A method for actively inducing deep impact by superimposing blast-induced seismic waves.

Abstract

A method for actively inducing deep rockbursts by superimposing blast-induced seismic waves is disclosed. First, the deep location of the coal and rock mass requiring active rockburst induction is determined, and multiple blasting points are selected based on geological conditions and working face mining conditions. Then, the distance between each blasting point and the active rockburst induction location is calculated. Based on the calculated distances, the propagation time of the blast-induced seismic waves from each blasting point to the active rockburst induction location is calculated, and the detonation time of each blasting point is then determined. Simultaneously, the peak particle velocity of the blast-induced seismic waves from each blasting point to the active rockburst induction location is calculated. Based on the superposition characteristics of signals in a linear system, the peak particle velocity of the blast-induced seismic waves from all blasting points to the active rockburst induction location is calculated, and the explosive charge at each blasting point is determined. This method achieves active induction of deep rockbursts in coal and rock masses, effectively relieves pressure in high-stress areas deep within the coal and rock mass, and provides reasonable and comprehensive prevention of rockbursts, meeting the needs of safe underground mining.

Description

Technical Field

[0001] This invention relates to a method for actively inducing deep impact by superimposing blasting-induced seismic waves, belonging to the field of coal mine safety mining technology. Background Technology

[0002] Rockburst is a dynamic phenomenon characterized by the instantaneous collapse of coal and rock masses, releasing a large amount of elastic energy. Its immense destructive power poses a significant threat to safe underground mining, necessitating corresponding measures for prevention and control to ensure normal and safe coal mine production. Extensive practical experience shows that preventing rockburst essentially involves controlling the stress state of the coal and rock mass or reducing the generation of high stress within it. Local mitigation methods such as coal seam decompression blasting and roof blasting have been widely adopted in most rockburst-prone mines and have achieved good results.

[0003] However, for high-stress areas located deep within coal and rock masses, due to their distance from roadways, drilling is difficult to reach them. The current method of using only deep-hole blasting cannot effectively relieve pressure and cannot meet the needs of safe underground mining. Summary of the Invention

[0004] The purpose of this invention is to provide a method for actively inducing deep impact by superimposing blasting-induced seismic waves. This method can overcome the drawback that single deep-hole blasting cannot induce deep impact in coal and rock masses, effectively relieve pressure in high-stress areas deep within coal and rock masses, and more rationally and comprehensively prevent and control rockburst, thus meeting the needs of safe underground mining.

[0005] To achieve the above objectives, the present invention provides a method for actively inducing deep impact by superimposing explosive-induced seismic waves, comprising the following steps:

[0006] (1) Determine the deep location L0(x0,y0,z0) of the coal and rock mass where active impact needs to be induced, and select multiple suitable blasting points L based on geological conditions and working face mining conditions. i ((x i ,y i ,z i );

[0007] (2) Calculate the distance r between each blast point and the location of the active induced impact. i The calculation formula is as follows:

[0008]

[0009] (3) Calculate the propagation time t of the shock wave generated at each blast point to the location of the active induced impact. i The calculation formula is as follows:

[0010]

[0011] In the formula, v is the propagation speed of the vibration wave, with the unit being m / s;

[0012] (4) Calculate the detonation time t at each blasting point. i The calculation formula is as follows:

[0013] t i =T i -t i ',

[0014] In the formula, T i The moment when the shock wave generated by the blasting at each blasting point propagates to the actively induced impact location;

[0015] (5) Calculate the peak particle velocity A of the vibration wave generated at each explosion point propagating to the actively induced impact location. i The calculation formula is as follows:

[0016]

[0017] In the formula, A i Q represents the peak velocity of the particles propelled by the shock wave generated at each explosion point to the actively induced impact location, expressed in cm / s; i The charge amount at each blasting point, in kg; r i α represents the distance between each blast point and the location of the active induced impact, in meters; k is the blasting medium coefficient; α is the blast attenuation index.

[0018] (6) Calculate the peak particle velocity A of the vibration wave generated at all explosion points propagating to the actively induced impact location based on the superposition characteristics of signals in a linear system. s And according to A s ≥A c The final amount of explosives at each blasting point is determined using the following formula:

[0019]

[0020] In the formula, n is the number of detonation points; A c The critical particle vibration velocity that causes new cracks to form in rocks.

