Identification and prevention methods of negative coal pillar impact hazard under dynamic load disturbance

Abstract

The present application relates to the technical field of coal mine safety, and provides a method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance. The method first traverses the microseismic monitoring data of the mining area and the immediate top and immediate bottom areas around the negative coal pillar tunnel under historical dynamic load, divides the dynamic load space type, and calculates the dynamic load energy coefficient and radial displacement corresponding to each historical dynamic load; then, the dynamic load energy coefficient and radial displacement corresponding to all historical dynamic loads are sorted, and based on the sorting results, the impact hazard of the negative coal pillar tunnel is identified according to the minimum dynamic load energy coefficient and the maximum radial displacement. Thus, the corresponding dynamic load energy coefficient and radial displacement are calculated according to the dynamic load space type, and the impact hazard of the negative coal pillar tunnel is divided, and the impact hazard of the negative coal pillar tunnel under dynamic load disturbance is quickly, accurately and scientifically determined, and targeted pressure relief measures are proposed, which provides theoretical guidance for on-site engineering practice and ensures the safe construction of the negative coal pillar tunnel.

Description

Technical Field

[0001] The present application relates to the field of coal mine safety technology, and in particular to a method for identifying and preventing the danger of negative coal pillar impact under dynamic load disturbance. Background Art

[0002] Deep mining has become a major trend in the coal mining industry. As mining depth increases, the frequency and energy of rock bursts are also increasing, which has a huge impact on the safe and efficient mining of deep resources. During the mining process, the two return mining tunnels of the longwall working face are arranged along the roof and floor respectively, and the lower end of the working face is arc-shaped. The staggered or overlapping arrangement of the two tunnels will produce a negative coal pillar. The negative coal pillar tunnel is located below the edge of the goaf and can avoid high stress, thereby reducing the risk of rock bursts in the tunnel. In order to solve the problem of frequent rock bursts and serious damage, the use of "negative coal pillars" to prevent rock burst disasters in goaf tunnels has been widely used in rock burst mines. Summary of the Invention

[0003] The purpose of this application is to provide a method for identifying and preventing the danger of negative coal pillar impact under dynamic load disturbance, so as to solve or alleviate the problems existing in the above-mentioned prior art.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] The present application provides a method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance, which is used to identify and prevent the impact hazard of negative coal pillar tunnels. The method includes: step S101, traversing the microseismic monitoring data of the mining area and the direct top and direct bottom areas around the negative coal pillar tunnel under historical dynamic loads to divide the dynamic load space type, and calculating the dynamic load energy coefficient and radial displacement corresponding to each historical dynamic load; step S102, sorting the dynamic load energy coefficients and radial displacements corresponding to all the historical dynamic loads, and based on the sorting results, identifying the impact hazard of the negative coal pillar tunnel according to the minimum dynamic load energy coefficient and the maximum radial displacement.

[0006] Preferably, in step S101, according to the formula:

[0007]

[0008] Determine the dynamic load energy coefficient under the i-th historical dynamic load and the radial displacement u i ;

[0009] Where ρ2 is the density of the broken coal seam corresponding to the negative coal pillar roadway, U i is the dynamic load source energy of the i-th historical dynamic load, i∈I, I is the total number of historical dynamic loads; i and I are both positive integers;

[0010] k m is the energy attenuation index of the dynamic load source energy in the medium; when m=1, k m =k 1 , k 1 is the energy attenuation index of the dynamic load source energy in the roof rock layer or broken coal seam. When m=2, k m =k 2 , k 2 is the energy attenuation index of the dynamic load source energy in the bottom rock layer;

[0011] p u is the support resistance of the U-shaped shed used to support the negative coal pillar roadway, b is the width of the negative coal pillar roadway, u o is the shed distance of the U-shaped shed, p z is the support resistance of the hydraulic support adapted to the U-shaped shed, u z is the distance between two adjacent hydraulic supports along the direction of the negative coal pillar roadway; s is the average displacement of the negative coal pillar roadway,

[0012] is the internal friction angle of the surrounding rock outside the negative coal pillar roadway, G is the shear modulus of the surrounding rock, p0 is the original rock stress corresponding to the negative coal pillar roadway, C is the original rock cohesion corresponding to the negative coal pillar roadway, is the peak dynamic load when the negative coal pillar roadway is subjected to the i-th historical dynamic load.

