A gob-side simply supported isolated roadway leaving method based on mine pressure control and adaptive device

Abstract

The application provides a gob-side simply-supported isolated remaining roadway method based on mine pressure control and an adaptive device, and relates to the technical field of mine safety, the gob-side simply-supported isolated remaining roadway method comprising the following steps: S1, constructing a "low stress environment" by high-position top unloading; S2, constructing a safe roadway by low-position simply-supported isolation; the method comprises low-position roof deformation limiting technology and a low-intensity isolated "wall" design beside the roadway; and S3, temporarily buffering and supporting in a lag area; the application provides a gob-side simply-supported isolated remaining roadway method based on mine pressure control, which takes mine pressure control as a breakthrough point, takes a near-field "low stress environment" as a construction basis, innovates a remaining roadway process of "high-position top unloading and low-position roof falling and filling", and improves a high-intensity support wall beside the roadway into a low-intensity isolated "wall", and improves roof support from full-roadway dense passive support into a mode of strengthening active support and cooperating with lag temporary passive support; the application can significantly improve production efficiency and reduce production cost on the basis of successfully remaining the roadway.

Description

Technical Field

[0001] This invention relates to the field of mine safety technology, and in particular to a method and adapter for simple-supported isolation roadway retention along the goaf based on mine pressure control. Background Technology

[0002] Goaf retention is a mining technique that maintains the original mining roadway along the edge of the goaf behind the coal mining face. It can not only avoid leaving coal pillars, thereby improving the coal resource extraction rate and recovery rate and reducing coal loss, but also effectively alleviate the pressure of mine production continuity and reduce the stress concentration around the roadway.

[0003] Traditional goaf retention techniques, due to their technical characteristics and engineering construction limitations, only involve direct blasting and cutting of the roof at a low level to create a cave-in filling effect in the goaf. This requires a high level of geological structure at the working face, and the construction of high-strength concrete support walls and dense reinforcement of the entire roadway presents problems such as high material costs and high labor intensity. Summary of the Invention

[0004] Based on the technical problems existing in the background art, the present invention proposes a method and adaptation device for simple-supported isolation roadway retention along the goaf based on mine pressure control.

[0005] This invention proposes a method for simply supported isolation roadway retention along the goaf based on mine pressure control. The method includes: S1, high-level top cutting and unloading creates a "low-stress environment"; S2, a low-level simply supported isolation structure for safe roadway construction; including low-level roof deformation limiting technology and low-strength isolation "wall" design along the roadway; S3, temporary buffer support for the lagging area.

[0006] Preferably, in S1, ground-penetrating radar and borehole inspection technology are used to thoroughly investigate the characteristics of the overlying rock structure in the mining area and determine the key locations of the cantilever beams that affect the roadway along the goaf.

[0007] Preferably, in S1, the physical and mechanical properties of coal and rock, in-situ stress, and parameters of the loosened zone of the surrounding rock in the roadway are analyzed through theoretical calculations, numerical simulations, and on-site geological exploration. The cutting position, angle, and drilling parameters are determined, and the corresponding high-position rock beam cutting technology is selected to enable the cantilever beam to be cut and unloaded.

[0008] Preferably, in the low-level roof deformation limiting technology of S2, on one side of the goaf of the roof in the roadway area, a row of solid anchor cable boreholes are constructed according to the design spacing and angle. The solid anchor cables are installed into the boreholes and suspended and fixed at a high level. Then, a new type of truss beam support device is installed to ensure close contact with the roof and form a stable support structure.

[0009] Preferably, the design of the low-intensity isolation "wall" along the alley of S2 includes a primary collapse-type "wall" and a secondary simply supported "wall".

[0010] Preferably, the operation steps for the primary collapse to form a "wall" are based on the rock fragmentation and swelling characteristics. After the working face is mined, a low-level roof cutting technique is used to cause the roof of the goaf to collapse, thereby achieving the initial filling of the goaf. After the roof of the goaf collapses, intermittent grouting is carried out in the collapsed area to fill the gaps.

[0011] Preferably, the operational steps for constructing a "wall" using two-stage simply supported structures are as follows: On one side of the goaf, U-shaped steel legs are installed at the designed intervals; Flame-retardant cloth and bar mesh for blocking slag are hung on the U-shaped steel legs to form a "false support". For "false plugs", timely spraying or spraying of inorganic flexible materials should be carried out to seal the leaks.

