A classification collaborative blasting pressure relief method based on stress distribution characteristics of coal pillar

Abstract

The application discloses a kind of classification collaborative blasting pressure relief methods based on coal pillar bearing stress distribution characteristics, first, coal pillar occurrence data and microseismic monitoring data are collected, then the lateral support pressure influence range of coal pillar is calculated and obtained, and then the relationship between the lateral support pressure superposition distribution characteristics of coal pillar and the width of coal pillar is considered comprehensively along the inclination direction of coal pillar to divide the type of coal pillar bearing stress curve; according to different curve types, the pressure relief parameters of different bearing stress distribution characteristics in the coal pillar area are formulated, and the reinforced pressure relief range in front of the coal wall is determined, and finally the pressure relief construction is carried out according to different curve types, so as to realize the classification collaborative blasting pressure relief in the coal pillar area. Through this method, the roof and coal pillar of the coal seam with rock burst can be classified and cooperatively relieved, the bearing efficiency of the coal pillar area is effectively improved, the risk of rock burst caused by insufficient or excessive pressure relief is reduced, and the stability of the roadway and the maximization of the pressure relief effect are improved.

Description

Technical Field

[0001] This invention relates to the field of pressure relief technology for coal pillar areas in rockburst-prone coal seams, and in particular to a classified and coordinated blasting pressure relief method based on the stress distribution characteristics of the coal pillar. Background Technology

[0002] Dynamic instantaneous failure of coal pillars is a common manifestation of rockburst disasters in un-mined coal seams prone to rock bursts, causing widespread damage to roadways, destruction of equipment and instruments at the working face, and even casualties, resulting in huge losses to coal mines. Current research indicates that the roof in un-mined working faces is the dynamic load source, and the coal pillars, as load-bearing bodies, often accumulate a large amount of elastic energy. Therefore, the roof and coal pillars should be the key targets for stress relief in preventing rockburst disasters caused by coal pillars. However, current research lacks a systematic analysis of the stress characteristics of coal pillars during the un-mining phase. The stress relief schemes in the coal pillar area are randomly combined, often resulting in isolated stress relief effects, leading to insufficient stress relief or excessive stress relief that causes the coal pillar to lose its load-bearing capacity. How to conduct targeted stress relief of the roof and coal pillars in un-mined working faces based on the stress distribution characteristics of the coal pillars, and improve the stress relief effect of the coal pillar area, has become the key to the safe mining of coal seams prone to rock bursts. Therefore, this invention proposes a classified and coordinated blasting stress relief method based on the distribution characteristics of coal pillar bearing stress. It comprehensively considers the distribution characteristics of coal pillar bearing stress in different sections, classifies and formulates pre-splitting blasting schemes for the roof of the coal pillar area and blasting stress relief schemes for the coal body, and coordinates the changes in the dynamic load source and energy carrier structure of the coal pillar area, thereby solving the shortcomings of the existing technology. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides a classified and coordinated blasting decompression method based on the stress distribution characteristics of coal pillars. This method can classify and formulate roof pre-splitting blasting and coal body blasting decompression schemes according to the stress distribution characteristics of the coal pillars, thereby coordinating decompression of the roof and coal pillars in the near-hole mining of coal seams prone to rockbursts. This improves the bearing capacity of the coal pillar area, reduces the risk of rockbursts caused by insufficient or excessive decompression, and is of great significance for improving roadway stability and maximizing decompression effect.

[0004] To achieve the above objectives, the technical solution adopted by this invention is: a classification-based coordinated blasting stress relief method based on the distribution characteristics of coal pillar bearing stress, the specific steps of which are as follows:

[0005] Step 1: Collect coal pillar occurrence data and microseismic monitoring data;

[0006] Step 2: Calculate the influence range of lateral support pressure based on the coal pillar occurrence data obtained in Step 1;

[0007] Step 3: Determine the superimposed distribution characteristics of the lateral support pressure of the coal pillar based on the influence range of the lateral support pressure in Step 2. Then, based on the relationship between the superimposed distribution characteristics of the lateral support pressure of the coal pillar and the width of the coal pillar, classify the bearing stress curve types of the coal pillar along the dip direction of the coal pillar. The bearing stress curve types include Class I, II, III, and IV.

[0008] Step 4: Based on the coal pillar bearing stress curve types identified in Step 3, formulate roof pre-splitting blasting and coal body blasting decompression parameters with different bearing stress distribution characteristics.

