A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars

Abstract

The present invention provides a method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars, including: obtaining the range where the plastic zone of the coal pillar is located on the goaf side; strengthening the plastic zone based on the range where the plastic zone is located; obtaining the range where the peak zone of the coal pillar is located on the roadway side; and relieving pressure on the peak zone based on the range where the peak zone is located. The method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention first obtains the range where the plastic zone of the coal pillar is located on the goaf side, strengthens the plastic zone, so as to enhance the bearing capacity of the coal pillar on the goaf side and avoid the transfer of stress outwards. Then, it obtains the range where the peak zone of the coal pillar is located on the roadway side, and relieves pressure on the peak zone, so that the stress balance position of its surrounding rock shifts away from the roadway side, reducing the impact risk of the gob-side entry.

Description

Technical Field

[0001] The present invention relates to the technical field of prevention and control of rock bursts in coal mines, and particularly to a method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars. Background Art

[0002] Coal pillars are one of the areas with the most concentrated stress in coal mining, which also makes them the areas where rock bursts occur most frequently. To avoid the influence of the goaf on the gob-side entry, most rock burst mines adopt the layout method of leaving small coal pillars or no coal pillars, and arrange the gob-side entry in the lateral stress reduction area to reduce the impact risk. However, some rock burst mines are affected by various disasters such as water, fire and gas, and small coal pillars cannot be left, so the method of leaving wide coal pillars is adopted, which greatly increases the impact risk during the mining process. For the gob-side entry with wide coal pillars left, generally, large-diameter drilling or coal seam blasting is used to relieve the pressure of the wide coal pillar to prevent the occurrence of rock bursts.

[0003] However, from the application effect, relieving the pressure of the coal pillar cannot eliminate the impact risk of the gob-side entry from the source, and there are mainly the following deficiencies: (1) Currently, the pressure relief is mainly carried out on the coal pillar. When the coal pillar is wide, the pressure relief range is limited, and the coal pillar is still a stress concentration area; (2) If the coal pillar is completely pressure-relieved, on the one hand, it cannot ensure its blocking effect on the water and gas in the goaf, and on the other hand, the lateral goaf stress may be transferred to the solid coal rib of the gob-side entry, increasing the impact risk on the other side of the entry. Summary of the Invention

[0004] The present invention provides a method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars, which is used to solve the problems that when the existing coal pillar is wide, the pressure relief range is limited, the coal pillar is still a stress concentration area, and at the same time, when the coal pillar is completely pressure-relieved, it cannot ensure its blocking effect on the water and gas in the goaf, and on the other hand, the lateral goaf stress may be transferred to the solid coal rib of the gob-side entry, resulting in a higher impact risk on the other side of the entry.

[0005] The present invention provides a method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars, including:

[0006] Obtaining the range where the plastic zone of the coal pillar is located on the goaf side;

[0007] Based on the range where the plastic zone is located, reinforcing the plastic zone;

[0008] Obtaining the range where the peak zone of the coal pillar is located on the entry side;

[0009] Based on the range where the peak zone is located, relieving the pressure of the peak zone.

[0010] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention, the step of obtaining the range of the plastic zone of the coal pillar on the goaf side includes:

[0011] Establish a mechanical analysis model of the stress distribution of the coal pillar;

[0012] Based on the mechanical analysis model, determine the range of the plastic zone.

[0013] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention, the step of determining the range of the plastic zone based on the mechanical analysis model includes:

[0014] Based on the mechanical analysis model, the thickness of the coal seam, the roof structure and the roadway support parameters, determine the length of the plastic zone.

[0015] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention, the step of strengthening the plastic zone based on the range of the plastic zone includes:

[0016] When the coal pillar has not been formed, use the coal seam grouting method to grout and reinforce the plastic zone.

[0017] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention, after the step of using the coal seam grouting method to grout and reinforce the plastic zone when the coal pillar has not been formed, further includes:

[0018] Pre-crack the roof of the corresponding goaf of the plastic zone to cause the roof of the goaf to fracture and subside.

[0019] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention, the step of obtaining the range of the peak zone of the coal pillar on the roadway side includes:

[0020] Establish a mechanical analysis model of the stress distribution after the coal pillar is strengthened;

[0021] Based on the strengthened mechanical analysis model, determine the range of the peak zone.

[0022] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention, the step of determining the range of the peak zone based on the strengthened mechanical analysis model includes:

[0023] Based on the strengthened mechanical analysis model, the roadway parameters and the stress condition, determine the length of the peak zone.

