Room-pillar type goaf underground grouting filling method

Abstract

The invention discloses an underground grouting and filling method for a room-and-pillar goaf, which comprises the following steps of: detecting the room-and-pillar goaf, and determining the size and azimuth angle of a coal pillar; a transportation roadway, an air return roadway and an open-off cut are arranged on the edge of the room-and-pillar goaf, the area, adjacent to the transportation roadway, the air return roadway and the open-off cut, in the room-and-pillar goaf is defined as a roadway treatment area, and the other areas are defined as working face treatment areas; according to the size and the azimuth angle of the coal pillar, a water exploration and drainage hole and a coal seam filling hole communicated with the roadway treatment area are formed in the coal seam through at least one of the transportation roadway, the air return roadway and the cut hole, and a roof filling hole communicated with the working face treatment area is formed in a coal seam roof; grouting is conducted on the roadway treatment area and the working face treatment area through the coal seam filling holes and the top plate filling holes correspondingly; and the grouting filling effect is monitored and analyzed. The room-pillar type goaf underground grouting filling method has the advantages of being low in land acquisition risk, high in filling efficiency and low in cost.

Description

Technical Field

[0001] This invention relates to the field of coal mine filling technology, specifically to a method for underground grouting and filling of room-and-pillar goaf. Background Technology

[0002] Depending on the location of the filling boreholes, room-and-pillar goaf filling technologies can be divided into surface filling technologies and underground filling technologies. Based on the filling materials, room-and-pillar goaf grouting can be categorized into gangue grouting, fly ash grouting, and gangue-fly ash grouting. Among these technologies, underground grouting filling for room-and-pillar goafs suffers from drawbacks such as high land acquisition risks, low filling efficiency, and high filling costs. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] Therefore, embodiments of the present invention propose a method for grouting and filling room-and-pillar goaf, which has the advantages of low land acquisition risk, high filling efficiency, and low cost.

[0005] The method for grouting and filling goaf in a room-and-pillar type well according to an embodiment of the present invention includes the following steps: Detect the goaf of a room-and-pillar type goaf and determine the size and azimuth of the coal pillar; Transport roadways, return air roadways, and cut-outs are set at the edge of the room-and-pillar goaf. The area adjacent to the transport roadways, return air roadways, and cut-outs in the room-and-pillar goaf is defined as the roadway treatment area, and the remaining area is defined as the working face treatment area. Based on the coal pillar size and azimuth, water exploration holes and coal seam filling holes are set in the coal seam through at least one of the transport roadway, return air roadway and cut-in, and roof filling holes are set in the coal seam roof, which are connected to the working face treatment area. Grouting is injected into the roadway treatment area and the working face treatment area through coal seam filling holes and roof filling holes, respectively; The grouting filling effect is monitored and analyzed.

[0006] The underground grouting and filling method for room-and-pillar goaf of this invention divides the room-and-pillar goaf into a roadway treatment zone adjacent to the transport roadway, return airway, and cut-off, and a working face treatment zone far from the transport roadway, return airway, and cut-off. The roadway treatment zone is connected to coal seam filling holes located within the coal seam, and the working face treatment zone is connected to roof filling holes located within the roof of the coal seam. This allows for shorter distances between the coal seam filling holes, resulting in lower drilling costs. Furthermore, grouting and filling operations can be performed on the roadway treatment zone and the working face treatment zone respectively through coal seam filling holes and roof filling holes in at least one of the transport roadway, return airway, and cut-off. This method offers high filling efficiency, and requires only a grouting station and supporting facilities on the surface, which can be dismantled after use, minimizing land acquisition risks.

[0007] In some embodiments, the step of setting water exploration and drainage holes and coal seam filling holes in the coal seam through at least one of the transport roadway, return air roadway and cut-off hole, which are connected to the roadway treatment area, according to the coal pillar size and azimuth angle, and setting roof filling holes in the coal seam roof that are connected to the working face treatment area includes: First, set the coal seam filling holes, then set the roof filling holes; The grouting into the roadway treatment area and the working face treatment area through coal seam filling holes and roof filling holes respectively includes: The filling of the roadway treatment area and the working face treatment area is completed sequentially from top to bottom along the extension direction of the coal seam.

