Filling and treatment method for old tunnel in residual coal re-mining area

Abstract

The present invention discloses a method for filling and treating old lanes in a residual coal re-mining area, comprising collecting and analyzing data from the residual coal re-mining area; selecting a working face location to be mined within the residual coal re-mining area, dividing and determining a laneway treatment area and a working face treatment area; determining the strength of the filling bodies in the laneway treatment area and the working face treatment area, respectively, and selecting filling materials and material proportions based on the filling body strength; performing advance pre-grouting in the laneway treatment area to compact the old lanes in the laneway treatment area; reserving a portion of the solid geological structure layer as a protective curtain, constructing a drill hole in the drift through the protective curtain and into the working face treatment area, and filling the working face treatment area. The present invention utilizes different filling bodies for the laneway treatment area and the working face treatment area for zonal filling, resulting in good surrounding rock stability. While ensuring safe mining, it reduces the amount of filling material used, lowering the cost of old lane treatment and the production cost of the residual coal re-mining area.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mining, and in particular relates to a method for filling and managing old lanes in a residual coal re-mining area. Background Art

[0002] In the relevant technologies, during the re-mining of residual coal areas, the main methods of passing through old tunnels during excavation and mining are: strengthening the support of old tunnels with dense pillars or wood piles, anchor cable and grouting reinforcement, polymer material grouting and filling, and advanced filling and reinforcement of old tunnels. After filling the old tunnels (empty areas), the following problems can be effectively eliminated: (1) the difficulty of roof management caused by the adverse effect of the advanced stress of the working face on the old tunnels (empty areas); (2) there may be water accumulation in the old tunnels (empty areas), which may lead to water seepage accidents; (3) due to the existence of a certain amount of space in the old tunnels (empty areas), a certain amount of toxic and harmful gases may accumulate in it, which may bring safety hazards to the safe production of mines. Summary of the Invention

[0003] To meet the need for safe and efficient remining of residual coal, with the continuous improvement of mining technology, the use of residual coal backfilling in small kiln damaged areas has rapidly increased. However, when backfilling old lanes (voids), a uniform backfill strength is generally applied across the entire area, failing to consider the varying support strength requirements of different areas. Therefore, while lower backfill strengths are used in both the mining face and the roadway, the support strength requirements of the mining face are met. However, during roadway excavation, the backfill strength in the roadway fails to meet roadway maintenance requirements, making roadway support difficult. When considering the support strength requirements of roadway excavation, higher backfill strengths are required, requiring more cement and other binders. While this approach meets the structural stability requirements of surrounding rock in lanes such as return chutes, transport chutes, and cut-holes during mining, it also results in excessively high backfilling costs and poor economic benefits for old lanes (voids), leading to its limited application in remining old lanes in residual coal areas.

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a method for filling and managing old lanes in residual coal re-mining areas, which improves the filling efficiency and stability of old lanes and reduces the production cost of residual coal re-mining areas.

[0006] The method for filling and treating an old lane in a residual coal re-mining area according to an embodiment of the present invention comprises:

[0007] Conduct data collection and analysis on residual coal mining areas;

[0008] Selecting the working face location to be mined in the residual coal mining area, dividing and determining the tunneling control area and the working face control area;

[0009] Determining the filling strength of the tunneling treatment area and the working face treatment area respectively, and selecting filling materials and material ratios according to the filling strength;

[0010] Pre-grouting is performed on the tunneling treatment area to fill the old tunnel in the tunneling treatment area densely;

[0011] A portion of the solid geological structure layer is reserved as a protective curtain, and a drilling hole is constructed in the trench to pass through the protective curtain and enter the working face treatment area to fill the working face treatment area.

[0012] The filling and treatment method for old tunnels in the residual coal re-mining area according to the embodiment of the present invention adopts different filling bodies for zoned filling in the tunneling treatment area and the working face treatment area respectively. After filling, the amount of filling materials can be reduced while ensuring the stability of the surrounding rock structure of the old tunnel (empty area) and achieving the purpose of safe mining, thereby effectively reducing the treatment cost of the old tunnel (empty area) and reducing the production cost of the residual coal re-mining area.

[0013] In some embodiments, the steps for collecting and analyzing data from the residual coal mining area include:

[0014] Collect data on the residual coal mining area, including geological structure, roadway distribution and surrounding rock characteristics;

[0015] Based on the data, a geological profile and a roadway distribution map of the residual coal mining area are drawn.

