Supporting system and method for large mining height working face gob-side entry retaining roof subsidence treatment

Abstract

The invention discloses a supporting system for large mining height working face gob-side entry retaining roof subsidence treatment. The supporting system is a system for multi-azimuth combined supporting of advanced working face reinforcing supporting, to-be-poured space reinforcing supporting and lagging temporary reinforcing supporting. According to the gob-side entry retaining roof sinking treatment supporting system for the large mining height working face, in the implementation process of gob-side entry retaining, when the roof sinks, the roof of a sinking roadway is treated in a targeted mode, the influence of roof sinking on production and safety of a mine is reduced, and safe production of the mine is ensured.

Description

Technical Field

[0001] This invention belongs to the field of coal mine support technology, specifically relating to a support system for addressing roof subsidence in goaf-side roadways of high mining faces, and also to a method for addressing roof subsidence in goaf-side roadways of high mining faces. Background Technology

[0002] To improve coal resource recovery rates and extend mine service life, goaf retention technology is being promoted and applied in many mines across China. This technology recovers traditional coal pillars used for roadway protection, increases coal resource recovery rates, reduces roadway excavation, and alleviates the tension in mining continuity, demonstrating significant technical and economic benefits.

[0003] Flexible mold gob-side entry technology, as one of the main gob-side entry technologies, has a wider range of applications, suitable for mines with different geological conditions and mining heights. During its application, especially in high-mining-height working faces, due to changes in geological conditions and mining activity, the roof of the entry roadway sometimes experiences varying degrees of subsidence. This subsidence reduces the roadway cross-section, hindering material transport, pedestrian passage, and mine ventilation, significantly impacting mine production and safety. Therefore, to ensure mine production safety, targeted measures are needed to address roof subsidence in high-mining-height entry roadways. Summary of the Invention

[0004] The first objective of this invention is to provide a support system for roof subsidence control in goaf-side roadways of high mining heights. This system is specifically designed to address roof subsidence during the goaf-side roadway construction process, thereby reducing the impact of roof subsidence on mine production and safety and ensuring safe mine production.

[0005] To achieve the above objectives, the technical solution adopted in this invention is: a support system for the treatment of roof subsidence in the goaf of a high mining face, which is a system of combined support from multiple directions, consisting of advanced working face reinforcement support, reinforcement support for the space to be poured, and delayed temporary reinforcement support.

[0006] The technical solution of the present invention also has the following characteristics:

[0007] The enhanced support of the advanced working face adopts grouting anchor cable to grout the roadway roof.

[0008] Grouting anchor cables are installed vertically to the top plate. The first row is arranged 500-700mm away from the coal face of the primary mining operation, and the second row is 1800-2200mm away from the first row of grouting anchor cables.

[0009] The grouting anchor cable has a diameter of 21.8mm, a length of 9300mm, and a row spacing of 2000mm.

[0010] The grouting material used is silicate-modified polyurethane material for coal mine reinforcement.

[0011] The reinforcement support for the space to be poured includes anchor bolts, prestressed anchor cables, and steel beam support.

[0012] The anchor bolt has a diameter of 22mm and a length of 2500mm; the anchor cable has a diameter of 21.8mm and a length of 12000mm; the steel beam has a length of 3200mm, a width of 300mm, a thickness of 10mm, and a row spacing of 2000mm.

[0013] The delayed temporary reinforcement support includes the coordinated reinforcement of temporary support by unit supports and U-shaped steel scaffolding.

[0014] The unit support is 650mm away from the tunnel wall and 3000mm apart along the longitudinal direction of the wall; U-shaped steel scaffolding is erected between the unit supports, using 36# U-shaped steel, with a row spacing of 3000mm.

[0015] The second objective of this invention is to provide a support method for addressing roof subsidence in goaf-side roadways in high-mining-height working faces. This method specifically addresses roof subsidence during the implementation of goaf-side roadways, addressing the subsided roof to reduce its impact on mine production and safety, and ensuring safe mine production.

