A method and system for demonstrating the safety of rock burst of coal pillars left in goaf

Abstract

The present application relates to the technical field of rock burst prevention and control, and provides a rock burst safety demonstration method and system for coal pillars left in goafs. In the method, when the coal pillars of the target rock burst mine have two non-adjacent goafs or three or more adjacent goafs, the coal pillars are determined to be coal pillars left in goafs to be demonstrated, and when there is mining disturbance on the working face of the coal pillars left in goafs during the demonstration period, the possibility of rock burst on the coal pillars left in goafs themselves and the adjacent mining working faces is demonstrated respectively; when there is no mining disturbance on the working face of the coal pillars left in goafs, the possibility of overall instability impact on the coal pillars left in goafs is demonstrated. Thus, by classifying whether the coal pillars left in goafs are affected by mining disturbances within the safety demonstration period, the anti-rock burst safety of the coal pillars left in goafs is effectively associated with the temporal and spatial impact of mining, and the reliability of the demonstration results of rock burst induced by coal pillars left in goafs is improved.

Description

Technical Field

[0001] The present application relates to the technical field of rock burst prevention and control, and in particular to a method and system for demonstrating the safety of rock burst of coal pillars left over from goaf areas. Background Art

[0002] In order to control surface subsidence and reduce damage to ground structures, coal mining enterprises often adopt the method of arranging strip working faces for mining. When the working face is mined, the strip coal pillars left behind are surrounded by the goaf to form residual coal pillars in the goaf.

[0003] According to relevant regulations, coal seams with rock bursts should be mined in strict sequence, and no isolated coal pillars should be left. When coal pillars must be left in the goaf under special circumstances, safety demonstration should be carried out, and the position, size and impact range of the coal pillars should be marked on the mining engineering plan; when mining a coal seam group downward, the impact of the coal pillars of the previous coal seam should be analyzed.

[0004] The coal pillars left in the goaf are affected by the transfer stress of the surrounding goaf overburden, with a high degree of stress concentration, and a large range of surrounding coal and rock mass affected. If the working face is arranged within the influence range of the coal pillars left in the goaf, whether it can be mined safely, that is, which ones cannot be mined, which ones can be mined safely, or which ones can be mined safely after taking corresponding rock burst prevention and control measures, there is still a lack of effective theoretical basis. Summary of the invention

[0005] The purpose of the present application is to provide a method and system for demonstrating the safety of rock burst of coal pillars left in goafs, so as to solve or alleviate the problems existing in the above-mentioned prior art.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] The present application provides a method for demonstrating the safety of rock burst of coal pillars left over in goafs, comprising: step S101, in response to the existence of two non-adjacent goafs or three or more adjacent goafs in a coal pillar of a target rock burst mine, determining that the coal pillar is a coal pillar left over in goafs to be demonstrated; step S102, determining whether the coal pillar left over in goafs to be demonstrated has been disturbed by mining at a working face within a demonstration period; step S103, in response to the existence of mining disturbance at a working face of the coal pillar left over in goafs, demonstrating the possibility of rock burst of the coal pillars left over in goafs themselves and of rock burst of the coal pillars left over in goafs inducing adjacent mining working faces; in response to the absence of mining disturbance at a working face of the coal pillars left over in goafs, demonstrating the possibility of overall instability impact of the coal pillars left over in goafs.

[0008] Preferably, in step S102, in response to the existence of an excavation working face within a first preset distance of the coal pillars left over in the goaf during the demonstration period, the coal pillars left over in the goaf have an excavation disturbance effect within the demonstration period; in response to the existence of a mining working face within a second preset distance of the coal pillars left over in the goaf during the demonstration period, the coal pillars left over in the goaf have a mining disturbance effect within the demonstration period.

[0009] Preferably, in step S103, the ultimate compressive strength R of the coal pillar remaining in the goaf is determined based on a pre-constructed overall instability type rock burst model of the coal pillar; in response to the ultimate compressive strength R of the coal pillar remaining in the goaf being greater than the maximum vertical stress of the coal pillar remaining in the goaf obtained by numerical simulation, the coal pillar remaining in the goaf itself has the possibility of rock burst.

