Supporting method of self-established roadway and gangue blocking at fully-mechanized caving face with top cutting and pressure releasing without coal pillar

Abstract

The present application belongs to the technical field of roadway support, and particularly relates to a kind of fully mechanized caving face cutting roof pressure relief no-pillar self-forming roadway gangue blocking support method;Including temporary gangue blocking structure, gangue blocking support system and roadway-remaining temporary support system, temporary gangue blocking structure is connected with the coal drawing scraper conveyor nose behind the top coal caving face hydraulic support, when the working face advances, temporary gangue blocking structure moves forward with top coal caving face hydraulic support and coal drawing scraper conveyor, gangue blocking support system is fixedly installed on the side of temporary gangue blocking structure away from gob caving gangue;Roadway-remaining temporary support system includes single hydraulic prop and bottom beam;Temporary gangue blocking structure can temporarily block the gangue falling in the gob behind the working face, providing timely safety protection for construction personnel, and roadway-remaining temporary support system not only can be used to support the roof in the roadway to prevent the influence of gob caving gangue dynamic pressure disturbance, but also can prevent gangue blocking support structure from falling before gob gangue completely collapses and compacts.

Description

Technical Field

[0001] This invention belongs to the field of roadway support technology, specifically relating to a method for supporting a self-forming roadway without coal pillars in a fully mechanized longwall mining face by cutting the roof and relieving pressure. Background Technology

[0002] In traditional longwall mining, mining a single working face requires excavating two return roadways before coal can be extracted. Furthermore, a 20-meter-wide coal pillar is typically maintained between adjacent working faces to protect the goaf roadway for the next face. This method, requiring the excavation of two return roadways before mining, often leads to tight transitions between working faces. In addition, the presence of protective coal pillars between adjacent working faces results in significant coal resource losses.

[0003] The roof-cutting and pressure-relief pillarless self-forming roadway technology is a novel roadway retention method. This method uses directional blasting to sever the connection between the goaf roof and the roadway roof, then utilizes special support techniques to form a gangue sidewall on the goaf side of the roadway, ultimately preserving one working face for the next working face. This mining method not only preserves one working face for the next but also completely eliminates protective coal pillars between working faces. Therefore, this method can greatly alleviate the problem of mining succession between working faces and, theoretically, can increase the coal resource recovery rate of the working face to 100%.

[0004] Currently, the technology of roof cutting and pressure relief without coal pillars forming a self-contained roadway is relatively mature in longwall mining faces with a coal seam thickness of less than 4.5 meters and has been widely promoted and applied throughout the country. However, in longwall mining faces with a coal seam thickness greater than 4.5 meters, especially longwall mining faces with top coal caving, this technology is still in the experimental stage. This is because the technical process of longwall mining with top coal caving in thick coal seams differs significantly from that of longwall mining in one go. Since longwall mining with top coal caving in thick coal seams is applicable to thick and extra-thick coal seams, the mine pressure manifestation is more intense. Furthermore, longwall mining with top coal caving requires a separate coal scraper conveyor behind the hydraulic supports of the working face. Therefore, the technology of roof cutting and pressure relief without coal pillars forming a self-contained roadway cannot be used for retaining rockfill support next to the end supports of the top coal caving face. Thus, a separate rockfill support method needs to be designed for the technology of roof cutting and pressure relief without coal pillars forming a self-contained roadway in top coal caving faces. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the fully mechanized top coal caving mining method requires a separate coal feeding scraper conveyor to be set up behind the hydraulic support of the working face. Therefore, the top cutting and pressure relief self-forming roadway technology cannot be used to retain the roadway with rock retaining support next to the end support of the top coal caving working face. It is also necessary to design a separate rock retaining support for the top cutting and pressure relief self-forming roadway technology of the top coal caving working face.