[0008] In some embodiments, monitoring and analyzing the grouting filling effect includes: The aforementioned water exploration and drainage holes are used as detection holes for the goaf and liquid level monitoring holes; And / or, by means of at least one of the transport roadway, return airway and cut-off hole, a liquid level monitoring hole connected to the roadway treatment area is installed in the coal seam; And / or, install pressure gauges and flow meters at the coal seam filling boreholes and roof grouting boreholes to monitor grouting pressure and flow rate; And / or, periodically sample and determine the strength of the filling material.

[0009] In some embodiments, the coal seam extends at an angle to the horizontal direction, there are multiple coal seam filling holes, the ends of the coal seam filling holes are adjacent to or located on the roof of the roadway treatment area, and at least some of the coal seam filling holes are arranged at intervals along the extension direction of the coal seam. The coal seam extends at an angle to the horizontal direction, and the roof filling holes are multiple and have multiple slurry outlets that communicate with the treatment area of ​​the working face. At least some of the slurry outlets are arranged at intervals along the extension direction of the coal seam.

[0010] In some embodiments, the roof filling hole includes interconnected directional boreholes and branch holes. The directional boreholes are located above the room-and-pillar goaf, and the branch holes are multiple and spaced apart along the extension direction of the directional boreholes. The branch holes are connected to the working face treatment area.

[0011] In some embodiments, the distance between the directional borehole and the room-and-pillar goaf is 8m-20m.

[0012] In some embodiments, a plurality of branch holes are constructed sequentially along a direction gradually moving away from the end of the directional borehole, and before the construction of subsequent branch holes, the area in the working face treatment zone corresponding to the previous branch hole is filled. And / or, the top plate filling holes include at least two parallel directional boreholes spaced apart along the height direction, and at least two sets of branch holes corresponding to the directional boreholes are arranged alternately along the extension direction of the directional boreholes.

[0013] In some embodiments, there are at least two room-and-pillar goaf areas arranged at intervals along a first direction. Each room-and-pillar goaf area is provided with a transport roadway, a return air roadway and a cut-off point. A connecting roadway is provided between the transport roadway corresponding to one of the room-and-pillar goaf areas and the return air roadway corresponding to the adjacent room-and-pillar goaf area.

[0014] In some embodiments, the cementitious grout injected into the roadway treatment area and the working face treatment area includes gangue paste material made of gangue and ordinary silicate cement, wherein the maximum particle size of the gangue does not exceed 10 mm, and the proportion of the gangue with a particle size of less than or equal to 3 mm is not less than 80%, and the slump of the gangue paste is 180 mm to 220 mm.

[0015] In some embodiments, the strength of the filling body formed after the gelling grout in the roadway treatment area solidifies is greater than or equal to 8 MPa, and the strength of the filling body formed after the gelling grout in the working face treatment area solidifies is greater than or equal to 2 MPa. And / or, the cementitious grout in the tunnel treatment area comprises gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, and water, wherein the proportions of gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, and water are 0.5-0.55, 0.2-0.25, 0.005-0.0055, 0.01-0.02, and 0.22-0.225, respectively; or, the tunnel treatment area The internal cementitious grout comprises gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, water, and fly ash, wherein the proportions of gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, water, and fly ash are 0.5-0.55, 0.15-0.22, 0.005-0.0055, 0.01-0.02, 0.22-0.225, and 0.02-0.025, respectively. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the distribution of the room-and-pillar goaf and its surrounding roadways and filling holes according to an embodiment of the present invention.

[0017] Figure 2 This is a side view of a room-and-pillar goaf area and its surrounding roadways and filling holes, according to an embodiment of the present invention.

[0018] Figure label: 1. Room-and-pillar goaf; 2. Coal seam; 21. Coal pillar; 3. Transport roadway; 4. Return airway; 5. Connecting roadway; 6. Cut-off hole; 8. Exploration and drainage hole; 9. Coal seam filling hole; 10. Roof filling hole. Detailed Implementation

[0019] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0020] The following is combined Figure 1 and Figure 2 This invention describes a method for grouting and filling goaf in a room-and-pillar type well according to an embodiment of the present invention.

[0021] The method for grouting and filling goaf in a room-and-pillar type well according to an embodiment of the present invention includes the following steps: The room-and-pillar goaf 1 is explored to determine the size and azimuth of the coal pillar 21. If drilling is used, observation boreholes are arranged from the ground and underground, and three-dimensional laser scanning is used to explore the distribution pattern and boundary of the room-and-pillar goaf 1, or geophysical exploration is used to determine the boundary range of the room-and-pillar goaf 1.