[0012] Preferably, the operational steps for temporary buffer support in the hysteresis region in S3 are as follows: Mine pressure monitoring equipment is deployed in the roadway area to monitor changes in mine pressure in real time. Based on the analysis of the monitoring data, the roadway area is divided into a mine pressure manifestation zone and a pressure stability zone. In the mining pressure manifestation area, temporary buffer passive support is carried out by using single hydraulic props in combination with π-shaped steel beams or hydraulic unit supports, according to the designed support density and method. As the working face advances, once the roadway area enters the pressure stabilization zone, the forward-moving lagging support equipment should be promptly dismantled and transported to the next mine pressure manifestation zone for reuse.

[0013] An adapter for a simple-supported isolation roadway retention method based on mine pressure control includes a sealing device for sealing blast holes in the mine. The sealing device includes a grouting pipe and a sealing sleeve. The grouting pipe has a grout outlet hole, and the sealing sleeve is fitted around the outer periphery of the grouting pipe to form a closed space, which is connected to the grout outlet hole.

[0014] Preferably, the novel truss beam support device includes a truss beam, a support plate, and a self-aligning ball pad; the top surface of the truss beam abuts against the top plate, the support plate is located in the bottom opening groove of the truss beam, a first through hole is formed through the truss beam, a second through hole is formed through the support plate, the first through hole and the second through hole are connected, and the self-aligning ball pad is rotatably installed at the bottom opening position of the second through hole on the support plate; The solid anchor cable passes through the first perforation hole, the second perforation hole, and the self-aligning ball pad in sequence and is connected to the self-aligning ball pad.

[0015] The present invention proposes a method and adaptable device for simple-supported isolation roadway retention based on mine pressure control, which has the following beneficial effects: By taking mine pressure control as the starting point and the near-field "low-stress environment" as the construction basis, it innovates the roadway retention process of "high-level roof breaking and unloading, low-level collapse and filling". The roadway side support can be improved from the original high-strength support wall to a low-strength isolation "wall", and the roof support can be improved from dense passive support throughout the roadway to a method of strengthening active support and lagging temporary passive support to control the roof. It can significantly improve production efficiency and reduce production costs on the basis of successful roadway retention. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the process for a simple-supported isolation roadway retention method based on mine pressure control proposed in this invention. Figure 2 This is a schematic diagram of the truss beam, support plate, and self-aligning ball pad in the adapter device for a simple-supported isolation roadway retention method based on mine pressure control proposed in this invention. Figure 3 This is a cross-sectional view of the truss beam, support plate, and self-aligning ball pad in the adapter device for a simple-supported isolation roadway retention method based on mine pressure control proposed in this invention. Figure 4 This is a schematic diagram of the truss beam, support plate, and self-aligning ball pad in use of the simple-supported isolation roadway retention method and adapter device based on mine pressure control proposed in this invention. Figure 5 This is a schematic diagram of the self-aligning ball pad in the goaf-supported simple-supported isolation roadway retention method and adapter device based on mine pressure control proposed in this invention. Figure 6 This is a schematic diagram of the grouting pipe and sealing sleeve in a simple-supported isolation roadway retention method and adapter device based on mine pressure control proposed in this invention. Figure 7 This is a schematic diagram showing the positions of the grout outlet, grouting pipe, and sealing sleeve in a simple-supported isolation roadway retention method and adapter device based on mine pressure control proposed in this invention.

[0017] In the diagram: 1. Truss beam; 2. Support plate; 3. Self-aligning ball pad; 4. Grouting pipe; 5. Sealing sleeve; 6. Grout outlet hole. Detailed Implementation

[0018] Reference Figures 1-6 This invention proposes a method for simply supported isolation roadway retention along the goaf based on mine pressure control. The method includes: S1, high-level roof cutting and unloading creates a "low-stress environment"; through ground-penetrating radar and borehole inspection technology, the characteristics of the overlying rock structure in the mining area are thoroughly investigated, and the key positions of the cantilever beams affecting the roadway along the goaf are determined. For example, a 100MHz low-frequency antenna is used to penetrate deep rock layers (50-80m), and a 400MHz high-frequency antenna is used to improve the resolution of shallow (0-20m) fractures, forming a three-dimensional detection network that combines deep and shallow layers. The borehole panoramic digital imaging system features a 360° fisheye lens assembly: equipped with a 2-megapixel CCD sensor and an LED ring lighting system, achieving panoramic stitching imaging of the borehole wall at a resolution of 0.2mm / pixel. The intelligent structural surface recognition algorithm utilizes a U-Net neural network model, with a training set containing 5000 borehole images, achieving an automatic fracture recognition accuracy of 92.3% and an attitude measurement error of <3°. The 3D borehole trajectory model integrates inclinometer data (accuracy 0.01°) to construct a borehole spatial trajectory model, combining CT scanning technology to invert the rock mass RQD value distribution and construct a rock mass quality index (RQD ≥ 75% indicates stable rock strata). Intelligent top cutting parameter decision Numerical simulation and mechanical analysis: A FDEM (finite element-discrete element coupled) model was established to simulate the stress field distribution under different cutting heights. Combined with the actual overburden structure characteristics of the mining area, high-level rock beam cutting treatment was implemented to unload the cantilever beam that affects the roadway along the goaf.