[0024] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention. The steps of determining the range where the peak zone is located based on the strengthened mechanical analysis model include:

[0025] Based on the strengthened mechanical analysis model and the weight of drill cuttings measured on site, determine the length of the peak zone.

[0026] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention. The steps of relieving pressure on the peak zone based on the range where the peak zone is located include:

[0027] Drill holes for pressure relief in the peak zone within a preset range before and after the peak zone.

[0028] A method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention. After the steps of relieving pressure on the peak zone based on the range where the peak zone is located, it further includes:

[0029] Carry out long-term on-site monitoring of parameters such as roadway surrounding rock deformation, microseismicity, and stress;

[0030] Establish a mechanical analysis model for the strengthening and pressure relief of the coal pillar, and perform feedback optimization on the established mechanical analysis model for strengthening and pressure relief.

[0031] The method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars provided by the present invention first obtains the range where the plastic zone of the coal pillar is located on the goaf side, strengthens the plastic zone, enhances the bearing capacity of the coal pillar on the goaf side, and avoids the transfer of stress outward. Then, it obtains the range where the peak zone of the coal pillar is located on the roadway side, relieves pressure on the peak zone, and makes the stress balance position of its surrounding rock transfer away from the roadway rib, reducing the impact risk of the gob-side entry. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is the stress condition of the wide coal pillar and the surrounding rock along the roadway after the formation of the goaf provided by the present invention;

[0034] Figure 2 It is the stress condition of the surrounding rock along the roadway after the wide coal pillar is strengthened provided by the present invention;

[0035] Figure 3It is a schematic flow chart of the method for preventing and controlling rock bursts by strengthening and pressure-relieving coal pillars provided by the present invention;

[0036] Figure 4 It is a schematic flow chart of another method for preventing and controlling rock bursts by strengthening and pressure-relieving coal pillars provided by the present invention;

[0037] Figure 5 It is a schematic flow chart of yet another method for preventing and controlling rock bursts by strengthening and pressure-relieving coal pillars provided by the present invention;

[0038] Figure 6 It is a schematic flow chart of the method for preventing and controlling rock bursts by strengthening and pressure-relieving coal pillars provided by the present invention;

[0039] Reference numerals:

[0040] 100, goaf; 200, roadway; 300, plastic zone; 400, peak zone. Detailed implementation manners

[0041] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0042] The following will be combined with Figure 1 - Figure 2 Describe the method for preventing and controlling rock bursts by strengthening and pressure-relieving coal pillars provided by the present invention. As Figure 3 shown, this method is used to strengthen the coal pillar before pressure relief. The specific steps of this method include:

[0043] Step S110: Obtain the range where the plastic zone of the coal pillar is located on the goaf side.

[0044] In this embodiment, the mine adopts the layout method of leaving wide coal pillars. There are a goaf 100 and a roadway 200 on both sides of the wide coal pillar. In order to arrange it in the lateral stress reduction area along the roadway 200, the wide coal pillar needs to be pressure-relieved by means of large-diameter drilling or coal seam blasting to enhance the bearing capacity of the coal pillar on the goaf 100 side. After the upper section of the working face is mined out, the wide coal pillar undergoes plastic failure, causing the stress to transfer along the roadway 200. Therefore, the reinforcement range should be the plastic zone 300 of the wide coal pillar, increasing the bearing capacity of this area and reducing the stress transfer to the roadway 200 side.

[0045] For this purpose, first obtain the range where the plastic zone 300 of the wide coal pillar is located on the goaf side, that is, as shown in Figure 1, obtain the range where the plastic zone 300 of the wide coal pillar is located on the goaf 100 side. The range where the plastic zone 300 is located is greatly affected by the force change.

[0046] Step S120: Reinforce the plastic zone based on the range where the plastic zone is located.

[0047] After determining the range where the plastic zone 300 is located, the plastic zone 300 can be reinforced by grouting or other means to enhance the bearing capacity on the side of the goaf 100. After the plastic zone 300 is reinforced, as Figure 2 shown, the peak value of the force on the plastic zone 300 decreases, effectively increasing the bearing capacity of this area. Correspondingly, the current force on the peak zone 400 decreases to a certain extent after the plastic zone 300 is reinforced, and at the same time, the range of the peak zone 400 increases.

[0048] Step S130: Obtain the range where the peak zone of the coal pillar is located on the roadway side.

[0049] After the plastic zone 300 is reinforced, as Figure 2 shown, obtain the range where the peak zone 400 of the wide coal pillar is located on the roadway side, that is, obtain the range where the peak zone 400 of the wide coal pillar is located on one side of the roadway 200. The force change in the range where the peak zone 400 is located is relatively large.

[0050] Step S140: Release pressure on the peak zone based on the range where the peak zone is located.

