Multi-seam coal pillarless self-forming roadway mining method

Abstract

The present invention provides a multi-seam coal pillarless self-forming roadway mining method, belonging to the technical field of coal mining. This method first obtains the mining technical conditions of the working face, including the basic mechanical parameters of the surrounding rock, the coal seam thickness and dip angle, the caving form of the overlying goaf, and the occurrence state of the geological structure. According to the coal seam thickness and dip angle in the mining technical conditions, the self-forming roadway shaping process is determined, and then an analysis model of the surrounding rock stress distribution law in the self-forming roadway area of the working face is established by integrating various conditions. According to the surrounding rock stress distribution law, a control scheme for the stability of the self-forming roadway is designed, and the on-site construction sequence of each item in the design parameters is determined. Finally, the on-site application and effect evaluation of this mining method are carried out, and the mining method is optimized by feedback. The present invention can guide the process design and construction of coal pillarless self-forming roadways under the conditions of multi-seam close-distance mining, and realize the popularization and application of the coal pillarless mining method.

Description

Technical Field

[0001] The present invention relates to a coal mining method for multi-seam pillarless self-forming roadway, belonging to the technical field of coal mining. Background Art

[0002] The coal mining method for multi-seam pillarless self-forming roadway, as a new type of mining method, has been applied in many coal mines. This method cancels the coal pillar setting in the working face, and at the same time retains one roadway of the current working face for use when the next working face is mined, which can reduce the roadway driving volume and improve the resource recovery rate, alleviating the problem of tight energy supply.

[0003] Due to different coal-forming conditions, the occurrence conditions, thickness and coal seam spacing of coal seams vary greatly; there are multiple workable coal seams in some mining areas; these coal seam spacings are relatively close, and when the lower coal seam is mined, it faces the fragmented layer structure in the overlying goaf, resulting in many new mine pressure phenomena in the roadway during the mining of the lower coal seam; a cut-top roadway-forming pillarless mining method for close-distance thin coal seams is disclosed in the prior art, including the following steps:

[0004] (1) Excavate two roadways in the coal seam as the upper and lower gate roadways of the first mining face, and the two ends of the upper and lower gate roadways are respectively connected to each other through two other roadways;

[0005] (2) Install the grouting constant-resistance anchor cables in place on the roof in the lower gate roadway, but do not grout, and install the grouting constant-resistance bolts in place on the lower sidewall of the lower gate roadway, but do not grout. Then, drill a row of energy-gathering pre-splitting cut-top holes shared by two coal seams along the roof in the lower gate roadway close to the first mining face, and implement blasting to form a pre-splitting seam, and set up single hydraulic props on the side close to the first mining face;

[0006] (3) Mine the upper coal seam of the first mining face until it is mined out;

[0007] (4) The stope roof collapses along the shallow energy-gathering pre-splitting seam;

[0008] (5) Spray a concrete layer on the upper sidewall of the lower gate roadway, and grout the grouting constant-resistance anchor cables and grouting constant-resistance bolts;

[0009] (6) Excavate a new upper gate roadway, and mine the lower coal seam of the first mining face until it is mined out. The roof of the lower coal seam collapses, and the stope roof collapses along the deep energy-gathering pre-splitting seam together with the roof of the lower coal seam;

[0010] (7) Use the roadway automatically formed at the position of the original lower gate roadway as the upper gate roadway of the next mining face, and excavate the lower gate roadway relative to this upper gate roadway to form a new mining face;

[0011] (8) Repeat the steps (2)-(7) to continuously mine coal until the coal seam is completely mined.

