Sealing wall for goaf sealing and construction method thereof

Abstract

The invention discloses a sealing wall for goaf sealing and a construction method of the sealing wall. A first wall body, a second wall body and a filling wall body are all arranged in a goaf roadway, and the first wall body is closest to a goaf; the filling wall body is located between the first wall body and the second wall body, and the two sides of the filling wall body make contact with the first wall body and the second wall body in a pressing mode correspondingly. The first wall body and the second wall body are rigid bodies and are respectively arranged in two circles of cutting grooves in a roadway, and the filling wall body is an elastic body; an elastic material is painted at the joint of the cut and the second wall body; based on the elastic capacity of the elastic material and the elastic body, even if the brick walls and the top plate are extruded by the stress of the goaf for multiple times, the filling wall body between the two brick walls and the joint of the sealing wall and the top plate can deform along with the stress, and air leakage caused by cracks is avoided, so that the leakproofness of the goaf is ensured. And the construction cost is low, and popularization and use are convenient.

Description

Technical Field

[0001] The present invention relates to the field of gob sealing construction, and specifically relates to a sealing wall for gob sealing and a construction method thereof. Background Art

[0002] With the retreat of the working face, the mined area becomes a gob. The gob contains some residual coal. In the case of sufficient oxygen, the residual coal is prone to spontaneous combustion, which may lead to fire and explosion accidents in the gob. Moreover, toxic and harmful gases such as gas and carbon monoxide may accumulate in the gob. If these gases flow out of the gob, it will not only cause poisoning and casualties to personnel, but also may trigger gas explosion accidents. In order to prevent fresh air from flowing into the gob and toxic and harmful gases from flowing out of the gob, the gob must be sealed with a sealing wall.

[0003] Currently, the gob sealing walls are generally earth-rock bag sealing walls, brick and stone sealing walls, concrete sealing walls and filling material sealing walls. For example, in the invention patent with the application number 2023112553796 and the name: Construction method of loess-filled sealing wall and sealing wall in coal mine, the roadway is sealed by the sealing wall body and the loess-filled wall, and spraying operation is carried out at the connection, which solves the problem of poor tight contact between the sealing wall and the roof. However, the loess-filled wall may be eroded when encountering water, and its durability is poor. In the invention patent with the application number 2024112875629 and the name: A rigid-flexible combined permanent sealing structure and construction method, a rigid-flexible combined method is used for sealing treatment. First, a flexible wall is constructed to flexibly seal the roadway, and then a wall component is constructed for rigid sealing to achieve high-quality sealing of the gob. However, the construction cost provided by this invention is relatively high and it is not conducive to large-scale promotion. In addition, in the invention patent with the application number 2017104469676 and the name: Construction method of a reinforced concrete sealing wall and its application, a reinforced concrete sealing wall is mainly used to seal the gob. This method solves the problems of laborious and time-consuming construction, poor safety and reliability, high economic cost and inability to quickly and effectively contain the spread of sudden accidents of the current sealing wall. However, since the concrete sealing wall is a rigid material, it is prone to cracks under the influence of the secondary stress in the gob, resulting in air leakage.

[0004] In summary, how to provide a new sealing wall and its construction method, the sealing wall of which not only has strong mechanical properties, but also is fully sealed with the roof, and even under the influence of the secondary stress in the gob, the sealing wall can maintain its airtightness, and its construction cost is relatively low and it is convenient for popularization and use, is the research direction required by the present invention. Summary of the Invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a sealing wall for gob closure and its construction method. The sealing wall not only has strong mechanical properties, but also is fully sealed with the roof. Even under the influence of secondary stress in the gob, the sealing wall can maintain its sealing performance, and its construction cost is relatively low, which is convenient for popularization and use.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a sealing wall for gob closure, including a first wall, a second wall and a filling wall;

[0007] The first wall, the second wall and the filling wall are all arranged in the gob roadway, and the first wall is closest to the gob; the filling wall is between the first wall and the second wall, and both sides of the filling wall are in pressing contact with the first wall and the second wall respectively; the first wall and the second wall are both rigid bodies, and the filling wall is an elastic body; when the whole sealing wall is impacted by multiple stresses in the gob, the filling wall can buffer and deform, so as to ensure the sealing performance of the gob.