[0016] In some embodiments, the working face position to be mined includes the return air chute position, the transport chute position and the cut-eye position; the width of the working face to be mined is satisfy: ;

[0017] in, The maximum construction depth of grouting drilling; is the slurry diffusion radius in the working face treatment area.

[0018] In some embodiments, the filling strength of the tunnel treatment area is satisfy: ;

[0019] in, is the safety factor, which is 1.2 to 1.5; is the average bulk density of the overlying rock strata, ; is the mining depth, m; is the lane width, m; is the width of the filling, m;

[0020] The filling strength of the working face treatment area satisfy: ;

[0021] in, is the safety factor, ranging from 1.0 to 1.2; is the average bulk density of the two overlying rock layers, ; The maximum development height of the two coal seam mining zones, m.

[0022] In some embodiments, the filling material includes at least one or more of cement, fly ash, sand and gravel, and coal; the step of selecting the filling material and the material ratio according to the strength of the filling body includes:

[0023] Select filling material and prepare it into slurry;

[0024] Conduct grouting tests and test the solidified blocks to determine whether the strength of the blocks reaches a preset threshold;

[0025] If not, the composition and / or proportion of the filling material is adjusted, and the grouting test is repeated until the strength of the consolidated block reaches a preset threshold.

[0026] In some embodiments, the step of pre-grouting the tunneling treatment area includes:

[0027] Arrange multiple boreholes at the tunnel head position in the tunnel driving control area, with the terminal positions of the boreholes extending beyond the outline of the tunnel driving control area, the boreholes including a first borehole, a second borehole, a third borehole, and a fourth borehole, wherein the multiple first boreholes are adjacent to the roof and spaced apart, the multiple second boreholes are adjacent to the left tunnel side and spaced apart, the multiple third boreholes are adjacent to the right tunnel side and spaced apart, and there is at least one fourth borehole, which is arranged in the middle of the tunnel head position;

[0028] The advance pre-grouting is carried out by using the drill hole at the head position of the tunnel in the tunnel excavation and treatment area through the multi-entry gradient circulation grouting method.

[0029] In some embodiments, the distance between the first borehole and the roof is 300 mm to 800 mm; the distance between the second borehole and the left lane side is 300 mm to 800 mm, and the distance between two adjacent second boreholes is 300 mm to 800 mm; the distance between the third borehole and the right lane side is 300 mm to 800 mm, and the distance between two adjacent third boreholes is 300 mm to 800 mm;

[0030] And / or, the multiple drill holes at the head of the tunnel in the tunnel excavation and management area are symmetrically arranged in the horizontal direction.

[0031] In some embodiments, the step of reserving a portion of the solid geological structure layer as a protective curtain includes: excavating the tunnel by drilling first and then advancing, with the excavation length being less than the drilling length to reserve the solid geological structure layer as a protective curtain;

[0032] The step of drilling a hole in the drift through the protective curtain and into the working face treatment area to fill the working face treatment area includes:

[0033] Drilling holes are constructed on the mining sides of the return air chute and the transport chute respectively. The mining sides of the return air chute and the transport chute each include multiple mining side sections. A group of drill holes is provided at the head of each mining side section. The drill holes pass through the protective curtain and enter the working face treatment area. The terminal hole positions of the drill holes extend beyond the contour line of the working face treatment area.

[0034] Grouting is performed into the working face treatment area through the drill holes on the mining wall in a multi-step gradient circulation grouting manner until the old tunnel in the working face treatment area is filled densely.

[0035] In some embodiments, a group of boreholes located on the same mining wall section includes a fifth borehole, a sixth borehole, a seventh borehole, and an eighth borehole, a plurality of the fifth boreholes are adjacent to the roof and spaced apart, a plurality of the sixth boreholes are spaced apart in the vertical direction and adjacent to one side of the plurality of the fifth boreholes in the horizontal direction, a plurality of the seventh boreholes are spaced apart in the vertical direction and adjacent to the other side of the plurality of the fifth boreholes in the horizontal direction, there is at least one eighth borehole, and the eighth borehole is located in the middle of the head position of the mining wall section, the spacing between the fifth borehole and the roof is 300 mm to 800 mm, the spacing between two adjacent sixth boreholes is 300 mm to 800 mm, and the spacing between two adjacent seventh boreholes is 300 mm to 800 mm;

[0036] And / or, the multiple drill holes located on the same mining wall section are arranged symmetrically in the horizontal direction.