[0006] This invention provides the following technical solution: a method for retaining rockfill in a fully mechanized longwall face with roof cutting, pressure relief, and pillarless self-forming roadway, comprising a temporary rockfill retaining structure, a rockfill retaining support system, and a temporary roadway retention support system. The temporary rockfill retaining structure is connected to the head of the coal feeding scraper conveyor behind the hydraulic support of the top coal caving face. When the longwall face advances, the temporary rockfill retaining structure moves forward along with the hydraulic support and the coal feeding scraper conveyor. The rockfill retaining support system is fixedly installed on the back of the temporary rockfill retaining structure. On the side where the goaf collapses, the temporary support system for retaining the rockfall is not connected to the temporary rockfall retaining structure. The temporary support system for the roadway includes individual hydraulic props and bottom beams. The individual hydraulic props are used to support the roof of the retained roadway to resist the dynamic pressure disturbance of the collapsing rockfall in the goaf. The bottom beams serve as the base of the individual hydraulic props to prevent them from sinking into the coal seam floor of the roadway. The bottom beams on the goaf side and the individual hydraulic props on the goaf side are in direct contact with the rockfall retaining support system.

[0007] Furthermore, the temporary rock-blocking structure includes several rock-blocking plates arranged along the working face advancing direction. The front and rear rock-blocking plates are connected by bolts, and the temporary rock-blocking structure is connected to the head of the coal discharge scraper conveyor through bolt holes.

[0008] Furthermore, the height of the temporary rock retaining structure is lower than the height of the roadway. The height of the temporary rock retaining structure = roadway height - 0.5m; the width of the temporary rock retaining structure = daily advance of the working face; the width of the temporary rock retaining structure is limited, and it only needs to provide temporary support for the collapsed rock within the daily advance length. At this time, the rock supported by the temporary rock retaining structure is mainly the direct roof of the coal seam and will not completely fill the goaf. Therefore, the height of the temporary rock retaining structure = roadway height - 0.5m.

[0009] Furthermore, the rockfall retaining support system includes retractable U-shaped steel and steel mesh. The retractable U-shaped steel is formed by overlapping two U-shaped steels and fixed by two sets of clamping cables. Several retractable U-shaped steels are arranged side by side, and the retractable U-shaped steels are connected to each other by two sets of connecting plates. The connecting plates and the two sets of clamping cables on the retractable U-shaped steels share bolts. The connecting plates connect multiple retractable U-shaped steels into a whole. The steel mesh is installed in the middle of the retractable U-shaped steel and the temporary rockfall retaining structure and is tied to the retractable U-shaped steel.

[0010] Furthermore, the height of the retractable U-shaped steel is equal to the height of the tunnel. However, since the retractable U-shaped steel is composed of two U-shaped steels overlapping each other, in order to ensure the stability of the retractable U-shaped steel, the overlap length of the two U-shaped steels that make up the retractable U-shaped steel is greater than or equal to 50cm.

[0011] Furthermore, the temporary rock-blocking structure consists of three rock-blocking plates, which facilitates transportation from the surface to the mine and makes it easier to install the temporary rock-blocking structure; the width of a single rock-blocking plate = [width of the temporary rock-blocking structure + 0.2m] / 3, because the overlap width between the rock-blocking plates is 0.1m.

[0012] Compared with the prior art, the advantages of the present invention are:

[0013] 1. Before the longwall top-coal caving face is mined, a temporary rock-blocking structure is first installed at the head of the coal feeding scraper conveyor and connected with bolts. During longwall mining, under the protection of the temporary rock-blocking structure, a rock-blocking support system and a temporary roadway support system can be simultaneously installed behind the longwall top-coal caving face. The temporary rock-blocking structure can temporarily block the rockfalling from the goaf behind the face, providing timely safety for construction personnel. Furthermore, because the temporary rock-blocking structure temporarily blocks the horizontal force from the rockfalling from the goaf, it facilitates the installation of the rock-blocking support system. The temporary roadway support system not only protects the roof within the roadway from the dynamic pressure disturbance of the rockfalling from the goaf, but also prevents the rock-blocking support structure from collapsing before the goaf rock has completely collapsed and stabilized.