[0009] Step 5: Based on the microseismic monitoring data during the longwall mining process, determine the range for enhanced pressure relief in front of the coal face;

[0010] Step Six: Based on the data obtained in Steps Three and Four, classify and depressurize the coal pillar area: When the bearing stress curve of the coal pillar area is Class I, II, or IV, construct roof pre-splitting blasting combined with coal body blasting depressurization according to the parameters determined in Step Four; when the bearing stress curve of the coal pillar area is Class III, first construct roof pre-splitting blasting and coal body blasting for pre-depressurization according to the parameters determined in Step Four, and then construct coal body blasting to strengthen depressurization within the depressurization range determined in Step Five; thus completing the classified and coordinated blasting depressurization based on the bearing stress distribution characteristics of the coal pillar.

[0011] Furthermore, the coal pillar occurrence data in step one includes working face mining data and coal and rock strata parameters.

[0012] Furthermore, the specific calculation process for the influence range of the lateral support pressure in step two is as follows:

[0013] The distance from the peak lateral support pressure to the coal face is obtained according to formula (1):

[0014]

[0015] Where M is the coal seam thickness; μ is the friction coefficient between coal and rock layers; γ is the internal friction angle of the coal seam; k is the stress concentration factor; γ is the average unit weight of the overburden; H is the coal seam mining depth; N0 is the vertical support force of the coal wall.

[0016] Calculate the lateral support pressure σ in the elastic zone of the coal pillar. H :

[0017]

[0018] Where λ is the lateral pressure coefficient;

[0019] When σ H When γH = γH, the influence range L1 of the lateral support pressure is calculated as shown in equation (3):

[0020]

[0021] Furthermore, the specific process of step three is as follows:

[0022] If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is less than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be that the lateral support pressures are not superimposed. In this case, the peak value of the support pressures on both sides of the coal pillar is k1γH. Taking k1 = 3, the bearing stress in the middle of the coal pillar is the original rock stress, i.e., σ H =γH, the bearing stress curve of the coal pillar is bimodal, and is denoted as the Class I bearing stress curve;

[0023] If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be superimposed lateral support pressures. In this case, the peak value of the support pressures on both sides of the coal pillar is k2γH, and k2 = 3.5 is taken. The bearing stress σ in the middle of the coal pillar is... H ∈(γH,0.5k2γH], the bearing stress curve of the coal pillar is saddle-shaped, and is denoted as the Class II bearing stress curve;

[0024] If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be superimposed lateral support pressures. In this case, the peak value of the support pressures on both sides of the coal pillar is k3γH, and k3 = 4 is taken. The bearing stress σ in the middle of the coal pillar is... H ∈(0.5k3γH,k3γH], the coal pillar bearing stress curve is plateau shaped, and is denoted as Class III bearing stress curve;

[0025] If the sum of the influence ranges of the support pressure on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, the superposition distribution characteristic of the lateral support pressure of the coal pillar is determined to be the superposition of lateral support pressure. At this time, the bearing stress in the middle of the coal pillar is the largest, with a peak value of k4γH. Taking k4≥5, the bearing stress curve of the coal pillar is unimodal, which is denoted as the Class IV bearing stress curve.

[0026] Furthermore, the specific process of step four is as follows:

[0027] When the bearing stress curve is Class I or II: pre-stress relief is carried out by combining roof pre-splitting blasting with coal body blasting; the roof pre-splitting blasting holes are 75mm in diameter, arranged in pairs, with the final hole positions reaching the top and middle of the immediate roof stratum respectively, and the charge is forward-directed, with the charge length being 1 / 2 of the blasting hole depth and the charge amount being 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in pairs, with a hole depth of L1, a charge length of L1 / 2, and a charge amount of 0.75kg / m;

[0028] When the bearing stress curve is Class III: The following method is adopted: pre-splitting blasting of the roof combined with pre-decompression blasting of the coal body, followed by enhanced decompression blasting of the coal body; the pre-splitting blasting holes of the roof are 75mm in diameter, arranged in three holes, with the final hole positions reaching the top of the immediate roof stratum, 2 / 3 of the thickness of the immediate roof stratum, and 1 / 3 of the thickness of the immediate roof stratum, respectively; the charge is forward-directed, with a charge length of 1 / 2 of the blasting hole depth and a charge amount of 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in three holes, with a hole depth of W / 2, a charge length of W / 4, and a charge amount of 0.75kg / m.

