Coal and rock mass supporting method for gob-side roadway
By installing through anchor cables, surface protection structures, and special-shaped anchor cables between goaf roadways and control roadways, and combining this with the use of grouting and pressure relief grooves, the problems of easy detachment of coal and rock mass support structures and large deformation of surrounding rock were solved, thereby improving the safety of coal mine production and the stability of roadways.
Patent Information
- Application Number
- CN202410391796.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-01
- Publication Date
- 2026-02-06
AI Technical Summary
During coal mining, the anchor bolt support structure in the fractured surrounding rock is prone to detachment. The poor permeability of the coal and rock mass makes it difficult for the grout to spread, resulting in large deformation of the surrounding rock in the roadway and affecting the safe production of the mine.
Through-hole anchor cables are installed between the goaf roadway and the control roadway, and protective structures are installed in the sidewalls and roof of the protective coal pillar. Special-shaped anchor cables with claw-shaped structures are used for anchoring, and grouting is used for reinforcement when necessary. The use of pressure relief grooves is combined to reduce deformation.
It effectively reinforces the sides and roof of the roadway, improves the safety of coal mine production, reduces surrounding rock deformation, and ensures roadway stability.
Smart Images
Figure CN121473874A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of coal mining, and in particular to a method for supporting coal and rock masses in roadways along the goaf. Background Technology
[0002] Coal is an important energy source and a crucial raw material for the metallurgical and chemical industries. During the mining of coal resources, the anchor bolt support structure in the fractured surrounding rock is prone to detachment. Most of the coal and rock mass around the coal roadway has a poor permeability coefficient, making it difficult for the grout to spread and prone to leakage. It is also difficult to modify the lithology of the fractured coal and rock mass. In particular, under the influence of dynamic pressure, the surrounding rock of the roadway deforms greatly, affecting the safe production of the mine. Summary of the Invention
[0003] In view of this, the embodiments of this application provide a method for coal and rock mass support in roadways with access points, which can improve the safety of mine production.
[0004] This application provides a method for supporting coal and rock mass in a goaf roadway, comprising: inserting through-bolts in a protective coal pillar located between the goaf roadway and the control roadway; setting a first protective structure on the first sidewall of the protective coal pillar and a second protective structure on the second sidewall; the first sidewall of the protective coal pillar and the first sidewall of the goaf roadway are the same sidewall; the second sidewall of the protective coal pillar and the first sidewall of the control roadway are the same sidewall; inserting irregularly shaped anchors with claw-shaped structures in the roof of the goaf roadway; and setting a third protective structure on the roof surface of the goaf roadway.
[0005] According to a specific implementation of this application, the step of installing a through-hole anchor cable in a protective coal pillar located between a goaf roadway and a protective roadway includes: after completing the goaf roadway excavation, constructing a through-hole of a first preset length along the direction from the current working face to the next working face, starting from the first sidewall of the goaf roadway; inserting a through-hole anchor cable with a traction line into the through-hole; leaving a coal pillar of the first preset length as the protective coal pillar starting from the first sidewall of the goaf roadway, and constructing a protective roadway of a preset width on the side of the protective coal pillar away from the current working face; pulling the through-hole anchor cable towards the protective roadway using the traction line until the end of the through-hole anchor cable near the protective roadway protrudes from the sidewall of the protective coal pillar of the protective roadway by a second preset length.
[0006] According to a specific implementation of an embodiment of this application, the step of inserting a shaped anchor cable with a claw-shaped structure into the roof of the goaf tunnel includes: drilling anchor cable holes of a predetermined depth in the roof of the goaf tunnel; forming an enlarged hole area at the bottom of the anchor cable hole by directional focusing of shaped explosive or high-pressure water jet; using the shaped anchor cable to push anchoring agent into the enlarged hole area, and using the shaped anchor cable to stir the anchoring agent; and placing at least a portion of the shaped anchor cable in the anchoring agent so that the anchoring agent anchors at least a portion of the shaped anchor cable.