[0013] Preferably, in response to the dynamic load space being a roof type or a coal seam type, according to the formula:

[0014]

[0015] Determine the peak dynamic load of the negative coal pillar roadway when it is subjected to the i-th historical dynamic load Where A i is the amplitude of the incident wave of the i-th historical dynamic load; k 1 is the energy attenuation index of the dynamic load source energy in the roof rock layer or broken coal seam;

[0016] When j = 1, ρ j =ρ1,E aj =E a1 , ρ1 is the density of the roof rock layer, E a1 is the elastic modulus of the roof rock layer;

[0017] When j = 2, ρ j =ρ2,E aj =E a2 , p2 is the density of the broken coal seam, E a2is the elastic modulus of the broken coal seam.

[0018] Preferably, in response to the dynamic load space being a bottom plate type, according to the formula:

[0019]

[0020] Determine the peak dynamic load of the negative coal pillar roadway when it is subjected to the i-th historical dynamic load Where A i is the amplitude of the incident wave of the i-th historical dynamic load; k 2 is the energy attenuation index of the dynamic load source energy in the bottom rock layer; ρ3 is the density of the bottom rock layer, E a3 is the elastic modulus of the bottom rock layer.

[0021] Preferably, in response to the dynamic load space being a roof type or a coal seam type, according to the formula:

[0022] k 1 =β1r1+β2r2

[0023] Determine the energy attenuation index k of the dynamic load source energy in the roof rock layer or the broken coal seam 1 Wherein, β1 is the attenuation coefficient of the dynamic load source energy in the roof rock layer, β2 is the attenuation coefficient of the dynamic load source energy in the broken coal seam, r1 is the length of the roof rock layer or coal seam section on the line connecting the source point of the historical dynamic load and the negative coal pillar roadway, and r2 is the length of the broken coal seam section on the line connecting the source point and the negative coal pillar roadway;

[0024] In response to the dynamic load space being a bottom plate type, according to the formula:

[0025] k 2 =β3r3

[0026] Determine the energy attenuation index k of the dynamic load source energy in the bottom rock layer 2 Wherein, β3 is the attenuation coefficient of the dynamic load source energy in the bottom rock layer, and r3 is the distance between the source point of the historical dynamic load and the negative coal pillar roadway.

[0027] Preferably, according to the formula:

[0028]

[0029] Calculate the attenuation coefficient β of the dynamic load source energy in the medium j ;

[0030] Among them, when j = 1, β j =β1,ρ j =ρ1,E aj =Ea1 , β1 is the attenuation coefficient of the dynamic load source energy in the roof rock layer; ρ1 is the density of the roof rock layer, E a1 is the elastic modulus of the roof rock layer;

[0031] When j = 2, β j =β2,ρ j =ρ2,E aj =E a2 , β2 is the attenuation coefficient of the dynamic load source energy in the broken coal seam; ρ2 is the density of the broken coal seam, E a2 is the elastic modulus of the broken coal seam;

[0032] When j = 3, β j =β3,ρ j =ρ3,E aj =E a3 , β3 is the attenuation coefficient of the dynamic load source energy in the bottom rock layer; ρ3 is the density of the bottom rock layer, E a3 is the elastic modulus of the bottom rock layer;

[0033] Where f is the frequency of the vibration wave of the dynamic source energy, E v is the stiffness of the structural weak plane of the original rock, η v is the viscosity coefficient of the weak surface of the structure.