[0029] When the bearing stress curve is Class IV: pre-decompression is carried out by combining roof pre-splitting blasting with coal body blasting; the roof pre-splitting blasting holes are 75mm in diameter, arranged in three holes, with the final hole positions reaching the top of the immediate roof stratum, 2 / 3 of the thickness of the immediate roof stratum, and 1 / 3 of the thickness of the immediate roof stratum, respectively, with forward charging, the charge length being 1 / 3 of the blasting hole depth, and the charge amount being 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in three holes, with a hole depth of W / 2, a charge length of W / 4, and a charge amount of 0.75kg / m.

[0030] Furthermore, the specific process for determining the enhanced pressure relief range in front of the coal face in step five is as follows:

[0031] Starting from the advancing position on the m-th day of working face recovery, the working face position is fixed, and the advancing depth of the working face on the n-th day is l. mn Assume that the i-th microseismic event Q occurs on day n. i The three-dimensional coordinates are (x i y i , z i If the i-th microseismic event on the nth day is Q, then... i Relative coordinates (X) i Y i Z i ) is represented as:

[0032]

[0033] Where α is the working face advance angle; β is the angle between the projection of the working face direction onto the horizontal plane and the x-axis;

[0034] If the range L of the statistical microseismic data relative to the advancing position of the working face is in the higher range in front of the coal face, then the range 0 to L in front of the coal face is the enhanced pressure relief range of the working face. The process of determining the range L in the higher range is as follows: using the maximum microseismic energy and frequency behind the already mined area of ​​the working face as the standard, microseismic monitoring is carried out in front of the working face. If the microseismic energy and frequency are lower than and no longer exceed this standard after a distance L in front of the working face, then the range 0 to L in front of the working face is regarded as the higher range of microseismic data.

[0035] Furthermore, in step six, when the bearing stress curve of the coal pillar area is Class III, the roof pre-splitting blasting and coal body blasting are carried out first to pre-depressurize according to the parameters determined in step four, and then coal body blasting is carried out in the range of 0 to L in front of the coal wall to strengthen the depressurization.

[0036] Compared with existing technologies, this invention first collects coal pillar occurrence data and microseismic monitoring data, then calculates the influence range of the lateral support pressure of the coal pillar, and further considers the relationship between the superimposed distribution characteristics of the lateral support pressure and the width of the coal pillar to classify the bearing stress curve type of the coal pillar along the dip direction. Based on different curve types, pressure relief parameters are formulated for different bearing stress distribution characteristics in the coal pillar area, and the range for enhanced pressure relief in front of the coal wall is determined. Finally, pressure relief construction is carried out according to different curve types, thereby achieving classified and coordinated blasting pressure relief in the coal pillar area. This method enables classified and coordinated pressure relief of the roof and coal pillar in the un-mined coal seam prone to rockburst, effectively improving the bearing capacity of the coal pillar area and reducing the risk of rockburst danger caused by insufficient or excessive pressure relief. It is of great significance for improving roadway stability and maximizing pressure relief effect. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of the process of the present invention;

[0038] Figure 2 This is a schematic diagram showing the distribution of bearing stress curves for coal pillars of different widths in this invention;

[0039] Figure 3 This is a cross-sectional layout diagram of the coal pillar in the working face section, as demonstrated in the experiment.

[0040] Figure 4 A schematic diagram of the drilling layout for pre-splitting blasting of the roof and pressure relief blasting of the coal seam is provided for experimental verification.

[0041] Figure 5 A schematic diagram illustrating the relative locations of micro-seismic events as demonstrated in experiments;

[0042] Figure 6 This is a schematic diagram illustrating the enhanced pressure relief range in front of the coal face for experimental verification.

[0043] Figure 7 This is a schematic diagram illustrating the changes in microseismic data during the period of classified and coordinated pressure relief using the present invention in experimental demonstration.

[0044] Figure 8 This is a schematic diagram illustrating the roadway deformation during the classified and coordinated decompression period when the present invention was used in the experimental demonstration. Detailed Implementation

[0045] The present invention will be further described below.

[0046] like Figure 1As shown, the specific steps of the present invention are as follows:

[0047] Step 1: Collect coal pillar occurrence data and microseismic monitoring data; the coal pillar occurrence data includes working face mining data and coal and rock strata parameters.