[0007] According to a specific implementation of an embodiment of this application, the claw-shaped anchor cable includes an anchor cable body and a claw-shaped structure, the claw-shaped structure being disposed on the anchor cable body; the claw-shaped structure includes a first claw-shaped structure and a second claw-shaped structure; one end of the first claw-shaped structure and the second claw-shaped structure are respectively connected to the anchor cable body segment of the anchor cable body; the step of using the shaped anchor cable to push the anchoring agent into the enlarged hole area includes: using the shaped anchor cable to push the anchoring agent into the bottom of the enlarged hole area; wherein, the step of disposing of at least a portion of the shaped anchor cable in the anchoring agent so that the anchoring agent anchors the at least a portion of the shaped anchor cable includes: disposing of the first claw-shaped structure, the second claw-shaped structure, and the anchor cable body segment in the anchoring agent so that the anchoring agent anchors the first claw-shaped structure, the second claw-shaped structure, and the anchor cable body segment.
[0008] According to a specific implementation of this application, both the first claw structure and the second claw structure are rod-shaped structures. The first end of the first claw structure and the second claw structure is connected to the main body section of the anchor cable; the second end is a free end; and the second end is further away from the bottom of the anchor cable hole than the first end.
[0009] According to one specific implementation of the embodiments of this application, grout is injected between the anchor cable hole and the claw-shaped irregular anchor cable; and / or, grout is injected between the through anchor cable hole and the through anchor cable.
[0010] According to a specific implementation of an embodiment of this application, the grouting between the anchor cable hole and the claw-shaped anchor cable includes: grouting between the anchor cable hole and the claw-shaped anchor cable when the deformation of the roof of the goaf roadway reaches a first preset deformation amount; and / or the grouting between the through anchor cable hole and the through anchor cable includes: grouting between the through anchor cable hole and the through anchor cable when the deformation of the protective coal pillar reaches a second preset deformation amount.
[0011] According to a specific implementation of an embodiment of this application, the method further includes: after the current working face is mined and before the next working face is mined, dismantling the first protective structure, the second protective structure, and the through anchor cable; and mining the protective coal pillar.
[0012] According to a specific implementation of an embodiment of this application, the method further includes: opening a first pressure relief groove in the roof of the roadway at a preset distance from the protective coal pillar; and / or opening a second pressure relief groove starting from a designated position on the top surface of the roof of the goaf roadway and moving towards the roof of the current working face.
[0013] According to a specific implementation of the embodiments of this application, the groove portion of the first pressure relief groove and / or the groove portion of the second pressure relief groove at least extend beyond the first key layer of overburden of the coal mining face.
[0014] The coal and rock mass support method for gob-side roadways in this embodiment strengthens the coal and rock mass of the gob-side roadways and the roof by installing through-bolts in the protective coal pillar between the gob-side roadway and the control roadway, setting a first protective structure on the first sidewall and a second protective structure on the second sidewall, and installing special-shaped anchors with claw-shaped structures in the roof of the gob-side roadway, and setting a third protective structure on the roof of the gob-side roadway. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 A schematic flowchart of a coal and rock mass support method for a roadway along the goaf provided in an embodiment of this application; Figure 2 This is a schematic diagram illustrating an application scenario according to an embodiment of this application; Figure 3 This is a schematic diagram of a structure in which explosives are placed in the anchor cable holes in the roof of a roadway in one embodiment of this application; Figure 4 This is a schematic diagram of the structure of the enlarged hole region in one embodiment of this application; Figure 5 This is a schematic diagram of the irregular anchor cable in the anchoring part of one embodiment of this application; Figure 6 This is a schematic diagram of the grouting structure between the anchor cable hole and the irregular anchor cable in one embodiment of this application; Figure 7 This is a schematic diagram of an application scenario where the current working face has been mined out, according to one embodiment of this application. Detailed Implementation
[0017] The embodiments of this application will now be described in detail with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0018] To enable those skilled in the art to better understand the technical concept, implementation scheme and beneficial effects of the embodiments of this application, detailed descriptions are provided below through specific embodiments.
