A construction method for coal pillar-free mining along the roadway with retaining wall in thick coal seams with large inclination angle

Abstract

The invention discloses a construction method for coal pillar-free mining along a lane with a thick coal seam with a large inclination angle, comprising the following steps: step 1: excavating a transport chute for a production return working face in the coal seam, and reserving a wall space for casting a soft film concrete wall on the side of the next production return working face; step 2: arranging a model in the reserved wall space in the transport chute and casting the soft film concrete wall; step 3: drilling a top cut pressure relief hole in a roof 0.5 meters away from the soft film concrete wall in the transport chute; step 4: during mining, charging and blasting the top cut pressure relief hole closely following the mining face, so that a crack is formed between the goaf and the unmined area, so as to facilitate the timely collapse of the roof; step 5: after mining, the roof collapses along the top cut pressure relief hole; step 6: excavating a return air chute for a production return working face along the other side of the soft film concrete wall; step 7: excavating a transport chute at the next production return working face, and reserving a wall space for casting a soft film concrete wall on the side of the next production return working face.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, in particular to a construction method for coal pillar-free mining in a thick coal seam with a large inclination along a tunnel with a retained wall. Background Art

[0002] my country's coal production mostly adopts a longwall mining method of comprehensive mining. The comprehensive mining face is arranged with two super-long tunnels, and two tunnels are excavated to pull the comprehensive mining face. However, most of the horizontal tunnels in the mining area have long been using tunnel protection coal pillars to protect the tunnels. The width of the tunnel protection coal pillars is generally 10-30 meters. The use of tunnel protection coal pillars to protect the tunnels will cause a large loss of coal resources, generally accounting for about 5-15% of the total coal resources in the mine. At this stage, with the continuous increase in the mining depth of the mine, the original rock stress also increases, and the width of the tunnel protection coal pillar must exceed 30 meters. In this way, not only the coal recovery rate is reduced, but the energy of the top and bottom pressure is also very huge, the difficulty of tunnel maintenance increases, and the stress formed by the wider coal pillars protecting the tunnel after the working face is mined is relatively concentrated, making the maintenance of the tunnel arranged at the next working face more difficult. In the case of high-gas mines or highly spontaneous combustion coal seam mines, there may even be phenomena such as excessive gas concentration and increased risk of coal seam spontaneous combustion, which increases the danger of underground operations and causes additional safety costs.

[0003] In order to increase the exploitable amount of coal resources and to safely and effectively recover coal pillars without retaining them, there are generally two types of coal pillar-free mining: one is to drive the roadway along the goaf, and the other is to leave the roadway along the goaf. Due to the changes in the spatial position and time relationship between the roadway and the coal mining face, the movement of the overlying strata and the distribution of the supporting pressure caused by mining in the roadway along the goaf and the roadway along the goaf are different, resulting in a great difference in the deformation and maintenance of the surrounding rock of the roadway.

[0004] In order to recover the coal pillars for protecting the lanes in the traditional mining method, the concrete wall or other material wall is cast along the edge of the goaf behind the coal mining face to replace the coal pillars for protecting the lanes. Then, through certain technical means, the drift of the previous section is re-supported and left for the next section. This method is difficult to construct and difficult to implement when the production height exceeds 3.5 meters, the speed of the comprehensive mining face is fast, and the inclination angle is greater than 12 degrees. In the case of sudden pressure from the roof, excessive pressure on the roof, and too long compression time, cracks will appear in the concrete wall, and local collapse will occur over time, and then slowly lose the pressure-bearing function. In other words, if the production height is too thick, the recovery speed is too fast, the inclination angle is too large, the roof is too hard, the bottom plate is too soft, and the mining depth is too large, it will restrict the construction effect of the goaf-retained lane.

[0005] The tunneling along the goaf must be excavated after the adjacent working face is mined and the rock strata in the goaf are generally stable. This creates many difficulties for mining and excavation, especially in the fully mechanized mining face with a faster advancement speed. In order to ease the tension between mining and excavation, the working face skipping arrangement is often adopted. Skipping mining leads to a large number of isolated working faces, which makes tunnel maintenance more difficult.

[0006] This method has great safety risks, slow construction progress and high construction costs. Even if the weight of large steel is increased and the distance between sheds is reduced, it is still difficult to maintain the stability of the remaining tunnels. In many complex geological conditions, coal seam tunnels are severely deformed and the supports are seriously damaged when the first working face is advanced. Some coal mines use large-section heavy U-shaped steel support and backfill technology to realize goaf-side tunneling, which will increase the cost per ton of coal and reduce economic benefits.

[0007] The best method of coal pillar-free mining now is to implement coal pillar-free mining by leaving lanes along the goaf, thereby replacing the coal pillars protecting the goaf with concrete walls. During the mining process, the goaf-leaving lanes along the edge of the goaf use reinforced concrete, dense pillars and other methods to maintain the transportation chute of the upper section, leaving it for the return air chute of the lower section, but this method is only suitable for production heights below 3.5 meters and has the best effect. This method is not effective for high production, production heights above 3.5 meters or too large an inclination angle, and has huge safety hazards. In addition, if the construction scheduling is unreasonable or the project progress is not coordinated, it will cause great harm to construction safety. In addition, the concrete wall has a limited time to withstand pressure, which to a certain extent also affects the progress of mining work and increases construction safety risks.