[0048] Step 2: Calculate the influence range of lateral support pressure based on the coal pillar occurrence data obtained in Step 1. The specific calculation process is as follows:

[0049] The distance from the peak lateral support pressure to the coal face is obtained according to formula (1):

[0050]

[0051] Where M is the coal seam thickness; μ is the friction coefficient between coal and rock layers; γ is the internal friction angle of the coal seam; k is the stress concentration factor; γ is the average unit weight of the overburden; H is the coal seam mining depth; N0 is the vertical support force of the coal wall.

[0052] Calculate the lateral support pressure σ in the elastic zone of the coal pillar. H :

[0053]

[0054] Where λ is the lateral pressure coefficient;

[0055] When σ H When γH = γH, the influence range L1 of the lateral support pressure is calculated as shown in equation (3):

[0056]

[0057] Step 3: Determine the superimposed distribution characteristics of the lateral support pressure of the coal pillar based on the influence range of the lateral support pressure in Step 2. Then, based on the relationship between the superimposed distribution characteristics of the lateral support pressure and the width of the coal pillar, classify the bearing stress curve types of the coal pillar along the dip direction. The bearing stress curve types include types I, II, III, and IV. The specific process is as follows:

[0058] If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is less than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be that the lateral support pressures are not superimposed. In this case, the peak value of the support pressures on both sides of the coal pillar is k1γH. Taking k1 = 3, the bearing stress in the middle of the coal pillar is the original rock stress, i.e., σ H =γH, the bearing stress curve of the coal pillar is bimodal, and is denoted as the Class I bearing stress curve;

[0059] If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be superimposed lateral support pressures. In this case, the peak value of the support pressures on both sides of the coal pillar is k2γH, and k2 = 3.5 is taken. The bearing stress σ in the middle of the coal pillar is...H ∈(γH,0.5k2γH], the bearing stress curve of the coal pillar is saddle-shaped, and is denoted as the Class II bearing stress curve;

[0060] If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be superimposed lateral support pressures. In this case, the peak value of the support pressures on both sides of the coal pillar is k3γH, and k3 = 4 is taken. The bearing stress σ in the middle of the coal pillar is... H ∈(0.5k3γH,k3γH], the coal pillar bearing stress curve is plateau shaped, and is denoted as Class III bearing stress curve;

[0061] If the sum of the influence ranges of the support pressure on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, the superposition distribution characteristic of the lateral support pressure of the coal pillar is determined to be the superposition of lateral support pressure. At this time, the bearing stress in the middle of the coal pillar is the largest, with a peak value of k4γH. Taking k4≥5, the bearing stress curve of the coal pillar is unimodal, which is denoted as the Class IV bearing stress curve.

[0062] Step 4: Based on the coal pillar bearing stress curve types identified in Step 3, formulate roof pre-splitting blasting and coal body blasting stress relief parameters with different bearing stress distribution characteristics. The specific process is as follows:

[0063] When the bearing stress curve is Class I or II: pre-stress relief is carried out by combining roof pre-splitting blasting with coal body blasting; the roof pre-splitting blasting holes are 75mm in diameter, arranged in pairs, with the final hole positions reaching the top and middle of the immediate roof stratum respectively, and the charge is forward-directed, with the charge length being 1 / 2 of the blasting hole depth and the charge amount being 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in pairs, with a hole depth of L1, a charge length of L1 / 2, and a charge amount of 0.75kg / m;

[0064] When the bearing stress curve is Class III: The following method is adopted: pre-splitting blasting of the roof combined with pre-decompression blasting of the coal body, followed by enhanced decompression blasting of the coal body; the pre-splitting blasting holes of the roof are 75mm in diameter, arranged in three holes, with the final hole positions reaching the top of the immediate roof stratum, 2 / 3 of the thickness of the immediate roof stratum, and 1 / 3 of the thickness of the immediate roof stratum, respectively; the charge is forward-directed, with a charge length of 1 / 2 of the blasting hole depth and a charge amount of 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in three holes, with a hole depth of W / 2, a charge length of W / 4, and a charge amount of 0.75kg / m.

[0065] When the bearing stress curve is Class IV: pre-decompression is carried out by combining roof pre-splitting blasting with coal body blasting; the roof pre-splitting blasting holes are 75mm in diameter, arranged in three holes, with the final hole positions reaching the top of the immediate roof stratum, 2 / 3 of the thickness of the immediate roof stratum, and 1 / 3 of the thickness of the immediate roof stratum, respectively, with forward charging, the charge length being 1 / 3 of the blasting hole depth, and the charge amount being 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in three holes, with a hole depth of W / 2, a charge length of W / 4, and a charge amount of 0.75kg / m.