[0010] Preferably, the overall instability type rock burst model of the coal pillar is:

[0011]

[0012] Where R is the ultimate compressive strength of the coal pillar left in the goaf, σ c is the uniaxial compressive strength of the coal body, x i is the plastic zone width of the coal pillars left in the goaf in four directions, i=1, 2, 3, 4; B is the inclination width of the coal pillars left in the goaf; L is the strike width of the coal pillars left in the goaf; is the elastic zone coal body compression coefficient of the target rock burst mine, It is the compressive coefficient of the coal body in the plastic zone of the target rock burst mine.

[0013] Preferably, in step S103, based on the pre-constructed roadway wall ejection rock burst model, the stress F at which the ejection rock burst occurs in the roadway wall of the mining working face is determined. 冲 , and the stress F against ejection-type rock burst 阻 ; In response to F 冲 >F 阻 , it is determined that the coal pillars left in the goaf have the potential to induce ejection-type rock bursts adjacent to the mining working face.

[0014] Preferably, the road side ejection type rock burst model is:

[0015]

[0016] In the formula, F 冲 is the stress of the road side ejection type rock burst; λ is the stress concentration coefficient, F1 is the vertical stress value of the road side coal body, F e The pressure generated by the expansion of coal body; F 阻In order to resist the stress of the thrown-out impact rock pressure of the road side, P x is the restraint force of the support system on the coal wall, f is the friction coefficient of the coal body, and γ is the bulk density of the coal body.

[0017] Preferably, in step S103, based on numerical simulation, the stress field distribution of the bottom coal adjacent to the mining working face when the coal pillars left behind in the goaf are mined is calculated; based on a pre-constructed bottom coal buckling type rock burst model, according to the stress field distribution of the bottom coal of the mining working face, it is determined that the coal pillars left behind in the goaf may induce bottom coal buckling type rock burst adjacent to the mining working face.

[0018] Preferably, the bottom coal buckling rock burst model is:

[0019]

[0020] Where N s is the minimum stress for buckling type rock burst in bottom coal, EJ is the bending stiffness of bottom rock beam, and l is the width of bottom coal.

[0021] Preferably, in step S103, the microseismic monitoring data of the mine at least one year before the demonstration period is projected onto the mining engineering plan of the target rock burst mine, and the microseismic monitoring data of the mine is classified according to the energy size, and the movement state of the roof rock layer of the coal pillar left in the goaf is inverted to determine the energy E>10 of the roof rock layer of the coal pillar left in the goaf. 4 J's microseismic events.

[0022] The embodiment of the present application also provides a safety demonstration system for rock burst of coal pillars left over in goafs, comprising: a residual coal pillar unit, configured to determine that the coal pillar is a residual coal pillar in the goaf to be demonstrated in response to the presence of two non-adjacent goafs or three or more adjacent goafs in the target rock burst mine; a mining disturbance unit, configured to determine whether the residual coal pillar in the goaf to be demonstrated has been disturbed by mining at the working face within the demonstration period; a possibility demonstration unit, configured to conduct a possibility demonstration of rock burst of the residual coal pillar in the goaf itself and rock burst of the residual coal pillar in the goaf induced by the residual coal pillar in the goaf at the adjacent mining working face in response to the presence of mining disturbance at the working face of the residual coal pillar in the goaf; and conduct a possibility demonstration of overall instability impact of the residual coal pillar in the goaf in response to the absence of mining disturbance at the working face of the residual coal pillar in the goaf.

[0023] Beneficial effects:

[0024] In the safety demonstration method for rock burst of coal pillars left in goafs provided in the embodiments of the present application, whether the coal pillar is a coal pillar left in goafs to be demonstrated is determined based on whether the coal pillar of the target rock burst mine has two non-adjacent goafs or three or more adjacent goafs. When the coal pillar of the target rock burst mine has two non-adjacent goafs or three or more adjacent goafs, the coal pillar is determined to be a coal pillar left in goafs to be demonstrated, and it is determined whether the coal pillar left in goafs to be demonstrated has been disturbed by mining at the working face within the demonstration period. When the coal pillar left in goafs has been disturbed by mining at the working face, the possibility of rock burst of the coal pillars left in goafs themselves and the possibility of rock burst of the adjacent mining working faces induced by the coal pillars left in goafs are demonstrated respectively. When the coal pillars left in goafs have no mining disturbance at the working face, the possibility of overall instability impact of the coal pillars left in goafs is demonstrated.