[0034] Preferably, in step S102, in response to Or, u max >200, the negative coal pillar roadway has a strong impact risk, then the width of the pressure relief protection zone of the negative coal pillar roadway is increased and the source energy of the negative coal pillar roadway is reduced; wherein, is the minimum dynamic load energy coefficient, u max is the maximum radial displacement.

[0035] Preferably, according to the formula:

[0036]

[0037] Determine the width of the pressure relief protection zone of the negative coal pillar roadway under the influence of the historical dynamic load for the i-th time Where x is the distance from the dynamic load to the negative coal pillar roadway; ρ2 is the density of the broken coal seam, p u is the support resistance of the U-shaped shed used to support the negative coal pillar roadway, b is the width of the negative coal pillar roadway, u o is the shed distance of the U-shaped shed, p z is the support resistance of the hydraulic support adapted to the U-shaped shed, u zis the distance between two adjacent hydraulic supports along the direction of the negative coal pillar roadway; s is the average displacement of the negative coal pillar roadway,

[0038] U i is the dynamic load source energy of the i-th historical dynamic load, i∈I, I is the total number of historical dynamic loads; i and I are both positive integers, β1 is the attenuation coefficient of the shock wave energy in the roof rock layer or coal seam, and β2 is the attenuation coefficient of the shock wave energy in the broken coal seam.

[0039] Beneficial effects:

[0040] The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance provided in the embodiment of the present application is used to identify and prevent the impact hazard of negative coal pillar tunnels. First, the microseismic monitoring data of the mining area and the direct top and direct bottom areas around the negative coal pillar tunnels under historical dynamic loads are traversed to divide the dynamic load space type, and the dynamic load energy coefficient and radial displacement corresponding to each historical dynamic load are calculated; then, the dynamic load energy coefficients and radial displacements corresponding to all historical dynamic loads are sorted, and based on the sorting results, the impact hazard of the negative coal pillar tunnels is identified according to the minimum dynamic load energy coefficient and the maximum radial displacement. Thus, the corresponding dynamic load energy coefficient and radial displacement are calculated according to the dynamic load space type, and the impact hazard of the negative coal pillar tunnels is divided. The impact hazard of the negative coal pillar tunnels under dynamic load disturbance is quickly, accurately and scientifically determined, and targeted pressure relief measures are proposed, which provides theoretical guidance for on-site engineering practice and ensures the safe construction of negative coal pillar tunnels. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings in the specification, which constitute a part of this application, are used to provide further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute improper limitations on this application.

[0042] in:

[0043] Figure 1 A schematic flow chart of a method for identifying and preventing the danger of negative coal pillar impact under dynamic load disturbance provided in accordance with some embodiments of the present application;

[0044] Figure 2 A logic diagram of a method for identifying and preventing the danger of negative coal pillar impact under dynamic load disturbance provided in accordance with some embodiments of the present application;

[0045] Figure 3 Schematic diagram of energy transfer of shock waves in different types of dynamic loading spaces according to some embodiments of the present application. DETAILED DESCRIPTION

[0046] 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 can 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 part of one embodiment can 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 present invention should fall within the scope of protection of the embodiments of the present invention.

[0047] In the existing application of preventing and controlling rock burst disasters in goaf-side tunnels through negative coal pillars, the focus is mainly on how the "negative coal pillar" layout can effectively avoid the peak value of the supporting static load to achieve the effect of rock burst prevention and control. However, there is a lack of analysis and research on the rock burst disasters induced by dynamic loads in negative coal pillar tunnels, making it difficult to accurately prevent and control this type of rock burst.

[0048] Based on this, the embodiment of the present application proposes a method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance, which calculates the corresponding dynamic load energy coefficient and radial displacement according to the dynamic load space type, realizes the division of the impact hazard of negative coal pillar tunnels, and then carries out targeted anti-impact measures on negative coal pillar tunnels according to the division results, ensuring the safety of excavation, protecting the safety of underground personnel, improving production efficiency, and filling the gap in the impact ground pressure mechanism of traditional negative coal pillar tunnels. Figures 1 to 3 As shown, the method for identifying and preventing impact hazards in a negative coal pillar roadway includes:

[0049] Step S101: traverse the microseismic monitoring data of the stope and the immediate roof and immediate bottom areas around the negative coal pillar roadway under historical dynamic loads to classify the dynamic load space type, and calculate the dynamic load energy coefficient and radial displacement corresponding to each historical dynamic load.