[0037] In some embodiments, the method for filling and treating old lanes in the residual coal re-mining area further comprises:

[0038] Conduct performance evaluation on old lanes in the residual coal mining area after treatment to determine whether the bearing capacity of the treated area meets the preset requirements;

[0039] If not, perform secondary grouting or adjust the above steps. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a flow chart of the method for filling and controlling old lanes in residual coal re-mining areas according to an embodiment of the present invention.

[0041] Figure 2It is a schematic diagram of the divisions of the tunneling management area and the working face management area in an embodiment of the present invention.

[0042] Figure 3 Schematic diagram of the front view of the drilling arrangement in the tunneling treatment area in the embodiment of the present invention.

[0043] Figure 4 It is a side view schematic diagram of the drilling arrangement in the tunneling treatment area in an embodiment of the present invention.

[0044] Figure 5 Schematic top view of the drilling arrangement in the tunneling control area according to an embodiment of the present invention.

[0045] Figure 6 It is a front view schematic diagram of the drilling arrangement of the working face treatment area in an embodiment of the present invention.

[0046] Figure 7 Schematic diagram of the test of the drilling arrangement of the working face treatment area in the embodiment of the present invention.

[0047] Figure 8 Schematic top view of the drilling arrangement in the working face treatment area according to an embodiment of the present invention.

[0048] Reference numerals:

[0049] 1. Residual coal mining area; 11. Roadway management area; 12. Working face management area; 13. Outline of roadway management area; 14. Outline of working face management area;

[0050] 21. Return air chute; 22. Transport chute; 23. Cutting eye; 24. Mining side;

[0051] 31. First borehole; 32. Second borehole; 33. Third borehole; 34. Fourth borehole;

[0052] 41. Top plate; 42. Left lane side; 43. Right lane side; 44. Bottom plate;

[0053] 5. Protective curtain;

[0054] 61. Fifth borehole; 62. Sixth borehole; 63. Seventh borehole; 64. Eighth borehole. DETAILED DESCRIPTION

[0055] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0056] The following describes a method for filling and treating an old lane in a residual coal re-mining area according to an embodiment of the present invention.

[0057] See also Figures 1 to 8The method for filling and treating old lanes in a residual coal mining area according to an embodiment of the present invention comprises:

[0058] S101. Collect and analyze data for Residual Coal Re-mining Area 1. The collected data may include the geological structure, roadway (existing old roadway) distribution, and surrounding rock characteristics of Residual Coal Re-mining Area 1. Previous production drawings may also be consulted to more accurately understand the current status of the Residual Coal Re-mining Area. After obtaining the relevant data, a geological profile and roadway distribution map of the Residual Coal Re-mining Area can be drawn based on the data. This provides a more intuitive display of the current status of the Residual Coal Re-mining Area, facilitating subsequent operations and providing a basis for subsequent remediation work.

[0059] S102. Select the working face location for mining within the residual coal recovery area, and divide and determine the tunneling control area 11 and the working face control area 12. Based on information such as the residual coal inventory, residual coal distribution, distribution of old tunnels (empty areas), and stratum stability, rationally plan tunneling control area 11 and working face control area 12 to provide a stable structural foundation for subsequent recovery operations, improve construction safety, and increase the amount of residual coal recovered.

[0060] S103. Determine the backfill strength for each of the tunneling control area 11 and the working face control area 12, and select the backfill material and material ratio based on the backfill strength. Because the tunneling control area 11 and the working face control area 12 perform different functions during mining operations, the backfill strength of each control area can be determined based on their respective functional requirements. By selecting the appropriate backfill material for backfilling, backfill costs can be reduced while ensuring operational safety.

[0061] In the prior art, tunneling treatment area 11 and working face treatment area 12 are filled with a uniform filling strength. However, when using a filling material with a higher filling strength, more material is used, resulting in excessive filling and treatment costs and poor economic benefits. When using a filling material with a lower filling strength, the tunnel support strength does not meet the standard, making tunnel support difficult and posing a safety risk.

[0062] Compared with the means in related technologies, the embodiments of the present invention can divide the areas according to the functional requirements of the tunneling management area 11 and the working face management area 12, and select different filling materials and material ratios for each area, so as to improve economic benefits, reduce costs, and ensure the safety of construction operations and the stability of the underground support structure.