[0025] Therefore, by classifying whether the coal pillars left in the goaf are affected by mining disturbance within the safety demonstration period, the anti-bumping safety of the coal pillars left in the goaf is effectively linked to the temporal and spatial impact of mining, thereby improving the reliability of the demonstration results of the impact ground pressure induced by the coal pillars left in the goaf. In the demonstration process, numerical simulation, mechanics, microseismic monitoring and other analyses are combined to make the demonstration process more in line with the actual situation on the spot of the coal pillars left in the goaf, conduct a comprehensive assessment of whether the coal pillars left in the goaf are safe, and effectively guide the anti-bumping safety of mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting part of the present application are used to provide a further understanding of the present application. The exemplary embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. Among them:

[0027] Figure 1 A schematic flow chart of a method for demonstrating rock burst safety of coal pillars left in goafs according to some embodiments of the present application;

[0028] Figure 2 A schematic diagram of the adjacent goaf and the remaining coal pillars provided according to some embodiments of the present application;

[0029] Figure 3 A principle logic diagram of a method for demonstrating the safety of rock burst of coal pillars left in goafs according to some embodiments of the present application;

[0030] Figure 4 A schematic diagram of numerical simulation results of coal pillars left in goaf areas according to some embodiments of the present application;

[0031] Figure 5 A schematic diagram of the structure of a rock burst safety demonstration system for coal pillars left in goafs provided according to some embodiments of the present application. DETAILED DESCRIPTION

[0032] The present application will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present application and does not limit the present application. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present application without departing from the scope or spirit of the present application. For example, a feature shown or described as a part of an embodiment may be used in another embodiment to produce yet another embodiment. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the embodiments of the present invention should belong to the scope of protection of the embodiments of the present invention.

[0033] The existing rock burst prevention and control demonstration methods have not demonstrated the safety of rock burst caused by coal pillars left in goafs, and cannot determine the anti-rock burst safety of the mining working face around the coal pillars left in goafs. Usually, the arrangement of mining working faces around coal pillars left in goafs is based on past production experience, lacks reliable demonstration, and is unreasonable and unscientific. Based on this, the embodiment of the present application provides a rock burst safety demonstration method for coal pillars left in goafs, such as Figures 1 to 4 As shown, the safety demonstration method includes:

[0034] Step S101: In response to the existence of two non-adjacent goafs or three or more adjacent goafs in the target rock burst mine, the coal pillar is determined to be a residual coal pillar in the goaf to be verified.

[0035] The coal pillars left in the goaf refer to the unmined coal pillars left in the process of coal seam mining to control surface subsidence or prevent coal mine rock burst. The existence of these coal pillars has an important impact on the stability of the roadway when mining the coal seam or the adjacent coal seam. When mining within the influence range of the coal pillars left in the coal seam or the adjacent coal seam, it will affect the stability of the roadway, and corresponding control technology needs to be adopted to ensure safety.

[0036] The instability characteristics of the mining tunnel affected by the legacy coal pillar can be identified by monitoring the microseismic events of the roof. The legacy coal pillar is affected by the transfer stress of the overburden in the formed goaf, and the stress concentration is high, which will affect the subsequent mining working faces arranged within the influence range. When the legacy coal pillar is unstable, the dynamic load generated has a more significant impact on the mining working faces distributed within the influence range. At the same time, the chain instability of the legacy coal pillar group may also cause a variety of disasters, such as mine earthquakes, coal seam spontaneous combustion, etc.