[0051] After determining the range where the peak zone 400 is located, the wide coal pillar can be depressurized by means of large-diameter drilling or coal seam blasting.

[0052] The method for preventing and controlling rock bursts by reinforcing and depressurizing coal pillars provided by the present invention first obtains the range where the plastic zone of the coal pillar is located on the goaf side, reinforces the plastic zone, so that the bearing capacity of the coal pillar on the goaf side is enhanced, avoiding the outward transfer of stress, and then obtains the range where the peak zone of the coal pillar is located on the roadway side, releases pressure on the peak zone, so that the stress balance position of its surrounding rock transfers away from the roadway side, reducing the impact risk of the gob-side entry.

[0053] It should be noted that this method can also be applied to other structures (such as small coal pillars) other than wide coal pillars. By first reinforcing and then depressurizing the corresponding structures, the impact risk of the gob-side entry is reduced.

[0054] As Figure 4 shown, step S110: The step of obtaining the range where the plastic zone of the coal pillar is located on the goaf side specifically includes:

[0055] Step S111: Establish a mechanical analysis model of the stress distribution of the coal pillar.

[0056] Step S112: Determine the range where the plastic zone is located based on the mechanical analysis model.

[0057] Specifically, first establish a mechanical analysis model of the stress distribution of the wide coal pillar, and obtain the reinforcement range of the wide coal pillar according to the force on the wide coal pillar and the distribution of the plastic zone 300.

[0058] After the upper working face is mined out, plastic failure occurs in the wide coal pillar, causing stress to transfer along the roadway 200. Therefore, the reinforcement range should be the plastic zone 300 of the wide coal pillar, increasing the bearing capacity of this area and reducing the stress transfer to the roadway side. The range of the plastic zone 300 can be determined by theoretical calculation and numerical simulation methods.

[0059] When using theoretical calculation, the length of the plastic zone of the coal pillar is x0, which is mainly obtained by the following formula (1) according to the coal seam thickness, roof structure and roadway support parameters:

[0060]

[0061] In the formula, K is the stress concentration coefficient; p1 is the support resistance of the roadway rib in the goaf, MPa; f is the interlayer friction coefficient; m is the coal seam thickness, m; The internal friction angle of the coal body, degree; C is the cohesion of the coal body, MPa; ξ is the triaxial stress coefficient,

[0062] Step S120: The steps of reinforcing the plastic zone based on the range where the plastic zone is located specifically include:

[0063] When the coal pillar has not yet formed, use the coal seam grouting method to grout and reinforce the plastic zone 300.

[0064] Specifically, after obtaining the range of the plastic zone 300 on the goaf 100 side of the obtained wide coal pillar, use the coal seam grouting method to reinforce the coal pillar. After reinforcement, the coal pillar has strong support capacity on the side close to the goaf, avoiding the transfer of high stress in the coal pillar along the roadway 200.

[0065] The implementation timing of coal seam grouting should be before the upper working face is mined. Pre-grouting should be carried out when the coal pillar has not yet formed. The grouting material is selected as a material with a certain strength such as cement slurry or chemical slurry, and the grouting area is the range of the plastic zone 300 of the coal pillar.

[0066] After grouting, in order to reduce stress, the roof of the corresponding goaf 100 in the plastic zone 300 can be pre-cracked to make the roof of the goaf 100 fracture and subside.

[0067] Specifically, carry out lateral roof pre-cracking in the upper working face to further reduce the effect of the goaf 100 on the coal pillar. Lateral roof pre-cracking is to facilitate the further collapse of the roof after the working face is mined. Under the support of the reinforced coal pillar, the roof can further collapse, thereby reducing the hanging roof length and reducing the impact on the roadway 200.

[0068] As shown Figure 5 in, step S130: The step of obtaining the range where the peak zone of the coal pillar is located on the roadway side specifically includes:

[0069] Step S131: Establish a mechanical analysis model of the stress distribution after the coal pillar is reinforced.

[0070] Step S132: Based on the mechanical analysis model after reinforcement, determine the range where the peak zone is located.

[0071] Specifically, according to the stress distribution characteristics of the surrounding rock of the roadway after the wide coal pillar is reinforced, determine the position 400 of the stress peak zone on the coal pillar side of the roadway.

[0072] The determination of the stress peak zone 400 on the coal pillar side of the roadway adopts the methods of numerical simulation, theoretical calculation and on-site measurement.

[0073] During theoretical calculation, based on the mechanical analysis model after reinforcement and the roadway parameters and stress conditions, determine the length of the peak zone 400. The following formula is used for approximate calculation during theoretical calculation:

[0074]

[0075] In the formula: p is the original rock stress, MPa; p i , the roadway support resistance, MPa, a, the roadway width, m; C, the cohesion, MPa.