[0016] To achieve the above objectives, the technical solution adopted by the present invention is: a support method for the treatment of roof subsidence in the goaf-retaining roadway of a high mining face, which is implemented in accordance with the following steps; Step 1: Install grouting anchors in the grouting anchor installation area; Step 2: Grouting is carried out after the grouting anchor cables are installed; Step 3: Install anchor rods and prestressed anchor cables behind the end support of the working face and in front of the formwork device, then put on the steel beam and fix it. Step 4: After the tunnel wall is poured and the wall material strength is sufficient for demolding, move the formwork device forward after demolding, move the unit support to the vicinity of the tunnel wall for support and apply pressure to the top. Step 5: After the unit support is erected, add a U-shaped steel scaffold between the two unit supports; Step 6: Repeat steps 1-5 until the roof settlement is found to meet the requirements through roof settlement monitoring.

[0017] The beneficial effects of this invention are as follows: This invention provides a support system and method for treating roof subsidence in roadways with high mining height. For sections where roof subsidence occurs in roadways, it adopts a multi-faceted combined support approach, including enhanced support of the working face ahead of the project, enhanced support of the space to be poured, and temporary enhanced support behind the project. This achieves a mechanism that combines grouting reinforcement of the working face ahead of the project with resistance of the lagging working face. Combined with enhanced support of the space to be poured, it effectively reduces the amount of roof subsidence and minimizes the impact of roof subsidence on mine production and safety. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a plan view of the method for treating roof subsidence in roadways along the goaf provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the advanced working face reinforcement support section provided by an embodiment of the present invention for the treatment of roof subsidence in the goaf-retaining roadway of a high mining face; Figure 3 This is a schematic diagram of the reinforced support section of the space to be poured, provided in an embodiment of the present invention for the treatment of roof subsidence in the goaf-retaining roadway of a high mining face. Figure 4 This is a schematic diagram of the U-shaped temporary reinforced support section of the method for treating roof subsidence along the goaf in a high-extraction working face, provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the delayed temporary reinforcement section of the unit support for the method of treating roof subsidence along the goaf in a high mining face, provided in an embodiment of the present invention. Figure 6 This is a schematic diagram of a combined support reinforcement consisting of anchor bolts, prestressed anchor cables, and steel beams, provided in an embodiment of the present invention for a method to treat roof subsidence along the goaf in a high-extraction working face.

[0019] In the diagram, 1. Grouting anchor cable, 2. Anchor bolt, 3. Prestressed anchor cable, 4. Steel beam, 5. Unit support, 6. U-shaped scaffold, 7. Retained roadway wall, 8. Hanging formwork device, 9. Roadway roof, 10. Retained roadway in the working face, 11. Roadway primary mining side; 12. Working face; A. Grouting anchor cable installation area, B. Grouting anchor cable grouting area. Detailed Implementation

[0020] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 like Figure 1-6As shown, the present invention provides a support system for the treatment of roof subsidence in the goaf-retaining roadway of a high mining face, comprising a multi-faceted combined support system including advanced working face reinforcement support, reinforcement support for the space to be poured, and delayed temporary reinforcement support.

[0022] Advanced working face reinforcement support refers to the reinforcement of the roadway roof 9 by installing grouting anchor cables 1 on the existing support of the roadway 10 when subsidence occurs in the roadway roof 9. (See...) Figure 1 , Figure 2 .

[0023] The reinforced support for the space to be poured refers to installing two anchor rods 2 and one prestressed anchor cable 3 behind the end support of the working face and in front of the formwork device 8. Simultaneously, a steel beam 4 is suspended by the anchor rods 2 and the prestressed anchor cable 3 for combined reinforced support. (See...) Figure 1 , Figure 3 .