[0012] However, the above method has relatively weak pertinence, and the special features of the coal pillarless mining method under special mining conditions such as the presence of goaf above the coal seam during the close-range mining of multiple coal seams cannot be reflected from the specific steps. At the same time, there is no design for indoor test verification and on-site feedback optimization of this coal pillarless mining method in the application steps. Summary of the Invention

[0013] In order to solve the problems of insufficient pertinence, lack of indoor test verification and on-site feedback optimization in the existing technology, the present invention provides a multi-seam coal pillarless self-forming roadway mining method, which guides the design and construction of self-forming roadways under the condition of close-range mining of multi-seam working faces, ensures the safety and stability of roadway layout, cancels the layout of roadways between working faces under the condition of multi-seam mining, improves the resource extraction rate, and realizes the popularization and application of the coal pillarless self-forming roadway mining method.

[0014] In order to achieve the above object, the present invention adopts the following technical solutions:

[0015] The multi-seam coal pillarless self-forming roadway mining method proposed by the present invention includes the following steps:

[0016] Step 1: Obtain the mining technical conditions of the working face and construct a three-dimensional geological model of the self-forming roadway area of the working face;

[0017] Step 2: Establish an analysis model for the stress distribution law of the surrounding rock in the self-forming roadway area of the working face, including: determining the non-mining factors affecting the stress distribution law of the surrounding rock according to the caving form of the overlying goaf and the occurrence state of the geological structure; determining the mining factors affecting the stress distribution law of the surrounding rock according to the basic mechanical parameters of the surrounding rock, the coal seam thickness, and the coal seam dip angle.

[0018] Step 3: Determine the roadway forming process of the self-forming roadway according to the analysis model of the stress distribution law of the surrounding rock, the coal seam dip angle, and the mining height.

[0019] Step 4: Design a stability control scheme for the self-forming roadway according to the analysis model of the stress distribution law of the surrounding rock.

[0020] Step 5: Determine the on-site construction sequence of each item in the design parameters according to the roadway forming process and the roadway stability control scheme, and form a coal pillarless self-forming roadway mining method for the current working face.

[0021] Step 6: Apply the formed coal pillarless self-forming roadway mining method for the current working face on-site, set up multiple monitoring stations in the roadway to monitor the roadway stability in real time, and optimize the mining method according to the monitoring data.

[0022] As a further technical solution, the step 1 includes:

[0023] Step 1-1: Adopt the comprehensive physical exploration method on-site to explore the caving form of the overlying goaf and the occurrence state of the geological structure, obtain the occurrence states of the roof, top gangue and remaining coal pillars, as well as the spatial position relationship between the fold and fault geological structures and the self-forming roadway;

[0024] Step 1-2: Use the engineering drilling method to supplement and improve other mining technical conditions of the working face, obtain the surrounding rock samples at the same time, and correct the comprehensive physical exploration results at the same time;

[0025] Step 1-3: Conduct indoor test and detection on the surrounding rock samples to obtain the basic mechanical parameters of the surrounding rock;

[0026] Step 1-4: Construct a three-dimensional geological model of the self-forming roadway area of the working face according to all the mining technical conditions of the working face.

[0027] As a further technical solution, the step 2 includes: Carry out theoretical analysis and numerical simulation tests based on the three-dimensional geological model of the self-forming roadway area, and then establish an analysis model for the stress distribution law of the surrounding rock in the self-forming roadway area of the working face. The stress magnitude of the roadway per unit length in the model is:

[0028] G P =G P1 +G P2

[0029] Among them, G P is the stress magnitude of the roadway per unit length; G P1 is the stress generated by non-mining factors; G P2 is the stress generated by mining factors.

[0030] As a further technical solution, when G P is greater than the bearing capacity of the unbolted roadway, and the dip angle and mining height of the coal seam can form a roadway section that meets the use requirements, the roadway forming process is to mine a working face without driving a roadway, and the self-forming roadway gradually forms with the mining; if it does not meet the use requirements, the roadway forming process is to drive a roadway for mining a working face, and this roadway is the self-forming roadway.

[0031] As a further technical solution, the design requirements for the stability control scheme of the self-forming roadway in the step 4 are:

[0032] KηP S >ζG P

[0033] Among them, K is the safety factor; η is the support bearing efficiency; P S is the bearing strength of the roadway; ζ is the pressure relief coefficient, G Pis the stress magnitude of the roadway per unit length.