[0066] Step 5: Based on the microseismic monitoring data during the longwall mining process, determine the enhanced pressure relief range in front of the coal face. The specific process is as follows:

[0067] Starting from the advancing position on the m-th day of working face recovery, the working face position is fixed, and the advancing depth of the working face on the n-th day is l. mn Assume that the i-th microseismic event Q occurs on day n. i The three-dimensional coordinates are (x i y i , z i If the i-th microseismic event on the nth day is Q, then... i Relative coordinates (X) i Y i Z i ) is represented as:

[0068]

[0069] Where α is the working face advance angle; β is the angle between the projection of the working face direction onto the horizontal plane and the x-axis;

[0070] If the range L of the statistical microseismic data relative to the advancing position of the working face is in a higher range in front of the coal face, then the area from 0 to L in front of the coal face is considered the enhanced pressure relief range of the working face. The process for determining the range L in the higher range is as follows: using the maximum microseismic energy and frequency behind the already mined area of ​​the working face as a standard, microseismic monitoring is conducted in front of the working face. If the microseismic energy and frequency are lower than and do not exceed this standard after a distance L in front of the working face, then the range from 0 to L in front of the working face is considered the higher range of microseismic data.

[0071] Step Six: Based on the data obtained in Steps Three and Four, classify and depressurize the coal pillar area: When the bearing stress curve of the coal pillar area is Class I, II, or IV, construct roof pre-splitting blasting combined with coal body blasting depressurization according to the parameters determined in Step Four; when the bearing stress curve of the coal pillar area is Class III, first construct roof pre-splitting blasting and coal body blasting for pre-depressurization according to the parameters determined in Step Four, and then construct coal body blasting in the 0-L range in front of the coal wall to strengthen depressurization; thus completing the classified and coordinated blasting depressurization based on the bearing stress distribution characteristics of the coal pillar.

[0072] Experiments have shown that:

[0073] The method of this invention was tested on the 150403 working face of a mine in Gansu Province. One side of this working face consists of an irregular section of coal pillars, with a width ranging from 12 to 30 meters, gradually decreasing along the strike of the working face. During the mining process, high-energy micro-vibration events frequently occurred on the side of the coal pillars, resulting in large deformations in the roadways and a high risk of impact. The placement of the coal pillars in the section is as follows: Figure 2 As shown.

[0074] The stress distribution characteristics of a coal pillar are related to the coal seam occurrence conditions. This method obtains coal pillar occurrence data based on mine exploration results and calculates the lateral support pressure distribution range on both sides of the coal pillar. The coal pillar occurrence data is shown in Table 1.

[0075] Table 1

[0076]

[0077] According to equation (1), the distance from the peak lateral support pressure to the coal wall is:

[0078]

[0079] According to equation (3), the range of influence of lateral support pressure is:

[0080]

[0081] Based on the coal pillar occurrence in the mine, with a pillar width W = 30m, and assuming the lateral support pressure of the coal pillar decreases approximately linearly, the lateral support pressure at the middle of the coal pillar is approximately 0.75k3γH∈(0.5k3γH, k3γH]. Therefore, the bearing stress curve of the coal pillar is plateau-shaped, i.e., a Class III bearing stress curve. Figure 3 As shown;

[0082] Based on the stress distribution characteristics of the coal pillar, a stress relief scheme for the coal pillar area is formulated as shown in Table 2. Figure 4 As shown:

[0083] Table 2

[0084]

[0085] The absolute and relative positions of the microseismic data and the working face are as follows: Figure 5 As shown. Based on the working face recovery data, the working face advancement angle α = 0°, and the angle between the projection of the working face advancement direction onto the horizontal plane and the x-axis is 30°. The distribution of microseismic data relative to the working face position is obtained as follows. Figure 6 As shown, the working face reinforcement and pressure relief range L = 340m is thus determined.

[0086] Microseismic and roadway deformation monitoring methods were used to collect microseismic and roadway deformation data before, during, and after classified coordinated blasting for depressurization in a certain mine, as shown in Table 3. Figure 7 and Figure 8 As shown.

