Coal mine thick-layer spacing key-layer-containing close-distance coal seam pillar entry retaining stress control method

Abstract

The invention provides a coal mine thick-layer-spacing key-layer-containing close-distance coal seam coal pillar entry retaining stress control method, and relates to the technical field of coal mining. The coal mine thick-layer spacing key-layer-containing close-distance coal seam pillar entry retaining stress control method comprises the steps that a top plate, away from one side of a coal pillar, of a main transportation roadway is separated from an entry retaining top plate of the main transportation roadway, and a top plate, away from one side of the coal pillar, of an auxiliary transportation roadway is separated from an entry retaining top plate of the auxiliary transportation roadway. According to the control method provided by the invention, the overlying strata structures on two sides of the coal pillar of the lower coal seam are controlled by adopting a two-lane two-time roof cutting means, so that the overlying strata structures formed in the upper coal seam are changed and guided to safely move, and the movement situation of the overlying strata in mining of the upper and lower coal seams is coordinately controlled from bottom to top; the mining-induced stress formed by overlapping the close-distance thick layer spacing and the upper and lower key layers is controlled, so that the coal pillar entry retaining stress is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, and in particular to a method for controlling the stress of coal pillars and lanes in a coal mine with close distances between key layers and thick layers. Background Art

[0002] The surrounding rock deformation and destruction of coal pillars in single coal seam mining is strongly controlled by two mining stresses, which is one of the difficult problems in controlling the surrounding rock of dynamic pressure tunnels in my country's underground coal mines. Commonly used surrounding rock control methods include two categories: one is the active strong resistance pressure maintenance method; the other is the active stress release pressure relief method. Practice has fully proved that the pressure relief method has become an effective and applicable method for controlling strong mining stress. The surrounding rock environment of close-range coal seam mining is more complex and changeable. When there are key rock layers with large thickness, high strength and strong stability between the upper and lower coal seams, the lower coal seam will present a single coal seam overburden structure after mining. If the coal pillars are arranged in the mining tunnel of the lower coal seam, compared with the coal pillars in the mining of a single coal seam, the coal pillars in the mining of close-range coal seams are not only affected by the two mining stresses from the mining of the lower coal seam, but also by the additional mining stress formed by the mining of the upper coal seam. Therefore, for the surrounding rock of coal pillars in the mining of close-range coal seams with thick interlayer spacing and key layers, more complex multiple stress superposition coupling will be encountered, and the surrounding rock control of the tunnel will be more difficult. Summary of the invention

[0003] The invention provides a method for controlling the stress of coal pillars in coal mines with close distances between thick layers and key layers, so as to solve the problem of great difficulty in controlling surrounding rock of the tunnel in the prior art.

[0004] The present invention provides a method for controlling the stress of coal pillar lanes in a coal mine with close distance between key layers and thick layers, wherein a main transport lane and an auxiliary transport lane are respectively arranged on both sides of the coal pillar, comprising: Before mining in the main transport tunnel, the roof of the main transport tunnel away from the coal pillar is separated from the remaining tunnel roof of the main transport tunnel; Before mining in the auxiliary transport tunnel, the roof of the auxiliary transport tunnel on the side away from the coal pillar is separated from the remaining tunnel roof of the auxiliary transport tunnel.

[0005] According to a method for controlling the stress of coal pillars in coal mines with close distances between key layers and thick layers provided by the present invention, the steps of separating the roof of the main transport lane away from the coal pillar from the lane roof of the main transport lane include: A plurality of boreholes are opened upwards on the top plate of the main transport tunnel by a drilling machine, wherein the plurality of boreholes are arranged at intervals along the length direction of the main transport tunnel; The borehole is fractured by hydraulic fracturing equipment to separate the roof of the main transport tunnel away from the coal pillar from the remaining tunnel roof of the main transport tunnel.

[0006] According to a method for controlling the stress of coal pillars in coal mines with close distances between key layers and thick layers provided by the present invention, the steps of separating the roof of the auxiliary transport lane away from the coal pillar from the lane roof of the auxiliary transport lane include: A plurality of boreholes are opened upwards on the top plate of the auxiliary transport tunnel by a drilling machine, wherein the plurality of boreholes are arranged at intervals along the length direction of the auxiliary transport tunnel; The drill hole is fractured by using hydraulic fracturing equipment to separate the roof of the auxiliary transport tunnel away from the coal pillar from the remaining tunnel roof of the auxiliary transport tunnel.