[0037] In this application, the coal pillars of the target rock burst mine are checked, and the coal pillars in two non-adjacent goafs or two or more non-adjacent goafs are determined as the residual coal pillars in the goafs to be verified, and the residual coal pillars in the goafs to be verified are numbered. Among them, two or more non-adjacent goafs include two non-adjacent goafs and three or more adjacent goafs, and three or more adjacent goafs simultaneously include two non-adjacent goafs and two adjacent goafs. In other words, the residual coal pillars exist in four directions in space, and as long as there are goafs in two non-adjacent directions that surround the residual coal pillars, they are considered to be residual coal pillars in the goaf; if there are goafs in two adjacent directions, the residual coal pillars are semi-enclosed and cannot be considered as residual coal pillars in the goaf.

[0038] Step S102: Determine whether there is any working face disturbance in the coal pillars left in the goaf to be verified within the verification period.

[0039] The coal pillars left in the goaf are affected by mining disturbance. Here, mining disturbance mainly refers to the disturbance caused by working face excavation or mining. The working face excavation time and mining time usually formulate corresponding production plans (time periods). Within the production plan, the distribution positions of the mining working faces (excavation working faces and mining working faces) can be known; if it exceeds the production plan, the distribution positions of the mining faces cannot be clearly known, and it is impossible to determine whether the coal pillars left in the goaf are affected by mining disturbance.

[0040] Based on this, in this application, the numbered coal pillars left in the goaf to be demonstrated are classified according to whether they are affected by mining disturbance during the demonstration period. Thus, the coal pillars left in the goaf are divided into two categories: one is the coal pillars left in the goaf with mining disturbance of the working face, and the other is the coal pillars left in the goaf without mining disturbance of the working face. And the rock burst safety demonstration of the coal pillars left in the goaf with mining disturbance of the working face and the coal pillars left in the goaf without mining disturbance of the working face is carried out by category.

[0041] When judging whether there is mining disturbance on the working face of the coal pillars left in the goaf, the coal pillars left in the goaf with different numbers are analyzed one by one to see whether there is a mining working face within the preset distance, and then judge whether there is mining disturbance on the working face of the coal pillars left in the goaf. Specifically, when there is a driving working face within the first preset distance (150 meters) of the coal pillars left in the goaf during the demonstration period, the coal pillars left in the goaf are affected by driving disturbance during the demonstration period; when there is a mining working face within the second preset distance (500 meters) of the coal pillars left in the goaf during the demonstration period, the coal pillars left in the goaf are affected by mining disturbance during the demonstration period.

[0042] That is to say, it is necessary to determine whether there are mining faces within the vicinity of 150 meters and 500 meters of the remaining coal pillars in the goaf with different numbers, so as to determine whether the corresponding remaining coal pillars in the goaf have any disturbance effects within the demonstration period.

[0043] At the same time, according to the determined critical range of disturbance, it is also possible to determine whether the area with thick hard roof or rock formation group and more than half of the mining area and insufficient surface settlement after mining is affected by mining disturbance. Among them, the roof rock formation with a thickness greater than 10m and a uniaxial compressive strength greater than 60MPa is defined as thick hard roof, and the corresponding rock formation group is thick hard roof rock formation group.

[0044] Step S103, in response to the existence of working face disturbance in the coal pillars left over in the goaf, the possibility of rock burst in the coal pillars left over in the goaf themselves and rock burst in the adjacent mining working faces induced by the coal pillars left over in the goaf are demonstrated respectively; in response to the absence of working face mining disturbance in the coal pillars left over in the goaf, the possibility of overall instability of the coal pillars left over in the goaf is demonstrated.

[0045] The safety demonstration of rock burst of coal pillars left in goafs with mining disturbance mainly includes two aspects: one is the demonstration of the possibility of rock burst of coal pillars left in goafs themselves, and the other is the demonstration of the possibility of rock burst of coal pillars left in goafs inducing adjacent mining faces. In other words, the possibility of rock burst of coal pillars left in goafs affected by mining disturbance of working faces is demonstrated, and the possibility of rock burst of coal pillars left in goafs inducing adjacent mining faces (inducing ejection rock burst of adjacent mining faces, inducing bottom coal buckling rock burst of adjacent mining faces) is demonstrated.