[0019] Figure 1 This is a schematic flowchart of a coal and rock mass support method for roadways along the goaf provided in one embodiment of this application. Figure 2 This is a schematic diagram illustrating an application scenario of one embodiment of this application, such as... Figure 1 and Figure 2 As shown, the coal and rock mass support method for roadways along the goaf in this embodiment may include: S101. Through-anchor cables 4 are installed in the protective coal pillar 3 located between the goaf roadway 1 and the control roadway 2, and a first protective structure 5 is installed on the first side wall of the protective coal pillar 3, and a second protective structure 6 is installed on the second side wall.
[0020] In this embodiment, the first sidewall of the protective coal pillar 3 and the first sidewall of the goaf roadway 1 are the same sidewall; the second sidewall of the protective coal pillar 3 and the first sidewall of the control roadway 2 are the same sidewall.
[0021] In this embodiment, the goaf roadway 1 is close to the current coal mining face, and a coal pillar, i.e. a protective coal pillar 3, is set on the side of the goaf roadway 1 away from the current coal mining face. A protective roadway 2 is set on the side of the protective coal pillar 3 away from the goaf roadway 1.
[0022] Because the medium is soft, through-cables 4 are installed in the protective coal pillar 3. This can absorb a certain amount of destructive energy, so that the protective coal pillar 3 does not undergo large deformation, that is, the coal and rock mass along the goaf roadway 1 does not undergo large deformation, thereby improving the safety of mine production.
[0023] The first protective structure 5 and the second protective structure 6 can be protective structures with high strength. In some examples, the first protective structure 5 may include I-beams, U-shaped steel, high-strength tensile mesh and / or bulletproof mesh; the second protective structure 6 may include steel reinforcement beams and / or high-strength tensile mesh.
[0024] S102. Install irregularly shaped anchor cables 7 with claw-shaped structures in the roof of the goaf 1.
[0025] To reinforce the roof of the goaf roadway 1, a special-shaped anchor cable 7 with a claw-shaped structure is inserted into the roof of the goaf roadway 1. In this embodiment, the special-shaped anchor cable 7 with a claw-shaped structure facilitates the improvement of the interlocking force between the special-shaped anchor cable 7 and the coal and rock.
[0026] Alternatively, a special-shaped anchor cable 7 with a claw-shaped structure can be installed in the roof of the measure roadway 2.
[0027] S103. A third protective structure is installed on the top surface of the tunnel 1.
[0028] The third protective structure can tightly bind the weak coal body of the roof of the goaf roadway 1 to the surrounding rock.
[0029] In this embodiment, through-bolts 4 are installed in the protective coal pillar 3 located between the goaf roadway 1 and the control roadway 2, and a first protective structure 5 is installed on the first sidewall of the protective coal pillar 3, a second protective structure 6 is installed on the second sidewall, and a special-shaped anchor 7 with a claw-shaped structure is installed in the roof of the goaf roadway 1, and a third protective structure is installed on the roof of the goaf roadway 1. In this way, the coal and rock mass of the sidewalls and roof of the goaf roadway 1 can be reinforced, thereby improving the safety of coal mine formation.
[0030] In some examples, the installation of through-bolts 4 in the protective coal pillar 3 located between the goaf roadway 1 and the intervention roadway 2 may include: S101a After completing the excavation of the goaf roadway 1, starting from the first sidewall of the goaf roadway 1, construct the first pre-set length of through hole along the direction from the current working face 8 to the next working face 9.
[0031] After completing the excavation of the goaf roadway 1, the cross-holes are constructed in the coal and rock mass within the anchorage range on the solid coal side, i.e. from the current working face 8 to the next working face 9.
[0032] S101b. Insert the through anchor cable 4 with a traction line into the through hole.
[0033] In the through-hole, a through-anchor cable 4 with a traction wire is inserted to the edge of the designed tunnel, leaving a certain length of anchor cable exposed on the insertion side. In some cases, a sealing plug can also be inserted for subsequent grouting.
[0034] S101c. Starting from the first sidewall of the goaf roadway 1, a coal pillar of the first preset length is reserved as a protective coal pillar 3, and a roadway 2 of the preset width is constructed on the side of the protective coal pillar 3 away from the current working face 8.
[0035] The initial preset length can be 2 to 10 meters. The cross-section of the second tunnel can be smaller and weaker, just enough to maintain the stability of the surrounding rock during excavation.