[0087] Based on microseismic monitoring data from conventional decompression zones and classified coordinated blasting decompression zones, the total microseismic energy during working face decompression decreased from 1.18 × 10⁻⁶ before decompression. 6 J decreased to 1.09 × 10 6 J decreased by 7.8%, and the total micro-seismic energy in the coal pillar area after depressurization decreased from 1.09 × 10⁻⁶ during depressurization. 6 J decreased to 9.9 × 10 5 The decrease in J increased to 9.2%; the frequency of micro-vibrations during the working face depressurization decreased from 36 before depressurization to 33, a decrease of approximately 8.3%, and after depressurization, the frequency of micro-vibrations decreased from 33 during depressurization to 22, a decrease of 33.3%. The average roof subsidence during depressurization decreased from 410mm before depressurization to 316mm, a decrease of 22.9%, and after depressurization, the average roof subsidence decreased from 316mm during depressurization to 182mm, a decrease of 42.4%; the average sidewall deformation during depressurization decreased from 1182mm before depressurization to 840mm, a decrease of 28.9%, and after depressurization, the average sidewall deformation decreased from 840mm before depressurization to 414mm, a decrease of 50.7%.

[0088] Table 3

[0089]

[0090] The above data shows that the stress level of the surrounding rock in the working face was effectively reduced after the classification and coordinated decompression of the present invention, which greatly reduced the amount of roadway maintenance, improved roadway stability, and significantly reduced the risk of coal pillar impact in the section; thus proving the decompression effect of the present invention.

[0091] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A classification-based coordinated blasting stress relief method based on the stress distribution characteristics of coal pillars, characterized in that, The specific steps are as follows: Step 1: Collect coal pillar occurrence data and microseismic monitoring data; Step 2: Calculate the influence range of lateral support pressure based on the coal pillar occurrence data obtained in Step 1; Step 3: Determine the superimposed distribution characteristics of the lateral support pressure of the coal pillar based on the influence range of the lateral support pressure in Step 2. Then, based on the relationship between the superimposed distribution characteristics of the lateral support pressure of the coal pillar and the width of the coal pillar, classify the bearing stress curve types of the coal pillar along the dip direction of the coal pillar. The bearing stress curve types include Class I, II, III, and IV. Step 4: Based on the coal pillar bearing stress curve types identified in Step 3, formulate roof pre-splitting blasting and coal body blasting decompression parameters with different bearing stress distribution characteristics. Step 5: Based on the microseismic monitoring data during the longwall mining process, determine the range for enhanced pressure relief in front of the coal face; Step Six: Based on the data obtained in Steps Three and Four, classify and depressurize the coal pillar area: When the bearing stress curve of the coal pillar area is Class I, II, or IV, construct roof pre-splitting blasting combined with coal body blasting depressurization according to the parameters determined in Step Four; when the bearing stress curve of the coal pillar area is Class III, first construct roof pre-splitting blasting and coal body blasting for pre-depressurization according to the parameters determined in Step Four, and then construct coal body blasting for enhanced depressurization within the enhanced depressurization range determined in Step Five; thus completing the classified and coordinated blasting depressurization based on the bearing stress distribution characteristics of the coal pillar.

2. The classification-based coordinated blasting stress relief method based on the stress distribution characteristics of coal pillars according to claim 1, characterized in that, The coal pillar occurrence data in step one includes working face mining data and coal and rock strata parameters.