[0024] Delayed temporary reinforcement refers to the reinforcement support provided near the roadway wall 7 by additional equipment and devices after the formwork device 8 has been moved forward, including unit supports 5 and U-shaped steel scaffolding 6, etc. (See below) Figure 1 , Figure 4 , Figure 5 and Figure 6 .

[0025] A mine face with a high extraction height was used for roadway retention. Flexible formwork concrete roadway retention technology was employed, with a roadway width of 4.6m and a wall width of 1.2m. During the roadway retention period, due to dynamic pressure from mining, roof subsidence occurred in the 1180-1370m section, with the cumulative maximum subsidence reaching 490mm based on on-site monitoring data. Emergency measures implemented on-site to address the roof subsidence included installing grouting anchors to reinforce the roof in subsidence-affected areas and erecting U-shaped steel scaffolding between unit supports for enhanced support. To control further roof subsidence, grouting anchors and grouting were installed in the advancing face, while the space awaiting pouring in the lagging face was reinforced with a combined support structure consisting of anchor bolts, prestressed anchors, and steel beams. Within the roadway, measures were taken to strengthen the unit supports and erect U-shaped steel scaffolding between them to control roof subsidence. On-site monitoring showed that the roof subsidence was between 10 and 20 mm, effectively controlling the subsidence of the roadway roof.

[0026] Example 2 The present invention provides a method for supporting the roof subsidence of a goaf-side roadway in a high-extraction working face, which is implemented according to the following steps: Step 1: Start installing grouting anchors 1 in grouting anchor installation area A, 60m away from working face 12. Install 2 grouting anchors 1 per row. The diameter of the grouting anchor is 21.8mm and the length is 9300mm. The row spacing is 2000mm. The first grouting anchor 1 is 500mm away from the primary mining side 11 of the roadway. The second grouting anchor 1 is 1800mm away from the first one. The grouting anchors 1 are all arranged perpendicular to the roadway roof 9.

[0027] Step 2: After the grouting anchor cable 1 is installed, grouting is carried out on the roadway roof 9 using the grouting anchor cable 1 in the grouting area B 20m away from the working face 12 to reinforce the roof of the roadway in the subsided section, enhance the strength of the roof, and ensure the integrity of the roof. The grouting material used for the reinforcement support of the advanced working face is silicate modified polyurethane material for coal mine reinforcement of coal and rock.

[0028] Step 3: Drill holes for two anchor rods 2 and one prestressed anchor cable 3 behind the end support of the working face and in front of the formwork device 8. The anchor rod 2 holes are drilled on both sides of the retaining wall 7, at least 150mm away from the retaining wall 7. The prestressed anchor cable 3 hole is 1150mm away from the anchor rod 2 in the retaining roadway. The anchor rod 2 and prestressed anchor cable 3 holes are drilled perpendicular to the roadway roof 9. After the anchor rod 2 and prestressed anchor cable 3 holes are drilled, begin the installation of the anchor rod 2 and prestressed anchor cable 3. Before installing the trays of the anchor rod 1 and prestressed anchor cable 3, first put a steel beam 4 on top of the flexible formwork wall. The cantilever length at one end of the goaf is not less than 300mm. Then, the trays for anchor bolts 2 and prestressed anchor cables 3 are installed. The distance between the anchor bolts and the end of the steel beam is not less than 150mm, and they are tightened and fixed. The specifications of anchor bolts 2 match the existing anchor bolts in the roadway, with a diameter of 22mm and a length of 2500mm. The prestressed anchor cable 3 has a diameter of 21.8mm and a length of 12000mm. The steel beam 4 has a length of not less than 3200mm, a width of 300mm, and a thickness of 10mm, and the material meets the requirements of Q235. Anchor bolts 2, prestressed anchor cables 3, and steel beams 4 form a combined support reinforcement. The row spacing of the combined support reinforcement is 1800mm.