[0007] According to a method for controlling coal pillar lane stress in a coal mine with close distance between key layers and thick layers provided by the present invention, the control method further comprises: The fissure development between two adjacent boreholes is detected, and when the fissure does not meet the predetermined requirement, the borehole is subjected to secondary fracturing.

[0008] According to a method for controlling coal pillar lane stress in a coal mine with close-range coal seams including key layers and thick intervals provided by the present invention, the distance between two adjacent drill holes is equal.

[0009] According to a method for controlling coal pillar lane stress in a coal mine with thick intervals and close distances between key layers provided by the present invention, the distance between two adjacent boreholes is 8-10m.

[0010] According to a method for controlling coal pillar lane stress in a coal mine with close-range coal seams including key layers and thick intervals provided by the present invention, the angle between the central axis of the borehole and the horizontal plane is 40°-50°.

[0011] According to a method for controlling coal pillar lane stress in a coal mine with thick inter-layer spacing and close-range coal seams including key layers provided by the present invention, the depth of the drilling hole is 1.2 times the inter-layer spacing between two adjacent coal seams.

[0012] According to a method for controlling coal pillar lane stress in a coal mine with close distance between thick layers including key layers provided by the present invention, the inner diameter of each of the drill holes is equal.

[0013] According to a method for controlling stress of coal pillars in coal mines with close distances between thick layers and key layers provided by the present invention, the width of the coal pillars is 15-25m.

[0014] Due to the variety of types of close-range coal seams, for close-range coal seams with thick layer spacing or containing key layers, the lower coal seam mining tunnel adopts a coal pillar retaining tunnel layout method. During the service period, the surrounding rock of the retained tunnel undergoes repeated superposition and coupling of multiple mining stresses, resulting in severe deformation and damage in the retained tunnel, which has become a major problem in the management of dynamic pressure tunnels in coal mines.

[0015] The method for controlling the stress of coal pillars in coal mines with close-range coal seams containing key layers and in thick-layer spacing provided by the present invention is based on the root causes of the formation of mining stress, clarifies the essence of the movement of the overburden structure in the upper and lower coal seams in close-range mining to generate multiple mining stresses, and controls and changes the key overburden structure and movement mode of the close-range lower coal seam to weaken and reduce multiple mining stresses. Therefore, it is proposed to use two lanes and two top cutting methods to control the overburden structure on both sides of the coal pillar of the lower coal seam, and then change and guide the overburden structure of the upper coal seam to move safely, realize the coordinated control of the overburden movement situation of the upper and lower coal seams from bottom to top, solve the mining stress formed by controlling the close-range thick-layer spacing and the superposition of the upper and lower key layers, and thus reduce the stress of coal pillars in the lanes. It not only solves the surrounding rock control problems of thick-layer spacing, containing key layers, and close-range coal seams, but also promotes the progress of the theoretical method of surrounding rock control of the close-range coal seam mining lanes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the layout of the coal pillar and lane retaining working face in close-range coal seam mining provided by the present invention.

[0018] Figure 2 The present invention provides a model of the overburden structure of the residual coal pillars of the 4# coal seam above a certain mine after mining.

[0019] Figure 3 It is a schematic diagram of the structure of the overburden rock after excavation of the lower 9# coal seam provided by the present invention.

[0020] Figure 4 The invention provides a structural model of overburden after excavation of a lane retaining working face.

[0021] Figure 5 It is the overburden structure model of the main transport tunnel of the 19111 working face after top cutting provided by the present invention.

[0022] Figure 6 The invention provides a model of the overburden structure of the auxiliary transport lane after roof cutting.

[0023] Figure 7 This is one of the schematic diagrams of the arrangement of the drilling holes provided by the present invention.

[0024] Figure 8 This is the second schematic diagram of the arrangement of the drilling holes provided by the present invention.

[0025] Fig. 9It is a flow chart of a method for controlling stress of coal pillars and lanes in coal mines with close distances between thick layers including key layers provided by the present invention.

[0026] Reference numerals: 100, main transport lane; 200, auxiliary transport lane; 300, coal pillar; 400, drilling hole. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" 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 an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0030] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0032] Combine the following Figure 1-Figure 9 The invention describes a method for controlling coal pillar lane stress in coal mines with close distances between thick layers and key layers.