[0050] In this application, microseismic monitoring data (historical data) is obtained through the microseismic monitoring system of the mining area (KJ551 microseismic monitoring system or SOS microseismic monitoring system), and the dynamic load space type of the mining area and the direct top area and the direct bottom area of the negative coal pillar roadway are divided according to the microseismic monitoring data (source coordinates, source energy) of the mining area and the direct top area and the direct bottom area of the negative coal pillar roadway under historical dynamic load (large energy microseismic events). Then, the dynamic load space of the roadway is divided into roof type, coal seam type and bottom plate type according to the spatial relationship between the source coordinates, source energy and the spatial position of the roadway. Then, according to different dynamic load space types, the dynamic load energy coefficient and radial displacement (displacement of the roadway induced by mine earthquake) corresponding to each historical dynamic load are calculated. Specifically, according to the formula:

[0051]

[0052] Determine the dynamic load energy coefficient under the i-th historical dynamic load and the radial displacement u i .

[0053] Where ρ2 is the density of the broken coal seam corresponding to the negative coal pillar roadway, U i is the dynamic load source energy of the i-th historical dynamic load, i∈I, I is the total number of historical dynamic loads; i and I are both positive integers; k m is the energy attenuation index of the dynamic load source energy in the medium; when m=1, k m =k 1 , k 1 is the energy attenuation index of the dynamic load source energy in the roof rock layer or broken coal seam. When m=2, k m =k 2 , k 2 is the energy attenuation index of the dynamic load source energy in the bottom rock layer; p u is the support resistance of the U-shaped shed used to support the negative coal pillar roadway, b is the width of the negative coal pillar roadway, u o is the shed distance of the U-shaped shed, p z is the support resistance of the hydraulic support adapted to the U-shaped shed, u z is the distance between two adjacent hydraulic supports along the direction of the negative coal pillar roadway; s is the average displacement of the negative coal pillar roadway, is the internal friction angle of the surrounding rock outside the negative coal pillar roadway, G is the shear modulus of the surrounding rock, p0 is the original rock stress corresponding to the negative coal pillar roadway, C is the original rock cohesion corresponding to the negative coal pillar roadway, is the peak dynamic load when the negative coal pillar roadway is subjected to the i-th historical dynamic load.

[0054] Here, it should be noted that the U-shaped shed and the matching hydraulic support together constitute the support assembly of the negative coal pillar roadway, which is used to support the negative coal pillar roadway to keep the roadway unobstructed and the surrounding rock stable, thereby achieving the purpose of safe production.

[0055] In the roof type dynamic load space type, the propagation path of the shock wave is the earthquake source (roof) - roof rock layer - broken coal seam - negative coal pillar roadway; in the coal seam type dynamic load space type, the propagation path of the shock wave is the coal seam earthquake source - broken coal seam - negative coal pillar roadway. When the dynamic load space is roof type or coal seam type, according to the formula:

[0056]

[0057] Determine the peak dynamic load of the negative coal pillar roadway when it is subjected to the i-th historical dynamic load Where A i is the amplitude of the incident wave of the i-th historical dynamic load; k 1 is the energy attenuation index of the dynamic load source energy in the roof rock layer or broken coal seam; where, when j = 1, ρ j =ρ1,Eaj =E a1 , ρ1 is the density of the roof rock layer, E a1 is the elastic modulus of the roof rock; when j = 2, ρ j =ρ2,E aj =E a2 , ρ2 is the density of the broken coal seam, E a2 is the elastic modulus of the broken coal seam.