[0029] Step 4: After the tunnel wall 7 is poured and the wall material strength meets the demolding requirements, the formwork device 8 is demolded and moved forward. Then, the ZQ6400 / 22 / 45D two-column support unit bracket 5 is moved to the vicinity of the tunnel wall 7 using the WC8YLY unit bracket transport vehicle for support and pressure connection to reduce the impact of dynamic pressure on the young tunnel wall 7. The unit bracket 5 adopts a two-column structure and its strength meets the calculation requirements. The unit brackets 5 are arranged at intervals along the length of the tunnel, with a spacing of 2800mm and a distance of 550mm from the flexible formwork wall 7, ensuring stable and reliable support.

[0030] Step 5: After the unit support 5 is erected, a U-shaped steel shed 6 is added between the two unit supports 5 to strengthen the support strength of the roof 9 of the working face roadway between the unit supports 5. The U-shaped steel shed 6 is made of 36# U-shaped steel, and the spacing between the sheds along the longitudinal direction of the roadway wall 7 is no more than 3000mm.

[0031] Step 6: Repeat steps 1-5 until roof subsidence monitoring shows that it is not very obvious before stopping; the roof subsidence monitoring method shall be performed in accordance with the "Method for Monitoring the Manifestation of Mine Pressure in Coal Mine Roadways" (KA T11-2023).

[0032] Example 3 The present invention provides a method for supporting the roof subsidence of a goaf-side roadway in a high-extraction working face, which is implemented according to the following steps: Step 1: Start installing grouting anchors 1 in grouting anchor installation area A, 80m away from working face 12. Install 2 grouting anchors 1 per row. The diameter of the grouting anchor is 21.8mm, the length is 9300mm, and the row spacing is 2000mm. The first grouting anchor 1 is 700mm away from the primary mining side 11 of the roadway, and the second grouting anchor 1 is 2200mm away from the first one. All grouting anchors 1 are arranged perpendicular to the roadway roof 9.

[0033] Step 2: After the grouting anchor cable 1 is installed, grouting is carried out on the roadway roof 9 using the grouting anchor cable 1 in the grouting area B 30m away from the working face 12 to reinforce the roof of the roadway in the subsided section, enhance the strength of the roof, and ensure the integrity of the roof. The grouting material used for the reinforcement support of the advanced working face is silicate modified polyurethane material for coal mine reinforcement of coal and rock.

[0034] Step 3: Drill holes for two anchor rods 2 and one prestressed anchor cable 3 behind the end support of the working face and in front of the formwork device 8. The anchor rod 2 holes are drilled on both sides of the retaining wall 7, at least 150mm away from the retaining wall 7. The prestressed anchor cable 3 hole is 1350mm away from the anchor rod 2 in the retaining roadway. The anchor rod 2 and prestressed anchor cable 3 holes are drilled perpendicular to the roadway roof 9. After the anchor rod 2 and prestressed anchor cable 3 holes are drilled, begin the installation of the anchor rod 2 and prestressed anchor cable 3. Before installing the trays of the anchor rod 1 and prestressed anchor cable 3, first put a steel beam 4 on top of the flexible formwork wall. The cantilever length at one end of the goaf is not less than 300mm. Then, the trays for anchor bolts 2 and prestressed anchor cables 3 are installed. The anchor bolts are not less than 150mm away from the end of the steel beam and are tightened. The specifications of anchor bolts 2 match those of the existing anchor bolts in the roadway: 22mm in diameter and 2500mm in length. The prestressed anchor cables 3 have a diameter of 21.8mm and a length of 12000mm. The steel beams 4 are not less than 3200mm in length, 300mm in width, and 10mm in thickness, and are made of Q235 material. Anchor bolts 2, prestressed anchor cables 3, and steel beams 4 form a combined support reinforcement. The spacing between rows of the combined support reinforcement is 2200mm.