[0033] Before introducing the stress control method of coal pillar lanes in coal mines with thick intervals and close distances between key layers, a specific example of deformation and damage of the lane is introduced.

[0034] 1. Overview of coal pillar and lane retaining working face in close-range coal seam mining

[0035] The 4# coal seam and 9# coal seam of a mine are the main mining seams. The 4# coal seam located at the top has been fully mined, and the 9# coal seam at the bottom is currently being mined. The average inter-layer distance between the 4# coal seam at the top and the 9# coal seam at the bottom is about 40m, which is a thick-layered and close-spaced coal seam.

[0036] Figure 1 The schematic diagram of the working face layout of the coal pillar and lane retention in the close-range coal seam mining provided by the present invention is illustrated as follows: Figure 1 As shown, a 20m protective coal pillar is left in the goaf of the 14111 working face and the 14112 working face of the upper 4# coal seam; the main transportation lane of the lower 9# coal seam is arranged 9.5m inwardly below the goaf of the upper 14111 working face, and the auxiliary transportation lane is arranged 4.5m outwardly below the coal pillar of the upper 4# coal seam. A 20m protective coal pillar is also left in the 19111 working face and the 19112 working face. The auxiliary transportation lane is excavated and connected before the 19111 working face is mined, so it belongs to the typical coal pillar retaining lane type.

[0037] 2. Deformation and damage of surrounding rock in coal pillars and lanes in close-range coal seam mining

[0038] The auxiliary transport tunnel is supported by high-strength and high-prestressed anchor cables, and the deformation of the tunnel surrounding rock can be controlled during excavation. Before the main transport tunnel was mined, the roof of the auxiliary transport tunnel was reinforced with strong anchor cables, and the two sides were protected by 150mm large-diameter drill holes for pressure relief. After the main transport tunnel was mined, the bottom plate of the auxiliary transport tunnel bulged violently, and the roof sank significantly, causing large deformation damage.

[0039] 3. Analysis of the causes of deformation and damage of surrounding rock in coal pillars and lanes during close-range coal seam mining

[0040] Figure 2 The present invention provides an example of a residual coal pillar overburden structure model of the 4# coal seam above a certain mine after mining. Figure 2 As shown in the figure, the coal pillar of the upper 4# coal seam working face section is 20m, the thickness of the coal seam is 9.26m, and the fully mechanized top coal caving mining method is adopted. Due to the large mining space of the 4# extra-thick coal seam, the overburden in the triangular area on both sides of the coal pillar forms a structure with the end of the coal pillar as the supporting axis, which fully rotates and slides, causing the coal pillar to accumulate high stress and transmit and expand to the bottom plate of the coal pillar area, resulting in high stress in the 9# coal seam roadway at the bottom of the corresponding area.

[0041] The thickness of the lower 9# coal seam is 12.7m, and it is also mined by fully mechanized top coal caving. The average thickness of the coal rock layer between the upper and lower coal seams is 37m. It contains mudstone, sandy mudstone, siltstone, fine sandstone and other rock strata with large distribution thickness, high strength and hard sandstone layers. Therefore, after mining, the lower 9# coal seam forms an overburden structure similar to the upper 4# coal seam.

[0042] Figure 3 The schematic diagram of the structure of the overburden after excavation of the lower 9# coal seam provided by the present invention is illustrated as follows: Figure 3 As shown in the figure, due to the larger mining space of the 9# coal seam, the overburden in the end triangle area forms a more violent rotation and sliding movement with the end of the coal pillar as the supporting axis structure, causing the surrounding rock of the retained lane to be subjected to high stress. In addition, the mining of the lower 9# coal seam caused the collapsed rock layer in the goaf area of ​​the upper 4# coal seam and the overlying stable rock layer to lose stability again, and the lower 9# coal seam formed multiple superimposed mining stresses, resulting in large deformation and damage to the retained lane.

[0043] Figure 4 The structural model of the overburden after the excavation of the lane retaining working face provided by the present invention is illustrated as follows: Figure 4 As shown in the figure, the advanced fracture movement of the overburden during the mining process of the lane-retaining working face generates advanced support pressure, which acts on the lane-retaining together with the mining stress on the empty side of the coal pillar. At the same time, the mining of the lane-retaining working face causes the overburden in the triangular area of ​​the coal pillar side of the upper 4# coal seam to move again, forcing the concentrated stress of the coal pillar to be transferred to the lane-retaining again. Therefore, during the mining process of the coal pillar-retaining working face, the lane-retaining encounters multiple mining stress superposition again, resulting in strong deformation and damage disasters in the lane.

