Gob-side entry retaining method using gangue filling

Abstract

The application provides a gangue filling along empty roadway method, comprising: an advance supporting step; a gangue filling step: a first area is filled with gangue of a coarse particle size to form a grouting cementing part, then a second area is filled with gangue of a fine particle size to form a middle blocking part, then a third area is filled with gangue of the coarse particle size to form a bearing part, the coarse particle size is larger than the fine particle size; finally, the filled gangue is rammed; a reinforcing step; a seepage-proof layer spraying step: a seepage-proof material is sprayed on a side of the grouting cementing part facing the along empty roadway and a side of the grouting cementing part facing an unfilled goaf; a grouting step: the grouting cementing part is grouted and reinforced by using a grouting anchor rod. The application realizes efficient utilization of the gangue and improves the surrounding rock stability of the along empty roadway; the application solves the problems of a complex process, more materials and high cost of the gangue filling along empty roadway method in the prior art, and is suitable for large-scale popularization and use.

Description

Technical Field

[0001] This invention relates to the field of mine gangue backfilling technology, and more specifically, to a method for gangue backfilling and leaving a roadway along the goaf. Background Technology

[0002] Currently, coal resources, as my country's primary energy source, have a significant impact on the country's economic development. However, the mining process has resulted in serious resource waste and environmental damage, primarily manifested in surface subsidence, water resource destruction and pollution, gangue pile accumulation, low extraction rates, and environmental damage in mining areas. Gangue backfilling mining technology has significant technical advantages in improving mine extraction rates, weakening mine pressure manifestations, reducing roadway surrounding rock stress, and reducing mine gangue emissions, making it an important technical means to achieve green mining. Meanwhile, goaf retention technology, through the replacement and utilization of roadways, has outstanding advantages such as improving coal resource recovery rates, reducing roadway excavation rates, alleviating difficulties in mining replacement, and also reducing the probability of underground disasters caused by coal pillars.

[0003] In existing technologies, gob-side retainers are typically isolated from the goaf by filling them with filler material to control the stability of the surrounding rock. Current methods for filling gob-side retainers usually involve using conventional high-water-content materials or concrete. Both methods suffer from complex procedures, high material input during construction, and high costs. Consequently, mines with complex geological conditions and poor profitability are often reluctant to use these technologies for gob-side retainer filling, making it impossible to safely isolate the gob-side retainer from the goaf, potentially leading to safety accidents. Summary of the Invention

[0004] This invention provides a method for backfilling gob-side tunnels with gangue, which solves the problems of complex procedures, large material inputs, and high costs in existing backfilling methods.

[0005] To address the aforementioned problems, this invention provides a method for backfilling gob-side retaining roadways with gangue, comprising: a pre-support step: multiple hydraulic props are spaced apart along the extension direction of the gob-side retaining roadway to support the roadway roof; then a shielding assembly is fixed relative to the hydraulic props, the shielding assembly being used to seal the gob-side retaining roadway and temporarily separating it from the gob-side retaining roadway; a gangue backfilling step: a section of the gob-side is divided into a first region, a second region, and a third region arranged sequentially and adjacently, the first region, the second region, and the third region all extending along the mining direction, and the extension direction being parallel to the extension direction of the gob-side retaining roadway; the first region is located close to the gob-side retaining roadway; the first region is backfilled with coarse-grained gangue to form a grouting cemented section, and then the second region is backfilled with fine-grained gangue to form a central section. The process involves several steps: First, a barrier section is formed. Then, a third area is filled with coarse-grained gangue to form a support section, where the coarse-grained diameter is larger than the fine-grained diameter. Finally, the filled gangue is compacted. Second, a reinforcement step is performed: holes are drilled on the side of the grouting bonded section facing the goaf, and grouting anchors or cables are placed in each of the drilled holes to reinforce and fix the grouting bonded section. Third, an anti-seepage layer is sprayed: anti-seepage material is sprayed on both the side of the grouting bonded section facing the goaf and the side facing the unfilled goaf to form a slurry anti-seepage layer on the surface. This slurry anti-seepage layer prevents the grouting material in the grouting bonded section from seeping to the surface. Fourth, grouting is performed: grouting anchors are used to reinforce the grouting bonded section, and a central barrier section prevents the grouting material from penetrating into the support section. After grouting is completed, the isolation between the goaf and the goaf is achieved.

[0006] Furthermore, the method for backfilling gob-side retaining with gangue also includes a first post-treatment step: after the grouting step is completed, multiple hydraulic supports are disassembled, and then foamed concrete material is sprayed onto the side of the grouting bond facing the gob-side retaining to form a concrete layer on the surface.

[0007] Furthermore, the method of backfilling along the goaf and leaving a roadway also includes a second follow-up treatment step: after the first follow-up treatment step is completed, wait for the concrete layer to solidify and form, and then spray polyurethane material on the surface of the concrete layer to form a weather-resistant coating on the surface of the concrete layer.

