dam of the reservoir. Therefore, the coal pillar dam body must have extremely high bearing capacity and anti-seepage performance. Since the service life of underground reservoirs is usually one to twenty years or even longer, during the service life of the reservoir, as coal mines are mined and the overlying rock strata move, the coal pillar dam body must have long-term reliability and the ability to adapt to the deformation of the overlying rock strata.

[0003] In the prior art, the reinforcement measures for the coal pillar dam body are usually to reserve thick coal pillars and set up concrete walls at certain locations to ensure the long-term safety of the coal pillar dam body. However, since most coal rocks are soft rocks with low strength, the coal pillar dam body is in a unidirectional pressure-bearing state, resulting in limited bearing capacity. In addition, the coal rock itself contains many primary cracks. Under the influence of mining disturbances, not only the strength of the coal pillar dam body decreases, but the permeability is also enhanced, increasing the risk of instability of the coal pillar dam body. In addition, although the local concrete wall in the mining area can play a role in reinforcing the coal pillar dam body and improving the bearing capacity within a certain range, the construction of the concrete wall will destroy the overall stability of the coal pillar dam body. Although the concrete wall has high strength and high rigidity, when the overlying rock strata move, it will cause stress concentration in the concrete wall and induce brittle failure of the concrete wall. In addition, the stress-strain incoordination and cracking are prone to occur at the connection with the coal pillar dam body. These will bury hidden dangers for the safety of the reservoir dam body.

[0004] Therefore, the coal pillar dam reinforcement method in the prior art has the following deficiencies: First, the segmented reinforcement method requires the removal of the coal pillar dam and the use of concrete wall reinforcement, which has high construction intensity and will cause secondary damage to the coal pillar dam; Second, the unreinforced coal pillar dam is in a uniaxial compressive state, and the thickness of the coal pillar dam must be increased to effectively improve the bearing capacity, which will lead to a waste of coal resources; Third, although the concrete wall reinforcement has high rigidity and strength, it has weak deformation ability to adapt to the movement of the overlying rock strata and is prone to brittle failure, which is not conducive to the long-term service of the coal pillar dam. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for reinforcing a coal pillar dam body, so as to solve the problem that the method for reinforcing a coal pillar dam body in the prior art cannot meet the needs of users.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a method for reinforcing a coal pillar dam, comprising: step S1: drilling positioning on the surface to be reinforced of the coal pillar dam, and performing drilling operation after completing the drilling positioning; step S2: placing anchor rods or anchor cables into the holes after the drilling is completed; step S3: pouring a plurality of lattice beams on the surface to be reinforced so that the two ends of each lattice beam extend to two adjacent holes; step S4: installing anchor heads at the holes, and reserving grouting holes on the anchor heads that are connected to the holes, and grouting into the holes through the grouting holes; step S5: hanging a mesh and spraying concrete on the water-facing surface of the coal pillar dam.

[0007] Furthermore, in step S1, after the drilling operation is completed, the coal pillar dam reinforcement method further includes: cleaning debris in the hole.

[0008] Further, in step S2, after the anchor rod or anchor cable is placed into the hole, the length of the portion of any end of the anchor rod or anchor cable located outside the hole is greater than or equal to 0.5 m.

[0009] Furthermore, the coal pillar dam reinforcement method also includes step S1 located between step S1 and step S2: obtaining the thickness of the coal pillar dam and the reinforcement strength requirement value; if the reinforcement strength requirement value is less than the preset strength value or the thickness of the coal pillar dam is less than 10m, then selecting anchor rods to be placed in the holes after drilling is completed; if the reinforcement strength requirement value is greater than or equal to the preset strength value or the thickness of the coal pillar dam is greater than or equal to 10m, then selecting anchor cables to be placed in the holes after drilling is completed.

[0010] Furthermore, the coal pillar dam reinforcement method further includes step S20 located between step S2 and step S3: obtaining the size of the lattice beam according to the force requirements and determining whether reinforcement needs to be installed, and nailing steel rods into the surface to be reinforced.

[0011] Furthermore, the method for casting a plurality of lattice beams on a surface to be reinforced comprises: step S61: installing a lattice beam formwork at each hole along the longitudinal and transverse directions of the surface to be reinforced; step S62: installing a steel cage inside the lattice beam so that the steel cage is connected to the anchor head; step S63: pouring concrete to form the lattice beam; step S64: removing the lattice beam formwork after at least two weeks.

[0012] Furthermore, in step S63, during the concrete pouring process, steel bar joints are reserved at both ends of the lattice beam; before the construction of two adjacent sections of lattice beams, the end faces of each lattice beam are roughened and wetted with water.