[0076] During on-site measurement, based on the mechanical analysis model after reinforcement and the weight of the drill cuttings measured on site, determine the length of the peak zone 400. By constructing drill cutting holes from the roadway to the coal pillar side, and judging according to the weight of the drill cuttings per meter, the section with the highest drill cuttings volume is the stress peak zone 400 of the surrounding rock of the roadway. To ensure the accuracy of the measurement results, multiple drill cutting holes can be constructed for judgment.

[0077] Step S140: The step of relieving pressure on the peak zone based on the range where the peak zone is located specifically includes: drilling and relieving pressure on the peak zone 400 within a preset range before and after the peak zone 400.

[0078] Specifically, at the obtained stress peak position of the surrounding rock of the roadway, within a range of 1 m before and after the peak position, use a directional drilling rig to construct at least 3 large-diameter long holes along the strike for pressure relief.

[0079] As shown Figure 6 in, step S140: After relieving pressure on the peak zone based on the range where the peak zone is located, it further includes:

[0080] Step S150: Carry out long-term on-site monitoring of parameters such as the deformation, microseismicity, and stress of the surrounding rock of the roadway.

[0081] Step S160: Establish a mechanical analysis model for the reinforcement and pressure relief of the coal pillar, and perform feedback optimization on the established mechanical analysis model for reinforcement and pressure relief.

[0082] After the reinforced plastic zone 300 and the pressure relief peak zone 400, long-term on-site monitoring of parameters such as roadway surrounding rock deformation, microseismicity, and stress is carried out. The on-site data is detected in real time by the detection device, and feedback optimization is performed on the established mechanical analysis model and parameter design for the wide coal pillar reinforcement-pressure relief. Thus, after the actual pressure relief is completed, the stress condition can be determined, and the impact risk of the gob-side entry can be further reduced.

[0083] In a specific embodiment, as Figure 1 and Figure 2 shown, first establish a mechanical analysis model for the stress distribution of the wide coal pillar, and obtain the reinforcement range of the wide coal pillar according to the stress and plastic zone 300 distribution of the wide coal pillar.

[0084] After the upper section working face is mined out, plastic failure occurs in the wide coal pillar, causing stress to transfer to the roadway 200. Therefore, the reinforcement range should be the plastic zone 300 of the wide coal pillar, increasing the bearing capacity of this area and reducing the stress transfer to the roadway side. The range of the plastic zone 300 can be determined by theoretical calculation and numerical simulation methods.

[0085] When using theoretical calculation, the length of the plastic zone of the coal pillar is x0, which is mainly obtained by the following formula (1) according to the coal seam thickness, roof structure, and roadway support parameters:

[0086]

[0087] In the formula, K is the stress concentration coefficient; p1 is the support resistance of the roadway side in the gob area, MPa; f is the interlayer friction coefficient; m is the coal seam thickness, m; the internal friction angle of the coal body, degree; C is the cohesion of the coal body, MPa; ξ is the triaxial stress coefficient,

[0088] After obtaining the range of the plastic zone 300 on the gob area 100 side of the wide coal pillar, the coal pillar is reinforced by means of coal seam grouting. After reinforcement, the side of the coal pillar adjacent to the gob area has strong support capacity, avoiding the transfer of high stress in the coal pillar to the roadway 200.

[0089] The implementation timing of coal seam grouting should be before the upper section working face is mined, and pre-grouting should be carried out when the coal pillar has not yet formed. The grouting material is selected as a material with a certain strength such as cement slurry or chemical slurry, and the grouting area is the range of the plastic zone 300 of the coal pillar.

[0090] Lateral roof pre - splitting is carried out in the upper - section working face to further reduce the effect on the 100 coal pillars in the goaf. The lateral roof pre - splitting is to facilitate the further caving of the roof under the supporting action of the reinforced coal pillars after the working face is mined, so as to reduce the hanging - roof length and the influence on the roadway 200.

[0091] After reinforcement, according to the stress distribution characteristics of the surrounding rock of the roadway after the wide coal pillar is reinforced, the position of the stress peak area 400 on the coal - pillar side of the roadway is determined.

[0092] The determination of the stress peak area 400 on the coal - pillar side of the roadway adopts the methods of numerical simulation, theoretical calculation and on - site measurement.

[0093] During theoretical calculation, based on the mechanical analysis model after reinforcement, as well as the roadway parameters and stress conditions, the length of the peak area 400 is determined. The following formula (2) is used for approximate calculation during theoretical calculation:

[0094]

[0095] In the formula: \(p_0\) is the virgin rock stress, MPa; \(p\) i , the roadway support resistance, MPa, \(a\), the roadway width, m; \(C\), the cohesion, MPa.