[0035] Step 4: After the tunnel wall 7 is poured and the wall material strength meets the demolding requirements, demold the formwork device 8 and move it forward. Then, use the WC8YLY unit support transport vehicle to move the ZQ6400 / 22 / 45D type two-column support unit support 5 to the vicinity of the tunnel wall 7 for support and pressure connection to reduce the impact of dynamic pressure on the young tunnel wall 7. The unit support 5 adopts a two-column structure and its strength meets the calculation requirements. The unit supports 5 are arranged at intervals along the length of the tunnel, with a spacing of 3200mm and a distance of 750mm from the flexible formwork wall 7, ensuring stable and reliable support.

[0036] Step 5: After the unit support 5 is erected, a U-shaped steel shed 6 is added between the two unit supports 5 to strengthen the support strength of the roof 9 of the working face roadway between the unit supports 5. The U-shaped steel shed 6 is made of 36# U-shaped steel, and the spacing between the sheds along the longitudinal direction of the roadway wall 7 is no more than 3000mm.

[0037] Step 6: Repeat steps 1-5 until roof subsidence monitoring shows that it is not very obvious before stopping; the roof subsidence monitoring method shall be performed in accordance with the "Method for Monitoring the Manifestation of Mine Pressure in Coal Mine Roadways" (KA T11-2023).

[0038] Example 4 The present invention provides a method for supporting the roof subsidence of a goaf-side roadway in a high-extraction working face, which is implemented according to the following steps: Step 1: Start installing grouting anchors 1 in grouting anchor installation area A, 70m away from working face 12. Install 2 grouting anchors 1 per row. The diameter of the grouting anchor is 21.8mm, the length is 9300mm, and the row spacing is 2000mm. The first grouting anchor 1 is 600mm away from the primary mining side 11 of the roadway, and the second grouting anchor 1 is 2000mm away from the first one. All grouting anchors 1 are arranged perpendicular to the roadway roof 9.

[0039] Step 2: After the grouting anchor cable 1 is installed, grouting is carried out on the roadway roof 9 using the grouting anchor cable 1 in the grouting area B 25m away from the working face 12 to reinforce the roof of the roadway in the subsided section, enhance the strength of the roof, and ensure the integrity of the roof. The grouting material used for the reinforcement support of the advanced working face is silicate modified polyurethane material for coal mine reinforcement of coal and rock.

[0040] Step 3: Drill holes for two anchor rods 2 and one prestressed anchor cable 3 behind the end support of the working face and in front of the formwork device 8. The anchor rod 2 holes are drilled on both sides of the retaining wall 7, at least 150mm away from the retaining wall 7. The prestressed anchor cable 3 hole is 1250mm away from the anchor rod 2 in the retaining roadway. The anchor rod 2 and prestressed anchor cable 3 holes are drilled perpendicular to the roadway roof 9. After the anchor rod 2 and prestressed anchor cable 3 holes are drilled, begin the installation of the anchor rod 2 and prestressed anchor cable 3. Before installing the trays of the anchor rod 1 and prestressed anchor cable 3, first put a steel beam 4 on top of the flexible formwork wall. The cantilever length at one end of the goaf shall be no less than 300mm. Then, the trays for anchor bolts 2 and prestressed anchor cables 3 shall be installed. The distance between the anchor bolts and the end of the steel beam shall be no less than 150mm, and they shall be tightened and fixed. The specifications of anchor bolts 2 shall match those of the existing anchor bolts in the roadway, with a diameter of 22mm and a length of 2500mm. The prestressed anchor cables 3 shall have a diameter of 21.8mm and a length of 12000mm. The steel beams 4 shall have a length of no less than 3200mm, a width of 300mm, and a thickness of 10mm, and shall be made of Q235 material. Anchor bolts 2, prestressed anchor cables 3, and steel beams 4 shall form a combined support reinforcement. The spacing between rows of the combined support reinforcement shall be 2000mm.