[0014] 2. By setting up a temporary rock-blocking structure, even in fully mechanized top-coal caving faces with a coal scraper conveyor, construction workers can safely and efficiently install the rock-blocking support system and the temporary roadway support system. Furthermore, since the temporary rock-blocking structure is connected to the coal scraper conveyor head, it can move forward along with the coal scraper conveyor as the working face advances. This allows construction workers to continuously advance with the working face to install the rock-blocking support system and the temporary roadway support system. In addition, the temporary rock-blocking structure is a modification of the existing hydraulic supports and scraper conveyor in the top-coal caving face, by installing three rock-blocking plates. This not only saves the mine a significant amount of financial investment but also saves workers a considerable amount of time.

[0015] 3. Through the joint support of the rock-blocking support system and the temporary roadway support system, the bottom beams and individual hydraulic props of the temporary roadway support system on the goaf side can effectively prevent the rock-blocking support system from collapsing due to horizontal forces when impacted by rockfall from the goaf. Thus, as the rockfall in the goaf behind the working face gradually collapses and compacts, even if the temporary roadway support system is withdrawn, the rock-blocking support system will no longer be subject to horizontal forces and will not collapse. Attached Figure Description

[0016] Figure 1 A schematic diagram of the overall structure of the rockfill support method for roof cutting and pressure relief without coal pillars in fully mechanized longwall mining faces;

[0017] Figure 2 This is a schematic diagram of the temporary retaining structure connection;

[0018] Figure 3 This is a schematic diagram of a temporary retaining structure.

[0019] Figure 4 This is a schematic diagram of a rockfall retaining plate;

[0020] Figure 5 This is a schematic diagram of the rockfill retaining support system.

[0021] Figure 6 This is a schematic diagram of a retractable U-shaped steel connection.

[0022] Figure 7 This is a schematic diagram of the tunnel cross-section;

[0023] In the diagram: 1-Hydraulic support for the top coal caving face; 2-Coal caving scraper conveyor; 3-Temporary rock retaining structure; 301-Rotten rock retaining plate connecting bolt holes; 302-Upper fixing bolt holes of the temporary rock retaining structure; 303-Lower fixing bolt holes of the temporary rock retaining structure; 304-Bolt; 305-Left side rock retaining plate; 306-Middle side rock retaining plate; 307-Right side rock retaining plate; 4-Rotten rock retaining support system; 401-Reinforcing mesh; 402-Cable clamp; 403-Right side bolt hole of the cable clamp; 404-Left side bolt hole of the cable clamp; 405-Connecting plate; 406-Compressible U-shaped steel; 407-U-shaped steel; 5-Directional cut; 6-Collapsed rock in the goaf; 7-Coal body; 8-Temporary support system for roadway retention; 801-Single hydraulic prop; 802-Bottom beam. Detailed Implementation

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] like Figure 1-7The diagram shows a method for supporting a self-forming roadway without coal pillars in a fully mechanized longwall caving face, including a temporary rock-blocking structure 3, a rock-blocking support system 4, and a temporary roadway support system 8. The temporary rock-blocking structure 3 is composed of a left rock-blocking plate 305, a middle rock-blocking plate 306, and a right rock-blocking plate 307 connected by bolts 304. The left rock-blocking plate 305, the middle rock-blocking plate 306, and the right rock-blocking plate 307 are all provided with rock-blocking plate connecting bolt holes 301, which facilitates the use of bolts 304 to connect the three rock-blocking plates to form the temporary rock-blocking structure 3. During the longwall caving face mining, the temporary rock-blocking structure 3 is connected to the coal feeding scraper conveyor 2 behind the hydraulic support 1 of the longwall caving face.

[0026] In addition, since there are two bolt holes on the right-side rock-blocking plate 307, including the upper fixing bolt hole 302 of the temporary rock-blocking structure and the lower fixing bolt hole 303 of the temporary rock-blocking structure, the temporary rock-blocking structure 3 can be connected to the coal feeding scraper conveyor 2 behind the hydraulic support 1 of the top coal caving face using bolts 304.

[0027] The temporary rock-blocking structure 3 can protect construction personnel and efficiently install the rock-blocking support system 4 and the temporary roadway support system 8 when the longwall top coal caving face has a coal feeding scraper conveyor 2. Moreover, the temporary rock-blocking structure 3 can move forward together with the coal feeding scraper conveyor 2 as the working face advances, so that construction personnel can move forward with the working face to install the rock-blocking support system 4 and the temporary roadway support system 8.