[0022] Transport roadway 3, return air roadway 4 and cut-in 6 are set at the edge of the room-and-pillar goaf 1. The area in the room-and-pillar goaf 1 adjacent to transport roadway 3, return air roadway 4 and cut-in 6 is defined as the roadway treatment area, and the remaining area is defined as the working face treatment area. Based on the size and azimuth of the coal pillar 21, at least one of the transport roadway 3, return air roadway 4 and cut-out 6 is used to set up a water exploration hole 8 and a coal seam filling hole 9 in the coal seam 2 that are connected to the roadway treatment area, and a roof filling hole 10 in the roof of the coal seam 2 that is connected to the working face treatment area. Grouting is injected into the roadway treatment area and the working face treatment area through coal seam filling hole 9 and roof filling hole 10, respectively; The grouting filling effect is monitored and analyzed.

[0023] The method for grouting and filling a room-and-pillar goaf in this invention divides the room-and-pillar goaf 1 into a roadway treatment area adjacent to the transport roadway 3, return air roadway 4, and cut-in 6, and a working face treatment area far from these roadways. The roadway treatment area is connected to coal seam filling holes 9 located within the coal seam 2, and the working face treatment area is connected to roof filling holes 10 located within the roof of the coal seam 2. This allows for a shorter distance between the coal seam filling holes 9, resulting in lower drilling costs. Based on this, grouting and filling operations can be performed on the roadway treatment area and the working face treatment area respectively through the coal seam filling holes 9 and roof filling holes 10 in at least one of the transport roadway 3, return air roadway 4, and cut-in 6. This method offers high filling efficiency, and at this point, only a grouting station and supporting facilities are needed on the surface, which can be dismantled after use, resulting in low land acquisition risk.

[0024] It should be noted that grouting into the roadway treatment area and the working face treatment area through the coal seam filling hole 9 and the roof filling hole 10 respectively includes: the ground grouting station uses a filling pump to transport the gelling grout underground through filling boreholes and filling pipelines, and then grouting into the roadway treatment area and the working face treatment area through the coal seam filling hole 9 and the roof filling hole 10 respectively. The area covered by the cut-out 6, transport roadway 3 and return air roadway 4 and the area about 10m on both sides are divided into roadway treatment areas within the room-pillar goaf. In other words, the roadway treatment area is the area within 100m-150m from the edge of the room-pillar goaf 1, and the working face treatment area is the area beyond 100m-150m from the edge of the room-pillar goaf 1. In addition, the length and width of the coal pillar 21 in this embodiment are generally between 8m and 10m.

[0025] In addition, the water exploration and drainage holes 8 are mainly used to pump out the accumulated water in the room-and-pillar goaf 1 before and / or during the filling process, so as to effectively ensure the filling strength of the slurry. Among them, multiple sets of water exploration and drainage holes 8 are arranged along the lowest point of the contour line of the coal seam 2 floor in the roadway treatment area, and are located at different heights, such as at 1 / 4, 1 / 2 and 3 / 4 of the height of the coal pillar 21, respectively.

[0026] In some embodiments, based on the size and azimuth of the coal pillar 21, at least one of the transport roadway 3, return air roadway 4, and cut-out 6 is used to set up a water exploration hole 8 and a coal seam filling hole 9 in the coal seam 2 that communicate with the roadway treatment area, and to set up a roof filling hole 10 in the roof of the coal seam 2 that communicates with the working face treatment area. This includes: first setting up the coal seam filling hole 9, and then setting up the roof filling hole 10; at this time, the edge range and internal geological conditions of the room-and-pillar goaf 1 can be gradually explored, avoiding blindly drilling directly into the working face treatment area and causing safety accidents.

[0027] Grouting into the roadway treatment area and the working face treatment area through coal seam filling holes 9 and roof filling holes 10 respectively includes: filling the roadway treatment area and the working face treatment area sequentially from top to bottom along the extension direction of coal seam 2. Given that coal seam 2 has an inclination angle, priority is given to filling the lowest point of the room-and-pillar goaf 1 to avoid the grout flowing towards the lowest point when filling higher goaf areas, which would affect the roof contact rate at that point. This makes it easier to determine the roof contact rate at each location in the roadway treatment area and the working face treatment area by detecting the grouting volume.