[0034] As a further technical solution, the calculation formula for the bearing strength of the roadway is:

[0035] P S =P S0+ P S1 +P S2 +P S3

[0036] Wherein, P S is the bearing strength; P S0 is the self-bearing strength of the surrounding rock; P S1 is the active support strength; P S2 is the passive support strength; P S3 is the gangue retaining support strength.

[0037] As a further technical solution, in step 2: by carrying out a three-dimensional geomechanical model test, the distribution law of the surrounding rock stress caused by mining factors is obtained, and then the roadway is divided into a non-advanced disturbance area, an advanced disturbance area, a lagging dynamic pressure area, and a lagging stable area.

[0038] As a further technical solution, the on-site construction sequence in step 5 is: carry out roof cutting pressure relief and active support in the non-advanced disturbance area; carry out passive support in the advanced disturbance area; carry out passive support and gangue retaining support in the lagging dynamic pressure area, and optionally carry out active support; adjust the passive support in the lagging stable area and inject inert gas into the goaf.

[0039] As a further technical solution, the roof cutting pressure relief adopts tension blasting roof cutting, dense drilling roof cutting, instantaneous cracking roof cutting or mechanical cracking roof cutting.

[0040] As a further technical solution, the active support adopts energy-absorbing bolts, energy-absorbing cables, grouting bolts or grouting cables; the passive support adopts confined concrete support, unit support, steel arch support or hydraulic single column support; the gangue retaining support adopts steel section lapping support, flexible vertical wall support or flexible airtight spray layer.

[0041] The beneficial effects of the present invention are as follows:

[0042] In view of the problem of the safe application of the self-forming roadway in pillarless mining under the condition of multi-seam close-distance mining at present, the present invention proposes a systematic implementation method. Considering the special conditions of close-distance mining, a roadway stability control scheme is designed. Through carrying out simulation tests and model tests on the on-site mining technical conditions, construction parameters are optimized and construction processes are designed to guide on-site engineering. At the same time, the construction parameters and construction processes are feedback-optimized through on-site monitoring data, so as to realize the safe application of the self-forming roadway method in pillarless mining under the condition of close-distance coal seams. It can provide a solution for reducing the roadway driving volume and improving the coal resource recovery rate in coal mining under the condition of multi-seam close occurrence in coal mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The attached drawings forming a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0044] Figure 1 It is a schematic flow chart of the implementation of the multi-seam pillarless self-forming roadway mining method of the present invention;

[0045] Figure 2 It is a schematic diagram of the roadway forming process of the self-forming roadway of the present invention Figure 1 ;

[0046] Figure 3 It is a schematic diagram of the roadway forming process of the self-forming roadway of the present invention Figure 2 ;

[0047] Figure 4 It is a schematic diagram of the roadway area division of the self-forming roadway in the working face of the present invention.

[0048] In the figure: 1. goaf; 2. roof; 3. self-forming roadway of the upper working face; 4. self-forming roadway of the present working face; 5. working face; 6. non-advance disturbance area; 7. advance disturbance area; 8. post-advance dynamic pressure area; 9. post-advance stable area; 10. roof cutting and pressure relief; 11. passive support; 12. gangue retaining support; 13. active support. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the present invention clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof;

[0051] As Figure 1 shown, this embodiment provides a multi-seam pillarless self-forming roadway mining method for the pillarless mining practice of closely spaced seams under the multi-seam occurrence conditions in underground coal mining. When mining the current coal seam, due to the existence of the goaf 1 structure of other coal seams above it, and the rock stratum between the previously mined coal seam and the goaf 1 of the upper coal seam cannot form an effective rock beam support structure, the movement law of the upper rock stratum changes during the mining of the current coal seam, and the mine pressure caused also has characteristics different from the past. In order to study the migration law of mine pressure under this condition and at the same time guide the design parameters of the self-forming roadway method for pillarless mining of closely spaced coal seams, it is necessary to conduct a detailed survey of the working face mining technical conditions in the mining area, and then establish an analysis model of the surrounding rock stress distribution law in the self-forming roadway area of the working face, carry out the design of the stability control scheme for the self-forming roadway and guide the on-site construction work.