[0046] Among them, based on the pre-constructed overall instability impact rock pressure model of the coal pillar, the ultimate compressive strength R of the coal pillar left in the goaf is determined; when the ultimate compressive strength R of the coal pillar left in the goaf is greater than the maximum vertical stress of the coal pillar left in the goaf obtained by numerical simulation, it is determined that the coal pillar left in the goaf itself has the possibility of impact rock pressure.

[0047] Specifically, the technical parameters of the coal pillars left in the goaf are substituted into the overall instability rock burst model of the coal pillars to calculate the ultimate compressive strength R of the coal pillars left in the goaf. The overall instability rock burst model of the coal pillars is:

[0048]

[0049] Where R is the ultimate compressive strength of the coal pillar left in the goaf, is the comprehensive compressive strength coefficient of the coal pillar left in the goaf, σ c is the uniaxial compressive strength of the coal body, x i (i=1,2,3,4) is the width of the plastic zone in four directions of the coal pillars left in the goaf; B is the inclination width of the coal pillars left in the goaf; L is the strike width of the coal pillars left in the goaf; is the elastic zone coal body compression coefficient of the target rock burst mine, It is the compressive coefficient of the coal mass in the plastic zone of the target rock burst mine.

[0050] While determining that the coal pillars left in the goaf have the potential to cause rock bursts themselves, the possibility of the coal pillars left in the goaf inducing rock bursts in the adjacent mining working faces is determined based on different pre-constructed rock burst models.

[0051] Among them, based on the pre-constructed roadway wall ejection-type rock burst model, the stress F of the roadway wall ejection-type rock burst occurring in the mining working face is determined. 冲 , and the stress E to resist the ejection-type rock burst 阻 When F 冲 >F 阻 When the coal pillars left in the goaf are found to have the potential to induce ejection-type rock bursts in the adjacent mining working faces,

[0052] Specifically, the model of the road side ejection type rock burst is:

[0053]

[0054] In the formula, F 冲 is the stress of the road side ejection type rock burst; λ is the stress concentration coefficient, F1 is the vertical stress value of the road side coal body, F e The pressure generated by the expansion of coal body; F 阻 In order to resist the stress of the thrown-out impact rock pressure of the road side, P x is the restraint force of the support system on the coal wall, f is the friction coefficient of the coal body, and γ is the bulk density of the coal body.

[0055] While determining whether the coal pillars left behind in the goaf have the possibility of inducing ejection-type rock bursts in the adjacent mining face, the stress field distribution of the bottom coal of the adjacent mining face when the coal pillars left behind in the goaf are mined is calculated based on numerical simulation. Specifically, according to the geological and mining technical conditions between the mining face adjacent to the coal pillars left behind in the goaf, simulations are performed using software such as FLAC-3D, 3DE, ANSYS, and Abaqus to determine the stress field distribution of the bottom coal of the adjacent mining face when the coal pillars left behind in the goaf are mined; and based on the pre-constructed bottom coal buckling rock burst model, according to the stress field distribution of the bottom coal of the mining face, the possibility of the coal pillars left behind in the goaf inducing bottom coal buckling rock bursts in the adjacent mining face is determined.

[0056] Specifically, the bottom coal buckling type rock burst model is:

[0057]

[0058] Where N s is the minimum stress for buckling type rock burst in bottom coal, EJ is the bending stiffness of bottom rock beam, and l is the width of bottom coal.

[0059] The safety demonstration of rock burst of coal pillars left in goafs without mining disturbance is mainly to demonstrate the possibility of overall instability of coal pillars left in goafs. Specifically, the microseismic monitoring data of the mine with a demonstration period of at least one year before the demonstration is projected onto the mining engineering plan of the target rock burst mine, and the microseismic monitoring data of the mine is classified according to the energy size, and the movement state of the roof rock layer of the coal pillar left in the goaf is inverted to determine the energy E>10 of the roof rock layer of the coal pillar left in the goaf. 4 J's microseismic events.

[0060] If the rock layer on the roof of the coal pillar left in the goaf has energy E>10 4 J microseismic event, the coal pillars left in the goaf may be unstable. According to the results of the rock burst safety demonstration of the coal pillars left in the goaf, the range of rock burst affected by the coal pillars left in the goaf is circled and marked on the mining engineering plan, so as to take targeted anti-burst measures in the affected area. 4 J's microseismic event will determine the safety of the coal pillars left in the goaf.