3. The classification-based coordinated blasting stress relief method based on the stress distribution characteristics of coal pillars according to claim 1, characterized in that, The specific calculation process for the lateral support pressure influence range in step two is as follows: The distance L0 from the peak lateral support pressure to the coal wall is obtained according to formula (1): （1） Where M is the coal seam thickness; μ is the friction coefficient between coal and rock layers; φ0 is the internal friction angle of the coal; k is the stress concentration factor; γ is the average unit weight of the overburden; H is the coal seam mining depth; and N0 is the vertical support force of the coal wall. Calculate the lateral support pressure σ in the elastic zone of the coal pillar. H : （2） Where λ is the lateral pressure coefficient; When σ H When γH = γH, the influence range L1 of the lateral support pressure is calculated as shown in equation (3): （3）。 4. The classification-based coordinated blasting stress relief method based on the stress distribution characteristics of coal pillars according to claim 1, characterized in that, The specific process of step three is as follows: If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is less than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures is determined to be that the lateral support pressures are not superimposed. In this case, if the peak value of the support pressures on both sides of the coal pillar is k1γH, and k1=3 is taken, the bearing stress in the middle of the coal pillar is the original rock stress, i.e., σ H =γH, if the bearing stress curve of the coal pillar is bimodal, it is denoted as a Class I bearing stress curve; If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures of the coal pillar is determined to be superimposed lateral support pressures. In this case, if the peak value of the support pressures on both sides of the coal pillar is k2γH, and k2 = 3.5 is taken, then the bearing stress σ in the middle of the coal pillar... H If the bearing stress curve of the coal pillar is saddle-shaped, it is denoted as a Class II bearing stress curve; If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, then the superimposed distribution characteristic of the lateral support pressures on the coal pillar is determined to be superimposed lateral support pressures. In this case, if the peak value of the support pressures on both sides of the coal pillar is k3γH, and k3 = 4, then the bearing stress σ in the middle of the coal pillar is... H If the bearing stress curve of the coal pillar is plateau-shaped, it is denoted as a Class III bearing stress curve; If the sum of the influence ranges of the support pressures on both sides of the coal pillar, 2L1, is greater than the width W of the coal pillar, the superposition distribution characteristics of the lateral support pressures of the coal pillar are determined to be superposition of lateral support pressures. At this time, if the bearing stress in the middle of the coal pillar is the largest, with a peak value of k4γH, and k4≥5 is taken, the bearing stress curve of the coal pillar is unimodal, then it is recorded as a Class IV bearing stress curve.

5. The classification-based coordinated blasting stress relief method based on the stress distribution characteristics of coal pillars according to claim 1, characterized in that, The specific process of step four is as follows: When the bearing stress curve is Class I or II: Decompression is achieved by combining roof pre-splitting blasting with coal body blasting; the roof pre-splitting blasting holes are 75mm in diameter, arranged in pairs, with the final hole positions reaching the top and middle of the immediate roof stratum respectively, using forward charging, with a charge length of 1 / 2 the blasting hole depth and a charge amount of 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in pairs, with a hole depth of L1, a charge length of L1 / 2, and a charge amount of 0.75kg / m. When the bearing stress curve is Class III: The following method is adopted: pre-splitting blasting of the roof combined with pre-decompression blasting of the coal body, followed by enhanced decompression blasting of the coal body; the pre-splitting blasting holes of the roof are 75mm in diameter, arranged in three holes, with the final hole positions reaching the top of the immediate roof stratum, 2 / 3 of the thickness of the immediate roof stratum, and 1 / 3 of the thickness of the immediate roof stratum, respectively; the charge is forward-directed, with a charge length of 1 / 2 of the blasting hole depth and a charge amount of 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in three holes, with a hole depth of W / 2, a charge length of W / 4, and a charge amount of 0.75kg / m. When the bearing stress curve is Class IV: pressure relief is achieved by combining roof pre-splitting blasting with coal body blasting; the roof pre-splitting blasting holes are 75mm in diameter, arranged in three holes, with the final hole positions reaching the top of the immediate roof stratum, 2 / 3 of the thickness of the immediate roof stratum, and 1 / 3 of the thickness of the immediate roof stratum, respectively, with forward charging, the charge length being 1 / 3 of the blasting hole depth, and the charge amount being 3kg / m; the coal body blasting holes are 75mm in diameter, arranged in three holes, with a hole depth of W / 2, a charge length of W / 4, and a charge amount of 0.75kg / m.

6. The classification-based coordinated blasting stress relief method based on the stress distribution characteristics of coal pillars according to claim 1, characterized in that, The specific process for determining the enhanced pressure relief range in front of the coal face in step five is as follows: Starting from the advancing position on the m-th day of working face recovery, the working face position is fixed, and the advancing depth of the working face on the n-th day is l. mn Assume that the i-th microseismic event Q occurs on day n. i The three-dimensional coordinates are (x i y i , z i Then, the i-th micro-seismic event Q on the nth day... i Relative coordinates (X) i Y i Z i ) is represented as: （4） Where α is the working face advance angle; β is the angle between the projection of the working face direction onto the horizontal plane and the x-axis; The range L of the statistical microseismic data relative to the advancing position of the working face in front of the coal face is in a relatively high range. The specific determination process is as follows: using the maximum microseismic energy and frequency behind the already mined area of ​​the working face as the standard, microseismic monitoring is carried out in front of the working face. If the microseismic energy and frequency are lower than and no longer exceed this standard after a distance L in front of the working face, then the range 0~L in front of the working face is regarded as the higher range of microseismic data, which is the range of enhanced pressure relief of the working face.

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