[0008] Furthermore, the first follow-up treatment step also includes: dismantling multiple hydraulic supports when the distance between the mining face and the grouting bonding part is within the range of 150m to 180m; controlling the thickness of the concrete layer within the range of 40mm to 100mm; the foamed concrete material includes cement, sand, water and quick-setting agent, wherein the mass ratio of cement to sand is one to two.

[0009] Furthermore, in the advance support step, the shielding assembly includes a rock-blocking metal mesh and a polyester fiber cloth; the rock-blocking metal mesh is detachably and fixedly connected to the hydraulic props by fasteners to shield the rock; the polyester fiber cloth is bound and fixed to the surface of the rock-blocking metal mesh by wire to seal the rock-blocking metal mesh; wherein, the rock-blocking metal mesh and the polyester fiber cloth extend along the extension direction of the goaf-retention tunnel; the mesh of the rock-blocking metal mesh is square and the side length is less than or equal to 45mm; and / or, in the advance support step, multiple hydraulic props are arranged at equal intervals with a spacing of no more than 0.6m.

[0010] Furthermore, in the gangue filling step, the thickness of the grouting cemented section is 1.5m to 2.0m; the thickness of the central barrier section is not less than 0.5m; the coarse particle size is 20mm to 40mm; the fine particle size is 5mm to 10mm; and / or, in the gangue filling step, the filling hydraulic support used to support the goaf during mining is moved along the mining direction to form a blank area to be filled in the goaf, and the blank area to be filled is divided into a first area, a second area, and a third area; then, the first area, the second area, and the third area are filled with gangue in sequence using a filling scraper conveyor; wherein, when the filling scraper conveyor is filling, after a certain amount of gangue is discharged from the previous discharge hole on the filling scraper conveyor, the next discharge hole is opened for discharge, and the gangue discharged from the previous discharge hole is then compacted.

[0011] Furthermore, the reinforcement steps also include: drilling holes at intervals of 3m to 5m on the side of the grouting bonded section facing the goaf retaining roadway, and using W-shaped steel strips and support beams in conjunction with anchor cables to reinforce and fix the grouting bonded section; wherein, the W-shaped steel strips and support beams are arranged in a cross shape, with the W-shaped steel strips set vertically and the support beams set horizontally; at the cross position, the anchor cables pass through the W-shaped steel strips and support beams and extend into the bearing part for fixation; the grouting holes of the grouting anchor rods extend into the grouting bonded section.

[0012] Furthermore, in the reinforcement step: multiple grouting anchors are arranged horizontally in rows and vertically in columns to form an anchor matrix. In one row of the anchor matrix, the distance between two adjacent grouting anchors is no greater than 750 mm, and in one column of the anchor matrix, the distance between two adjacent grouting anchors is no greater than 550 mm. The internal diameter of the grouting anchor is greater than 20 mm, and the axial length is 1200 mm to 1800 mm. And / or, in the reinforcement step: multiple anchor cables are arranged horizontally in rows and vertically in columns to form an anchor cable matrix. In one row of the anchor cable matrix, the distance between two adjacent anchor cables is no greater than 800 mm, and in one column of the anchor cable matrix, the distance between two adjacent anchor cables is no greater than 600 mm. The external diameter of the anchor cable is greater than 22 mm, and the axial length is 2400 mm to 3000 mm.

[0013] Furthermore, in the anti-seepage layer spraying step, the anti-seepage materials include cement, fly ash, silica fume, polypropylene fiber, and composite inorganic chemical foaming agent.

[0014] Furthermore, in the grouting step, the grouting materials include water, silicate cement, grouting soil admixture, and grouting curing agent; wherein the silicate cement has a grade of not less than 325.

[0015] Applying the technical solution of this invention, this invention provides a method for backfilling gob-side retaining roadways with gangue, comprising: a pre-support step: multiple hydraulic props are spaced apart along the extension direction of the gob-side retaining roadway to support the roadway roof, and then a shielding assembly is fixed relative to the hydraulic props, the shielding assembly being used to seal the gob-side retaining roadway and temporarily separating it from the gob-side retaining roadway; a gangue backfilling step: a section of the gob-side is divided into a first region, a second region, and a third region arranged sequentially and adjacently, the first region, the second region, and the third region all extending along the mining direction, and the extension direction being parallel to the extension direction of the gob-side retaining roadway; the first region is located close to the gob-side retaining roadway; the first region is backfilled with coarse-grained gangue to form a grouting cemented section, and then the second region is backfilled with fine-grained gangue to form a medium-grained section. The process involves several steps: First, a barrier section is formed. Then, a third area is filled with coarse-grained gangue to form a support section, where the coarse-grained size is larger than the fine-grained size. Finally, the filled gangue is compacted. Second, a reinforcement step is performed: holes are drilled on the side of the grouting bonded section facing the goaf, and grouting anchors or cables are placed in each of the drilled holes to reinforce and fix the grouting bonded section. Third, an anti-seepage layer is sprayed: anti-seepage material is sprayed on both the side of the grouting bonded section facing the goaf and the side facing the unfilled goaf to form a slurry anti-seepage layer on the surface. This slurry anti-seepage layer prevents the grouting material in the grouting bonded section from seeping to the surface. Fourth, grouting is performed: grouting anchors are used to reinforce the grouting bonded section, and a central barrier section prevents the grouting material from penetrating into the support section. After grouting, the isolation between the goaf and the goaf is completed.