[0013] Further, in step S4, the method of installing the anchor head at the eyelet includes: machining a circular hole in the anchor head and installing the steel cage in the circular hole; or, installing a steel plate in the anchor head to cover the steel cage and connect the steel cage.

[0014] Furthermore, in step S4, before grouting into the hole, the coal pillar dam reinforcement method further includes: tensioning the anchor rod or anchor cable along both ends of the anchor rod or anchor cable respectively until the tension stress in the anchor rod or anchor cable reaches a preset stress value.

[0015] Furthermore, the method of performing mesh spraying on the water-facing surface of the coal pillar dam body includes: step S51: inserting steel nails into the mesh and the water-facing surface, and removing loose blocks on the water-facing surface; step S52: wetting the water-facing surface; step S53: spraying concrete.

[0016] By applying the technical solution of the present invention, when it is necessary to reinforce the coal pillar dam, first, drilling positioning is performed on the surface of the coal pillar dam to be reinforced, and drilling operation is performed after the drilling positioning is completed; secondly, anchor rods or anchor cables are placed in the holes after the drilling is completed, and multiple lattice beams are cast on the surface to be reinforced so that the two ends of each lattice beam extend to two adjacent holes; thirdly, anchor heads are installed at the holes, and grouting holes connected to the holes are reserved on the anchor heads, and grouting is injected into the holes through the grouting holes; finally, mesh spraying is performed on the water-facing surface of the coal pillar dam. In this way, through the coal pillar dam reinforcement method in this application, the coal pillar dam can be transformed from a unidirectional pressure state to a three-directional pressure state, thereby improving the compressive capacity of the coal pillar dam, and reducing or even eliminating the need to use concrete walls, thereby reducing the removal of the coal pillar dam. At the same time, the above-mentioned coal pillar dam reinforcement method effectively improves the adaptability of the coal pillar dam to the deformation of the overlying rock strata, avoids stress concentration and brittle failure on the coal pillar dam, plays an important role in improving the strength and service reliability of the coal pillar dam, and solves the problem that the reinforcement method of the coal pillar dam in the existing technology cannot meet the user's needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A cross-sectional view of a coal pillar dam according to an embodiment of a method for reinforcing a coal pillar dam according to the present invention is shown;

[0019] Figure 2 Shows Figure 1 Diagram of the reinforcement method on the water-facing surface of the coal pillar dam in the coal pillar dam reinforcement method.

[0020] The above drawings include the following reference numerals:

[0021] 1. Coal pillar dam body; 3. Holes; 4. Anchor rods or anchor cables; 5. Lattice beams; 6. Anchor heads; 7. Lattice beam formwork; 8. Grouting holes; 9. Cement mortar or preservatives; 11. Water-facing surface. DETAILED DESCRIPTION

[0022] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0023] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0024] In the present invention, unless otherwise specified, the directional words used, such as "up" and "down", usually refer to the directions shown in the drawings, or to the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "left" and "right" usually refer to the left and right shown in the drawings; "inside" and "outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0025] In order to solve the problem that the reinforcement method for coal pillar dam in the prior art cannot meet the needs of users, the present application provides a method for reinforcing a coal pillar dam.

[0026] like Figure 1 and Figure 2 As shown in the figure, the coal pillar dam reinforcement methods include:

[0027] Step S1: drilling positioning is performed on the surface to be reinforced of the coal pillar dam body 1, and drilling operation is performed after the drilling positioning is completed;

[0028] Step S2: placing the anchor rod or anchor cable 4 into the hole 3 after drilling;

[0029] Step S3: casting a plurality of lattice beams 5 on the surface to be reinforced so that both ends of each lattice beam 5 extend to two adjacent holes 3;

[0030] Step S4: installing the anchor head 6 at the hole 3, reserving a grouting hole 8 on the anchor head 6 to communicate with the hole 3, and injecting grout into the hole 3 through the grouting hole 8;

[0031] Step S5: spraying concrete on the water-facing surface 11 of the coal pillar dam body 1 with a mesh.