[0028] For example, the roof contact rate of the filling material in the roadway treatment area should be no less than 90%-95%; the roof contact rate of the filling material in the working face treatment area should be no less than 80%-85%. This roof contact rate is achieved through reasonable control of the grouting radius, reasonable design of grouting holes, grouting from low to high positions first, leaving sufficient venting holes at high positions, and supplementary grouting in the later stages of filling. For instance, in each grout outlet in the roadway treatment area and the working face treatment area, the distance between any two adjacent grout outlets should be less than or equal to 100m.

[0029] In some embodiments, monitoring and analyzing the grouting filling effect includes: The water exploration hole 8 is used as a detection hole and liquid level monitoring hole for the goaf; that is, the environment and slurry level in the room-and-pillar goaf 1 can be monitored through the water exploration hole 8, which effectively reduces drilling costs.

[0030] A liquid level monitoring hole connected to the roadway treatment area is set in the coal seam 2 through at least one of the transport roadway 3, return air roadway 4 and cut-off eye 6; that is, the environment and slurry level in the room-and-pillar goaf 1 are detected through the liquid level monitoring hole. At this time, a liquid level monitoring hole connected to the roadway treatment area is set in the coal seam 2 through each of the transport roadway 3, return air roadway 4 and cut-off eye 6, and the liquid level monitoring hole is adjacent to the water exploration and drainage hole 8.

[0031] Pressure gauges and flow meters are installed at the filling boreholes and roof grouting boreholes of coal seam 2 to monitor grouting pressure and flow rate. Based on the pre-completion measurement of the coal room size in the room-and-pillar goaf 1, by detecting the grouting pressure and flow rate, it is possible to effectively ensure the injection of a predetermined volume of grout into the room-and-pillar goaf 1, effectively ensure the roof contact rate of the filling body in the roadway treatment area and the working face treatment area, and effectively avoid ground subsidence.

[0032] And / or, periodically sample and measure the strength of the infill. This allows for the testing of the infill strength through sampling results, enabling a determination of whether the ground surface can meet functional requirements, such as for installing wind turbine foundations.

[0033] In some embodiments, the coal seam 2 extends at an angle to the horizontal direction, and there are multiple coal seam filling holes 9. The ends of the coal seam 2 filling holes are adjacent to or located on the roof of the roadway treatment area, and at least some of the coal seam filling holes 9 are spaced apart along the extension direction of the coal seam 2. In another embodiment, the coal seam 2 extends at an angle to the horizontal direction, and there are multiple roof filling holes 10 with multiple slurry outlets communicating with the working face treatment area. At least some of the slurry outlets are spaced apart along the extension direction of the coal seam 2.

[0034] This ensures that grouting is generally uniformly injected into each area of ​​the coal seam 2 treatment zone and the working face treatment zone through the coal seam filling hole 9 and the roof filling hole 10, so as to ensure that the minimum filling body in the coal seam 2 treatment zone and the working face treatment zone is kept within the set range.

[0035] In some embodiments, the top plate filling hole 10 includes interconnected directional boreholes and branch holes. The directional boreholes are located above the room-and-pillar goaf 1, and the branch holes are multiple and spaced apart along the extension direction of the directional boreholes. The branch holes are connected to the working face treatment area.

[0036] In other words, after the grout enters the directional borehole, it is injected into various areas of the treatment zone of the working face through multiple branch holes, effectively reducing the number of directional boreholes and thus reducing drilling costs. This setup also makes it easier to control the spacing of each branch hole, that is, to more accurately control the spacing of the grout outlets of each branch hole, so as to better ensure the top contact rate of the filling material in the treatment zone of the working face.

[0037] In some embodiments, the distance between the directional borehole and the room-and-pillar goaf 1 is 8m-20m. This arrangement reduces the construction cost of the branch boreholes and ensures that the construction of the directional boreholes does not affect the strength of the roof of the coal seam 2, thereby reducing the risk of goaf backfilling.

[0038] For example, the distance between the directional borehole and the room-and-pillar goaf 1 can be 8m, 10m, 14m, 17m and 20m.

[0039] In some embodiments, multiple branch holes are constructed sequentially along a direction gradually moving away from the end of the directional borehole, and the area in the working face treatment zone corresponding to the previous branch hole is filled before the subsequent branch hole is constructed; and / or, the top plate filling hole 10 includes at least two mutually parallel directional boreholes arranged at intervals along the height direction, and at least two sets of branch holes corresponding to the directional boreholes are arranged alternately along the extension direction of the directional boreholes.