[0016] This invention achieves temporary separation between the goaf and the goaf by setting up a pre-support step, thereby ensuring the safety of subsequent gangue filling. In the gangue filling step, different areas are filled and compacted using gangue of different particle sizes, ensuring the reliable formation of the grouting cementation section, the central barrier section, and the load-bearing section. This also ensures that the central barrier section, containing fine-particle gangue, reliably prevents grouting material from penetrating into the load-bearing section, thus avoiding waste of grouting material and saving costs. Furthermore, using gangue for filling achieves waste utilization and gangue treatment while effectively saving costs. The reinforcement step ensures the reliability of the grouting cementation section, guaranteeing smooth grouting of the subsequent section and preventing collapse accidents. The anti-seepage layer spraying step forms a grout anti-seepage layer on the outer surface of the grouting cementation section. The method avoids the seepage of grouting material from the surface of the grouting cementation layer, thereby saving grouting material and reducing material costs. The method of this invention can construct a gangue cemented filling body, including a grouting cementation layer, a central barrier layer, and a load-bearing layer, by filling the goaf and the goaf with gangue and then grouting and cementing it. This isolates the goaf and the goaf, achieving efficient utilization of gangue and improving the surrounding rock stability of the goaf. The method of this invention simplifies the filling process of the goaf and improves the filling efficiency. Using gangue waste as the filling material eliminates the need to purchase other filling materials, reducing filling costs and workload. Therefore, this invention solves the problems of complex procedures, high material input, and high costs in existing methods of filling goafs, making it suitable for large-scale promotion and use. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0018] Figure 1 A flowchart illustrating some steps of the gangue backfilling and gob-side retention method provided in an embodiment of the present invention is shown.

[0019] Figure 2 This diagram illustrates a partial structural schematic of a gob-side retaining tunnel during gangue backfilling, as provided by an embodiment of the present invention, viewed from above.

[0020] Figure 3 This diagram shows a partial structural schematic of grouting performed from a top-down view, according to an embodiment of the present invention.

[0021] Figure 4 This diagram shows a partial structural schematic of an embodiment of the present invention for early support from a side view angle.

[0022] Figure 5 A partial structural schematic diagram of grouting performed from a side view angle, provided by an embodiment of the present invention, is shown.

[0023] The above figures include the following reference numerals:

[0024] 10. Leave a lane along the edge;

[0025] 20. Goaf; 21. Grouting and cementing section; 22. Central barrier section; 23. Bearing section;

[0026] 30. Hydraulic support;

[0027] 40. Shielding components; 41. Metal mesh for retaining coal slag; 42. Polyester fiber cloth; 43. W-shaped steel strip; 44. Support beam; 45. Steel pallet;

[0028] 50. Grouting anchor bolts;

[0029] 60. Anchor cable;

[0030] 70. Grouting seepage prevention layer;

[0031] 80. Filling scraper conveyor;

[0032] 90. Filling hydraulic supports. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] like Figures 1 to 5As shown, an embodiment of the present invention provides a method for backfilling gob-side retaining roadways with gangue, comprising: a pre-support step: multiple hydraulic props 30 are spaced apart along the extension direction of the gob-side retaining roadway 10 between the gob-side retaining roadway 10 and the gob area 20 to support the roadway roof; then a shielding assembly 40 is fixed relative to the hydraulic props 30, the shielding assembly 40 is used to seal the gob area 20 and temporarily separate the gob-side retaining roadway 10 from the gob area 20; a gangue backfilling step: a section of the gob area 20 is divided into a first region, a second region, and a third region arranged sequentially and adjacently, the first region, the second region, and the third region all extending along the mining direction, and the extension direction is parallel to the extension direction of the gob-side retaining roadway 10; the first region is set close to the gob-side retaining roadway 10; the first region is backfilled with coarse-grained gangue to form a grouting cemented part 21, and then the second region is backfilled with fine-grained gangue to form a central barrier part 22, and then... Then, coarse-grained gangue is used to fill the third area to form the bearing part 23, with the coarse-grained size being larger than the fine-grained size; finally, the filled gangue is compacted; reinforcement steps: holes are drilled on the side of the grouting cemented part 21 facing the goaf retaining roadway 10, and grouting anchor rods 50 or anchor cables 60 are arranged in the drilled holes to reinforce and fix the grouting cemented part 21; seepage prevention layer spraying steps: on the side of the grouting cemented part 21 facing the goaf retaining roadway 10 and the grouting The cemented section 21 is sprayed with anti-seepage material on the side facing the unfilled goaf 20 to form a grout anti-seepage layer 70 on the surface. The grout anti-seepage layer 70 is used to prevent the grouting material in the cemented section 21 from seeping out of the surface. Grouting steps: Grouting anchors 50 are used to reinforce the cemented section 21. The middle barrier section 22 prevents the grouting material from penetrating into the bearing section 23. After grouting is completed, the isolation between the goaf roadway 10 and the goaf 20 is completed.