[0061] Whether it is the safety demonstration of rock burst of coal pillars left over in goafs with mining disturbance at the working face, or the safety demonstration of rock burst of coal pillars left over in goafs without mining disturbance at the working face, if there is a possibility of rock burst of coal pillars left over in goafs, targeted prevention and control measures for rock burst of coal pillars left over in goafs shall be taken.

[0062] Specifically, in addition to real-time monitoring of the rock burst affected by the coal pillars left in the goaf using the microseismic monitoring system, targeted stress measurement points are arranged in the affected area, and drilling cuttings inspection is strengthened. In order to avoid stress concentration in the area of ​​unequal width coal pillars, stress measurement points are arranged on the side of the coal pillars in the channel, and the spacing between each group of stress gauges is no more than 30 meters. The stress gauges are determined according to the anti-bumping design of the mining working face.

[0063] During the mining period of the working face, when an early warning appears at the prestressed measuring point on the side of the unequal width coal pillar, the coal powder monitoring exceeds the standard, or dynamic phenomena such as drill sticking, drill suction, top drill, abnormal noise and impact in the hole occur, large-diameter drilling or coal seam blasting is used to resolve the danger and relieve pressure.

[0064] Finally, the rock burst prevention and control measures taken for the coal pillars left in the goaf are analyzed, including: the establishment and staffing of rock burst prevention and control institutions, the construction of rock burst prevention and control systems, rock burst monitoring, early warning and emergency response, implementation of rock burst prevention and control measures, investment in rock burst prevention and control funds, and special training on rock burst.

[0065] Among them, during the rock burst monitoring process, if the microseismic energy around the excavation face exceeds the critical value, or the daily total energy release and frequency have an early warning, or the frequency and total energy of microseismic events continue to increase, or the frequency and total energy of microseismic events change abnormally, or microseismic events accumulate in a certain area for several consecutive days, and it is determined that there is a rock burst danger, the work on the face will be stopped immediately, the power will be cut off, and personnel will be evacuated. And the pressure will be relieved and the danger will be eliminated at the annex of the early warning microseismic event. After the danger is eliminated, production can be resumed only if there is no early warning after the online inspection of microseismic, drill cuttings and stress, otherwise the pressure will continue to be relieved.

[0066] When the stress monitoring increments, go to the warning location to implement the hazard relief and pressure relief and conduct effect inspection. Production can only be resumed when the stress drops by at least 2MPa and there is no warning after drilling cuttings. Among them, when the drilling cuttings method warns or there are serious drill sticking, drill suction (except caused by coal tide), top drilling, abnormal noise, hole impact and other dynamic effects during drilling, it is judged that there is an impact hazard. The working face should immediately stop the operation, cut off the power supply, evacuate the personnel, and carry out hazard relief and pressure relief according to the requirements of the measures. Production can only be resumed when there is no warning in the online inspection of drilling cuttings and stress, otherwise the pressure relief should continue.

[0067] When there are strong vibrations, loud noises, instant bottom (side) drums, coal and rock ejection and other dynamic phenomena at the mining site, and it is determined that there is a risk of rock burst, the operation must be stopped immediately, personnel must be evacuated quickly according to the rock burst disaster avoidance route, the power supply must be cut off, and the cause of the incident must be analyzed. The degree of danger at the location of the incident must be assessed. After confirming that there is no impact danger, the drill cuttings method verification must be carried out at the location of the incident. If the drill cuttings do not exceed the critical value and there is no stress warning, production can be resumed; if there is a drill cuttings or stress warning, pressure relief must be implemented immediately to eliminate the danger. Finally, production can be resumed only after the drill cuttings are tested to be below the warning critical value and there is no stress warning.