[0019] Based on the fracture mechanics model of cantilever beam (formula: L_max=√(2σth / 3γμ)), the critical span is calculated to be 8.2m (example of a mine), which guides the optimization of the top cutting angle to 15°±5°.

[0020] Directional blasting / hydraulic fracturing technology: Blasting parameters: hole diameter 75mm, spacing 1.2m, charge density 0.8kg / m³, millisecond micro-delay initiation (interval 25ms), forming a through crack width >15mm.

[0021] Hydraulic fracturing alternative: Dual directional jet pump station (pressure 76MPa, discharge 630L / min), with built-in packer maintaining pressure at 70MPa, to achieve open-hole directional fracturing.

[0022] Traditional roof cutting only involves blasting cuts in the lower direct roof (shallow 0-10m), which cannot effectively cut the upper cantilever beam structure, resulting in the roadway being in a high-stress environment for a long time. Compared with traditional roof cutting, this method can extend the roof cutting range from shallow to deep, reducing lateral support pressure by 30%-40%.

[0023] S2, a low-level simply supported isolation structure for safe roadway construction; including low-level roof deformation limiting technology, on one side of the goaf area of ​​the roof in the roadway retention area, a row of solid anchor cable boreholes is constructed according to the design spacing and angle (adjusted to two, three, or even more rows depending on the actual situation). Solid anchor cables are installed into the boreholes. The anchor cable material is 1860MPa grade steel strand, 22mm in diameter, with a preload of 200±10kN, and is suspended and fixed at a high level. Drilling parameters: spacing 1.5m, inclination angle 75°, depth 8m. Then, a new type of truss beam support device is installed to ensure… It fits tightly with the top plate to form a stable support structure. The curved steel truss structure uses Q355B high-strength steel (yield strength ≥355MPa), with a section height of 180mm (mid-span) to 250mm (end), and a bending modulus of 3.2×10^5mm³. The self-aligning ball pad design allows for anchor cable deflection of ±15°, expands the contact area to 0.25m², and the local compressive stress ≤50MPa. The design also includes a low-strength isolation "wall" along the roadside, which includes a primary collapse-forming "wall" and a secondary simply supported "wall".

[0024] The operation steps for primary caving to form a "wall" are based on the rock fragmentation and swelling characteristics. After the working face is mined, a low-level roof cutting technique is used to induce the roof of the goaf to collapse, achieving initial filling of the goaf. After the roof of the goaf collapses, intermittent grouting is performed to fill the gaps in the collapsed area. Primary caving to form a wall: Low-level roof cutting is used to induce caving (fracture and swelling coefficient 1.25-1.35), the caving height is ≥3 times the mining height, the filling rate is >80%, and the intermittent grouting process is as follows: grouting pressure is 0.5-1.2MPa, the grout is fly ash-silicate composite grout (ratio 1:0.3:0.1, fly ash: cement: quick-setting agent), and the initial setting time is 1 hour.

[0025] The operational steps for constructing a "wall" using a two-stage simply supported structure are as follows: On one side of the goaf, U-shaped steel legs are erected according to the designed spacing. Flame-retardant cloth and gangue-blocking steel mesh are hung on the U-shaped steel legs to form a "false wall." The "false wall" is promptly sealed with grout or sprayed with inorganic flexible material (U-shaped steel legs + flame-retardant cloth + gangue-blocking mesh (cost < 200 yuan / m): U-shaped steel leg spacing 1.0m, gangue-blocking mesh mesh size 50×50mm, grout thickness 50mm (compressive strength ≥ 15MPa); inorganic flexible sealing material: spray thickness 3-5mm, tensile strength ≥ 1.5MPa, fire resistance limit > 2 hours).