[0035] This invention, by setting a pre-support step, achieves a temporary separation between the goaf roadway 10 and the goaf area 20, thereby ensuring the safety of subsequent gangue filling. In the gangue filling step, different areas are filled and compacted using gangue of different particle sizes, ensuring the reliable formation of the grouting cementing section 21, the central barrier section 22, and the supporting section 23. This also ensures that the central barrier section, containing fine-particle gangue, can reliably prevent grouting material from penetrating into the supporting section 23, thus avoiding waste of grouting material and saving costs. Furthermore, using gangue for filling achieves waste utilization and gangue treatment, while also effectively saving costs. By setting a reinforcement step, the reliability of the grouting cementing section 21 is ensured, guaranteeing smooth grouting of the subsequent section and preventing collapse accidents. By setting a seepage-proof layer spraying step, a grout seepage-proof layer 70 can be formed on the outer surface of the grouting cementing section 21. This invention prevents grouting material from seeping out of the grouting cementation part 21, thereby saving grouting material and reducing material costs. The method of this invention can isolate the goaf 20 and the goaf roadway 10 by filling the space between the goaf 20 and the goaf roadway 10 with gangue and grouting cementation, constructing a gangue cemented filling body including a grouting cementation part 21, a central barrier part 22, and a bearing part 23. This achieves efficient utilization of gangue and improves the surrounding rock stability of the goaf roadway 10. The method of this invention simplifies the filling process of the goaf roadway 10, improves the filling efficiency, and uses gangue waste as the filling material, eliminating the need to purchase other filling materials, reducing filling costs, and lessening the workload of filling the goaf roadway 10. Therefore, this invention solves the problems of complex procedures, large material inputs, and high costs in existing goaf roadway filling methods, making it suitable for large-scale promotion and use.

[0036] Specifically, the method of backfilling goaf retention with gangue also includes a first post-treatment step: after the grouting step is completed, multiple hydraulic supports 30 are disassembled, and then foamed concrete material is sprayed onto the side of the grouting cement part 21 facing the goaf retention 10 to form a concrete layer on the surface.

[0037] By spraying foamed concrete material onto the side of the grouting bonding part 21 facing the goaf 10, a concrete layer can be formed on its surface, thereby ensuring the surface strength and sealing of the grouting bonding part 21.

[0038] Specifically, the gangue backfilling method also includes a second follow-up treatment step: after the first follow-up treatment step is completed, wait for the concrete layer to solidify and form, and then spray polyurethane material onto the surface of the concrete layer to form an anti-weathering coating on the surface of the concrete layer.

[0039] By spraying polyurethane material onto the surface of the concrete layer, an anti-weathering coating is formed on the surface of the concrete layer, thereby ensuring the weather resistance and airtightness of the grouting bonding part 21.

[0040] Specifically, the first follow-up treatment steps also include: dismantling multiple hydraulic supports 30 when the distance between the mining face and the grouting bonding part 21 is within the range of 150m to 180m; controlling the thickness of the concrete layer within the range of 40mm to 100mm; the foamed concrete material includes cement, sand, water and quick-setting agent, wherein the mass ratio of cement to sand is one to two.

[0041] By setting the distance between the mining face and the grouting bonding section 21 to be within 150m to 180m before dismantling multiple hydraulic props 30, the surrounding rock has already undergone a pressure release and adjustment process, and its self-stabilizing ability has been enhanced. At this time, the risk of removing the hydraulic props 30 is low, ensuring safety. At the same time, removing the hydraulic props 30 can free up operating space. By setting the thickness of the concrete layer, the grouting bonding section 21 can be effectively sealed, and material waste can be avoided.

[0042] It should be noted that: to ensure the integrity of the foamed concrete material after spraying, the foamed concrete material contains an appropriate amount of accelerator, which can be aluminate powder; when spraying the foamed concrete material, professional spraying equipment (e.g., PZ-5 spraying equipment) should be used, with a working pressure of 0.6MPa and an inner diameter of 50mm for conveying the foamed concrete material, to ensure smooth and reliable spraying.