[0041] Step 4: After the tunnel wall 7 is poured and the wall material strength meets the demolding requirements, the formwork device 8 is demolded and moved forward. Then, the ZQ6400 / 22 / 45D two-column support unit bracket 5 is moved to the vicinity of the tunnel wall 7 using the WC8YLY unit bracket transport vehicle for support and pressure connection to reduce the impact of dynamic pressure on the young tunnel wall 7. The unit bracket 5 adopts a two-column structure and its strength meets the calculation requirements. The unit brackets 5 are arranged at intervals along the length of the tunnel, with a spacing of 30,000 mm and a distance of 650 mm from the flexible formwork wall 7, ensuring stable and reliable support.

[0042] Step 5: After the unit support 5 is erected, a U-shaped steel shed 6 is added between the two unit supports 5 to strengthen the support strength of the roof 9 of the working face roadway between the unit supports 5. The U-shaped steel shed 6 is made of 36# U-shaped steel, and the spacing between the sheds along the longitudinal direction of the roadway wall 7 is no more than 3000mm.

[0043] Step 6: Repeat steps 1-5 until roof subsidence monitoring shows that it is not very obvious before stopping; the roof subsidence monitoring method shall be performed in accordance with the "Method for Monitoring the Manifestation of Mine Pressure in Coal Mine Roadways" (KA T11-2023).

[0044] Example 5 The present invention provides a method for supporting the roof subsidence of a goaf-side roadway in a high-extraction working face, which is implemented according to the following steps: Step 1: Start installing grouting anchors 1 in grouting anchor installation area A, 60m away from working face 12. Install 2 grouting anchors 1 per row. The diameter of the grouting anchor is 21.8mm and the length is 9300mm. The row spacing is 2000mm. The first grouting anchor 1 is 700mm away from the primary mining side 11 of the roadway. The second grouting anchor 1 is 2200mm away from the first one. The grouting anchors 1 are all arranged perpendicular to the roadway roof 9.

[0045] Step 2: After the grouting anchor cable 1 is installed, grouting is carried out on the roadway roof 9 using the grouting anchor cable 1 in the grouting area B 30m away from the working face 12 to reinforce the roof of the roadway in the subsided section, enhance the strength of the roof, and ensure the integrity of the roof. The grouting material used for the reinforcement support of the advanced working face is silicate modified polyurethane material for coal mine reinforcement of coal and rock.

[0046] Step 3: Drill holes for two anchor bolts 2 and one prestressed anchor cable 3 behind the end support of the working face and in front of the formwork device 8. The anchor bolt 2 holes are drilled on both sides of the retaining wall 7, at least 150mm away from the retaining wall 7. The prestressed anchor cable 3 hole is 1350mm away from the anchor bolt 2 in the retaining roadway. The anchor bolt 2 and prestressed anchor cable 3 holes are drilled perpendicular to the roadway roof 9. After the anchor bolt 2 and prestressed anchor cable 3 holes are drilled, begin the installation of the anchor bolt 2 and prestressed anchor cable 3. Before installing the trays of the anchor bolt 1 and prestressed anchor cable 3, first put a steel beam 4 on top of the flexible formwork wall. The cantilever length at one end of the section is not less than 300mm. Then, the trays for anchor bolts 2 and prestressed anchor cables 3 are installed. The anchor bolts are not less than 150mm away from the end of the steel beam and are tightened. The specifications of anchor bolts 2 match the existing anchor bolts in the tunnel, with a diameter of 22mm and a length of 2500mm. The prestressed anchor cables 3 have a diameter of 21.8mm and a length of 12000mm. The steel beams 4 have a length of not less than 3200mm, a width of 300mm, and a thickness of 10mm, and the material must meet the requirements of Q235. Anchor bolts 2, prestressed anchor cables 3, and steel beams 4 form a combined support reinforcement. The spacing between rows of the combined support reinforcement is 1800-2200mm.