[0032] By applying the technical solution of this embodiment, when it is necessary to reinforce the coal pillar dam, first, drilling positioning is performed on the surface of the coal pillar dam to be reinforced, and drilling is performed after the drilling positioning is completed; secondly, anchor rods or anchor cables are placed in the holes after the drilling is completed, and multiple lattice beams are cast on the surface to be reinforced so that the two ends of each lattice beam extend to two adjacent holes; thirdly, anchor heads are installed at the holes, and grouting holes connected to the holes are reserved on the anchor heads, and grouting is injected into the holes through the grouting holes; finally, mesh spraying is performed on the water-facing surface of the coal pillar dam. In this way, through the coal pillar dam reinforcement method in this embodiment, the coal pillar dam can be transformed from a unidirectional pressure state to a three-directional pressure state, thereby improving the compressive capacity of the coal pillar dam, and reducing or even eliminating the need to use concrete walls, thereby reducing the removal of the coal pillar dam. At the same time, the above-mentioned coal pillar dam reinforcement method effectively improves the adaptability of the coal pillar dam to the deformation of the overlying rock strata, avoids stress concentration and brittle failure on the coal pillar dam, plays an important role in improving the strength and service reliability of the coal pillar dam, and solves the problem that the reinforcement method of the coal pillar dam in the existing technology cannot meet the user's needs.

[0033] In this embodiment, the coal pillar dam reinforcement method can change the stress state of the coal pillar dam and adapt to the rock formation deformation to a certain extent, so as to achieve the purpose of both improving the compressive resistance of the coal pillar dam itself and adapting well to the stress characteristics of the underground rock formation in the coal mine.

[0034] In this embodiment, cement mortar or preservative 9 is injected into the hole 3 through the grouting hole 8 .

[0035] In this embodiment, in step S1 , after the drilling operation is completed, the coal pillar dam reinforcement method further includes: cleaning debris in the hole 3 .

[0036] Specifically, cleaning the debris in the hole can ensure the adequacy of grouting and the smooth installation of the anchor rod or anchor cable 4, so that the grouting material can fill the hole more evenly, enhance the bonding force between the anchor rod or anchor cable 4 and the coal pillar dam body 1, and improve the overall reinforcement effect.

[0037] In this embodiment, in step S2, after the anchor rod or anchor cable 4 is placed into the hole 3, the length of the portion of any end of the anchor rod or anchor cable 4 located outside the hole 3 is greater than or equal to 0.5 m.

[0038] Specifically, the above arrangement can ensure that the anchor rod or anchor cable 4 has sufficient operating space when being tensioned, while also ensuring its stable connection with the lattice beam 5, effectively avoiding damage to the reinforcement material during the construction process, and improving the construction efficiency and safety of the project.

[0039] In this embodiment, the coal pillar dam reinforcement method further includes step S1 located between step S1 and step S2:

[0040] Obtaining the thickness and reinforcement strength requirement of the coal pillar dam body 1;

[0041] If the required reinforcement strength value is less than the preset strength value or the thickness of the coal pillar dam body 1 is less than 10m, an anchor rod is selected and placed in the hole 3 after the drilling is completed;

[0042] If the required reinforcement strength value is greater than or equal to the preset strength value or the thickness of the coal pillar dam body 1 is greater than or equal to 10 m, an anchor cable is selected and placed in the hole 3 after the drilling is completed.

[0043] Specifically, selecting reinforcement materials according to the characteristics and reinforcement requirements of the coal pillar dam body 1 can more accurately meet the reinforcement requirements of different projects, improve the reinforcement efficiency and economy, and is suitable for coal pillar dam body reinforcement projects of various scales and conditions. At the same time, the above selection strategy not only optimizes the use of reinforcement materials, but also reduces project costs, avoids material waste, and improves the economic benefits of reinforcement projects.

[0044] In this embodiment, the coal pillar dam reinforcement method further includes step S20 located between step S2 and step S3:

[0045] The size of the lattice beam 5 is obtained according to the force requirements and it is determined whether reinforcement needs to be installed, and steel rods are nailed into the surface to be reinforced.

[0046] Specifically, through accurate calculation and installation of reinforcement, the lattice beam 5 can better bear and disperse the load, improve the overall performance of the reinforced structure, and is suitable for coal pillar dam reinforcement projects with complex forces and the need to enhance the bearing capacity. In practical applications, the size and reinforcement scheme of the lattice beam 5 determined by scientific calculation can significantly improve the bearing capacity of the coal pillar dam 1, effectively disperse the load under the action of water pressure and deadweight, avoid structural damage caused by local stress concentration, and provide a guarantee for the long-term stable operation of the project.

[0047] In this embodiment, the method of casting a plurality of lattice beams on the surface to be reinforced includes:

[0048] Step S61: installing a lattice beam formwork 7 at each hole 3 along the longitudinal and transverse directions of the surface to be reinforced;

[0049] Step S62: installing a steel cage inside the lattice beam 5 so that the steel cage is connected to the anchor head 6;

[0050] Step S63: pouring concrete to form a lattice beam 5;

[0051] Step S64: Remove the lattice beam formwork 7 after at least two weeks.