[0096] During on - site measurement, based on the mechanical analysis model after reinforcement and the weight of the drill cuttings measured on site, the length of the peak area 400 is determined. By constructing drill - cutting holes towards the coal - pillar side of the roadway and judging according to the weight of the drill cuttings per meter, the section with the highest drill - cutting volume is the stress peak area 400 of the surrounding rock of the roadway. To ensure the accuracy of the measurement results, multiple drill - cutting holes can be constructed for judgment.

[0097] For the obtained stress peak position of the surrounding rock of the roadway, within a range of 1 m before and after the peak position, at least 3 large - diameter long holes in the strike direction are constructed by a directional drill for pressure relief.

[0098] After the plastic zone 300 and the pressure - relief peak area 400 are reinforced, long - term on - site monitoring of parameters such as the deformation, micro - seismicity and stress of the surrounding rock of the roadway is carried out, and the wide - coal - pillar reinforcement - pressure - relief mechanical analysis model and parameter design established are feedback - optimized. Thus, after the actual pressure relief is completed, the stress condition can be determined, and the impact risk of the gob - side entry can be further reduced.

[0099] In summary, the beneficial effects of the coal - pillar reinforcement and pressure - relief method for preventing rock bursts provided in this embodiment are

[0100] 1. The method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars provided in this embodiment is based on the stress characteristics of coal pillars. By reinforcing the plastic zone of coal pillars, the bearing capacity of coal pillars on the goaf side is enhanced, avoiding the outward transfer of stress. In addition, through the strong supporting effect of the coal pillars on the goaf side on the roof, the roof is induced to fracture along the goaf edge, reducing its influence on the gob-side entry outside.

[0101] 2. The method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars provided in this embodiment simultaneously relieves the pressure in the peak stress area of the gob-side entry, causing the stress balance position of its surrounding rock to shift away from the roadway rib, reducing the rock burst risk of the gob-side entry.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars, characterized in that, Including: Obtaining the range where the plastic zone of the coal pillar is located on the goaf side; Based on the range where the plastic zone is located, reinforcing the plastic zone, including when the coal pillar has not been formed, grouting and reinforcing the plastic zone by means of coal seam grouting; pre-cracking the roof of the corresponding goaf of the plastic zone to cause the roof of the goaf to fracture and subside; Obtaining the range where the peak zone of the coal pillar is located on the roadway side, including: establishing a mechanical analysis model of the stress distribution after the coal pillar is reinforced; based on the reinforced mechanical analysis model, determining the range where the peak zone is located; Relieving pressure on the peak zone based on the range where the peak zone is located.

2. The method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars according to claim 1, wherein The step of obtaining the range where the plastic zone of the coal pillar is located on the goaf side includes: Establishing a mechanical analysis model of the stress distribution of the coal pillar; Based on the mechanical analysis model, determining the range where the plastic zone is located.

3. The method for preventing and controlling rock burst by strengthening and pressure relief of coal pillars according to claim 2, characterized in that, The step of determining the range where the plastic zone is located based on the mechanical analysis model includes: Based on the mechanical analysis model, the coal seam thickness, the roof structure and the roadway support parameters, determining the length of the plastic zone.

4. The method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars according to claim 1, characterized in that, The step of determining the range where the peak zone is located based on the reinforced mechanical analysis model includes: Based on the reinforced mechanical analysis model, the roadway parameters and the stress condition, determining the length of the peak zone.

5. The method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars according to claim 1, wherein, The step of determining the range where the peak zone is located based on the reinforced mechanical analysis model includes: Based on the reinforced mechanical analysis model and the weight of the drill cuttings measured on site, determining the length of the peak zone.

6. The method for preventing and controlling rock bursts by reinforcing and pressure-relieving coal pillars according to any one of claims 1-3, characterized in that, The step of relieving pressure on the peak zone based on the range where the peak zone is located includes: Drilling and relieving pressure on the peak zone within a preset range before and after the peak zone.

7. The method for preventing and controlling rock bursts by strengthening and pressure relief of coal pillars according to any one of claims 1-3, characterized in that, After the step of relieving pressure on the peak zone based on the range where the peak zone is located, it further includes: Carrying out long-term on-site monitoring of the roadway surrounding rock deformation, microseismicity and stress parameters; Establishing a mechanical analysis model of the reinforcement and pressure relief of the coal pillar, and performing feedback optimization on the established mechanical analysis model of the reinforcement and pressure relief.

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