[0043] like Figure 4 and Figure 5 As shown, in the advance support step, the shielding assembly 40 includes a gangue-blocking metal mesh 41 and a polyester fiber cloth 42; the gangue-blocking metal mesh 41 is detachably and fixedly connected to the hydraulic prop 30 by fasteners to shield the gangue; the polyester fiber cloth 42 is fixed to the surface of the gangue-blocking metal mesh 41 by wire binding to seal the gangue-blocking metal mesh 41; wherein, the gangue-blocking metal mesh 41 and the polyester fiber cloth 42 extend along the extension direction of the goaf 10; the mesh of the gangue-blocking metal mesh 41 is square and the side length is less than or equal to 45mm; and / or, in the advance support step, multiple hydraulic props 30 are arranged at equal intervals with a spacing of no more than 0.6m.

[0044] The reason for setting the grid of the retaining metal mesh 41 to be square with a side length of less than or equal to 45mm is to take into account the size and looseness of the filling gangue, so as to ensure that the retaining metal mesh 41 can effectively support and reinforce the surrounding rock, while also avoiding local stress concentration. The reason for setting the hydraulic props 30 at equal intervals with a spacing of no more than 0.6m is to take into account the distribution of surrounding rock pressure and economy. This interval setting can make the hydraulic props 30 evenly distribute the load, improve the stability and support effect of the roadway, and at the same time, reduce construction costs.

[0045] like Figure 2 and Figure 3 As shown, in the gangue filling step, the thickness of the grouting cementing part 21 is 1.5m to 2.0m; the thickness of the middle barrier part 22 is not less than 0.5m; the coarse particle size is 20mm to 40mm; the fine particle size is 5mm to 10mm; and / or, in the gangue filling step, the filling hydraulic support 90 used to support the goaf 20 during mining is moved along the mining direction so that the goaf 20 forms a blank area to be filled, and the blank area to be filled is divided into a first area, a second area and a third area; then the filling scraper conveyor 80 is used to fill the first area, the second area and the third area with gangue in sequence; wherein, when the filling scraper conveyor 80 is filling, after a certain amount of gangue is discharged from the previous discharge hole on the filling scraper conveyor 80, the next discharge hole is opened for discharge, and the gangue discharged from the previous discharge hole is compacted immediately.

[0046] By setting a fine particle size, the blocking effect of the central barrier section 22 on the grouting material is ensured; by setting the working process of the filling scraper conveyor 80 and removing the filling hydraulic support 90, the overall working efficiency of the gangue filling goaf retention method can be further improved.

[0047] like Figure 5 As shown, the reinforcement steps also include: drilling holes at intervals of 3m to 5m on the side of the grouting bonded part 21 facing the goaf retaining roadway 10, and using W-shaped steel strips 43 and support beams 44 in conjunction with anchor cables 60 to reinforce and fix the grouting bonded part 21; wherein, the W-shaped steel strips 43 and support beams 44 are arranged in a cross shape, with the W-shaped steel strips 43 set vertically and the support beams 44 set horizontally; at the cross position, the anchor cables 60 pass through the W-shaped steel strips 43 and support beams 44 and extend into the bearing part 23 for fixation; the grouting holes of the grouting anchor rods 50 extend into the grouting bonded part 21.

[0048] By setting the drilling spacing, the grouting effect and anchor cable fixing effect are ensured; by using W-shaped steel strip 43 and support beam 44 in conjunction with anchor cable 60 to reinforce and fix the grouting cement part 21, the cost is further reduced by using a low-cost and readily available structure in the roadway to achieve reliable fixing of the grouting cement part 21.

[0049] like Figure 5 As shown, in the reinforcement step: multiple grouting anchors 50 are arranged horizontally in rows and vertically in columns to form an anchor matrix. In one row of the anchor matrix, the distance between two adjacent grouting anchors 50 is no greater than 750 mm, and in one column of the anchor matrix, the distance between two adjacent grouting anchors 50 is no greater than 550 mm. The internal diameter of the grouting anchor 50 is greater than 20 mm, and the axial length is 1200 mm to 1800 mm. And / or, in the reinforcement step: multiple anchor cables 60 are arranged horizontally in rows and vertically in columns to form an anchor cable matrix. In one row of the anchor cable matrix, the distance between two adjacent anchor cables 60 is no greater than 800 mm, and in one column of the anchor cable matrix, the distance between two adjacent anchor cables 60 is no greater than 600 mm. The external diameter of the anchor cable 60 is greater than 22 mm, and the axial length is 2400 mm to 3000 mm.

[0050] By setting up anchor bolt and anchor cable matrices, the grouting and reinforcement effects were ensured.

[0051] In one specific embodiment of the present invention, each anchor cable 60 is extended and anchored by two sections of Z2360 and one section of K2360 resin cartridges to ensure that the anchor cable 60 can be driven into the bearing part 23.