[0026] Traditional roadway side support uses high-strength concrete support walls (C30 concrete, 1.2-1.5m thick), which is costly (approximately 800 RMB / m³) and has a long construction period (3-5 days / section). Roof support uses dense anchor bolts and steel strip passive support throughout the roadway, with a support density >2 bolts / m², which has poor adaptability to the roof (easily sheared and broken). The advantages of this solution are that the roadway side support cost is reduced by 70% (traditional concrete wall costs 1200 RMB / m, while this technology only costs 360 RMB / m); the roof support density is reduced by 50%, and the anchor cable breakage rate is reduced by 80%; the curved steel truss structure (Q355B high-strength steel) combined with self-aligning ball pads increases the bending modulus to 3.2×10^5mm³; the anchor cable preload is 200±10kN (traditional truss ≤150kN), which can adapt to roof undulations of ±15°.

[0027] S3, temporary buffer support for the lagging area.

[0028] Operational steps for temporary buffer support in the delayed area: Mine pressure monitoring equipment is deployed in the roadway area to monitor changes in mine pressure in real time. Based on the analysis of the monitoring data, the roadway area is divided into a mine pressure manifestation zone and a pressure stability zone. In the mining pressure manifestation area, temporary buffer passive support is carried out by using single hydraulic props in combination with π-shaped steel beams or hydraulic unit supports, according to the designed support density and method. As the working face advances, once the roadway area enters the pressure stabilization zone, the forward-moving lagging support equipment should be promptly dismantled and transported to the next mine pressure manifestation zone for reuse. Dynamic partitioning support strategy Mine pressure monitoring system: Deploy GPY200-M anchor bolt (cable) force sensors and KJ513 mine roof pressure wireless monitoring system Real-time data on roof delamination and surrounding rock strain are collected and transmitted wirelessly to the ground control center via LoRa to analyze the manifestation patterns of mine pressure.

[0029] Support equipment configuration: The mining pressure manifestation area uses unit-type hydraulic supports (working resistance 800kN / support), with a support density of 1 support / 2m; Remove the support in the pressure stabilization zone; recycling rate > 80%.

[0030] Traditional construction methods involve high-strength concrete support walls (or flexible formwork walls, etc.) and densely reinforced passive support throughout the entire roadway. The support equipment occupies 30%-40% of the roadway space, affecting ventilation and transportation. The support equipment cannot be reused, resulting in serious material waste. This solution uses dynamic zoned support: in the mining pressure manifestation zone, hydraulic unit supports (support center distance 2m) or single hydraulic props are used in conjunction with π-shaped steel beams. In the pressure stable zone, the support equipment is removed and reused, increasing the utilization rate by 80%.

[0031] The grouting pipe and sealing sleeve system, multi-layer bag grouting structure, and adapter for the goaf simply supported isolation roadway method include a sealing device for sealing boreholes in the mine. The sealing device includes a grouting pipe 4 and a sealing sleeve 5. The grouting pipe 4 has a grout outlet 6. The sealing sleeve 5 is fitted around the outer periphery of the grouting pipe 4 to form a closed space, which is connected to the grout outlet 6. The grouting pipe 4 is made of seamless steel pipe (outer diameter 42mm, wall thickness 5mm), the grout outlet diameter is 8mm and the spacing is 200mm, and the sealing sleeve 5 is a pressure-resistant rubber bag (pressure ≥1.5MPa). The borehole is sealed by pressurized grouting expansion, and the grout leakage rate is <5%.

[0032] The novel truss beam support device includes a truss beam 1, a support plate 2, and a self-aligning ball pad 3. The top surface of the truss beam 1 abuts against the top plate. The support plate 2 is located in the bottom opening groove of the truss beam 1. A first through hole is opened through the truss beam 1, and a second through hole is opened through the support plate 2. The first through hole and the second through hole are connected. The self-aligning ball pad 3 is rotatably installed at the bottom opening position of the second through hole on the support plate 2. Solid anchor cables pass through the first through hole, the second through hole, and the self-aligning ball pad 3 in sequence and are connected to the self-aligning ball pad 3. The top curved surface radius of the truss beam 1 is R=1500mm, and the contact length with the top plate is increased to 1.2m to reduce local stress concentration. The self-aligning ball pad 3 is made of high chromium alloy steel (hardness HRC55-60), with a spherical radius R=50mm and a friction coefficient <0.1.

[0033] Mechanical fixed-position gun: Power system: Compressed air driven (pressure 0.6-0.8MPa), drug delivery speed 2m / min, drug loading efficiency increased by 40%; Safety design: Remote control console (control distance ≥20m), equipped with infrared obstacle avoidance sensor to prevent equipment collision.