[0036] S101d, Pull the through anchor cable 4 towards the measure roadway 2 via the traction line until the end of the through anchor cable 4 near the measure roadway 2 protrudes from the side wall of the measure roadway 2 near the protective coal pillar 3 by the second preset length.
[0037] The measures tunnel exposes the through hole, and the through anchor cable 4 is pulled out through the traction line of the through anchor cable 4, and the hole plug and tray lock are installed.
[0038] Pre-tighten the tie anchor cables, inject sealing material, seal the through holes, and complete the normal coal seam support.
[0039] In some examples, the installation of irregularly shaped anchor cables 7 (S102) with claw-shaped structures in the roof of the goaf 1 may include: S102a. Drill anchor cable holes of a predetermined depth in the roof of the goaf 1.
[0040] See Figure 3 In this embodiment, a larger drill bit can be used to drill a deep hole to a predetermined depth.
[0041] S102b. At the bottom of the anchor cable hole, a hole-enlarging zone is formed by the directional focusing of shaped charge explosive.
[0042] See Figure 4 After drilling, a directional shaped charge is placed. After the charge explodes, it creates an explosion-expanded hole zone or a blast-crack zone. The debris is then blown away by wind or water.
[0043] As an alternative, a hole-enlarging zone can also be formed using high-pressure water jetting.
[0044] The cross-sectional area of the enlarged hole is larger than that of the anchor cable hole.
[0045] S102c. Use the special-shaped anchor cable 7 to push the anchoring agent into the hole expansion area, and use the special-shaped anchor cable 7 to stir the anchoring agent.
[0046] The anchoring agent is pushed into the enlarged hole area using anchor cables, and the anchoring agent is stirred. After anchoring is completed, the sealing plug is pushed in, and the tray lock is tightened to complete the anchor cable support.
[0047] S102d, At least a portion of the irregular anchor cable 7 is placed in the anchoring agent so that the anchoring agent anchors at least a portion of the irregular anchor cable 7.
[0048] See Figure 5 At least a portion of the irregularly shaped anchor cable 7 is placed in the anchoring agent to complete the anchoring.
[0049] At least some of the irregular anchor cables 7 can be partial irregular anchor cables 7, or they can be the entire irregular anchor cables 7.
[0050] In some examples, a plug can be pushed in and the tray lock tightened to complete the cable bolt support.
[0051] In some examples, the special-shaped cable bolt 7 with a claw structure can include a cable bolt body and a claw structure, and the claw structure is provided on the cable bolt body; the claw structure can include a first claw structure and a second claw structure; one ends of the first claw structure and the second claw structure are respectively connected to the cable bolt body section of the cable bolt body.
[0052] In this embodiment, using the special-shaped cable bolt 7 to push the anchoring agent into the re-bored area includes: A1. Using the special-shaped cable bolt 7 to push the anchoring agent to the bottom of the re-bored area.
[0053] In this embodiment, setting at least part of the special-shaped cable bolt 7 in the anchoring agent so that the anchoring agent anchors at least part of the special-shaped cable bolt 7 (S102d) can include: B1. Setting the first claw structure, the second claw structure and the cable bolt body section in the anchoring agent so that the anchoring agent anchors the first claw structure, the second claw structure and the cable bolt body section.
[0054] See Figure 5 , the first claw structure and the second claw structure are anchored in the re-bored area through the anchoring agent, which can increase the mechanical biting force and further improve the anchoring force of the cable bolt.
[0055] In some examples, both the first claw structure and the second claw structure are rod-shaped structures. The first ends of the first claw structure and the second claw structure are connected to the cable bolt body section; the second ends are free ends; the second ends are farther from the bottom of the cable bolt hole than the first ends.
[0056] In this embodiment, the first claw structure, the second claw structure and the cable bolt body section form a "个" shape.
[0057] The first end of the first claw structure is connected to the cable bolt body section, and the second end is a free end.
[0058] The first end of the second claw structure is connected to the cable bolt body section, and the second end is a free end.