[0063] S104: Pre-grouting is performed in advance in the tunneling control area 11 to fill the old tunnel in the tunneling control area 11 tightly. During the filling process, the tunneling control area 11 can be filled first. The pre-grouting method not only fills the old tunnel (empty area) in front tightly, but also cements the broken surrounding rock within the reinforcement area to form a stable geological structure, thereby reshaping the stratum structure and achieving the desired structural strength, which facilitates subsequent construction operations.

[0064] S105. Reserve part of the solid geological structure layer as a protective curtain 5, drill holes through the protective curtain 5 and enter the working face treatment area 12 in the drift, and fill the working face treatment area 12. When filling the working face treatment area 12, a solid geological structure layer of a certain thickness in front of the working face treatment area 12 can be used as a protective curtain 5. The solid geological structure layer can be a coal seam of a certain thickness. Drill holes through the protective curtain 5 in the drift, and then enter the working face treatment area 12, and grouting is performed into the working face treatment area 12 through the drill holes. During the filling process, not only can the old tunnel (empty area) in front be filled densely, but the broken surrounding rock within the reinforcement range can also be cemented together to form a stable geological structure, so that the coal seam structure is reshaped, the integrity and bearing capacity of the coal seam are improved, and after achieving the ideal structural strength, subsequent construction operations are facilitated.

[0065] The filling and treatment method for old tunnels in the residual coal re-mining area according to the embodiment of the present invention adopts different filling body strengths for zoned filling in the tunneling treatment area 11 and the working face treatment area 12. After filling, the amount of filling materials can be reduced while ensuring the stability of the surrounding rock structure of the old tunnel (empty area) and achieving the purpose of safe mining, thereby effectively reducing the treatment cost of the old tunnel (empty area) and reducing the production cost of the residual coal re-mining area.

[0066] The following describes some specific embodiments of the present invention for the filling and treatment methods of old lanes in residual coal re-mining areas.

[0067] See also Figures 1 to 8 A method for filling and treating old lanes in residual coal re-mining areas, comprising:

[0068] S101. Collect and analyze data from the residual coal mining area. The collected data may include the geological structure, roadway (existing old roadway) distribution, and surrounding rock characteristics of the residual coal mining area. Previous production drawings may also be consulted to more accurately understand the current status of the residual coal mining area. After obtaining the developed data, a geological profile and roadway distribution map of the residual coal mining area can be drawn based on the data. This provides a more intuitive display of the current status of the residual coal mining area, facilitating subsequent operations and providing a basis for subsequent remediation work.

[0069] S102, such as Figure 2As shown, the working face position to be mined is selected in the residual coal mining area, and the tunneling control area 11 and the working face control area 12 are divided and determined.

[0070] The working face positions to be mined include the return air chute 21, the transport chute 22 and the cut-hole 23. By determining the corresponding positions, it is convenient to divide and fill different treatment areas, and it is also convenient for the subsequent residual coal mining. satisfy: .in, The maximum construction depth of grouting drilling; is the slurry diffusion radius in the working face treatment area 12.

[0071] In the embodiment of the present invention, the width of the working face to be mined is determined by the maximum construction depth of the grouting drilling during construction and the diffusion radius of the slurry in the working face treatment area 12. The slurry diffusion radius is determined based on the geological conditions, water permeability, composition and ratio of the slurry in the working face treatment area 12, etc., which can ensure the filling effect of the treatment area and improve the safety of construction operations and the efficiency of construction.

[0072] Based on information such as the amount of residual coal, the distribution of residual coal, the distribution of old tunnels (empty areas), and the stability of the stratum, the tunneling control area 11 and the working face control area 12 are rationally planned to provide a stable structural foundation for subsequent mining operations, improve the safety of construction operations, and increase the amount of residual coal recovered.

[0073] S103. Determine the backfill strength for each of the tunneling control area 11 and the working face control area 12, and select the backfill material and material ratio based on the backfill strength. Because the tunneling control area 11 and the working face control area 12 perform different functions during mining operations, the backfill strength of each control area can be determined based on their respective functional requirements. By selecting the appropriate backfill material for backfilling, backfill costs can be reduced while ensuring operational safety.

[0074] In related art, tunneling treatment area 11 and working face treatment area 12 are filled with a uniform filling strength. Using a higher filling strength filler results in a higher material consumption, high filling treatment costs, and poor economic benefits. Using a lower filling strength filler results in substandard tunnel support strength, making tunnel support difficult and posing safety risks.