[0052] Specifically, it includes the following steps:

[0053] Step 1: Obtain the mining technical conditions of the working face 5, including: basic mechanical parameters of the surrounding rock, coal seam thickness, coal seam dip angle, caving form of the overlying goaf, and occurrence state of the geological structure; construct a three-dimensional geological model of the self-forming roadway area of the working face 5 according to the mining information;

[0054] Step 2: Establish an analysis model of the surrounding rock stress distribution law in the self-forming roadway area of the working face 5, including: determining the non-mining factors affecting the surrounding rock stress distribution law according to the caving form of the overlying goaf and the occurrence state of the geological structure; determining the mining factors affecting the surrounding rock stress distribution law according to the basic mechanical parameters of the surrounding rock, coal seam thickness, and coal seam dip angle;

[0055] Step 3: Determine the forming process of the self-forming roadway according to the analysis model of the surrounding rock stress distribution law, the coal seam dip angle, and the mining height;

[0056] Step 4: Design the stability control scheme for the self-forming roadway according to the analysis model of the surrounding rock stress distribution law. The main contents of the scheme design include: roof cutting and pressure relief design, active support design, passive support design, and gangue retaining support design;

[0057] Step 5: According to the roadway forming technology and the roadway stability control plan, determine the on-site construction sequence of each item in the design parameters, and form the non-pillar self-forming roadway mining method for the current working face 5.

[0058] Step 6: Apply the non-pillar self-forming roadway mining method for the current working face 5 formed on-site, and set up multiple monitoring stations in the roadway to monitor the roadway stability in real time. Optimize the mining method based on the monitoring data.

[0059] Furthermore, in this embodiment, the specific content of Step 1 is as follows:

[0060] Step 1-1): Use the comprehensive physical exploration method on-site to explore the caving form of the overlying goaf and the occurrence state of the geological structure, obtain the occurrence states of the roof, top gangue, and remaining coal pillars, as well as the spatial position relationship between the fold and fault geological structures and the self-forming roadway.

[0061] Step 1-2): Use the engineering drilling method to supplement and improve other mining technical conditions of the working face 5. Other mining technical conditions include coal seam thickness, coal seam dip angle, etc. At the same time, obtain surrounding rock samples and correct the comprehensive physical exploration results.

[0062] Step 1-3): Conduct indoor test and detection on the surrounding rock samples to obtain the basic mechanical parameters of the surrounding rock. The specific test method can be carried out according to the existing test methods and will not be elaborated in this embodiment.

[0063] Step 1-4): Based on all the mining technical conditions of the working face 5, construct a three-dimensional geological model of the self-forming roadway area of the working face 5. There are many methods for constructing the three-dimensional geological model of the self-forming roadway area. For example: use the mining engineering plan and the contour maps of the coal seam roof and floor, combined with physical exploration and engineering drilling means to obtain the mining technical conditions of the self-forming area decomposed into multiple groups of three-dimensional coordinates, classify and sort the three-dimensional coordinates and number them to form a three-dimensional geological feature database, and construct a three-dimensional geological model of the self-forming roadway area according to the three-dimensional geological feature database. The model can be constructed using existing relevant software such as XModel, Surpac, GOCAD, etc.