[0052] like Figure 5 As shown, in another specific embodiment of the present invention, the shielding component 40 further includes a steel tray 45, which is connected to the W-shaped steel strip 43 and / or the support beam 44, and serves to support the anchor cable 60 when it is driven.

[0053] Optionally, in the anti-seepage layer spraying step, the anti-seepage material includes cement, fly ash, silica fume, polypropylene fiber, and composite inorganic chemical foaming agent.

[0054] By setting the specific composition of the seepage-proof material, the reliable seepage prevention of the slurry seepage-proof layer 70 is ensured, and the cost is effectively reduced.

[0055] Optionally, in the grouting step, the grouting materials include water, silicate cement, grouting soil admixture, and grouting curing agent; wherein the silicate cement has a grade of not less than 325.

[0056] By setting the specific composition of the grouting material, the reliable grouting reinforcement effect is ensured, and the cost is effectively reduced.

[0057] It should be noted that cement number 325 is an existing method for indicating cement strength grade, commonly used to describe cement performance; this number indicates the cement's compressive strength. Specifically, 325 represents that the cement's compressive strength is 32.5 MPa after a 28-day curing period. Cement has different strength grades, with numbers such as 325, 425, and 525; these numbers represent the cement's compressive strength after a 28-day curing period. The higher the strength grade, the stronger the cement's load-bearing capacity. Therefore, the cement number comprehensively represents information such as cement type, strength grade, and production process, helping users select the appropriate cement according to their actual needs. When using cement, the cement number and related instructions should be carefully checked to ensure that the appropriate cement product is selected.

[0058] The specific working process and principle of a particular embodiment of the present invention will now be described in detail as follows:

[0059] Step 1: Closely follow the coal mining face. During the advance of the working face, set up hydraulic props 30 on the side of the goaf 10 near the goaf 20, and hang the gangue-blocking metal mesh 41 and polyester fiber cloth 42 in sequence to temporarily block gangue and seal the goaf 20.

[0060] Step 2: The filling scraper conveyor 80 of the filling hydraulic support 90 fills the area with gangue of different particle sizes from the tail end to the head end. First, the first area is filled with coarse-grained gangue to form the grouting cementing part 21. After filling to the set width, the second area is filled with fine-grained gangue to form the middle barrier part 22. Finally, the coarse-grained gangue is used to fill the area to form the bearing part 23.

[0061] Step 3: After the gangue backfilling is advanced a certain distance along the direction of the coal mining face, i.e. the mining direction, drill holes towards the goaf 20 on the grouting cementation part 21, arrange grouting anchor rods 50, and use anchor cables 60 to install W-shaped steel strips 43 and ladder beams (i.e. support beams 44) for joint reinforcement and support.

[0062] Step 4: Spray foamed concrete onto the outer surface of the grouting bonding part 21 to form a grout seepage prevention layer 70. Then, use the grouting anchor 50 to grout the grouting bonding part 21 in the filling gangue to construct the gangue cemented roadway side filling body.

[0063] Step 5: After the working face has advanced a certain distance into the roadway section, remove the hydraulic support 30 and spray foamed concrete onto the surface of the gangue cemented roadway side filling body in the roadway. After the concrete has solidified, spray a polyurethane anti-weathering coating on the outside of the foamed concrete spray layer.

[0064] In the first step, the hydraulic support 30 is connected to the retaining metal mesh 41 by fasteners, and the polyester fiber cloth 42 is tied to the inside of the metal mesh by wire.

[0065] In the second step, after the gangue along the side of the goaf-retention tunnel 10 is grouted and cemented, a gangue-cemented tunnelside backfill body is formed. Its function is equivalent to the tunnelside wall of the goaf-retention tunnel 10. The width of the gangue-cemented tunnelside backfill body is designed to be 1.5–2.0 m to ensure the stability of the backfill wall during long-term use. The central barrier section 22 is formed by filling with fine-grained gangue to a certain width to prevent grout from diffusing into the distant bearing section 23 during subsequent grouting. The central barrier section is designed to be... The barrier section 22 has a width of 0.5m, ensuring both barrier performance and economy. In the second step, both the grouting and bonding section 21 and the load-bearing section 23 are filled with large-diameter gangue, with a designed gangue particle size of 20-40mm, to provide better mechanical strength and stability. The middle barrier section 22 is filled with small-diameter gangue, with a designed gangue particle size of 5-10mm, to form a dense filling layer and effectively prevent grout diffusion.