[0044] In summary, for coal pillar lanes in coal seams with key layers, thick layer spacing and close distance, the fundamental reason for the severe large deformation damage of the lanes is that they are subjected to repeated multiple mining stress coupling and superposition during the entire service life.

[0045] Understanding and mastering the root causes of mining stress formation is the basic principle for managing mining tunnels in coal mines. Regardless of the type of dynamic pressure tunnel, the mining stress borne is related to the movement of the overburden after coal seam excavation. Changing the overburden structure after coal seam mining is the key to releasing and reducing mining stress. For close-range coal seams with thick intervals and key layers, the lower coal seam forms an overburden structure similar to that after single coal seam mining after mining. The coal pillars of the lower coal seams are subjected to two mining stresses from the mining of the lower coal seams. At the same time, the excavation of the lower coal seam will inevitably lead to the instability of the stable overburden structure of the upper coal seam. In this way, the movement of the overburden structure of the upper and lower coal seams will inevitably superimpose the coupling effect to produce multiple mining stresses with greater intensity, which is the fundamental reason for the large deformation and damage disaster of the coal pillars of such close-range coal seams.

[0046] Fig. 9 The flowchart of the method for controlling the stress of coal pillars in coal mines with close distances between key layers provided by the present invention is illustrated as follows: Fig. 9 As shown in the figure, the main transport lane and the auxiliary transport lane are respectively arranged on both sides of the coal pillar. The stress control method of the coal pillar lane in the coal mine with thick intervals including key layers and close distance coal seams includes: Step S100, before mining in the main transport tunnel, the roof of the main transport tunnel away from the coal pillar is separated from the remaining tunnel roof of the main transport tunnel; Step S200, before the auxiliary transport tunnel is mined, the roof of the auxiliary transport tunnel away from the coal pillar is separated from the remaining tunnel roof of the auxiliary transport tunnel.

[0047] The method for controlling the stress of coal pillars in coal mines with close-range coal seams containing key layers and in thick-layer spacing provided by the present invention is based on the root causes of the formation of mining stress, clarifies the essence of the movement of the overburden structure in the upper and lower coal seams in close-range mining to generate multiple mining stresses, and controls and changes the key overburden structure and movement mode of the close-range lower coal seam to weaken and reduce multiple mining stresses. Therefore, it is proposed to use two lanes and two top cutting methods to control the overburden structure on both sides of the coal pillar of the lower coal seam, and then change and guide the overburden structure of the upper coal seam to move safely, realize the coordinated control of the overburden movement situation of the upper and lower coal seams from bottom to top, solve the mining stress formed by controlling the close-range thick-layer spacing and the superposition of the upper and lower key layers, and thus reduce the stress of coal pillars in the lanes. It not only solves the surrounding rock control problems of thick-layer spacing, containing key layers, and close-range coal seams, but also promotes the progress of the theoretical method of surrounding rock control of the close-range coal seam mining lanes.

[0048] In one embodiment of the present invention, the step of separating the roof of the main transport tunnel away from the coal pillar from the remaining tunnel roof of the main transport tunnel comprises: Step S110, using a drilling machine to open a plurality of boreholes upward on the top plate of the main transport tunnel, wherein the plurality of boreholes are arranged at intervals along the length direction of the main transport tunnel; Step S120, hydraulic fracturing equipment is used to fracture the borehole, so as to separate the roof of the main transport tunnel away from the coal pillar from the remaining tunnel roof of the main transport tunnel.

[0049] Figure 5 The overburden structure model of the main transport lane of the 19111 working face after top cutting provided by the present invention is illustrated as follows: Figure 5 As shown in the figure, the drilling rig is used to drill the top plate of the main transport tunnel ( Figure 5 and Figure 6 A in the figure is drilled upwards, and the drill holes are fractured by hydraulic fracturing equipment to cut off the roof of the main transport roadway away from the coal pillar (the roof of the triangular area on the coal pillar side of the main transport roadway) from the remaining roadway roof of the main transport roadway, so as to separate the roof of the main transport roadway away from the coal pillar from the remaining roadway roof of the main transport roadway, and relieve the supporting function of the roof of the main transport roadway away from the coal pillar. After the 19111 working face is pushed and mined, the roof naturally collapses to the goaf and no longer attaches to the coal pillar, and does not form a supporting structure that compresses the coal pillar. By cutting off the roof of the main transport roadway away from the coal pillar from the remaining roadway roof of the main transport roadway, the coal pillar no longer forms accumulated high stress, thereby reducing the remaining roadway pressure; moreover, due to the collapse of the overburden of the 9# coal seam at the bottom to fill the goaf, the overburden of the triangular area of ​​the coal pillar of the 4# coal seam at the top moves again, and then slides to the goaf and no longer attaches to the coal pillar, thus reducing the concentrated stress of the coal pillar of the 4# coal seam and reducing the remaining roadway pressure.