[0064] Furthermore, in this embodiment, the specific steps of Step 3 are as follows:

[0065] If the thickness and dip angle of the coal seam can form a roadway section that meets the usage requirements, and when the height and width of the space formed after the shearer mining can be used for self-forming roadway construction and the cross-sectional area can meet the roadway usage requirements, the forming process is as follows: It is not necessary to advance the roadway in advance when mining a working face 5. As the working face 5 is mined, the self-forming roadway 4 of this working face is gradually formed. For details, please refer to Figure 2 ;

[0066] If the usage requirements are not met, the roadway forming process is to advance the self-forming roadway 4 of this working face in advance before mining a working face 5. As the working face 5 is mined, supplementary rock retaining support is provided on the mining side to prevent the caving gangue from filling the roadway, and the self-forming roadway 4 of this working face is left for the next working face to use; specifically, reference can be made to Figure 3 ;

[0067] Furthermore, in step 2, it includes: carrying out theoretical analysis and numerical simulation tests based on the three-dimensional geological model of the self-forming roadway area, analyzing the stress path of the surrounding rock during the mining of the working face and identifying the stress concentration areas around the roadway, and then establishing an analysis model for the stress distribution law of the surrounding rock in the self-forming roadway area of the working face 5. The stress magnitude of the roadway per unit length in the model is:

[0068] G P =G P1 +G P2

[0069] where G P is the stress magnitude of the roadway per unit length; G P1 is the stress generated by non-mining factors; G P2 is the stress generated by mining factors.

[0070] Furthermore, in step 4, it includes: according to the stress distribution model of the surrounding rock in the self-driving roadway area, combined with the rock mass mechanical parameters of the surrounding rock, applying the Mohr-Coulomb criterion or Hoek-Brown criterion to judge the possibility of surrounding rock failure to obtain the limit equilibrium curve between P S and G P . According to the limit equilibrium curve, considering the roadway safety, support efficiency and pressure relief efficiency at the same time, the design requirements for the stability control scheme of the self-forming roadway are:

[0071] KηP S >ζG P

[0072] where G P is the stress magnitude of the roadway per unit length; K is the safety factor; η is the support bearing efficiency; P S is the bearing strength of the roadway; ζ is the pressure relief coefficient.

[0073] Furthermore, the calculation formula for the bearing strength P S of the roadway is:

[0074] P S =P S0+ P S1 +P S2 +P S3

[0075] where P S0 is the self-bearing strength of the surrounding rock; P S1is the active support strength; P S2 is the passive support strength; P S3 is the gangue retaining support strength.

[0076] Furthermore, the three-dimensional geomechanical model test can truly reflect the relationship between the engineering structure and the geological structure, more accurately simulate the mining construction process and the interaction relationship, and the test results are intuitive, making it easier for people to comprehensively grasp the stress evolution characteristics and deformation trends of the project. Therefore, according to the obtained mining technical conditions of working face 5 and the roadway forming process of self-forming roadway, a three-dimensional geomechanical model test is carried out to verify the rationality of the parameter design of the self-forming roadway stability control scheme.

[0077] By carrying out the three-dimensional geomechanical model test, the distribution law of surrounding rock stress caused by mining factors is obtained. Then, the roadway is divided into a non-advance disturbance area 6, an advance disturbance area 7, a post-dynamic pressure area 8, and a post-stable area 9, as specifically shown in Figure 4 shown. In Figure 4 , along the mining direction, from the outside to the inside, the roadway is successively divided into a post-stable area 9, a post-dynamic pressure area 8, an advance disturbance area 7, and a non-advance disturbance area 6;

[0078] According to the zoning of the roadway by the three-dimensional geomechanical model test, the on-site construction sequence determined in step 5 is as follows:

[0079] In the non-advance disturbance area 6, roof cutting pressure relief 10 and active support 13 are carried out; in the advance disturbance area 7, passive support 11 is carried out; in the post-dynamic pressure area 8, passive support 11 and gangue retaining support 12 are carried out, and active support 13 can be optionally carried out; in the post-stable area 9, the passive support 11 is adjusted, and inert gas is injected into the goaf 1.