[0047] Step 4: After the tunnel wall 7 is poured and the wall material strength meets the demolding requirements, demold the formwork device 8 and move it forward. Then, use the WC8YLY unit support transport vehicle to move the ZQ6400 / 22 / 45D type two-column support unit support 5 to the vicinity of the tunnel wall 7 for support and pressure connection to reduce the impact of dynamic pressure on the young tunnel wall 7. The unit support 5 adopts a two-column structure and its strength meets the calculation requirements. The unit supports 5 are arranged at intervals along the length of the tunnel, with a spacing of 3200mm and a distance of 750mm from the flexible formwork wall 7, ensuring stable and reliable support.

[0048] Step 5: After the unit support 5 is erected, a U-shaped steel shed 6 is added between the two unit supports 5 to strengthen the support strength of the roof 9 of the working face roadway between the unit supports 5. The U-shaped steel shed 6 is made of 36# U-shaped steel, and the spacing between the sheds along the longitudinal direction of the roadway wall 7 is no more than 3000mm.

[0049] Step 6: Repeat steps 1-5 until roof subsidence monitoring shows that it is not very obvious before stopping; the roof subsidence monitoring method shall be performed in accordance with the "Method for Monitoring the Manifestation of Mine Pressure in Coal Mine Roadways" (KA T11-2023).

[0050] Example 6 The present invention provides a method for supporting the roof subsidence of a goaf-side roadway in a high-extraction working face, which is implemented according to the following steps: Step 1: Start installing grouting anchors 1 in grouting anchor installation area A, 80m away from working face 12. Install 2 grouting anchors 1 per row. The diameter of the grouting anchor is 21.8mm, the length is 9300mm, and the row spacing is 2000mm. The first grouting anchor 1 is 500mm away from the primary mining side 11 of the roadway, and the second grouting anchor 1 is 1800mm away from the first one. The grouting anchors 1 are all arranged perpendicular to the roadway roof 9.

[0051] Step 2: After the grouting anchor cable 1 is installed, grouting is carried out on the roadway roof 9 using the grouting anchor cable 1 in the grouting area B 20m away from the working face 12 to reinforce the roof of the roadway in the subsided section, enhance the strength of the roof, and ensure the integrity of the roof. The grouting material used for the reinforcement support of the advanced working face is silicate modified polyurethane material for coal mine reinforcement of coal and rock.

[0052] Step 3: Drill holes for two anchor bolts 2 and one prestressed anchor cable 3 behind the end support of the working face and in front of the formwork device 8. The anchor bolt 2 holes are drilled on both sides of the retaining wall 7, at least 150mm away from the retaining wall 7. The prestressed anchor cable 3 hole is 1250mm away from the anchor bolt 2 in the retaining roadway. The anchor bolt 2 and prestressed anchor cable 3 holes are drilled perpendicular to the roadway roof 9. After the anchor bolt 2 and prestressed anchor cable 3 holes are drilled, begin the installation of the anchor bolt 2 and prestressed anchor cable 3. Before installing the trays of the anchor bolt 1 and prestressed anchor cable 3, first put a steel beam 4 on top of the flexible formwork wall. The cantilever length at one end of the section is not less than 300mm. Then, the trays for anchor bolts 2 and prestressed anchor cables 3 are installed. The anchor bolts are not less than 150mm away from the end of the steel beam and are tightened. The specifications of anchor bolts 2 match the existing anchor bolts in the tunnel, with a diameter of 22mm and a length of 2500mm. The prestressed anchor cables 3 have a diameter of 21.8mm and a length of 12000mm. The steel beams 4 have a length of not less than 3200mm, a width of 300mm, and a thickness of 10mm, and the material must meet the requirements of Q235. Anchor bolts 2, prestressed anchor cables 3, and steel beams 4 form a combined support reinforcement. The spacing between rows of the combined support reinforcement is 1800-2200mm.