[0075] Compared with the means in related technologies, the embodiments of the present invention can divide the areas according to the functional requirements of the tunneling management area 11 and the working face management area 12, and select different filling materials and material ratios for each area, so as to improve economic benefits, reduce costs, and ensure the safety of construction operations and the stability of the underground support structure.

[0076] In the embodiment of the present invention, the filling strength of the tunnel treatment area 11 is satisfy:

[0077] .

[0078] in, is the filling strength, MPa; is the safety factor, which is 1.2 to 1.5; is the average bulk density of the overlying rock strata, ; is the mining depth, m; is the lane width, m; is the width of the filling body, m.

[0079] Filling strength of working face treatment area 12 satisfy:

[0080] .

[0081] in, is the filling strength, MPa; is the safety factor, ranging from 1.0 to 1.2; is the average bulk density of the two overlying rock layers, ; The maximum development height of the two zones in the coal seam mining, m. The two zones can be the collapse zone and fracture zone in the overlying rock strata in the working face treatment area 12.

[0082] The filling material in embodiments of the present invention includes at least one or more of cement, fly ash, sand and gravel, and coal. For example, the filling material may be a slurry containing cement and fly ash. In another example, the filling material may be a slurry containing coal, cement, and fly ash. In another example, the filling material may be a slurry containing cement, fly ash, and sand and gravel.

[0083] In practical applications, the composition and proportion parameters of the filling slurry can be determined according to the stratum characteristics of the tunneling management area 11 and the working face management area 12 in the residual coal mining area, and the concentration of the slurry can also be adjusted according to the fluidity of the slurry.

[0084] When selecting filling materials and material ratios, the selected filling materials can be prepared into a slurry and a grouting test can be performed. After the slurry solidifies, the solidified consolidation block is tested to determine whether the strength of the consolidation block meets a preset threshold. For example, the strength can be tested through a pressure test. If the requirements are met, the corresponding materials and ratios can be used. If the strength requirements are not met, the composition and / or ratio of the filling materials can be adjusted, and the grouting test can be repeated until the strength of the consolidation block reaches the preset threshold.

[0085] S104, such as Figures 3 to 5 As shown, multiple boreholes are arranged at the head of the tunnel in the tunneling control area 11. The boreholes include a first borehole 31, a second borehole 32, a third borehole 33, and a fourth borehole 34. The tunnel in the tunneling control area 11 has a roof 41, a floor 44, a left tunnel side 42, and a right tunnel side 43. Multiple first boreholes 31 are adjacent to the roof 41 and spaced apart. The spacing between the first boreholes 31 and the roof 41 is 300 mm to 800 mm. Multiple second boreholes 32 are adjacent to the left tunnel side 42 and spaced apart. The spacing between the second boreholes 32 and the left tunnel side 42 is 300 mm to 800 mm, and the spacing between adjacent second boreholes 32 is 300 mm to 800 mm. Multiple third boreholes 33 are adjacent to the right tunnel side 43 and spaced apart. The spacing between the third boreholes 33 and the right tunnel side 43 is 300 mm to 800 mm, and the spacing between adjacent third boreholes 33 is 300 mm to 800 mm. There is at least one fourth bore hole 34 , and the fourth bore hole 34 is arranged in the middle of the head position of the tunnel.

[0086] Preferably, in this example, there are three first boreholes 31, one of which is located in the middle of the tunnel head position in the horizontal direction of the tunnel excavation management area 11, and the other two first boreholes 31 are respectively arranged adjacent to the left tunnel side 42 and the right tunnel side 43. There are two second boreholes 32, which are located below the leftmost first borehole 31. There are two third boreholes 33, which are located below the rightmost first borehole 31. There is one fourth borehole 34, which is located below the middle first borehole 31. Figure 3 As shown in FIG, the eight boreholes at the head of the tunnel in the tunneling treatment area 11 are arranged symmetrically in the horizontal direction.

[0087] During the drilling process, the final hole position of the borehole extends beyond the outline 13 of the tunneling treatment area. Figure 4 and Figure 5 shown. Figure 4 Direction A in the figure represents the excavation direction. The boreholes at the head of the tunnel in the tunneling control area 11 generally extend in direction A, with some boreholes tilted generally upward or toward the left or right tunnel side. By setting the inclination angles and extension directions of the multiple boreholes to form a gradient distribution, during grouting, pre-grouting can be performed using the boreholes at the head of the tunnel in the tunneling control area 11 through a multi-step gradient cyclic grouting method.