[0028] The temporary rock-blocking structure 3 is modified by installing the left-side rock-blocking plate 305, the middle rock-blocking plate 306, and the right-side rock-blocking plate 307 on the basis of the original hydraulic support 1 and coal feeding scraper conveyor 2 of the top coal caving face. This not only saves investment for the working face, but also saves time.

[0029] The width W2 of the temporary rock retaining structure 3 is equal to the daily advance of the working face. This is because the temporary rock retaining structure 3 only needs to protect the construction personnel from installing the rock retaining support system 4 and the temporary support system 8 in the roadway within the daily advance range of the working face.

[0030] The temporary rock-blocking structure 3 is composed of a left-side rock-blocking plate 305, a middle rock-blocking plate 306, and a right-side rock-blocking plate 307 of equal width connected together. The width W2 of the temporary rock-blocking structure 3 is equal to the daily advance of the working face = W 21 +W 22 +W 23 -0.2m, because the overlap width when the left-side rock-blocking plate 305, the middle rock-blocking plate 306 and the right-side rock-blocking plate 307 are connected is 0.1m.

[0031] The temporary rock retaining structure 3 is connected to the coal feeding scraper conveyor 2 by bolts 304. Moreover, the temporary rock retaining structure 3 is located inside the goaf, providing temporary support for construction personnel to install the rock retaining support system 4 and the temporary support system 8 in the roadway.

[0032] The height of the temporary rock retaining structure 3 is lower than the height of the roadway, i.e., H2 = H - 0.5m. This is because the rock supported by the temporary rock retaining structure 3 is mainly the direct roof of the coal seam and will not completely fill the goaf. Therefore, the height of the temporary rock retaining structure is H2 = H - 0.5m.

[0033] like Figure 5-7 As shown, directional cutting 5 is performed on the roof of the goaf side in front of the working face. Since the temporary rock retaining structure 3 has been connected to the coal feeding scraper conveyor 2 with bolts 304, as the working face advances, the direct roof above the coal seam collapses as it is mined. The temporary rock retaining structure 3 plays a temporary support role for the collapsed rock in the goaf. At this time, the construction workers simultaneously install the rock retaining support system 4 and the temporary support system 8 in the roadway under the protection of the temporary rock retaining structure 3.

[0034] The rockfall retaining support system 4 is installed inside the temporary rockfall retaining structure 3, i.e., inside the roadway. A steel mesh 401 is installed between the retractable U-shaped steel 406 and the temporary rockfall retaining structure 3 to prevent fragments from the collapsed rockfall from falling into the roadway. The retractable U-shaped steel 406 is installed inside the steel mesh 401. The retractable U-shaped steel 406 does not bear the pressure of the roadway roof and floor, but is only used to support the collapsed rockfall inside the goaf 6.

[0035] The collapsible U-shaped steel 406 is composed of two U-shaped steels 407 overlapping each other, with an overlap length of not less than 50cm. The upper and lower overlap parts are fixedly connected by cable clamps 402. The height of the collapsible U-shaped steel = the tunnel height H = the height of the U-shaped steel H1*2-0.5m.

[0036] The compressible U-shaped steels 406 are connected into a whole by connecting plates 405. The connecting plates 405 are connected to the right bolt hole 403 and the left bolt hole 404 of the cable clamp using bolts 304. This is to prevent individual compressible U-shaped steels 401 from being overturned by the horizontal force of the collapsing gangue.

[0037] The spacing W1 between adjacent compressible U-shaped steels 406 is 0.5 * the spacing of the single hydraulic props on the goaf side. This is because the single hydraulic props 801 and bottom beams 802 on the goaf side in the temporary support system 8 are close to the compressible U-shaped steels 406. Moreover, since the compressible U-shaped steels 406 are a whole, the temporary support system 8 can allow the retaining rock support structure to collapse before the gangue in the goaf 6 completely collapses, compacts, and stabilizes.