[0008] Further, both the first wall and the second wall are brick walls.

[0009] Further, the elastic body is formed by mixing gangue and an elastic material.

[0010] Further, the elastic material is prepared by mixing component A and component B in a mass ratio of 1:3 and reacting. Among them, component A is a semi-prepolymer, and component B is a curing agent. This elastic material is a solid and dense elastic body after consolidation. This material has strong adhesiveness with building materials such as cement and brick walls, and the material has good mechanical properties and flame retardancy.

[0011] The construction method of the above-mentioned sealing wall includes the following steps:

[0012] Step 1: Determine the location for constructing the sealing wall according to the stress distribution law of the coal and rock mass around the gob roadway;

[0013] Step 2: According to the location determined in Step 1, construct two circles of cuttings in the gob roadway at a certain distance from the surrounding coal and rock mass respectively. Each circle of cuttings is in the same cross-section as a whole, and the cross-sections where the two circles of cuttings are located are parallel to each other;

[0014] Step 3: First, build the first wall at the cutting position close to the gob, and the periphery of the first wall extends into the corresponding cutting. Then, build the second wall at the other cutting position, and the periphery of the second wall extends into the corresponding cutting. During the construction of the second wall, fill the space between the two walls with gangue, and install a grouting pipe on the second wall;

[0015] Step 4: Inject the elastic material between the two walls through the grouting pipe, so that the elastic material is mixed with the coal gangue to form a filled wall. Then, inject the elastic material through the grouting pipe to the connection between the second wall and the cut. Finally, apply the elastic material on the surface of the connection between the second wall and the cut, thus completing the construction process of the airtight wall.

[0016] Further, the position for constructing the airtight wall determined in Step 1 is specifically as follows: According to the stress distribution law, a pressure relief zone with a stress lower than the original rock stress will be formed at the edge of the goaf. The stress in the pressure relief zone is relatively small. Therefore, the position for constructing the airtight wall is selected within the pressure relief zone.

[0017] Further, the grouting pipe is a T-shaped grouting pipe, which includes a main grouting pipe and a branch grouting pipe. One end of the branch grouting pipe is connected to the side of the main grouting pipe to form a T-shaped structure. A control valve is installed on the main grouting pipe to control the on-off between the branch grouting pipe and the main grouting pipe.

[0018] Further, when the T-shaped grouting pipe is installed on the second wall in Step 3, the inlet of the main grouting pipe is located outside the second wall, and the outlet of the main grouting pipe is between the two walls, for injecting the elastic material between the two walls; the outlet of the branch grouting pipe is within the cut, for injecting the elastic material to the connection between the second wall and the cut; there are multiple T-shaped grouting pipes, and the multiple T-shaped grouting pipes are distributed along the connection between the second wall and the cut, so that the branch grouting pipes of different T-shaped grouting pipes respectively correspond to different positions of the cut.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The present invention uses coal gangue as one of the constituent materials of the filled wall during construction, which not only reduces the construction cost but also realizes the environmental protection benefit.

[0021] 2. The present invention uses the elastic material as one of the constituent materials of the filled wall to fill the airtight wall to form an elastic filled wall, and also uses the elastic material to seal between the brick wall and the cut; based on the adhesiveness of the elastic material, the elastic material forms a dense supporting body with the roof, preventing phenomena such as the roof from becoming loose, displaced, and caving, and ensuring that there is no air leakage between the airtight wall and the roof and floor; based on the elasticity of the material, even if the brick wall and the roof are repeatedly squeezed by the stress in the goaf, the filled wall between the two brick walls and the connection between the airtight wall and the roof can deform with the stress, so that there will be no cracks leading to air leakage; in this way, after the airtight wall is formed, the outside air cannot enter the goaf, the residual coal in the goaf cannot spontaneously combust due to the lack of appropriate oxygen, and the toxic and harmful gases such as gas in the goaf cannot flow out of the goaf, achieving the required airtight effect.