[0088] The embodiment of the present invention fills the tunneling management area 11 in the form of advance pre-grouting. During the filling process, not only the old tunnel (empty area) in front can be filled densely, but also the broken surrounding rocks within the reinforcement range can be cemented together to form a stable geological structure, so that the stratum structure can be reshaped. After achieving the ideal structural strength, subsequent construction operations are facilitated.

[0089] Drill holes are arranged at the head of the mining tunnel to carry out advance pre-grouting reinforcement of the old tunnel. The principle of "explore first, then dig" and "explore more, dig less" (that is, the excavation length after each drilling is completed is not greater than the drilling length) are adopted. According to the results of drilling the old tunnel (empty area), a certain amount of solid coal is reserved as a protective curtain each time excavation is carried out5.

[0090] S105, such as Figures 6 to 8 As shown, a portion of the solid geological structure layer is reserved as a protective curtain 5. This protective curtain can be reserved during excavation by drilling first and then excavating. For example, the protective curtain 5 can be a coal seam 20 to 30 meters thick. Leveraging the protective curtain 5 structure formed during excavation, a borehole is drilled through the protective curtain 5 and into the working face treatment area 12 within the trench to fill the working face treatment area 12.

[0091] In actual operations, drilling holes are constructed in the mining walls 24 of the return air chute 21 and the transport chute 22. Each of these walls 24 includes multiple mining wall sections. It is understood that the mining wall 24 can be divided into multiple mining wall sections along the extension direction of the return air chute 21 or the transport chute 22, with a set of drill holes arranged in the middle of the head position of each mining wall section. The drill holes pass through the protective curtain 5 and enter the working face treatment area 12. The final drilling position of the drill holes extends beyond the working face treatment area contour line 14.

[0092] Among them, Figure 6 As shown, a group of boreholes located on the same mining wall section includes a fifth borehole 61, a sixth borehole 62, a seventh borehole 63 and an eighth borehole 64. Multiple fifth boreholes 61 are adjacent to the top plate 41 and are spaced apart. The spacing between the fifth borehole 61 and the top plate 41 is 300 mm to 800 mm. Multiple sixth boreholes 62 are spaced apart in the vertical direction and adjacent to one side of the multiple fifth boreholes 61 in the horizontal direction. The spacing between two adjacent sixth boreholes 62 is 300 mm to 800 mm. Multiple seventh boreholes 63 are spaced apart in the vertical direction and adjacent to the other side of the multiple fifth boreholes 61 in the horizontal direction. The spacing between two adjacent seventh boreholes 63 is 300 mm to 800 mm. There is at least one eighth borehole 64, and the eighth borehole 64 is located in the middle of the head position of the mining wall section.

[0093] Preferably, if Figure 6As shown, in this example, a group of boreholes located on the same mining wall section is located in the middle part of the mining wall section. The number of fifth boreholes 61 is three, and the three fifth boreholes 61 are arranged at intervals in the horizontal direction. The number of sixth boreholes 62 is two, and the two sixth boreholes 62 are located below a fifth borehole 61 at one end of the three fifth boreholes 61. The number of seventh boreholes 63 is two, and the two seventh boreholes 63 are located below a fifth borehole 61 at the other end of the three fifth boreholes 61. The number of eighth borehole 64 is one, and the eighth borehole 64 is located below the fifth borehole 61 in the middle of the three fifth boreholes 61. Figure 6 As shown in the figure, the eight drill holes at the head of the roadway in the mining section are arranged symmetrically in the horizontal direction.

[0094] like Figure 7 and Figure 8 As shown, during the drilling process, the final position of the borehole extends beyond the contour line 14 of the working face treatment area. A group of boreholes in the same mining wall section can cover the area covered by the corresponding mining wall section by designing the inclination direction and angle of the boreholes, ensuring sufficient filling of the working face treatment area 12. By setting the inclination angles and extension directions of multiple boreholes to form a gradient distribution, when grouting is performed, grouting is injected into the working face treatment area 12 through the boreholes on the mining wall 24 in a multi-step gradient circulation grouting method until the old lanes in the working face treatment area 12 are filled densely.