[0050] In one embodiment of the present invention, the step of separating the roof of the auxiliary transport tunnel away from the coal pillar from the tunnel retaining roof of the auxiliary transport tunnel comprises: Step S210, using a drilling machine to open a plurality of boreholes upward on the top plate of the auxiliary transport tunnel, wherein the plurality of boreholes are arranged at intervals along the length direction of the auxiliary transport tunnel; Step S220, hydraulic fracturing equipment is used to fracture the borehole so as to separate the roof of the auxiliary transport tunnel away from the coal pillar from the remaining tunnel roof of the auxiliary transport tunnel.

[0051] Figure 6 The overburden structure model of the auxiliary transport tunnel after top cutting provided by the present invention is illustrated as follows: Figure 6 As shown in the figure, the drilling rig is used to drill the top plate of the auxiliary transport tunnel ( Figure 6 Multiple boreholes were drilled upward (at B in the figure), and hydraulic fracturing equipment was used to fracture the boreholes, cutting off the roof of the auxiliary transport roadway away from the coal pillar (the roof of the triangular area on the working face side of the auxiliary transport roadway) from the remaining roadway roof of the auxiliary transport roadway, thus separating the roof of the auxiliary transport roadway away from the coal pillar from the remaining roadway roof of the auxiliary transport roadway, and controlling the advance support pressure of the 19112 working face to act on the remaining roadway. In addition, since the integrity of the remaining roadway roof and the working face was cut off, the concentrated stress of the coal pillar of the upper 4# coal seam could not be transmitted to the remaining roadway roof.

[0052] In summary, the method of two-tunnel two-top cutting was adopted to solve the problem of the remaining tunnel being subjected to multiple and multiple mining stress coupling and superposition, achieve the purpose of stress relief caused by strong mining in the remaining tunnel, and control the large deformation and damage disaster of the remaining tunnel.

[0053] In one embodiment of the present invention, the method for controlling the stress of coal pillars in coal mines with close distances between key layers and thick layers also includes: Detect the development of fractures between two adjacent boreholes, and perform secondary fracturing on the boreholes if the fractures do not meet the predetermined requirements.

[0054] By detecting the development of cracks between two adjacent boreholes and performing secondary fracturing on the boreholes if the cracks do not meet the predetermined requirements, it can be ensured that the top plate of the remaining lane is completely cut off from the top plate of the working face and that stress is not transmitted to the top plate of the remaining lane.

[0055] In one embodiment of the present invention, Figure 7 One of the schematic diagrams of the arrangement of the drilling holes provided by the present invention is illustrated, such as Figure 7 As shown, the distance between two adjacent boreholes is equal. Of course, for some special formations, the distance between two adjacent boreholes may not be equal, for example, the distance between two adjacent boreholes is reduced in an area with higher formation hardness, and increased in an area with lower formation hardness. Preferably, the distance between two adjacent boreholes is 8-10m.

[0056] In one embodiment of the present invention, Figure 8 The second schematic diagram of the arrangement of the drilling holes provided by the present invention is illustrated as follows: Figure 8 As shown, two adjacent boreholes are arranged in parallel, and the angle between the central axis of the borehole and the horizontal plane is 40°-50°.

[0057] In one embodiment of the present invention, the depth of the borehole is 1.2 times the interlayer distance between two adjacent coal seams, so as to ensure that the borehole can completely penetrate the intermediate coal rock between the two adjacent coal seams.

[0058] It should be noted here that the interlayer distance between two adjacent coal seams is the distance between the bottom surface of the upper coal seam and the top surface of the lower coal seam.

[0059] In one embodiment of the present invention, the inner diameter of each borehole is equal, so that the same drilling rig can be used to open multiple boreholes, avoiding the step of replacing the drill bit in the middle, and effectively improving the working efficiency.