[0052] Specifically, the above casting method can ensure the shape and size of the lattice beam 5 are accurate, improve its bonding strength with the coal pillar dam body 1, and is suitable for engineering scenarios that require long-term stable reinforcement effects. At the same time, removing the lattice beam template 7 after two weeks not only ensures the solidification and strength of the lattice beam 5, but also effectively avoids the continuous compression of the lattice beam template 7 on the coal pillar dam body 1, reduces potential damage to the reinforced structure, and ensures the smooth progress of the project and the convenience of later maintenance.

[0053] In this embodiment, in step S63, during the concrete pouring process, steel bar joints are reserved at both ends of the lattice beam 5; before the construction of two adjacent sections of the lattice beam 5, the end faces of each lattice beam 5 are roughened and wetted with water.

[0054] Specifically, the above arrangement can enhance the connection strength between adjacent lattice beams 5, improve the integrity and durability of the reinforced structure, and is suitable for projects that require continuous reinforcement operations, such as long-distance coal pillar dam reinforcement. At the same time, the above connection method not only improves the integrity of the reinforced structure, but also enhances its durability, effectively responds to stress changes and environmental erosion that may occur in long-distance reinforcement projects, and extends the service life of the reinforced structure.

[0055] In this embodiment, in step S4, the method of installing the anchor head at the hole 3 includes:

[0056] Process a circular hole in the anchor head 6 and install the steel cage in the circular hole; or,

[0057] A steel plate is installed in the anchor head 6 so as to cover the steel plate outside the steel cage and connect the steel cage.

[0058] Specifically, the above-mentioned anchor head installation method can ensure the firm connection between the anchor rod or anchor cable and the lattice beam 5, is suitable for the installation of various reinforcement materials, and improves the reliability of the reinforcement structure. At the same time, the above-mentioned anchor head installation method can not only ensure the tight combination of the reinforcement material and the lattice beam 5, but also effectively avoid the connection failure caused by material aging or environmental erosion, thereby improving the overall performance and reliability of the reinforcement structure.

[0059] In this embodiment, in step S4, before grouting into the hole 3, the coal pillar dam reinforcement method further includes:

[0060] The anchor rod or anchor cable 4 is tensioned along both ends of the anchor rod or anchor cable 4 until the tension stress in the anchor rod or anchor cable 4 reaches a preset stress value.

[0061] Specifically, the tensioning operation of the anchor rod or anchor cable 4 can ensure the prestressed state of the anchor rod or anchor cable 4 in the reinforced structure, improve its bearing capacity and anti-deformation ability, and is suitable for reinforcement projects that need to enhance tensile strength. At the same time, through prestressed tensioning, the anchor rod or anchor cable 4 can better resist the tensile force under the action of water pressure and deadweight, improve the overall tensile performance of the reinforced structure, effectively prevent the deformation and damage of the coal pillar dam body 1, and provide a guarantee for the safe operation of the project.

[0062] In this embodiment, the method of spraying concrete on the water-facing surface of the coal pillar dam body 1 includes:

[0063] Step S51: inserting steel nails into the hanging net and the water-facing surface 11, and removing loose blocks on the water-facing surface 11;

[0064] Step S52: Wetting the water-facing surface 11;

[0065] Step S53: spraying concrete.

[0066] Specifically, mesh spraying can effectively prevent water erosion and surface peeling, improve the waterproof performance and durability of the coal pillar dam body 1, and is suitable for reinforcement projects under frequent water level changes and water pressure. At the same time, the water-facing surface 11 of the coal pillar dam body after implementation not only has good waterproof performance, but also can effectively resist erosion under water level changes and water pressure, maintain the integrity and long-term stability of the reinforcement structure, and significantly improve the safety and economic benefits of the project.

[0067] In this embodiment, after the anchor rod or anchor cable 4 is tensioned, a net is hung on the water-facing surface 11 of the coal pillar dam body, and steel nails are used to ensure that the net is firmly connected to the coal pillar dam body 1, and loose blocks on the water-facing surface 11 are removed. Before spraying concrete, the coal pillar dam body 1 is first moistened to ensure the bonding effect of the sprayed anchor. Spraying concrete ensures a certain degree of impermeability, and then spraying concrete maintenance is carried out.