[0008] Improving the coal recovery rate of coal enterprises and implementing pillar-free mining will not only extend the life of the mine and improve social benefits, but also increase the scientific and technological level of production mines, ease the mining and excavation relationship, and improve safe construction conditions.

[0009] Therefore, a construction method for coal pillar-free mining in thick coal seams with large inclination angles along the roadway with retained walls is provided to solve the current shortcomings. Summary of the invention

[0010] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned technology and provide a construction method for coal pillar-free mining along the lane retaining wall in a thick coal seam with a large inclination angle.

[0011] In order to solve the above technical problems, the technical solution provided by the present invention is a construction method for coal pillar-free mining along the roadway with retaining wall in a thick coal seam with a large dip angle, comprising the following steps:

[0012] Step (1): when excavating a transport drift of a return working face in a coal seam, a wall space for pouring a flexible film concrete wall is reserved on the side of the next return working face;

[0013] Step (2): Arrange the model in the wall space reserved in the transport chute and pour the soft film concrete wall; when encountering a hard bottom plate of the coal seam, lay a 30~50cm arc-shaped sand pile or coal gangue pile at the bottom of the mold; when encountering a soft bottom plate of the coal seam, dig 30~50cm below the bottom of the soft film wall before hanging the soft film and then arrange the model;

[0014] Step (3): drilling a top-cutting pressure relief hole in the top plate at a position 0.5 m away from the flexible membrane concrete wall in the transport chute;

[0015] Step (4): During mining, explosives are charged and blasted at the top pressure relief holes immediately following the mining surface, so that cracks are formed between the goaf and the unmined area, facilitating the timely collapse of the roof to reduce the pressure on the soft film concrete wall;

[0016] Step (5): After mining, the roof collapses along the top cut pressure relief hole;

[0017] Step (6): excavating a return air chute for the return production working face along the other side of the flexible membrane concrete wall;

[0018] Step (7): excavating a transport trench at the next return working face, and reserving a wall space for pouring a flexible film concrete wall at the next return working face;

[0019] Step (8): Repeat the above steps.

[0020] As an improvement, in step (4), blasting is performed at the top cut pressure relief hole to cause the roof above the mined coal seam to collapse.

[0021] Compared with the prior art, the advantages of the present invention are: 1. It is conducive to improving the output and work efficiency and centralizing the production; while achieving high output and high efficiency, it reduces the loss of coal pillars and improves the resource recovery rate;

[0022] It makes up for the restrictive defects of many gob-side tunnels in high-yield mines, thick coal seams, complex geological conditions, etc., and is not affected by ventilation, thereby increasing the safety of mining work and is not affected by the mining progress. The construction method is safe, simple, efficient and reliable;

[0023] Different model layout plans are formulated according to the hardness and softness of the coal seam floor, which increases the applicability of this method. The deposits under the hard floor mold can break in advance and play a buffering role when the roof suddenly presses; the downward excavation of the soft floor can increase the stability of the wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural schematic diagram of step 1 in a construction method for coal pillar-free mining along a laneway with retaining walls in a thick coal seam with a large inclination angle according to the present invention.

[0025] Figure 2It is a structural schematic diagram of step 2 in a construction method for coal pillar-free mining along a laneway with retained walls in a thick coal seam with a large inclination angle according to the present invention.

[0026] Figure 3 It is a structural schematic diagram of step 3 in a construction method for coal pillar-free mining along a laneway with retained walls in a thick coal seam with a large dip angle according to the present invention.

[0027] Figure 4 It is a structural schematic diagram of step 4 in a construction method for coal pillar-free mining along a laneway with retained walls in a thick coal seam with a large inclination angle according to the present invention.

[0028] Figure 5 It is a structural schematic diagram of step 5 in a construction method for coal pillar-free mining along a laneway with retained walls in a thick coal seam with a large inclination angle according to the present invention.

[0029] Figure 6 It is a structural schematic diagram of step 6 in a construction method for coal pillar-free mining along a laneway with a thick coal seam having a large inclination angle according to the present invention.

[0030] Figure 7 It is a structural schematic diagram of step 7 in a construction method for coal pillar-free mining along a laneway with retaining walls in a thick coal seam with a large dip angle according to the present invention.

[0031] As shown in the figure: 1. Transport chute, 2. Wall space, 3. Return air chute, 4. Roof, 5. Top cut pressure relief hole, 6. Soft membrane concrete wall, 7. Coal seam, 8. Model. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the invention clearer, the technical solution in the embodiments of the invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the invention. Obviously, the described embodiments are part of the embodiments of the invention, not all of the embodiments. Generally, the components of the embodiments of the invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] In the description of the embodiments of the invention, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the invention product is usually placed when in use, it is only for the convenience of describing the invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0034] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0035] In the description of the embodiments of the invention, "a plurality of" means at least two.