[0022] 3. The present invention uses gangue to fill the infilled wall, thus saving the amount of elastic material; and the elastic material used in the present invention has good durability and is not easily aged, thereby effectively solving the problems such as easy aging of the filling material and high material price commonly existing in the airtight wall of the filling material.

[0023] 4. The present invention uses a T-shaped grouting pipe for grouting, and adjusts the grouting direction by controlling the on-off between the grouting branch pipe and the grouting main pipe. It can not only grout the filling wall, but also seal the gap between the brick wall and the cut. Two different grouting directions are realized on the same grouting pipe, which also makes the construction more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the overall construction flow chart of the present invention;

[0025] Figure 2 is the side view of the airtight wall in the present invention;

[0026] Figure 3 is the front view of the airtight wall in the present invention;

[0027] Figure 4 is the perspective view of the T-shaped grouting pipe in the present invention;

[0028] Figure 5 is Figure 3 the enlarged view of the connection between the brick wall and the cut in

[0029] Figure 6 the stress distribution law diagram of the coal and rock mass around the roadway;

[0030] Figure 7 is the schematic diagram of plugging air leakage after the construction of the gob airtight wall in the present invention is completed.

[0031] In the figure: 1, roadway; 11, roof; 12, floor; 2, cut; 21, first cut; 22, second cut; 3, brick wall; 4, filling wall; 41, elastic material; 5, T-shaped grouting pipe; 511, grouting main pipe inlet; 512, grouting main pipe outlet; 513, grouting branch pipe; 514, built-in baffle; 515, switch; Ⅰ, pressure relief area; Ⅱ, stress concentration area; Ⅲ, original stress area. DETAILED DESCRIPTION OF THE INVENTION

[0032] The present invention will be further described below.

[0033] As Figure 2 and 3 shown, an airtight wall for gob airtight includes a first wall, a second wall and a filling wall 4; both the first wall and the second wall are brick walls;

[0034] The first wall, the second wall and the filling wall 4 are evenly arranged in the gob roadway 1, and the first wall is closest to the gob; the filling wall 4 is located between the first wall and the second wall, and both sides of the filling wall 4 are in close contact with the first wall and the second wall respectively; the first wall and the second wall are both rigid bodies, and the filling wall 4 is an elastic body; when the whole airtight wall is repeatedly stressed by the gob, the filling wall can buffer deformation, so as to ensure the airtightness of the gob; the elastic body is formed by mixing coal gangue and elastic material 41. The elastic material 41 is prepared by mixing component A and component B in a mass ratio of 1:3 and reacting. Among them, component A is a semi-prepolymer and component B is a curing agent. Component A includes: 70-75 parts of 1,4-phenylene diisocyanate, 18-25 parts of polytetrahydrofuran, and 0.5-1.5 parts of waste phosphoric acid. Component B includes: 7-10 parts of diethyl toluene diamine, 48-55 parts of slag powder, 35-42 parts of diisodecyl adipate, and 3-5 parts of calcium oxide. This elastic material 41 is a solid and dense elastic body after consolidation. This material has strong adhesiveness with building materials such as cement and brick walls, and the material has good mechanical properties and flame retardant properties. The specific properties are shown in Table 1;

[0035] Table 1 Mechanical Property Test Table of Elastic Material

[0036] Test Items Specific Values Tensile Strength (MPa) 5.2 Compressive Strength (MPa) 8.1 Shear Strength (MPa) 3.3 Adhesive Strength (MPa) 3.9 Solid Content (wt%) 98.6 Bubble Content in the Finished Product after Curing (%) ＜2.7％ Elongation at Break (%) 790 Limiting Oxygen Index (LOI) 28.3

[0037] As Figure 1 shown, the construction method of the above airtight wall includes the following steps:

[0038] Step 1: Determine the location of the airtight wall construction according to the stress distribution law of the coal and rock mass around the gob roadway. Specifically: As Figure 6 shown, a pressure relief zone with a stress lower than the original rock stress will be formed at the edge of the gob. The stress in the pressure relief zone is relatively small. In order to further reduce the stress on the airtight wall and the coal and rock mass around it, the airtight wall should be set within the range of the ultimate equilibrium zone in the pressure relief zone; according to the calculation formula of the width X0 of the ultimate equilibrium zone, the construction location of the airtight wall is obtained; the calculation formula of the width x0 of the ultimate equilibrium zone is:

[0039]

[0040] In the formula: m is the coal seam thickness, m; λ is the lateral pressure coefficient; K is the stress concentration coefficient; H is the burial depth, m; is the internal friction angle of the coal body, °; C is the cohesion of the coal body, MPa; P is the binding force of the support on the coal wall direction, MPa.

[0041] Even within the range of the ultimate equilibrium zone, the roof may still experience phenomena such as loosening, displacement, and caving. After injecting the elastic material 4, the material adheres tightly to the roof, forming a dense supporting body. Due to the elasticity and good mechanical properties of the material itself, the dense supporting body formed between the material and the roof will not experience loosening, displacement, or caving under the influence of the stress in the goaf.

[0042] Step 2: According to the positions determined in Step 1, two circles of cuttings 2 are constructed in the surrounding coal and rock masses at a certain distance apart in the goaf roadway, namely the first cutting 21 and the second cutting 22. Each circle of cuttings 2 is entirely within the same cross-section, and the cross-sections where the two circles of cuttings are located are parallel to each other.

[0043] Step 3: First, a first wall is constructed at the position of the first cutting 21, and the periphery of the first wall extends into the first cutting 21. Then, a second wall is constructed at the position of the second cutting 22, and the periphery of the second wall extends into the second cutting 22. During the construction of the second wall, the space between the two walls is filled with coal gangue. As Figure 4 shown, the grouting pipe is a T-shaped grouting pipe, which includes a grouting main pipe and a grouting branch pipe 513. One end of the grouting branch pipe 513 is connected to the side of the grouting main pipe to form a T-shaped structure. A control valve is installed on the grouting main pipe to control the on-off between the grouting branch pipe 513 and the grouting main pipe. When the T-shaped grouting pipe is installed in the second wall, the inlet 511 of the grouting main pipe is located outside the second wall, and the outlet 512 of the grouting main pipe is located between the two walls, for injecting the elastic material 4 between the two walls; the outlet of the grouting branch pipe 513 is located in the second cutting 22, for injecting the elastic material 4 into the connection between the second wall and the second cutting 22. As Figure 3 shown, there are multiple T-shaped grouting pipes, and the multiple T-shaped grouting pipes are distributed along the connection between the second wall and the second cutting 22, so that the grouting branch pipes of different T-shaped grouting pipes respectively correspond to different positions of the second cutting 22.

[0044] Step 4: First, use the control valve to disconnect the grouting branch pipe 513 from the grouting main pipe. At this time, only the inside of the grouting main pipe is connected. Inject the elastic material 4 between the two walls through the T-shaped grouting pipe, so that the elastic material 4 is mixed with the coal gangue to form a filling wall. After grouting, use the control valve to connect the grouting branch pipe 513 to the grouting main pipe. At this time, the elastic material 4 in the grouting main pipe is injected into the connection between the second wall and the second cutting 22. As Figure 5 shown, stop when the elastic material 4 can no longer be injected. Finally, apply the elastic material 4 on the surface of the connection between the second wall and the second cutting 22, thus completing the construction process of the airtight wall. As Figure 7 shown.

[0045] The above control valve can be implemented by any existing valve opening and closing mechanism. In this embodiment, the following existing structure is adopted, which includes a built-in baffle 514 and a switch 515. The built-in baffle 514 is closely attached to the inner wall of the grouting main pipe. There is a semi-circular cut on the pipe wall of the grouting main pipe, and the cut is located directly above the pipe wall. The switch 515 is outside the grouting main pipe, and its lower end extends into the grouting main pipe through the cut and is connected to the built-in baffle 514. Moreover, the width of its upper end is greater than the width of the cut, so that the switch 515 is attached to the outer wall of the grouting pipe and covers the cut to prevent the slurry from flowing out of the cut during grouting. Rotate the switch 515 along the cut, so that the built-in baffle 514 originally below the pipe wall synchronously rotates to the upper part, thereby blocking the connection between the grouting branch pipe 513 and the grouting main pipe. The switch 515 is used to control the blocking and opening of the connection between the built-in baffle 514 and the grouting main pipe and the grouting branch pipe 513, so as to realize the on-off between the grouting branch pipe 513 and the grouting main pipe.