[0060] In one embodiment of the present invention, the width of the coal pillar is 15-25 m, preferably, the width of the coal pillar is 20 m.

[0061] The method for controlling stress of coal pillars in coal mines with thick-layer spacing and close-range coal seams containing key layers provided by the present invention is based on the root causes of mining stress, clarifies the essence of the movement of overburden structure in the close-range upper and lower coal seams for generating multiple mining stresses, and controls and changes the key overburden structure and movement mode of the close-range lower coal seam to weaken and reduce multiple mining stresses. Therefore, it is proposed to adopt two-lane and two-top cutting means to control the overburden structure on both sides of the coal pillar of the lower coal seam, and then change and guide the movement of the overburden structure that has been formed in the upper coal seam, so as to realize the coordinated control of the overburden movement situation of the upper and lower coal seams from bottom to top, solve the mining stress formed by controlling the close-range thick layer spacing and the superposition of the upper and lower double key layers, thereby reducing and reducing the stress of coal pillars in the lanes, which not only solves the surrounding rock control problems of coal pillars in thick layer spacing, containing key layers and close-range coal seams, but also promotes the progress of theoretical methods of surrounding rock control of close-range coal seam mining lanes.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the stress of coal pillar lanes in coal mines with close distances between key layers, wherein the main transport lane and the auxiliary transport lane are respectively arranged on both sides of the coal pillar, and the method is characterized in that: include: Before mining in the main transport tunnel, the roof of the main transport tunnel away from the coal pillar is separated from the remaining tunnel roof of the main transport tunnel; Before mining in the auxiliary transport tunnel, the roof of the auxiliary transport tunnel on the side away from the coal pillar is separated from the remaining tunnel roof of the auxiliary transport tunnel.

2. The method for controlling coal pillar lane stress in coal mines with close distances between key layers and thick layers according to claim 1 is characterized in that: The step of separating the roof of the main transport tunnel away from the coal pillar from the remaining tunnel roof of the main transport tunnel comprises: A plurality of boreholes are opened upwards on the top plate of the main transport tunnel by a drilling machine, wherein the plurality of boreholes are arranged at intervals along the length direction of the main transport tunnel; The borehole is fractured by hydraulic fracturing equipment to separate the roof of the main transport tunnel away from the coal pillar from the remaining tunnel roof of the main transport tunnel.

3. The method for controlling coal pillar lane stress in coal mines with close distances between key layers and thick layers according to claim 1 is characterized in that: The step of separating the roof of the auxiliary transport roadway away from the coal pillar from the roadway retaining roof of the auxiliary transport roadway comprises: A plurality of boreholes are opened upwards on the top plate of the auxiliary transport tunnel by a drilling machine, wherein the plurality of boreholes are arranged at intervals along the length direction of the auxiliary transport tunnel; The drill hole is fractured by using hydraulic fracturing equipment to separate the roof of the auxiliary transport tunnel away from the coal pillar from the remaining tunnel roof of the auxiliary transport tunnel.

4. The method for controlling coal pillar lane stress in coal mines with close distances between key layers and thick layers according to claim 2 or 3, characterized in that: The control method further comprises: The fissure development between two adjacent boreholes is detected, and when the fissure does not meet the predetermined requirement, the borehole is subjected to secondary fracturing.

5. The method for controlling coal pillar lane stress in coal mines with thick intervals and close distances between key layers according to claim 2 or 3, characterized in that: The distances between two adjacent boreholes are equal.

6. The method for controlling coal pillar lane stress in coal mines with close distance between key layers and thick layers according to claim 2 or 3, characterized in that: The distance between two adjacent boreholes is 8-10m.

7. The method for controlling coal pillar lane stress in coal mines with close distance between key layers and thick layers according to claim 2 or 3, characterized in that: The angle between the central axis of the borehole and the horizontal plane is 40°-50°.

8. The method for controlling coal pillar lane stress in coal mines with close distances between key layers and thick layers according to claim 2 or 3, characterized in that: The depth of the borehole is 1.2 times the interlayer distance between two adjacent coal seams.

9. The method for controlling coal pillar lane stress in coal mines with close distance between key layers and thick layers according to claim 2 or 3, characterized in that: The inner diameter of each of the boreholes is equal.

10. The method for controlling coal pillar lane stress in coal mines with close distances between key layers and thick layers according to claim 2 or 3, characterized in that: The width of the coal pillar is 15-25m.

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