[0036] In the description of the embodiments of the invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0037] Combined with Figure 1-7 As shown, a construction method for coal pillar-free mining along the roadway with retaining wall in a thick coal seam with a large inclination angle comprises the following steps:

[0038] Step (1): when excavating a transport drift 1 of a return working face in a coal seam, a wall space 2 for pouring a flexible film concrete wall 6 is reserved on the next return working face side;

[0039] Step (2): Arrange the model 8 in the wall space 2 reserved in the transport chute 1 and cast the flexible membrane concrete wall 6;

[0040] In the specific implementation, the size of the support model is determined according to the cross-sectional size of the transport chute 1 and the construction requirements; meanwhile, the flexible film concrete wall 6 is generally constructed by artificial pouring;

[0041] The transport chute 1 is reinforced by the soft film concrete wall 6, thereby ensuring the structural stability of the transport chute 1 and improving the safety of operation. In addition, the soft film concrete wall 6 can block the goaf to prevent the leakage of harmful gases caused by air leakage in the goaf. On the other hand, the soft film concrete wall 6 can also effectively support the top plate 4 to prevent it from collapsing and sinking, thereby ensuring the overall safety and stability of the transport chute 1.

[0042] Furthermore, when encountering a hard bottom plate of the coal seam, a 30-50 cm arc-shaped sand pile or coal gangue pile is laid at the bottom of the model 8, or the mold in patent number CN212296484U is used.

[0043] When encountering a soft bottom plate of the coal seam, before hanging the soft film, it is necessary to dig 30~50cm below the bottom of the soft film concrete wall 6 and then arrange the model 8.

[0044] Step (3): drilling a top-cutting pressure relief hole 5 in the top plate 4 at a position 0.5 m away from the flexible membrane concrete wall 6 in the transport chute 1;

[0045] Step (4): during mining, explosives are charged and blasted in the top pressure relief hole 5 immediately following the mining surface, so that a crack is formed between the goaf and the unmined area, so that the top plate 4 can collapse in time to reduce the pressure on the soft membrane concrete wall 6;

[0046] Furthermore, the roof 4 above the mined coal seam is collapsed by blasting the top cut pressure relief hole 5 .

[0047] In addition, the natural collapse of the roof 4 can be used to cause the roof 4 above the coal seam to collapse naturally.

[0048] Step (5): After mining, the roof 4 collapses along the top cutting pressure relief hole 5;

[0049] Step (6): excavating a return air chute 3 for the return production working face along the other side of the flexible membrane concrete wall 6;

[0050] Step (7): excavating a transport trench at the next return working face, and reserving a wall space 2 for pouring a flexible film concrete wall 6 at the next return working face side;

[0051] Step (8): Repeat the above steps.

[0052] This mining construction method eliminates the coal pillars in the coal seam area, avoiding the waste of coal resources. At the same time, the safety of mining is improved by setting the soft membrane concrete wall 6, and safe and efficient mining is carried out in the coal seam without coal pillars, thereby effectively improving the coal output rate of the coal mine.

[0053] At the same time, it will help solve and realize the safe, efficient and green mining of coal seam mines, improve the recovery rate of coal resources in coal seams, and delay the scrapping of mines.

[0054] The present invention and its embodiments are described above, and such description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A construction method for coal pillar-free mining along the roadway with retaining wall in a thick coal seam with a large inclination angle, characterized in that: The following steps are involved: Step (1): when a transport chute (1) of a return working face is excavated in a coal seam, a wall space (2) for pouring a flexible film concrete wall (6) is reserved on the side of the next return working face; Step (2): Arrange the model (8) in the wall space (2) reserved in the transport chute (1) and pour the soft film concrete wall (6); when encountering a hard bottom plate of the coal seam, lay a 30-50 cm arc-shaped sand pile or coal gangue pile at the bottom of the mold; when encountering a soft bottom plate of the coal seam, dig 30-50 cm below the bottom of the soft film wall before hanging the soft film and then arrange the model; Step (3): drilling a top-cutting pressure relief hole (5) in the top plate (4) at a position 0.5 m away from the flexible membrane concrete wall (6) in the transport chute (1); Step (4): during mining, explosives are charged and blasted at the top pressure relief hole (5) immediately following the mining surface, so that a crack is formed between the goaf area and the unmined area, so that the top plate (4) can collapse in time to reduce the pressure on the soft film concrete wall (6); Step (5): after mining, the roof (4) collapses along the top cutting pressure relief hole (5); Step (6): excavating a return air chute (3) for the return production working face along the other side of the flexible membrane concrete wall (6); Step (7): excavating a transport trench (1) at the next return work surface, and at the same time reserving a wall space (2) for pouring a flexible film concrete wall (6) at the next return work surface.

2. The method for coal pillar-free mining along the roadway with retaining wall in a thick coal seam with a high inclination angle according to claim 1, characterized in that: In step (4), blasting is performed at the top-cutting pressure relief hole to cause the roof above the mined coal seam to collapse.

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