[0059] In this embodiment, the second end of the first claw structure is farther from the bottom of the cable bolt hole than the first end, and the second end of the second claw structure is farther from the bottom of the cable bolt hole than the first end. In this way, the special-shaped cable bolt 7 is barbed in the anchoring agent, which can further increase the mechanical biting force and further improve the anchoring force of the cable bolt.
[0060] In order to increase the anchoring force of the cable bolt, in some embodiments, the method further includes: S104. Grouting between the cable bolt hole and the special-shaped cable bolt 7 of the claw structure.
[0061] See Figure 6 The shallow surrounding rock of the anchor cable can be sealed by injecting sealing material through a sealing pipe. After the sealing material hardens, high-pressure grouting is started through the pre-reserved grouting pipe to fill the fissures in the surrounding rock. The high tensile strength micro-expansion grouting material "takes root" in the fissures of the surrounding rock, reinforcing the weak coal and rock mass and further improving the anchoring force of the anchor cable. In this embodiment, the sealing pipe can also be a pre-reserved anchor cable hole in the roof.
[0062] In one embodiment, grouting (S104) between the anchor cable hole and the claw-shaped anchor cable 7 may include: S104a. When the deformation of the roof of the goaf 1 reaches the first preset deformation, grout is injected between the anchor cable hole and the claw-shaped anchor cable 7.
[0063] In some examples, the method may also include: S105, Grouting is performed between the four holes of the through anchor cable and the four through anchor cables.
[0064] In one embodiment, grouting (S105) between the through anchor cable 4 hole and the through anchor cable 4 may include: When the deformation of the protective coal pillar 3 reaches the second preset deformation amount, grout is injected into the hole of the through anchor cable 4 and between the through anchor cable 4.
[0065] In one embodiment, steps S104 and S105 may exist either one or both.
[0066] Under the influence of dynamic pressure during mining, after the roadway support is formed, the coal pillar and coal-rock mass develops fissures, and the surrounding rock begins to undergo small deformations. Grouting can then be performed on the four holes of the through-hole anchor cable and the roof anchor cable of the goaf roadway 1 through the reserved grouting pipe to reinforce the weak coal-rock mass and achieve full-length anchoring of the four through-hole anchor cables and the roof anchor cable of the goaf roadway 1.
[0067] To facilitate increasing coal production, in some examples, the method may further include: S106. After the current working face 8 is completed and before the next working face 9 is mined, the first protective structure 5, the second protective structure 6, and the through anchor cable 4 shall be removed.
[0068] When the next coal face is mined, the through anchor cable 4 and the strong protective structure, namely the first protective structure 5 and the second protective structure 6, will be removed in advance.
[0069] S107, Mining protective coal pillar 3.
[0070] See Figure 7 The solid coal and protective coal pillar 3 are mined together, and there is only roadway support in the goaf.
[0071] In some cases, a pressure relief trough 10 is opened in the roof of the control roadway at a predetermined distance from the protective coal pillar 3.
[0072] Implementing roof cutting and pressure relief in roadway 2 can reduce the mechanical connection between the roof rock beams. Specifically, directional pre-splitting blasting can be used to create the first pressure relief groove 10.
[0073] In other examples, a second pressure relief groove 11 is opened from a designated position on the top surface of the roof of the goaf 1, toward the roof of the current working face.
[0074] Implementing roof cutting and pressure relief in the goaf roadway 1 can reduce the mechanical connection between the roof rock beams. Specifically, directional pre-splitting blasting can be used to open a second pressure relief trough 11 on the solid coal side.
[0075] In one specific example, the portion of the first pressure relief groove 10 and / or the portion of the second pressure relief groove 11 extends at least beyond the first critical layer of overburden in the coal mining face.
[0076] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.
[0077] The various embodiments in this specification are described in a related manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.
[0078] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A method for supporting coal and rock mass in a roadway with an open runoff, characterized in that, include: Through-bolts are installed in the protective coal pillar located between the goaf roadway and the control roadway, and a first protective surface structure is installed on the first side of the protective coal pillar, and a second protective surface structure is installed on the second side; the first side of the protective coal pillar is the same side as the first side of the goaf roadway; the second side of the protective coal pillar is the same side as the first side of the control roadway. A special-shaped anchor cable with a claw-shaped structure is inserted into the roof slab of the tunnel. A third protective structure is installed on the top surface of the tunnel.