[0066] In the third step, the W-shaped steel strip 43 and the ladder beam are arranged in a cross shape on the outside of the retaining metal mesh 41, and are connected by anchor cables 60 at the intersection of the W-shaped steel strip 43 and the ladder beam. The anchor cables 60 are driven into the bearing part 23. The grouting anchor 50 is driven deep into the grouting bonding part 21 through the retaining metal mesh 41. In the third step, the distance between the backfill and compaction of the gangue in the goaf 20 is 3-5m to avoid affecting the filling quality. The spacing between multiple grouting anchors 50 is 550mm×750mm to ensure that the filling wall is fully supported and to control costs. The specifications are ∮20mm×1200-1800mm to ensure that the grouting anchors 50 can be driven deep into the grouting bonding part 21. The spacing between multiple anchor cables 60 is 600mm×800mm, and the matching specifications are ∮22mm×2400-3000mm to match the W-shaped steel strip 43 and the ladder beam installation specifications. Each anchor cable 60 is extended and anchored with 2 sections of Z2360 and 1 section of K2360 resin cartridges to ensure that the anchor cable 60 can be driven into the bearing part 23.

[0067] In summary, this invention provides a method for backfilling goaf-side retaining roadways with gangue. By setting up a pre-support step, this invention achieves a temporary separation between the goaf-side retaining roadway 10 and the goaf area 20, thereby ensuring the safety of subsequent gangue backfilling. In the gangue backfilling step, by using gangue of different particle sizes to fill different areas and compact them, it ensures the reliable formation of the grouting cementing part 21, the middle barrier part 22, and the bearing part 23, and also allows the middle barrier part containing fine-particle gangue to... The system reliably prevents grouting material from penetrating into the bearing portion 23, thus avoiding waste of grouting material and saving costs. Furthermore, using gangue for filling achieves both waste utilization and gangue treatment, while also effectively saving costs. By incorporating reinforcement steps, the reliability of the grouting bonded portion 21 is ensured, guaranteeing smooth subsequent grouting and preventing tipping accidents. The inclusion of an anti-seepage layer spraying step ensures that the outer surface of the grouting bonded portion 21... This method can form a grout impermeable layer 70, preventing grouting material from seeping out from the surface of the grouting cementation part 21, thereby further saving grouting material and reducing material costs. The method of this invention can fill the gap between the goaf 20 and the goaf roadway 10 with gangue and grout cement it, constructing a gangue cemented filling body including a grout cementation part 21, a central barrier part 22, and a bearing part 23 to isolate the goaf 20 and the goaf roadway 10, thereby achieving efficient utilization of gangue and improving the efficiency of goaf roadway construction. The method of this invention simplifies the filling process of the gob-side retaining roadway 10, improves the filling efficiency of the gob-side retaining roadway 10, and uses gangue waste as the filling material for the gob-side retaining roadway 10, eliminating the need to purchase other filling materials, reducing filling costs, and alleviating the workload of filling the gob-side retaining roadway 10. Therefore, this invention solves the problems of complex procedures, large material input, and high cost in the existing gob-side retaining roadway filling methods, and is suitable for large-scale promotion and use.

[0068] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0069] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0070] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0071] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0072] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0073] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for backfilling and retaining roadways along the goaf with gangue, characterized in that, include: Advance support steps: Multiple hydraulic props (30) are installed at intervals along the extension direction of the goaf roadway (10) between the goaf roadway (10) and the goaf area (20) to support the roadway roof. Then, a shielding assembly (40) is fixed relative to the hydraulic props (30). The shielding assembly (40) is used to seal the goaf area (20) and temporarily separate the goaf roadway (10) from the goaf area (20). Gangue backfilling steps: Divide a section of the goaf (20) into a first area, a second area and a third area arranged in succession, the first area, the second area and the third area all extend along the mining direction and the extension direction is parallel to the extension direction of the goaf retainer (10); the first area is set close to the goaf retainer (10); the first area is filled with coarse-grained gangue to form a grouting cementing part (21), then the second area is filled with fine-grained gangue to form a central barrier part (22), then the third area is filled with coarse-grained gangue to form a bearing part (23), the coarse-grained part is larger than the fine-grained part; finally, the backfilled gangue is compacted. Reinforcement steps: Drill holes on the side of the grouting cemented part (21) facing the goaf retainer (10), and arrange grouting anchor rods (50) or anchor cables (60) in the drilled holes one by one to reinforce and fix the grouting cemented part (21); Anti-seepage layer spraying step: anti-seepage material is sprayed on the side of the grouting cement part (21) facing the goaf (10) and the side of the grouting cement part (21) facing the unfilled goaf (20) to form a grout anti-seepage layer (70) on the surface. The grout anti-seepage layer (70) is used to prevent the grouting material in the grouting cement part (21) from seeping out of the surface. Grouting steps: The grouting anchor (50) is used to reinforce the grouting cement part (21), and the middle barrier part (22) prevents the grouting material from penetrating into the bearing part (23); after grouting is completed, the isolation between the goaf retaining roadway (10) and the goaf area (20) is completed; In the pre-support step, the shielding assembly (40) includes a gangue-blocking metal mesh (41) and a polyester fiber cloth (42); the gangue-blocking metal mesh (41) is detachably and fixedly connected to the hydraulic support (30) by fasteners for shielding gangue; the polyester fiber cloth (42) is fixedly bound to the surface of the gangue-blocking metal mesh (41) by wire for sealing the gangue-blocking metal mesh (41); wherein, the gangue-blocking metal mesh (41) and the polyester fiber cloth (42) extend along the extension direction of the goaf-retention tunnel (10); the grid of the gangue-blocking metal mesh (41) is square and the side length is less than or equal to 45mm; And / or, in the pre-support step, a plurality of the hydraulic struts (30) are arranged at equal intervals with a spacing not greater than 0.6m; The reinforcement step further includes: drilling holes at intervals of 3m to 5m on the side of the grouting bonded part (21) facing the goaf retainer (10), and using W-shaped steel strips (43) and support beams (44) in conjunction with the anchor cable (60) to reinforce and fix the grouting bonded part (21); wherein the W-shaped steel strips (43) and the support beams (44) are arranged in a cross shape, the W-shaped steel strips (43) are set vertically, and the support beams (44) are set horizontally; at the cross position, the anchor cable (60) passes through the W-shaped steel strips (43) and the support beams (44) and extends into the bearing part (23) for fixation; the grouting hole of the grouting anchor rod (50) extends into the grouting bonded part (21).