[0040] By alternating between branch holes and filling, the defects of long-distance borehole filling, such as easy grout leakage, incomplete filling, and difficulty in controlling roof settlement, are solved, resulting in high construction efficiency, filling quality, and downhole construction safety. By setting at least two directional boreholes spaced apart along the height direction, the construction cost of directional boreholes is effectively reduced. Furthermore, the arrangement of at least two sets of branch holes corresponding to the directional boreholes, alternating sequentially along the extension direction of the directional boreholes, allows for simultaneous construction of branch holes connected to the other directional borehole while grouting into the treatment area through one directional borehole and its corresponding branch hole, further improving the filling efficiency of the treatment area.

[0041] In some embodiments, such as Figure 1 As shown, there are at least two room-and-pillar goaf areas 1, which are arranged at intervals along the first direction. Each room-and-pillar goaf area 1 is provided with a transport roadway 3, a return air roadway 4, and a cut-off 6. A connecting roadway 5 is provided between the transport roadway 3 corresponding to one room-and-pillar goaf area 1 and the return air roadway 4 corresponding to the adjacent room-and-pillar goaf area 1.

[0042] The installation of connecting roadway 5 improves the connectivity between adjacent transport roadway 3 and return air roadway 4, facilitates the movement of grouting equipment, and increases filling efficiency. Furthermore, coal seam filling holes 9 and / or roof filling holes 10 can be constructed in connecting roadway 5, offering greater construction flexibility.

[0043] In some embodiments, the gelling grout comprises a gangue paste material formed from gangue and ordinary silicate cement, wherein the maximum particle size of the gangue does not exceed 10 mm, and the proportion of gangue particles with a particle size of 3 mm or less is not less than 80%, and the slump of the gangue paste is 180 mm-220 mm. This gangue paste material exhibits good fluidity, enabling horizontal pumping over a distance of 1000 m. Furthermore, after being injected into the room-and-pillar goaf 1, it possesses a larger expansion radius and accumulation height, achieving reliable filling of the room-and-pillar goaf 1 with fewer filling holes and lower filling costs. When grouting into the roadway treatment area and working face treatment area through coal seam filling holes 9 and roof filling holes 10, the grouting radius should be 100m-150m. The termination of grouting is determined by the grouting level, pressure, and flow rate. The accumulation morphology is related to the fluidity of the gangue paste, the dip angle of coal seam 2, the outlet height, and the continuous filling state. The better the fluidity of the gangue paste, the larger the expansion radius and the higher the accumulation height. When the dip angle of coal seam 2 is horizontal or small, the gangue paste is insufficient to flow with the dip angle of coal seam 2 on the horizontal plane and accumulates and expands only by its own fluidity. It is generally circular with the grout outlet as the radius, and the expansion radius generally does not exceed 100-150m. Coal seam 2 has a relatively large dip angle, resulting in a generally larger expansion radius and higher accumulation height. The gangue paste, aided by the dip angle of coal seam 2 and its own fluidity, accumulates and expands, typically flowing first to the lowest part of the goaf, accumulating and filling from the bottom, and gradually advancing towards higher levels. Grouting fills the goaf, and the expansion range of the gangue paste can reach over 150m. The higher the grout outlet height (i.e., the closer the grout outlet is to the upper edge of coal pillar 21), the larger the expansion radius generally is. Within a treatment zone, single-hole grouting achieves continuous filling, ensuring a completely continuous distribution of the filling material within the structural plane.

[0044] For example, the slump of the gangue paste entering the pump is preferably controlled between 190mm and 210mm, with a spread of 550mm-700mm, good cohesiveness, and water retention as key indicators. Specifically, the requirements for the slump of the gangue paste entering the pump are as follows: 1. Deviation and loss: The deviation between the measured value and the design value at the pump entry point ≤ ±20mm; slump loss ≤ 50mm in 1 hour; pressure bleeding rate ≤ 1.5%. 2. Mix proportion optimization: Sand ratio 42%-45%, medium sand with ≥15% residue on a 0.315mm sieve; maximum crushed stone particle size ≤25mm (ratio to pipe diameter ≤1:4); add high-efficiency water-reducing agent + retarder, and add air-entraining agent if necessary; cementitious material ≥360kg / m³, water-cement ratio 0.40-0.45. 3. On-site operation: Direct water addition is strictly prohibited; adjust with the same proportion of water-reducing agent if slump is insufficient; minimize bends and diameter changes in pipelines; control pump pressure within 70% of the equipment's rated pressure, gradually increasing pressure from slow to fast. 4. Special working conditions: High temperature (>30℃) use the upper limit and strengthen slump retention; Low temperature (<5℃) use the lower limit and add early-strength agent; When there are many bends / diameter changes and long vertical sections, the slump can be increased by 10mm-20mm and verified through pump testing.