[0046] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and retouches can be made, and these improvements and retouches should also be regarded as the protection scope of the present invention.

Claims

1. A sealed wall for gob sealing, characterized in that, It includes a first wall, a second wall and a filling wall; The first wall, the second wall and the filling wall are evenly arranged in the gob roadway, and the first wall is closest to the gob; the filling wall is between the first wall and the second wall, and both sides of the filling wall are in close contact with the first wall and the second wall respectively; the first wall and the second wall are both rigid bodies, and the filling wall is an elastic body; when the whole airtight wall is subjected to multiple stress impacts in the gob, the filling wall can buffer deformation, so as to ensure the airtightness of the gob.

2. The airtight wall for gob sealing according to claim 1, characterized in that, Both the first wall and the second wall are brick walls.

3. The airtight wall for gob sealing according to claim 1, characterized in that, The elastic body is formed by mixing gangue and an elastic material.

4. The airtight wall for goaf sealing according to claim 3, characterized in that, The elastic material is prepared by mixing component A and component B in a mass ratio of 1:3 and reacting, wherein component A is a semi-prepolymer and component B is a curing agent.

5. A construction method of the airtight wall according to any one of claims 1 to 4, characterized in that, It includes the following steps: Step 1: Determine the location for constructing the airtight wall according to the stress distribution law of the coal and rock mass around the gob roadway; Step 2: According to the location determined in Step 1, construct two circles of cuttings in the gob roadway at a certain distance from the surrounding coal and rock mass respectively. Each circle of cuttings is in the same cross-section as a whole, and the cross-sections where the two circles of cuttings are located are parallel to each other; Step 3: First, build the first wall at the cutting position close to the gob, and the periphery of the first wall extends into the corresponding cutting. Then, build the second wall at the other cutting position, and the periphery of the second wall extends into the corresponding cutting. During the construction of the second wall, fill the space between the two walls with gangue, and install a grouting pipe on the second wall; Step 4: Inject the elastic material between the two walls through the grouting pipe, so that the elastic material is mixed with the gangue to form a filling wall. Then, inject the elastic material through the grouting pipe to the connection between the second wall and the cutting. Finally, coat the surface of the connection between the second wall and the cutting with the elastic material, thus completing the construction process of the airtight wall.

6. The construction method according to claim 5, wherein The location for constructing the airtight wall determined in Step 1 is specifically as follows: According to the stress distribution law, a pressure-relief zone with a stress lower than the original rock stress will be formed at the edge of the gob. The stress in the pressure-relief zone is relatively small, so the location for constructing the airtight wall is selected in the pressure-relief zone.

7. The construction method according to claim 5, characterized in that, The grouting pipe is a T-shaped grouting pipe, which includes a grouting main pipe and a grouting branch pipe. One end of the grouting branch pipe is connected to the side of the grouting main pipe to form a T-shaped structure. A control valve is installed on the grouting main pipe to control the on-off between the grouting branch pipe and the grouting main pipe.

8. The construction method according to claim 7, characterized in that, When the T-shaped grouting pipe is installed on the second wall in Step 3, the inlet of the grouting main pipe is outside the second wall, and the outlet of the grouting main pipe is between the two walls, for injecting the elastic material between the two walls; the outlet of the grouting branch pipe is in the cutting, for injecting the elastic material to the connection between the second wall and the cutting; there are multiple T-shaped grouting pipes, and the multiple T-shaped grouting pipes are distributed along the connection between the second wall and the cutting, so that the grouting branch pipes of different T-shaped grouting pipes respectively correspond to different positions of the cutting.

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