2. The method for backfilling and retaining roadways along the goaf with gangue according to claim 1, characterized in that, The method for filling goaf-side retaining roadway with gangue also includes a first follow-up treatment step: after the grouting step is completed, multiple hydraulic supports (30) are disassembled, and then foamed concrete material is sprayed onto the side of the grouting cement part (21) facing the goaf-side retaining roadway (10) to form a concrete layer on the surface.

3. The method for backfilling and retaining roadways along the goaf with gangue according to claim 2, characterized in that, The gangue backfilling and goaf retention method further includes a second follow-up treatment step: after the first follow-up treatment step is completed, wait for the concrete layer to solidify and form, and then spray polyurethane material onto the surface of the concrete layer to form an anti-weathering coating on the surface of the concrete layer.

4. The method for backfilling and retaining roadways along the goaf with gangue according to claim 2, characterized in that, The first follow-up processing step further includes: when the distance between the mining face and the grouting bonding part (21) is within the range of 150m to 180m, dismantling multiple hydraulic supports (30); controlling the thickness of the concrete layer within the range of 40mm to 100mm; the foamed concrete material includes cement, sand, water and quick-setting agent, wherein the mass ratio of the cement to the sand is one to two.

5. The method for backfilling and retaining roadways along the goaf with gangue according to claim 1, characterized in that, In the gangue filling step, the thickness of the grouting cementing part (21) is 1.5m to 2.0m; the thickness of the middle barrier part (22) is not less than 0.5m; the coarse particle size is 20mm to 40mm; and the fine particle size is 5mm to 10mm. And / or, in the gangue filling step, the filling hydraulic support (90) used to support the goaf (20) during mining is moved along the mining direction so that the goaf (20) forms a blank area to be filled, and the blank area to be filled is divided into the first area, the second area and the third area; then the first area, the second area and the third area are filled with gangue in sequence by the filling scraper conveyor (80); wherein, when the filling scraper conveyor (80) is filling, after a certain amount of gangue is discharged from the previous discharge hole on the filling scraper conveyor (80), the next discharge hole is opened for discharge, and the gangue discharged from the previous discharge hole is compacted.

6. The method for backfilling and retaining roadways along the goaf with gangue according to claim 1, characterized in that, In the reinforcement step: multiple grouting anchors (50) are arranged horizontally in rows and vertically in columns to form an anchor matrix. In a row of the anchor matrix, the distance between two adjacent grouting anchors (50) is no greater than 750mm, and in a column of the anchor matrix, the distance between two adjacent grouting anchors (50) is no greater than 550mm. The internal diameter of the grouting anchor (50) is greater than 20mm, and the axial length is 1200mm~1800mm. And / or, in the reinforcement step: a plurality of anchor cables (60) are arranged horizontally in rows and vertically in columns to form an anchor cable matrix, wherein in a row of the anchor cable matrix, the distance between two adjacent anchor cables (60) is no greater than 800 mm, and in a column of the anchor cable matrix, the distance between two adjacent anchor cables (60) is no greater than 600 mm; the outer diameter of the anchor cable (60) is greater than 22 mm, and the axial length is 2400 mm to 3000 mm.

7. The method for backfilling and retaining roadways along the goaf with gangue according to claim 1, characterized in that, In the step of spraying the impermeable layer, the impermeable material includes cement, fly ash, silica fume, polypropylene fiber, and composite inorganic chemical foaming agent.

8. The method for backfilling and retaining roadways along the goaf with gangue according to claim 1, characterized in that, In the grouting step, the grouting material includes water, silicate cement, grouting soil admixture, and grouting curing agent; wherein the silicate cement has a number of not less than 325.

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