[0045] Optionally, the strength of the filling material formed after the cementitious grout solidifies in the roadway treatment area is greater than or equal to 8 MPa, and the strength of the filling material formed after the cementitious grout solidifies in the working face treatment area is greater than or equal to 2 MPa. The strength of the filling material is achieved by adjusting the proportion of cement and other cementitious materials. This design saves on filling costs and provides a technical basis for subsequent re-mining.

[0046] Optionally, the cementitious grout in the roadway treatment area includes gangue, ordinary Portland cement, water-reducing agent, accelerator, and water, with the proportions of gangue, ordinary Portland cement, water-reducing agent, accelerator, and water being 0.5-0.55, 0.2-0.25, 0.005-0.0055, 0.01-0.02, and 0.22-0.225, respectively; or, the cementitious grout in the roadway treatment area includes gangue, ordinary Portland cement, water-reducing agent, accelerator, water, and fly ash, with the proportions of gangue, ordinary Portland cement, water-reducing agent, accelerator, water, and fly ash being 0.5-0.55, 0.15-0.22, 0.005-0.0055, 0.01-0.02, 0.22-0.225, and 0.02-0.025, respectively. At this point, it can ensure that the strength of the filling body formed after the cementitious grout solidifies remains at around 10MPa, which not only meets the strength requirements but also better meets the slump requirements, allowing it to be stacked upwards in a smaller area until it reaches the top.

[0047] For example, the cementitious grout in the roadway treatment area includes gangue, ordinary Portland cement, water-reducing agent, accelerator, and water. When the gangue content is 1000 kg, the amounts of ordinary Portland cement, water-reducing agent, accelerator, and water are 400 kg, 10 kg, 32 kg, and 415 kg, respectively. Alternatively, the cementitious grout in the roadway treatment area includes gangue, ordinary Portland cement, water-reducing agent, accelerator, water, and fly ash. When the gangue content is 1000 kg, the amounts of ordinary Portland cement, water-reducing agent, accelerator, water, and fly ash are 360 ​​kg, 10 kg, 32 kg, 415 kg, and 40 kg, respectively.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0051] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0052] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Although the above embodiments have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Any changes, modifications, substitutions and variations made to the above embodiments by those skilled in the art are within the protection scope of the present invention.

Claims

1. A method for grouting and filling goaf in a room-and-pillar type well, characterized in that, Includes the following steps: The goaf of the room-and-pillar type goaf (1) was detected, and the size and azimuth of the coal pillar (21) were determined; Transport roadway (3), return air roadway (4) and cut-out (6) are set at the edge of the room-and-pillar goaf (1). The area in the room-and-pillar goaf (1) adjacent to the transport roadway (3), return air roadway (4) and cut-out (6) is defined as the roadway treatment area, and the remaining area is defined as the working face treatment area. Based on the size and azimuth of the coal pillar (21), at least one of the transport roadway (3), return air roadway (4) and cut-out (6) is used to set up a water exploration hole (8) and a coal seam filling hole (9) in the coal seam (2) that are connected to the roadway treatment area, and a roof filling hole (10) is set up in the roof of the coal seam (2) that is connected to the working face treatment area; Grouting is injected into the roadway treatment area and the working face treatment area through the coal seam filling hole (9) and the roof filling hole (10), respectively; The grouting filling effect is monitored and analyzed.

2. The method for grouting and filling goaf in a room-and-pillar type well according to claim 1, characterized in that, The provision of a water exploration and drainage hole (8) and a coal seam filling hole (9) in the coal seam (2) through at least one of the transport roadway (3), return air roadway (4), and cut-off (6) according to the size and azimuth of the coal pillar (21), and the provision of a roof filling hole (10) in the roof of the coal seam (2) in connection with the working face treatment area, and the provision of a roof filling hole (10) in the roof of the coal seam (2) in connection with the working face treatment area, includes: First, set the coal seam filling hole (9), then set the roof filling hole (10); The grouting into the roadway treatment area and the working face treatment area through the coal seam filling holes (9) and the roof filling holes (10) respectively includes: The roadway treatment area and the working face treatment area are filled sequentially from top to bottom along the extension direction of the coal seam (2).