[0068] In this application, by classifying whether the coal pillars left in the goaf are affected by mining disturbance within the safety demonstration period, the anti-bumping safety of the coal pillars left in the goaf is effectively linked to the temporal and spatial impact of mining, thereby improving the reliability of the demonstration results of the impact ground pressure induced by the coal pillars left in the goaf; and in the demonstration process, numerical simulation, mechanics, microseismic monitoring and other analyses are combined to make the demonstration process more in line with the actual on-site situation of the coal pillars left in the goaf, conduct a comprehensive assessment of whether the coal pillars left in the goaf are safe, and effectively guide the anti-bumping safety of mines.

[0069] The present application also provides a safety demonstration system for rock burst of coal pillars left in goaf areas, such as Figure 5 As shown, the system includes:

[0070] The remaining coal pillar unit 501 is configured to determine that the coal pillar is a remaining coal pillar in the goaf to be verified in response to the coal pillar in the target rock burst mine having two non-adjacent goafs or three or more adjacent goafs;

[0071] The mining disturbance unit 502 is configured to determine whether the coal pillars left in the goaf to be verified are disturbed by mining at the working face within the verification period;

[0072] The possibility demonstration unit 503 is configured to respectively demonstrate the possibility of rock bursts caused by the coal pillars left in the goaf itself and rock bursts caused by the coal pillars left in the goaf inducing adjacent mining working faces in response to the mining disturbance caused by the coal pillars left in the goaf;

[0073] In response to the fact that there is no working face mining disturbance in the remaining coal pillars in the goaf, the possibility of overall instability impact of the remaining coal pillars in the goaf is demonstrated.

[0074] The system for demonstrating the rock burst safety of coal pillars left behind in goafs provided in the embodiments of the present application can implement the steps and processes of the method for demonstrating the rock burst safety of coal pillars left behind in goafs described in any of the above embodiments, and achieve the same technical effects, which will not be described in detail here.

[0075] In the description of the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0076] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for demonstrating the safety of rock burst of coal pillars left in goaf, characterized in that: include: Step S101: In response to the coal pillar of the target rock burst mine having two non-adjacent goafs or three or more adjacent goafs, determining that the coal pillar is a goaf-remaining coal pillar to be verified; Step S102, determining whether the coal pillars left in the goaf to be verified are disturbed by mining at the working face within the verification period; Step S103, in response to the presence of mining disturbance in the working face of the coal pillar left in the goaf, the possibility of rock burst in the coal pillar left in the goaf itself and rock burst in the adjacent mining working face induced by the coal pillar left in the goaf are respectively demonstrated; In response to the fact that there is no mining disturbance on the working face in the coal pillars left in the goaf, the possibility of overall instability impact of the coal pillars left in the goaf is demonstrated; wherein, based on the pre-constructed overall instability impact rock pressure model of the coal pillars: Determine the ultimate compressive strength R of the coal pillar left in the goaf; where σ c is the uniaxial compressive strength of the coal body, x i is the plastic zone width of the coal pillars left in the goaf in four directions, i=1, 2, 3, 4; B is the inclination width of the coal pillars left in the goaf; L is the strike width of the coal pillars left in the goaf; is the elastic zone coal body compression coefficient of the target rock burst mine, is the compressive strength coefficient of the coal body in the plastic zone of the target rock burst mine; In response to the ultimate compressive strength R of the coal pillar left in the goaf being greater than the maximum vertical stress of the coal pillar left in the goaf obtained by numerical simulation, the coal pillar left in the goaf itself has the possibility of generating rock burst; Based on the pre-built road side ejection rock burst model: Determine the stress F of the ejection-type rock burst at the side of the tunnel of the mining working face 冲 , and the stress F against ejection-type rock burst 阻 ; In the formula, λ is the stress concentration coefficient, F1 is the vertical stress value of the coal body on the side of the roadway, and F e The pressure formed by the expansion of coal body; P x is the restraint force of the support system on the coal wall, f is the friction coefficient of the coal body, and γ is the bulk density of the coal body; In response to F 冲 >F 阻 , it is determined that the coal pillars left in the goaf have the potential to induce ejection-type rock bursts adjacent to the mining working face; Based on numerical simulation, the stress field distribution of the bottom coal adjacent to the mining working face when the coal pillars left in the goaf are mined is calculated; based on the pre-constructed bottom coal buckling rock burst model: According to the stress field distribution of the bottom coal of the mining working face, the possibility of the coal pillar left in the goaf inducing the buckling type rock burst of the bottom coal adjacent to the mining working face is determined; where N s is the minimum stress for buckling type rock burst in bottom coal, EJ is the bending stiffness of bottom rock beam, and l is the width of bottom coal.