[0080] Furthermore, among the types of on-site construction, roof cutting pressure relief 10 can adopt tension blasting roof cutting, dense drilling roof cutting, instantaneous expansion cracking roof cutting, or mechanical cracking roof cutting; the specific operation methods of tension blasting roof cutting, dense drilling roof cutting, instantaneous expansion cracking roof cutting, and mechanical cracking roof cutting can refer to the existing technology. For example, tension blasting roof cutting includes: first, the drilling construction design is carried out, and the roof cutting angle, roof cutting height, and drilling spacing are designed according to the mining technical conditions, the rock dilation coefficient, and the roadway stress distribution model in the self-forming roadway area. Then, the blasting parameters are designed according to the roof lithology to determine the charging method, the single-hole charge amount, and the detonator amount. During on-site construction, drilling construction is carried out in front of the working face according to the drilling construction design, and then tension blasting roof cutting is carried out according to the blasting parameter design.

[0081] The active support 13 can adopt energy-absorbing bolts or energy-absorbing cables, grouting bolts or grouting cables; for example, when the surrounding rock of the roadway is severely deformed and damaged in cases such as the roadway having capping coal, extremely soft rock, and broken zones, etc., grouting cables and grouting cables can be used for active support ahead of the working face. First, based on borehole peeping and grouting tests of the roadway, determine the broken range of the roadway surrounding rock and the grouting diffusion range, and then design the lengths and row spacings of the grouting cables and grouting cables, and carry out on-site construction according to the design parameters.

[0082] The passive support 11 can adopt confined concrete support, unit support, steel arch support or hydraulic single column support;

[0083] The gangue retaining support 12 can adopt steel section lapping support, flexible vertical wall support or flexible airtight spraying layer. Immediately carry out steel section lapping support and flexible vertical wall support in the area behind the working face, so as to form a partition between the mining side of the roadway and the goaf to prevent gangue from flowing into the roadway. When the steel section lapping support or flexible vertical wall support is completed on the mining side of the retained roadway, immediately spray the inside and outside of the support with a flexible airtight spraying layer to enhance the gas isolation effect between the roadway and the goaf.

[0084] Then, repeat all the above steps to complete the mining of all working faces 5 in the current coal seam, and then continue to mine all working faces 5 in the next coal seam.

[0085] In summary, the present invention adjusts the roadway stability control plan by combining numerical tests and three-dimensional geomechanical model tests, and optimizes the roadway stability control plan at any time according to on-site monitoring data and application effects. Considering the special conditions of close-distance mining, design the roadway stability control plan. Through carrying out simulation tests and model tests on on-site mining technical conditions, optimize construction parameters and design construction processes to guide on-site engineering. At the same time, feedback optimization of construction parameters and construction processes is carried out through on-site monitoring data to realize the safe application of the non-pillar mining and self-forming roadway method under the conditions of close-distance coal seams. It can provide a solution for reducing the roadway driving volume and improving the coal resource recovery rate in coal mine mining under the condition of multi-coal seam close occurrence in coal mines.