[0095] By drilling holes through the protective curtain 5 in the drift and then entering the working face treatment area 12, grouting is carried out through the drilled holes. The filling process not only densely fills the old roadway (empty area) ahead, but also cements the broken surrounding rock within the reinforcement area to form a stable geological structure, reshapes the coal seam structure, improves the integrity and bearing capacity of the coal seam, and facilitates subsequent construction operations after achieving the ideal structural strength.

[0096] After treatment, the performance of the old lanes in the residual coal mining area is evaluated to determine whether the bearing capacity of the treated area meets the preset requirements. If not, secondary grouting is performed or the above steps are adjusted. It is understood that after the treatment is completed, a comprehensive evaluation of the treatment results can be conducted to test whether the old lanes (empty areas) have been effectively reinforced and whether the coal seam has sufficient bearing capacity. Based on the evaluation results, the treatment plan can be optimized and adjusted to provide reference for subsequent treatment work. At the same time, the treated area can also be backfilled to ensure that it meets quality requirements.

[0097] The filling and treatment method for old tunnels in the residual coal re-mining area according to the embodiment of the present invention adopts different filling body strengths for zoned filling in the tunneling treatment area and the working face treatment area respectively. After filling, the amount of filling materials can be reduced while ensuring the stability of the surrounding rock structure of the old tunnel (empty area) and achieving the purpose of safe mining, thereby effectively reducing the treatment cost of the old tunnel (empty area) and reducing the production cost of the residual coal re-mining area.

[0098] In this embodiment of the present invention, strength-based backfilling is employed in both the tunneling and working face management zones. The backfill strength in the tunneling management zone primarily considers the integrity of the surrounding rock mass and support requirements, and therefore can be high-strength backfill. The working face management zone, on the other hand, primarily considers the need for the coal seam to maintain good integrity and stability under advanced support pressure, and therefore can utilize low-strength backfill. Therefore, the backfill material ratio can be optimized and adjusted based on the desired backfill strength in different management zones, significantly reducing production and backfilling costs.

[0099] After the embodiment of the present invention performs grouting filling on the goaf or damaged area in the re-mining area, the goaf space is filled with filling materials, which effectively eliminates hidden disaster-causing factors such as harmful gases / accumulated water / spontaneous combustion in the old goaf damaged area, ensures the normal and safe advancement of the mining face, and avoids safety hazards in the coal mining process such as irregular working face cutting and passing old tunnels during the working face mining process, thereby ensuring the normal mining of the working face and improving mining efficiency.

[0100] In related technologies, the coal resource recovery rate in goaf or damaged areas of small coal mines within re-mining areas is less than 30%, often below 20%. Using the backfilling method of the present invention, the coal resource recovery rate after re-mining residual coal can reach over 95%, while reducing backfilling costs. This not only improves resource recovery and frees up a large amount of stagnant coal resources in the damaged areas of small coal mines, but also effectively extends the service life of the mine, significantly improving the economic, environmental, and social benefits of the enterprise.

[0101] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0102] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0103] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0104] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0105] In the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples" mean 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 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 can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification, as well as features of different embodiments or examples, unless they are mutually inconsistent.