2. The method for demonstrating the safety of rock burst of coal pillars left in goaf according to claim 1 is characterized in that: In step S102, In response to the presence of a tunneling working face within the first preset distance of the coal pillar left in the goaf during the demonstration period, the coal pillar left in the goaf has a tunneling disturbance effect during the demonstration period; In response to the presence of a mining face within a second preset distance of the remaining coal pillar in the goaf during the demonstration period, the remaining coal pillar in the goaf has a mining disturbance effect during the demonstration period.

3. The method for demonstrating the safety of rock burst of coal pillars left in goaf according to claim 1 is characterized in that: In step S103, Project the mine microseismic monitoring data of at least one year before the demonstration period onto the mining engineering plan of the target rock burst mine, and classify the mine microseismic monitoring data according to the energy size, invert the movement state of the roof rock layer of the coal pillar left in the goaf, and determine the energy E>10 of the roof rock layer of the coal pillar left in the goaf. 4 J's microseismic events.

4. A safety demonstration system for rock burst of coal pillars left in goaf, characterized in that: include: A residual coal pillar unit is configured to determine that the coal pillar is a residual coal pillar in the goaf to be verified in response to the existence of two non-adjacent goafs or three or more adjacent goafs in the coal pillar of the target rock burst mine; A mining disturbance unit, configured to determine whether the coal pillars left in the goaf to be verified are disturbed by mining at the working face within the verification period; A possibility demonstration unit is configured to, in response to the presence of mining disturbance of the working face due to the coal pillar left in the goaf, respectively demonstrate the possibility of rock burst caused by the coal pillar left in the goaf itself and rock burst caused by the coal pillar left in the goaf inducing adjacent mining working faces; In response to the fact that there is no mining disturbance on the working face in the coal pillars left in the goaf, the possibility of overall instability impact of the coal pillars left in the goaf is demonstrated; wherein, based on the pre-constructed overall instability impact rock pressure model of the coal pillars: Determine the ultimate compressive strength R of the coal pillar left in the goaf; where σ c is the uniaxial compressive strength of the coal body, x i is the plastic zone width of the coal pillars left in the goaf in four directions, i=1, 2, 3, 4; B is the inclination width of the coal pillars left in the goaf; L is the strike width of the coal pillars left in the goaf; is the elastic zone coal body compression coefficient of the target rock burst mine, is the compressive strength coefficient of the coal body in the plastic zone of the target rock burst mine; In response to the ultimate compressive strength R of the coal pillar left in the goaf being greater than the maximum vertical stress of the coal pillar left in the goaf obtained by numerical simulation, the coal pillar left in the goaf itself has the possibility of generating rock burst; Based on the pre-built road side ejection rock burst model: Determine the stress F of the ejection-type rock burst at the side of the tunnel of the mining working face 冲 , and the stress F against ejection-type rock burst 阻 ; In the formula, λ is the stress concentration coefficient, F1 is the vertical stress value of the coal body on the side of the roadway, and F e The pressure formed by the expansion of coal body; P x is the restraint force of the support system on the coal wall, f is the friction coefficient of the coal body, and γ is the bulk density of the coal body; In response to F 冲 >F 阻 , it is determined that the coal pillars left in the goaf have the potential to induce ejection-type rock bursts adjacent to the mining working face; Based on numerical simulation, the stress field distribution of the bottom coal adjacent to the mining working face when the coal pillars left in the goaf are mined is calculated; based on the pre-constructed bottom coal buckling type rock burst model: According to the stress field distribution of the bottom coal of the mining working face, the possibility of the coal pillar left in the goaf inducing the buckling type rock burst of the bottom coal adjacent to the mining working face is determined; where N s is the minimum stress for buckling type rock burst in bottom coal, EJ is the bending stiffness of bottom rock beam, and l is the width of bottom coal.

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