[0058] At the same time, according to the formula:

[0059] k 1 =β1r1+β2r2

[0060] Determine the energy attenuation index k of the dynamic load source energy in the roof rock layer or broken coal seam 1 Wherein, β1 is the attenuation coefficient of the dynamic load source energy in the roof rock layer, β2 is the attenuation coefficient of the dynamic load source energy in the broken coal seam, r1 is the length of the roof rock layer or coal seam section on the line connecting the historical dynamic load source point and the negative coal pillar roadway, and r2 is the length of the broken coal seam section on the line connecting the source point and the negative coal pillar roadway.

[0061] In the floor type dynamic load space, the propagation path of the shock wave is floor source-floor rock layer-negative coal pillar roadway. At this time, according to the formula:

[0062]

[0063] Determine the peak dynamic load of the negative coal pillar roadway when it is subjected to the i-th historical dynamic load Where A i is the amplitude of the incident wave of the i-th historical dynamic load; k 2 is the energy attenuation index of the dynamic load source energy in the bottom rock layer; ρ3 is the density of the bottom rock layer, E a3 is the elastic modulus of the bottom rock.

[0064] At the same time, according to the formula:

[0065] k 2 =β3r3

[0066] Determine the energy attenuation index k of the dynamic load source energy in the bottom rock layer 2 Where β3 is the attenuation coefficient of the dynamic load source energy in the floor rock layer, and r3 is the distance between the source point of the historical dynamic load and the negative coal pillar roadway.

[0067] In different types of dynamic load spaces, the transmission paths of shock waves are different, and the energy attenuation of dynamic load source energy along different propagation paths is also different.

[0068]

[0069] Calculate the attenuation coefficient β of the dynamic load source energy in the medium j Where f is the frequency of the vibration wave of the dynamic source energy, E v is the stiffness of the structural weak plane of the original rock, η v is the viscosity coefficient of the weak surface of the structure.

[0070] Among them, when j = 1, β j =β1,ρ j =ρ1,E aj =E a1 , β1 is the attenuation coefficient of the dynamic load source energy in the roof rock layer; ρ1 is the density of the roof rock layer, E a1 is the elastic modulus of the roof rock; when j = 2, β j =β2,ρ j =ρ2,E aj =E a2 , β2 is the attenuation coefficient of the dynamic load source energy in the broken coal seam; ρ2 is the density of the broken coal seam, E a2 is the elastic modulus of the broken coal seam; when j=3, β j =β3,ρ j =ρ3,E aj =E a3 , β3 is the attenuation coefficient of the dynamic load source energy in the bottom rock layer; ρ3 is the density of the bottom rock layer, E a3 is the elastic modulus of the bottom rock.

[0071] Step S102: sort the dynamic load energy coefficients and radial displacements corresponding to all historical dynamic loads, and based on the sorting results, identify the impact hazard of the negative coal pillar roadway according to the minimum dynamic load energy coefficient and the maximum radial displacement.

[0072] After obtaining the dynamic load energy coefficient and radial displacement under each historical dynamic load, the minimum dynamic load energy coefficient is found by sorting I (I is a positive integer) dynamic load energy coefficients and radial displacements respectively. and the maximum radial displacement u max .when Or, u nax >200, the negative coal pillar roadway has a strong impact risk; when And u max When ≤200, the negative coal pillar roadway has a weak impact hazard.

[0073] When it is determined that the negative coal pillar roadway has a strong impact risk, the safety of roadway excavation can be ensured by increasing the width of the pressure relief protection zone of the negative coal pillar roadway, reducing the source energy and increasing the roadway support strength. Among them, according to the formula:

[0074]

[0075] Determine the width of the pressure relief protection zone of the negative coal pillar roadway under the influence of the i-th historical dynamic load The calculated I pressure relief protection zone widths are traversed to obtain the maximum pressure relief protection zone width, which is used as the construction width to reduce the impact hazard of the negative coal pillar roadway.