[0106] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for filling and treating old lanes in residual coal re-mining areas, characterized in that: include: Conduct data collection and analysis on residual coal mining areas; Selecting the working face location to be mined in the residual coal mining area, dividing and determining the tunneling control area and the working face control area; Determining the filling strength of the tunneling treatment area and the working face treatment area respectively, and selecting filling materials and material ratios according to the filling strength; Pre-grouting is performed on the tunneling treatment area to fill the old tunnel in the tunneling treatment area densely; A portion of the solid geological structure layer is reserved as a protective curtain for the working face treatment area, and a hole is drilled in the trench through the protective curtain and into the working face treatment area to fill the working face treatment area; The working face position to be mined includes the return air chute position, the transport chute position and the cut-eye position; the width of the working face to be mined is satisfy: ; in, The maximum construction depth of grouting drilling; is the slurry diffusion radius in the working face treatment area; The filling strength of the tunnel treatment area satisfy: ; in, is the safety factor, which is 1.2 to 1.5; is the average bulk density of the overlying rock strata, ; is the mining depth, m; is the lane width, m; is the width of the filling, m; The filling strength of the working face treatment area satisfy: ; in, is the safety factor, ranging from 1.0 to 1.2; is the average bulk density of the two overlying rock layers, ; is the maximum development height of the two zones of coal seam mining, m; The step of pre-grouting the tunneling treatment area comprises: Arrange multiple boreholes at the tunnel head position in the tunnel driving control area, with the terminal positions of the boreholes extending beyond the outline of the tunnel driving control area, the boreholes including a first borehole, a second borehole, a third borehole, and a fourth borehole, wherein the multiple first boreholes are adjacent to the roof and spaced apart, the multiple second boreholes are adjacent to the left tunnel side and spaced apart, the multiple third boreholes are adjacent to the right tunnel side and spaced apart, and there is at least one fourth borehole, which is arranged in the middle of the tunnel head position; Using the drill holes at the head of the tunnel in the tunneling treatment area, advance pre-grouting is performed by multi-step gradient circulation grouting; The step of reserving a part of the solid geological structure layer as a protective curtain includes: excavating the tunnel by drilling first and then driving, wherein the driving length is less than the drilling length to reserve the solid geological structure layer as a protective curtain; The step of drilling a hole in the drift through the protective curtain and into the working face treatment area to fill the working face treatment area includes: Drilling holes are respectively constructed on the mining sides of the return air chute and the transport chute, wherein the mining sides of the return air chute and the transport chute each include multiple mining side sections, and a group of drill holes is provided at the head position of each mining side section. The drill holes pass through the protective curtain and enter the working face treatment area, and the terminal hole positions of the drill holes extend beyond the contour line of the working face treatment area; Grouting is performed into the working face treatment area through the drill holes on the mining wall in a multi-step gradient circulation grouting manner until the old tunnel in the working face treatment area is filled densely.

2. The method for filling and treating old lanes in residual coal re-mining areas according to claim 1 is characterized in that: The following steps are used to collect and analyze data from the residual coal mining area: Collect data on the residual coal mining area, including geological structure, roadway distribution and surrounding rock characteristics; Based on the data, a geological profile and a roadway distribution map of the residual coal mining area are drawn.

3. The method for filling and treating old lanes in residual coal re-mining areas according to claim 1 is characterized in that: The filling material includes at least one or more of cement, fly ash, sand and gravel, and coal; the step of selecting the filling material and the material ratio according to the strength of the filling body includes: Select filling material and prepare it into slurry; Conduct grouting tests and test the solidified blocks to determine whether the strength of the blocks reaches a preset threshold; If not, the composition and / or proportion of the filling material is adjusted, and the grouting test is repeated until the strength of the consolidated block reaches a preset threshold.

4. The method for filling and treating old lanes in residual coal re-mining areas according to claim 1 is characterized in that: The distance between the first borehole and the roof is 300mm to 800mm; the distance between the second borehole and the left lane side is 300mm to 800mm, and the distance between two adjacent second boreholes is 300mm to 800mm; the distance between the third borehole and the right lane side is 300mm to 800mm, and the distance between two adjacent third boreholes is 300mm to 800mm; And / or, the multiple drill holes at the head of the tunnel in the tunnel excavation and management area are symmetrically arranged in the horizontal direction.

5. The method for filling and treating old lanes in residual coal re-mining areas according to claim 1 is characterized in that: A group of boreholes located on the same mining wall section includes a fifth borehole, a sixth borehole, a seventh borehole and an eighth borehole, a plurality of the fifth boreholes are adjacent to the roof and are spaced apart, a plurality of the sixth boreholes are spaced apart in the vertical direction and are adjacent to one side of the plurality of the fifth boreholes in the horizontal direction, a plurality of the seventh boreholes are spaced apart in the vertical direction and are adjacent to the other side of the plurality of the fifth boreholes in the horizontal direction, there is at least one eighth borehole, and the eighth borehole is located in the middle of the head position of the mining wall section, the spacing between the fifth borehole and the roof is 300 mm to 800 mm, the spacing between two adjacent sixth boreholes is 300 mm to 800 mm, and the spacing between two adjacent seventh boreholes is 300 mm to 800 mm; And / or, the multiple drill holes located on the same mining wall section are arranged symmetrically in the horizontal direction.

6. The method for filling and treating old lanes in residual coal re-mining areas according to any one of claims 1 to 5, characterized in that: The method for filling and treating old lanes in the residual coal re-mining area also includes: Conduct performance evaluation on old lanes in the residual coal mining area after treatment to determine whether the bearing capacity of the treated area meets the preset requirements; If not, perform secondary grouting.

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