[0053] Step 4: After the tunnel wall 7 is poured and the wall material strength meets the demolding requirements, the formwork device 8 is demolded and moved forward. Then, the ZQ6400 / 22 / 45D two-column support unit bracket 5 is moved to the vicinity of the tunnel wall 7 using the WC8YLY unit bracket transport vehicle for support and pressure connection to reduce the impact of dynamic pressure on the young tunnel wall 7. The unit bracket 5 adopts a two-column structure and its strength meets the calculation requirements. The unit brackets 5 are arranged at intervals along the length of the tunnel, with a spacing of 3000mm and a distance of 650mm from the flexible formwork wall 7, ensuring stable and reliable support.

[0054] Step 5: After the unit support 5 is erected, a U-shaped steel shed 6 is added between the two unit supports 5 to strengthen the support strength of the roof 9 of the working face roadway between the unit supports 5. The U-shaped steel shed 6 is made of 36# U-shaped steel, and the spacing between the sheds along the longitudinal direction of the roadway wall 7 is no more than 3000mm.

[0055] Step 6: Repeat steps 1-5 until roof subsidence monitoring shows that it is not very obvious before stopping; the roof subsidence monitoring method shall be performed in accordance with the "Method for Monitoring the Manifestation of Mine Pressure in Coal Mine Roadways" (KA T11-2023).

Claims

1. A support system for treating roof subsidence in goaf-side roadways of high-extraction working faces, characterized in that, It is a system that provides combined support from multiple directions, consisting of enhanced support for the working face, enhanced support for the space to be poured, and delayed temporary enhanced support.

2. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 1, characterized in that, The enhanced support of the advanced working face adopts grouting anchor cable to grout the roadway roof.

3. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 2, characterized in that, Grouting anchor cables are installed vertically to the top plate. The first row is arranged 500-700mm away from the coal face of the primary mining operation, and the second row is 1800-2200mm away from the first row of grouting anchor cables.

4. A support system for treating roof subsidence in goaf-side roadways of high-extraction working faces, characterized in that: The grouting anchor cable has a diameter of 21.8mm, a length of 9300mm, and a row spacing of 2000mm.

5. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 4, characterized in that, The grouting material used is silicate-modified polyurethane material for coal mine reinforcement.

6. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 5, characterized in that, The reinforcement support for the space to be poured includes anchor bolts, prestressed anchor cables, and steel beam support.

7. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 6, characterized in that, The anchor bolt has a diameter of 22mm and a length of 2500mm; the anchor cable has a diameter of 21.8mm and a length of 12000mm; the steel beam has a length of 3200mm, a width of 300mm, a thickness of 10mm, and a row spacing of 2000mm.

8. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 7, characterized in that, The delayed temporary reinforcement support includes the coordinated reinforcement of temporary support by unit supports and U-shaped steel scaffolding.

9. The support system for treating roof subsidence in a goaf-side roadway in a high-extraction working face according to claim 8, characterized in that, The unit support is 650mm away from the tunnel wall and 3000mm apart along the longitudinal direction of the wall; U-shaped steel scaffolding is erected between the unit supports, using 36# U-shaped steel, with a row spacing of 3000mm.

10. A method for supporting the roof of a goaf-side roadway in a high-extraction working face to address subsidence, characterized in that... include; Step 1: Install grouting anchors in the grouting anchor installation area; Step 2: Grouting is carried out after the grouting anchor cables are installed; Step 3: Install anchor rods and prestressed anchor cables behind the end support of the working face and in front of the formwork device, then put on the steel beam and fix it. Step 4: After the tunnel wall is poured and the wall material strength is sufficient for demolding, move the formwork device forward after demolding, move the unit support to the vicinity of the tunnel wall for support and apply pressure to the top. Step 5: After the unit support is erected, add a U-shaped steel scaffold between the two unit supports; Step 6: Repeat steps 1-5 until the roof settlement is found to meet the requirements through roof settlement monitoring.

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