3. The method for grouting and filling goaf in a room-and-pillar type well according to claim 1, characterized in that, The monitoring and analysis of the grouting filling effect includes: The water exploration hole (8) is used as a detection hole and a liquid level monitoring hole for the goaf area; And / or, a liquid level monitoring hole connected to the roadway treatment area is provided in the coal seam (2) through at least one of the transport roadway (3), return air roadway (4) and cut-off (6); And / or, pressure gauges and flow meters are installed at the filling boreholes and roof grouting boreholes of the coal seam (2) to monitor the grouting pressure and flow rate; And / or, periodically sample and determine the strength of the filling material.

4. The method for grouting and filling goaf in a room-and-pillar type well according to claim 1, characterized in that, The coal seam (2) extends at an angle to the horizontal direction. There are multiple coal seam filling holes (9). The ends of the coal seam (2) filling holes are adjacent to or located on the roof of the roadway treatment area. At least some of the coal seam filling holes (9) are arranged at intervals along the extension direction of the coal seam (2). The coal seam (2) extends at an angle to the horizontal direction. The roof filling holes (10) are multiple and have multiple slurry outlets connected to the treatment area of ​​the working face. At least some of the slurry outlets are arranged at intervals along the extension direction of the coal seam (2).

5. The method for grouting and filling goaf in a room-and-pillar type well according to claim 1, characterized in that, The top plate filling hole (10) includes interconnected directional boreholes and branch holes. The directional boreholes are located above the room-and-pillar goaf (1). There are multiple branch holes arranged at intervals along the extension direction of the directional boreholes. The branch holes are connected to the working face treatment area.

6. The method for grouting and filling goaf in a room-and-pillar type well according to claim 5, characterized in that, The distance between the directional borehole and the room-and-pillar goaf (1) is 8m-20m.

7. The method for grouting and filling goaf in a room-and-pillar type well according to claim 5, characterized in that, Multiple branch holes are constructed sequentially in a direction that gradually moves away from the end of the directional borehole, and before the construction of subsequent branch holes, the area in the working face treatment zone corresponding to the previous branch hole is filled. And / or, the top plate filling hole (10) includes at least two parallel directional boreholes arranged at intervals along the height direction, and at least two sets of branch holes corresponding to the directional boreholes are arranged alternately along the extension direction of the directional boreholes.

8. The method for downhole grouting and filling of room-and-pillar goaf according to any one of claims 1-7, characterized in that, The room-and-pillar goaf (1) consists of at least two and is arranged at intervals along a first direction. Each room-and-pillar goaf (1) is provided with a transport roadway (3), a return air roadway (4) and a cut-off point (6). A connecting roadway (5) is provided between the transport roadway (3) corresponding to one of the room-and-pillar goafs (1) and the return air roadway (4) corresponding to the adjacent room-and-pillar goaf (1).

9. The method for downhole grouting and filling of a room-and-pillar goaf according to any one of claims 1-7, characterized in that, The cementitious grout injected into the roadway treatment area and the working face treatment area includes gangue paste material made of gangue and ordinary silicate cement, wherein the maximum particle size of gangue does not exceed 10mm, and the proportion of gangue particles with a particle size of less than or equal to 3mm is not less than 80%, and the slump of the gangue paste is 180mm-220mm.

10. The method for grouting and filling goaf in a room-and-pillar type well according to claim 9, characterized in that, The strength of the filling body formed after the gelling grout in the roadway treatment area solidifies is greater than or equal to 8MPa, and the strength of the filling body formed after the gelling grout in the working face treatment area solidifies is greater than or equal to 2MPa. And / or, the cementitious grout in the tunnel treatment area comprises gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, and water, wherein the proportions of gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, and water are 0.5-0.55, 0.2-0.25, 0.005-0.0055, 0.01-0.02, and 0.22-0.225, respectively; or, the tunnel treatment area The internal cementitious grout comprises gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, water, and fly ash, wherein the proportions of gangue, ordinary Portland cement, water-reducing agent, quick-setting agent, water, and fly ash are 0.5-0.55, 0.15-0.22, 0.005-0.0055, 0.01-0.02, 0.22-0.225, and 0.02-0.025, respectively.

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