[0068] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0069] When the coal pillar dam needs to be reinforced, first, drilling positioning is performed on the surface of the coal pillar dam to be reinforced, and drilling is performed after the drilling positioning is completed; secondly, anchor rods or anchor cables are placed in the holes after the drilling is completed, and multiple lattice beams are cast on the surface to be reinforced so that the two ends of each lattice beam extend to two adjacent holes; thirdly, anchor heads are installed at the holes, and grouting holes connected to the holes are reserved on the anchor heads, and grouting is injected into the holes through the grouting holes; finally, mesh spraying is performed on the water-facing surface of the coal pillar dam. In this way, through the coal pillar dam reinforcement method in this application, the coal pillar dam can be transformed from a unidirectional pressure state to a three-directional pressure state, thereby improving the compressive capacity of the coal pillar dam, and reducing or even eliminating the need to use concrete walls, thereby reducing the removal of the coal pillar dam. At the same time, the above-mentioned coal pillar dam reinforcement method effectively improves the adaptability of the coal pillar dam to the deformation of the overlying rock strata, avoids stress concentration and brittle failure on the coal pillar dam, plays an important role in improving the strength and service reliability of the coal pillar dam, and solves the problem that the reinforcement method of the coal pillar dam in the existing technology cannot meet the user's needs.

[0070] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0071] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0072] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for reinforcing a coal pillar dam, characterized in that: include: Step S1: drilling positioning is performed on the surface to be reinforced of the coal pillar dam body, and drilling operation is performed after the drilling positioning is completed; Step S2: placing the anchor rod or anchor cable into the hole after drilling; Step S3: pouring a plurality of lattice beams on the surface to be reinforced so that two ends of each lattice beam extend to two adjacent holes; Step S4: installing an anchor head at the hole, reserving a grouting hole in communication with the hole on the anchor head, and injecting grout into the hole through the grouting hole; Step S5: spraying concrete with a mesh on the water-facing surface of the coal pillar dam body.

2. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: In the step S1, after the drilling operation is completed, the coal pillar dam reinforcement method further includes: Clean the holes of debris.

3. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: In step S2, after the anchor rod or anchor cable is placed into the hole, the length of the portion of any end of the anchor rod or anchor cable located outside the hole is greater than or equal to 0.5 m.

4. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: The coal pillar dam reinforcement method further comprises a step S1 located between the step S1 and the step S2: Obtaining the thickness and reinforcement strength requirement of the coal pillar dam body; If the required reinforcement strength value is less than the preset strength value or the thickness of the coal pillar dam is less than 10m, an anchor rod is selected and placed in the hole after the drilling is completed; If the required reinforcement strength value is greater than or equal to the preset strength value or the thickness of the coal pillar dam is greater than or equal to 10 m, an anchor cable is selected and placed in the hole after the drilling is completed.

5. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: The coal pillar dam reinforcement method further includes step S20 located between step S2 and step S3: The size of the lattice beam is determined according to the force requirements and whether reinforcement is needed. Steel rods are nailed into the surface to be reinforced.

6. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: The method for casting a plurality of lattice beams on the surface to be reinforced comprises: Step S61: installing lattice beam templates at each of the holes along the longitudinal and transverse directions of the surface to be reinforced; Step S62: installing a steel cage inside the lattice beam so that the steel cage is connected to the anchor head; Step S63: pouring concrete to form a lattice beam; Step S64: Remove the lattice beam formwork after at least two weeks.

7. The method for reinforcing a coal pillar dam according to claim 6, characterized in that: In step S63, during the concrete pouring process, steel bar joints are reserved at both ends of the lattice beam; before the construction of two adjacent sections of lattice beams, the end faces of each lattice beam are roughened and wetted with water.

8. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: In the step S4, the method of installing the anchor head at the eyelet includes: Processing a circular hole in the anchor head and installing the steel cage in the circular hole; or, A steel plate is installed in the anchor head so as to cover the steel plate outside the steel cage and connect the steel cage.

9. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: In the step S4, before grouting into the hole, the coal pillar dam reinforcement method further includes: The anchor rod or anchor cable is tensioned along both ends of the anchor rod or anchor cable respectively until the tension stress in the anchor rod or anchor cable reaches a preset stress value.

10. The method for reinforcing a coal pillar dam according to claim 1, characterized in that: The method for spraying concrete with mesh on the water-facing surface of the coal pillar dam body comprises: Step S51: inserting steel nails into the hanging net and the water-facing surface, and removing loose blocks on the water-facing surface; Step S52: Wetting the water-facing surface; Step S53: spraying concrete.

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