[0076] Where x is the distance from the dynamic load to the negative coal pillar roadway; ρ2 is the density of the broken coal seam, p u is the support resistance of the U-shaped shed used to support the negative coal pillar roadway, b is the width of the negative coal pillar roadway, u o is the shed distance of the U-shaped shed, p z is the support resistance of the hydraulic support adapted to the U-shaped shed, u z is the distance between two adjacent hydraulic supports along the direction of the negative coal pillar roadway; s is the average displacement of the negative coal pillar roadway, U i is the dynamic load source energy of the i-th historical dynamic load, i∈I, I is the total number of historical dynamic loads; i and I are both positive integers, β1 is the attenuation coefficient of the shock wave energy in the roof rock layer or coal seam, and β2 is the attenuation coefficient of the shock wave energy in the broken coal seam.

[0077] By means of large-diameter pressure relief drilling and other measures, the width of the pressure relief zone on the production side of the roadway is increased to the theoretically calculated pressure relief protection zone width. It is recommended to increase the above to 1.2 times to allow for some margin of error. A specific measure to reduce earthquake source energy is roof pre-splitting blasting. Measures to strengthen roadway support strength include reducing the spacing between U-shaped sheds and hydraulic supports, adding U-shaped shed frame anti-collapse structures, and selecting U-shaped sheds and hydraulic supports with better support effectiveness. When a negative coal pillar roadway is determined to pose a risk of impact, a combination of hydraulic supports and U-shaped sheds can be used for combined support.

[0078] Therefore, the corresponding dynamic load energy coefficient and radial displacement are calculated according to the dynamic load space type, and the impact hazard of the negative coal pillar roadway is divided. The impact hazard of the negative coal pillar roadway under dynamic load disturbance is quickly, accurately and scientifically determined, and targeted pressure relief measures are proposed, which provides theoretical guidance for the actual on-site engineering and ensures the safe construction of the negative coal pillar roadway.

[0079] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0080] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0081] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0082] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0083] In the present invention, the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" 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 suitable manner in any one or more embodiments or examples.

[0084] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance, characterized in that: For identifying and preventing impact hazards in negative coal pillar tunnels, the method includes: Step S101: traverse the microseismic monitoring data of the stope and the immediate roof and immediate bottom areas around the negative coal pillar roadway under historical dynamic loads to classify the dynamic load space type, and calculate the dynamic load energy coefficient and radial displacement corresponding to each historical dynamic load; Step S102: sorting the dynamic load energy coefficients and radial displacements corresponding to all the historical dynamic loads, and based on the sorting results, identifying the impact hazard of the negative coal pillar roadway according to the minimum dynamic load energy coefficient and the maximum radial displacement.

2. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 1 is characterized in that: In step S101, According to the formula: ； Determine the The dynamic load energy coefficient under the historical dynamic load and the radial displacement ; Where, is the density of the broken coal seam corresponding to the negative coal pillar roadway, For the The dynamic source energy of the historical dynamic load is , is the total amount of the historical dynamic loads; are all positive integers; is the energy attenuation index of the dynamic load source energy in the medium; hour, , is the energy attenuation index of the dynamic load source energy in the roof rock layer or broken coal seam, hour, , is the energy attenuation index of the dynamic load source energy in the bottom rock layer; is the support resistance of the U-shaped shed used to support the negative coal pillar roadway, is the width of the negative coal pillar roadway, is the shed distance of the U-shaped shed, is the support resistance of the hydraulic support adapted to the U-shaped shed, is the distance between two adjacent hydraulic supports along the direction of the negative coal pillar roadway; is the average displacement of the negative coal pillar roadway, is the internal friction angle of the surrounding rock outside the negative coal pillar roadway, is the shear modulus of the surrounding rock, is the original rock stress corresponding to the negative coal pillar roadway, is the original rock cohesion corresponding to the negative coal pillar roadway, The negative coal pillar roadway is affected by the The peak dynamic load during the historical dynamic load mentioned above.

3. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 2 is characterized in that: In response to whether the dynamic load space is a roof type or a coal seam type, according to the formula: ； Determine the negative coal pillar roadway is affected by the Peak dynamic load at the time of the historical dynamic load Where, For the The amplitude of the incident wave of the historical dynamic load; is the energy attenuation index of the dynamic load source energy in the roof rock layer or broken coal seam; in, hour, , , is the density of the roof rock layer, is the elastic modulus of the roof rock layer; hour, , , is the density of the broken coal seam, is the elastic modulus of the broken coal seam.

4. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 2 is characterized in that: In response to the dynamic load space being a bottom plate type, according to the formula: ； Determine the negative coal pillar roadway is affected by the Peak dynamic load at the time of the historical dynamic load Where, For the The amplitude of the incident wave of the historical dynamic load; is the energy attenuation index of the dynamic load source energy in the bottom rock layer; is the density of the floor rock layer, is the elastic modulus of the bottom rock layer.

5. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 2 is characterized in that: In response to whether the dynamic load space is a roof type or a coal seam type, according to the formula: ； Determine the energy attenuation index of the dynamic load source energy in the roof rock layer or the broken coal seam Where, is the attenuation coefficient of the dynamic load source energy in the roof rock layer, is the attenuation coefficient of the dynamic load source energy in the broken coal seam, is the length of the roof rock layer or coal seam section on the line connecting the earthquake source point of the historical dynamic load and the negative coal pillar roadway, is the length of the broken coal seam section on the line connecting the earthquake source point and the negative coal pillar roadway; In response to the dynamic load space being a bottom plate type, according to the formula: ； Determine the energy attenuation index of the dynamic load source energy in the bottom rock layer Where, is the attenuation coefficient of the dynamic load source energy in the bottom rock layer, is the distance between the earthquake source point of the historical dynamic load and the negative coal pillar roadway.

6. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 5 is characterized in that: According to the formula: ； Calculate the attenuation coefficient of the dynamic load source energy in the medium ; in, hour, , , , is the attenuation coefficient of the dynamic load source energy in the roof rock layer; is the density of the roof rock layer, is the elastic modulus of the roof rock layer; hour, , , , is the attenuation coefficient of the dynamic load source energy in the broken coal seam; is the density of the broken coal seam, is the elastic modulus of the broken coal seam; hour, , , , is the attenuation coefficient of the dynamic load source energy in the bottom rock layer; is the density of the floor rock layer, is the elastic modulus of the bottom rock layer; Where, is the vibration wave frequency of the dynamic source energy, is the stiffness of the structural weak plane of the original rock, is the viscosity coefficient of the weak surface of the structure.

7. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 1 is characterized in that: In step S102, In response to ,or, , the negative coal pillar roadway has a strong impact risk, then the width of the pressure relief protection zone of the negative coal pillar roadway is increased and the source energy of the negative coal pillar roadway is reduced; wherein, is the minimum dynamic load energy coefficient, is the maximum radial displacement.

8. The method for identifying and preventing the impact hazard of negative coal pillars under dynamic load disturbance according to claim 7 is characterized in that: According to the formula: ； Determine the The width of the pressure relief protection zone of the negative coal pillar roadway under the influence of the historical dynamic load Where, is the distance from the dynamic load to the negative coal pillar roadway; is the density of the broken coal seam corresponding to the negative coal pillar roadway, is the support resistance of the U-shaped shed used to support the negative coal pillar roadway, is the width of the negative coal pillar roadway, is the shed distance of the U-shaped shed, is the support resistance of the hydraulic support adapted to the U-shaped shed, is the distance between two adjacent hydraulic supports along the direction of the negative coal pillar roadway; is the average displacement of the negative coal pillar roadway, For the The dynamic source energy of the historical dynamic load is , is the total amount of the historical dynamic loads; are all positive integers, is the attenuation coefficient of the shock wave energy in the roof rock layer or coal seam, is the attenuation coefficient of shock wave energy in the broken coal seam.

Images