[0086] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A multi-coal seam non-coal pillar self-forming mining method, characterized in that: The following steps are involved: Step 1: Obtain the mining technical conditions of the working face and construct a three-dimensional geological model of the working face self-forming area; Step 2: Establish a model for analyzing the stress distribution law of the surrounding rock in the self-forming tunnel area of ​​the working face, including: determining the non-mining factors that affect the stress distribution law of the surrounding rock according to the collapse form of the overlying void area and the state of geological structure; determining the mining factors that affect the stress distribution law of the surrounding rock according to the basic mechanical parameters of the surrounding rock, the thickness of the coal seam, and the inclination of the coal seam; The step 2 includes: conducting theoretical analysis and numerical simulation tests based on the three-dimensional geological model of the self-forming tunnel area, and then establishing a stress distribution law analysis model of the surrounding rock in the self-forming tunnel area of ​​the working face. The stress per unit length of the tunnel in the model is: G P =G P1 +G P2 Among them, G P is the stress per unit length of the tunnel; G P1 G is the stress caused by non-mining factors; P2 Stress caused by mining factors; When G P If the bearing capacity of the unsupported tunnel is greater than that of the unsupported tunnel, and the inclination angle and mining height of the coal seam can form a tunnel section that meets the use requirements, then the tunnel forming process is to mine a working face without digging a tunnel, and the self-forming tunnel is gradually formed with mining; if the use requirements are not met, then the tunnel forming process is to dig a tunnel for a working face, and the tunnel is a self-forming tunnel; In the step 2: by carrying out a three-dimensional geomechanical model test, the distribution law of surrounding rock stress caused by mining factors is obtained, and then the tunnel is divided into a non-advanced disturbance zone, an advanced disturbance zone, a delayed dynamic pressure zone and a delayed stable zone; Step 3: Determine the self-forming tunnel forming process according to the surrounding rock stress distribution law analysis model, coal seam inclination, and mining height; Step 4: According to the surrounding rock stress distribution law analysis model, the stability control scheme of the self-forming tunnel is designed; Step 5: According to the tunnel forming process and tunnel stability control plan, determine the on-site construction sequence of each content in the design parameters to form a coal pillar-free self-forming tunnel mining method for the current working face; Step 6: Apply the coal pillar-free self-forming lane mining method on site according to the current working face, set up multiple monitoring stations in the lane, monitor the lane stability in real time, and optimize the mining method based on the monitoring data.

2. The multi-coal seam non-coal pillar self-forming mining method according to claim 1, characterized in that: The step 1 includes: Step 1-1: Use comprehensive physical detection methods on site to explore the collapse form and geological structure of the overlying void area, obtain the occurrence state of the roof, top gangue and remaining coal pillars, and the spatial position relationship between the fold, fault geological structure and the self-formed roadway; Step 1-2 uses engineering drilling methods to supplement and improve other mining technical conditions of the working face, obtain surrounding rock samples, and correct the comprehensive physical detection results; Step 1-3: Perform indoor test on surrounding rock samples to obtain basic mechanical parameters of surrounding rocks; Steps 1-4 construct a three-dimensional geological model of the working face self-forming area based on the mining technical conditions of all working faces.

3. The multi-coal seam non-coal pillar self-forming mining method according to claim 1, characterized in that: The design requirements for the self-contained laneway stability control scheme in step 4 are: KηP S >ζG P Among them, K is the safety factor; η is the support bearing efficiency; P S is the bearing strength of the tunnel; ζ is the pressure relief coefficient, G P is the stress per unit length of the tunnel.

4. The multi-coal seam non-coal pillar self-forming mining method according to claim 3, characterized in that: The calculation formula for the bearing strength of the tunnel is: P S =P S0+ P S1 +P S2 +P S3 Among them, P S is the bearing strength; P S0 is the self-supporting strength of surrounding rock; S1 is the active support strength; P S2 is the passive support strength; P S3 For the strength of rock support.

5. The multi-coal seam non-coal pillar self-forming mining method according to claim 1, characterized in that: The on-site construction sequence in step 5 is: top cutting and pressure relief and active support in the non-advanced disturbance area; passive support in the advanced disturbance area; passive support and gangue retaining support, and active support in the delayed dynamic pressure area; passive support is adjusted in the delayed stable area, and inert gas is injected into the goaf.

6. The multi-coal seam non-coal pillar self-forming mining method according to claim 5, characterized in that: The top cutting and pressure relief adopts tension blasting top cutting, dense drilling top cutting, instantaneous expansion fracturing top cutting or mechanical fracturing top cutting.

7. The multi-coal seam non-coal pillar self-forming mining method according to claim 5, characterized in that: The active support adopts energy-absorbing anchor rods, energy-absorbing anchor cables, grouting anchor rods or grouting anchor cables; the passive support adopts constrained concrete support, unit bracket support, steel arch support or hydraulic single column support; the rock retaining support adopts steel lap support, flexible vertical wall support or flexible closed spray layer.

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