[0038] It should be noted that this invention is a method for retaining rockfill in fully mechanized longwall mining faces with roof cutting and pressure relief, forming a self-contained roadway without coal pillars. When carrying out retaining rockfill support in the roadway of a fully mechanized longwall mining face, before the longwall mining face is mined back, the construction personnel first install a temporary retaining rockfill structure 3 at the head of the coal feeding scraper conveyor 2 and connect it with bolts 304. When the longwall face is mined back, under the protection of the temporary retaining rockfill structure 3, the construction personnel can simultaneously install the retaining rockfill support system 3 and the temporary roadway support system 8 behind the fully mechanized longwall mining face. The temporary rock retaining structure 3 can temporarily block the rock falling from the goaf 6 behind the working face, providing timely safety for construction personnel. Moreover, since the temporary rock retaining structure 3 temporarily blocks the horizontal force from the rock falling from the goaf 6, it is easier to install the rock retaining support system 3. The temporary support system 8 for the roadway can not only be used to support the roof of the roadway from the dynamic pressure disturbance of the rock falling from the goaf 6, but also prevent the rock retaining support structure from collapsing before the rock in the goaf 6 is completely collapsed, compacted and stabilized.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A thick coal seam fully mechanized caving face cutting roof pressure relief no-pillar self-lane and waste rock retaining support method for thick coal seams with a seam thickness greater than 4.5 meters, characterized by: The system includes a temporary rock-blocking structure (3), a rock-blocking support system (4), and a temporary roadway support system (8). The temporary rock-blocking structure (3) is connected to the head of the coal feeding scraper conveyor (2) behind the hydraulic support (1) of the top coal caving face. When the working face advances, the temporary rock-blocking structure (3) moves forward with the hydraulic support (1) and the coal feeding scraper conveyor (2) of the top coal caving face. The rock-blocking support system (4) is fixedly installed on the side of the temporary rock-blocking structure (3) facing away from the collapsed rock in the goaf, and the rock-blocking support system (4) is not connected to the temporary rock-blocking structure. The structure (3) is connected; the temporary support system (8) for the roadway includes a single hydraulic prop (801) and a bottom beam (802). The single hydraulic prop (801) is used to support the roof of the roadway to resist the dynamic pressure disturbance of the collapsed gangue in the goaf. The bottom beam (802) serves as the base of the single hydraulic prop (801) to prevent the single hydraulic prop (801) from sinking into the bottom of the coal seam in the roadway. The bottom beam (802) on the goaf side and the single hydraulic prop (801) on the goaf side are in direct contact with the gangue retaining support system (4). The temporary rock-blocking structure (3) includes several rock-blocking plates arranged along the working face advancing direction. The front and rear rock-blocking plates are connected by bolts. The temporary rock-blocking structure is connected to the head of the coal feeding scraper conveyor (2) through bolt holes. The height of the temporary rock retaining structure (3) is lower than the height of the roadway, and the height of the temporary rock retaining structure (3) = roadway height - 0.5m; The width of the temporary rock-blocking structure (3) = the daily advance of the working face; The aforementioned rockfall retaining support system (4) includes a collapsible U-shaped steel (406) and a steel mesh (401). The collapsible U-shaped steel (406) is formed by two U-shaped steels overlapping each other and is fixed by two sets of upper and lower clamping cables (402). Several collapsible U-shaped steels (406) are arranged side by side, and the collapsible U-shaped steels (406) are connected to each other by two sets of upper and lower connecting plates (405). The connecting plates (405) and the two sets of clamping cables (402) on the collapsible U-shaped steel (406) share bolts. The steel mesh (401) is installed in the middle of the collapsible U-shaped steel (406) and the temporary rockfall retaining structure (3) and is tied to the collapsible U-shaped steel (406). The height of the retractable U-shaped steel (406) is equal to the height of the roadway, and the overlap length of the two U-shaped steels that make up the retractable U-shaped steel (406) is greater than or equal to 50cm; The temporary rock-blocking structure (3) consists of three rock-blocking plates, and the width of a single rock-blocking plate is equal to (width of the temporary rock-blocking structure - 0.2m) / 3.

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