[0034] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for simply supported isolation roadway retention along the goaf based on mine pressure control, characterized in that, The methods for simply supported isolation and retaining roadways along the goaf include: S1, high-level top-cutting unloading creates a "low-stress environment"; S2, low-level simply supported isolation construction for safe roadway formation; including low-level roof deformation limiting technology and low-strength isolation "wall" design beside the roadway; S3, temporary buffer support for the lagging area.

2. The method for simple-supported isolation roadway retention based on mine pressure control according to claim 1, characterized in that, In S1, ground-penetrating radar and borehole inspection technology were used to thoroughly investigate the characteristics of the overlying rock structure in the mining area and determine the key locations of the cantilever beams that affect the roadway along the goaf.

3. The method for simple-supported isolation roadway retention based on mine pressure control according to claim 1, characterized in that, In S1, through theoretical calculations, numerical simulations, and on-site geological exploration, the physical and mechanical properties of coal and rock, in-situ stress, and parameters of the loosened zone of the surrounding rock in the roadway are analyzed to determine the cutting position, angle, and drilling parameters. The corresponding high-position rock beam cutting technology is then selected to enable the cantilever beam to be cut and unloaded.

4. The method for simple-supported isolation roadway retention based on mine pressure control according to claim 1, characterized in that, In the S2 low-level roof deformation limitation technology, on one side of the goaf of the roof in the roadway area, a row of solid anchor cable boreholes are constructed according to the design spacing and angle. The solid anchor cables are installed into the boreholes and fixed by high-level suspension. Then, a new type of truss beam support device is installed to ensure close contact with the roof and form a stable support structure.

5. A method for simple-supported isolation roadway retention along the goaf based on mine pressure control according to claim 1, characterized in that, The design of the low-intensity isolation "wall" along the alley of S2 includes a primary collapse-type "wall" and a secondary simply supported "wall".

6. A method for simple-supported isolation roadway retention based on mine pressure control according to claim 5, characterized in that, The operation steps for the first-level collapse to form a "wall" are based on the rock fragmentation and swelling characteristics. After the working face is mined, the low-level roof cutting technology is used to cause the roof of the goaf to collapse, so as to achieve the initial filling of the goaf. After the roof of the goaf collapses, intermittent grouting is carried out in the collapsed area to fill the gaps.

7. A method for simple-supported isolation roadway retention based on mine pressure control according to claim 5, characterized in that, The steps for constructing a "wall" using a two-stage simply supported structure are as follows: On one side of the goaf, U-shaped steel legs are installed at the designed intervals; Flame-retardant cloth and bar mesh for blocking slag are hung on the U-shaped steel legs to form a "false support". For "false plugs", timely spraying or spraying of inorganic flexible materials should be carried out to seal the leaks.

8. A method for simple-supported isolation roadway retention along the goaf based on mine pressure control according to claim 1, characterized in that, Operational steps for temporary buffer support in the hysteresis region of S3: Mine pressure monitoring equipment is deployed in the roadway area to monitor changes in mine pressure in real time. Based on the analysis of the monitoring data, the roadway area is divided into a mine pressure manifestation zone and a pressure stability zone. In the mining pressure manifestation area, temporary buffer passive support is carried out by using single hydraulic props in combination with π-shaped steel beams or hydraulic unit supports, according to the designed support density and method. As the working face advances, once the roadway area enters the pressure stabilization zone, the forward-moving lagging support equipment should be promptly dismantled and transported to the next mine pressure manifestation zone for reuse.

9. An adapter for a gob-side simply supported isolation roadway retention method based on mine pressure control, as described in claim 3, characterized in that, The device includes a sealing device for sealing blast holes in the mine. The sealing device includes a grouting pipe (4) and a sealing sleeve (5). The grouting pipe (4) has a grout outlet hole (6). The sealing sleeve (5) is fitted around the outer periphery of the grouting pipe (4) to form a closed space, which is connected to the grout outlet hole (6).

10. An adapter for a gob-side simply supported isolation roadway retention method based on mine pressure control, as described in claim 4, characterized in that... The new truss beam support device includes a truss beam (1), a support plate (2) and a self-aligning ball pad (3); the top surface of the truss beam (1) abuts against the top plate, the support plate (2) is located in the bottom opening groove of the truss beam (1), a first through hole is opened through the truss beam (1), a second through hole is opened through the support plate (2), the first through hole and the second through hole are connected, and the self-aligning ball pad (3) is rotatably installed at the bottom opening position of the second through hole on the support plate (2); The solid anchor cable passes through the first perforation hole, the second perforation hole, and the self-aligning ball pad (3) in sequence and is connected to the self-aligning ball pad (3).

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