2. The method according to claim 1, characterized in that, The installation of through-bolts in the protective coal pillar located between the goaf roadway and the intervention roadway includes: After the excavation of the goaf roadway is completed, a first preset length of through hole is constructed along the direction from the current working face to the next working face, starting from the first sidewall of the goaf roadway. Insert a through-hole anchor cable with a traction line into the through-hole; Starting from the first sidewall of the goaf roadway, a coal pillar of the first preset length is left as the protective coal pillar, and a roadway of the preset width is constructed on the side of the protective coal pillar away from the current working face. Pull the through-cable cable toward the roadway using the traction line until the end of the through-cable cable near the roadway protrudes beyond the sidewall of the roadway near the protective coal pillar by a second predetermined length.
3. The method according to claim 1, characterized in that, The installation of irregularly shaped anchor cables with claw-shaped structures in the roof of the roadway includes: Anchor cable holes of a predetermined depth are drilled in the roof slab of the tunnel. At the bottom of the anchor cable hole, an enlarged hole zone is formed by the directional focusing of shaped charge explosives or high-pressure water jets; The anchoring agent is pushed into the enlarged hole area using the shaped anchor cable, and the anchoring agent is stirred using the shaped anchor cable; At least a portion of the irregularly shaped anchor cable is disposed in the anchoring agent so that the anchoring agent anchors the at least a portion of the irregularly shaped anchor cable.
4. The method according to claim 3, characterized in that, The claw-shaped anchor cable includes an anchor cable body and a claw-shaped structure, wherein the claw-shaped structure is disposed on the anchor cable body; the claw-shaped structure includes a first claw-shaped structure and a second claw-shaped structure; one end of the first claw-shaped structure and the second claw-shaped structure are respectively connected to the anchor cable body segment of the anchor cable body; The step of using the shaped anchor cable to push the anchoring agent into the enlarged hole area includes: The anchoring agent is pushed into the bottom of the enlarged hole area using the shaped anchor cable; Wherein, the step of placing at least a portion of the irregularly shaped anchor cables in the anchoring agent, so that the anchoring agent anchors the at least a portion of the irregularly shaped anchor cables, includes: The first claw-shaped structure, the second claw-shaped structure, and the anchor cable body segment are disposed in the anchoring agent so that the anchoring agent anchors the first claw-shaped structure, the second claw-shaped structure, and the anchor cable body segment.
5. The method according to claim 4, characterized in that, Both the first claw-shaped structure and the second claw-shaped structure are rod-shaped structures. The first end of the first claw-shaped structure and the second claw-shaped structure are connected to the main body of the anchor cable; the second end is a free end; the second end is further away from the bottom of the anchor cable hole than the first end.
6. The method according to claim 4, characterized in that, Grouting is injected between the anchor cable hole and the claw-shaped anchor cable; and / or, Grouting is injected between the through-anchor hole and the through-anchor cable.
7. The method according to claim 6, characterized in that, The grouting between the anchor hole and the claw-shaped anchor cable includes: When the deformation of the roof slab of the goaf reaches a first preset deformation amount, grout is injected between the anchor cable hole and the claw-shaped anchor cable; and / or The grouting between the through anchor cable hole and the through anchor cable includes: When the deformation of the protective coal pillar reaches the second preset deformation amount, grout is injected between the through anchor cable hole and the through anchor cable.
8. The method according to claim 2, characterized in that, The method further includes: After the current working face is completed and before the next working face is started, the first protective structure, the second protective structure, and the through anchor cable are removed. Mining the protective coal pillar.
9. The method according to claim 1, characterized in that, The method further includes: A first pressure relief groove is opened in the roof of the roadway under the aforementioned measures, at a predetermined distance from the protective coal pillar; and / or, Starting from a designated position on the top surface of the roof of the roadway, a second pressure relief groove is opened towards the roof of the current working face.
10. The method according to claim 9, characterized in that, The groove of the first pressure relief groove and / or the groove of the second pressure relief groove extend at least beyond the first key layer of overburden of the coal mining face.