[0021] Further, the steps for determining the active induced impact location L0(x0,y0,z0) in step (1) are as follows: First, the deep stress concentration area in front of the working face is determined by spatial prediction of the impact hazard area, such as seismic wave CT inversion, active CT inversion or impact deformation energy evolution; then, the active induced impact location L0(x0,y0,z0) that needs to be actively induced is determined.

[0022] Furthermore, in step (4), the detonation time t at each detonation point... i The calculation method is as follows: according to the formula Calculate the propagation time t of the shock wave generated at each blast point to the actively induced impact location. i Taking the blasting point furthest from the actively induced impact location as the first blasting point, and denoting its detonation time as t1, the time it takes for the shock wave generated by each blasting point to propagate to the actively induced impact location is T = T1 = t1 + t1', and thus the detonation time t of each blasting point is... i It can be obtained through formula t i =Tt i 'Calculation; In step (4), the shock waves generated by the blasting at each blasting point propagate to the actively induced impact position at the same time, that is, T1 = T2 = ... = T n .

[0023] Further, in step (5), the values ​​of the blasting medium coefficient k are as follows: when the blasting zone is hard rock, k is 50-150; when the blasting zone is medium-hard rock, k is 150-250; when the blasting zone is soft rock, k is 250-350; the range of the blasting attenuation index α is as follows: when the blasting zone is hard rock, α is 1.3-1.5; when the blasting zone is medium-hard rock, α is 1.5-1.8; when the blasting zone is soft rock, α is 1.8-2.0; wherein, the method for classifying the hardness of rock is as follows: hard rock has a hardness coefficient f greater than 6; medium-hard rock has a hardness coefficient f between 3 and 6; soft rock has a hardness coefficient f less than 3; and the formula for calculating the hardness coefficient f is as follows:

[0024]

[0025] In the formula, R c It represents the uniaxial compressive strength of the rock.

[0026] Furthermore, in step (6), A c The value of A is: when the area where the active-induced impact occurs is hard rock. c =70cm / s; when the area where the active-induced impact occurs is medium-hard rock, A c =60cm / s; when the area where the actively induced impact occurs is soft rock, A c = 40cm / s.

[0027] This invention first determines the deep location of the coal and rock mass where active rockburst needs to be induced, and selects multiple suitable blasting points based on geological conditions and working face mining conditions. Then, it calculates the distance between each blasting point and the active rockburst induced location. Based on the calculated distances, it calculates the propagation time of the vibration waves generated at each blasting point to the active rockburst induced location, and subsequently calculates the detonation time of each blasting point. Simultaneously, it calculates the peak particle velocity of the vibration waves generated at each blasting point propagating to the active rockburst induced location, and based on the superposition characteristics of signals in a linear system, calculates the peak particle velocity of the vibration waves generated at all blasting points propagating to the active rockburst induced location, determining the explosive charge at each blasting point. Through these methods, the location of each blasting point, the detonation time, and the explosive charge are finally obtained, achieving active induction of rockburst in the deep coal and rock mass, effectively reducing the stress state within its range, achieving effective pressure relief in the high-stress area of ​​the deep coal and rock mass, and providing reasonable and comprehensive prevention and control of rockburst, meeting the needs of safe underground mining. This method is simple, convenient, and highly operable. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the present invention;

[0029] Figure 2 This is a schematic diagram of the superposition of blast-induced shock waves in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the spatial distribution of impact deformation energy and the arrangement of blast holes in an embodiment of the present invention. Detailed Implementation

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] like Figure 1 As shown, a method for actively inducing deep impact by superimposing blast-induced seismic waves includes the following steps:

[0033] (1) Determine the deep location L0(x0,y0,z0) of the coal and rock mass where active impact needs to be induced, and select multiple suitable blasting points L based on geological conditions and working face mining conditions. i (x i ,y i ,z i );

[0034] (2) Calculate the distance r between each blast point and the location of the active induced impact. i The calculation formula is as follows:

[0035]

[0036] (3) Calculate the propagation time t of the shock wave generated at each blast point to the location of the active induced impact. i The calculation formula is as follows:

[0037]

[0038] In the formula, v is the propagation speed of the vibration wave, with the unit being m / s;

[0039] (4) Calculate the detonation time t at each blasting point. i The calculation formula is as follows:

[0040] t i =T i -t i ',

[0041] In the formula, T i The moment when the shock wave generated by the blasting at each blasting point propagates to the actively induced impact location;

[0042] (5) Calculate the peak particle velocity A of the vibration wave generated at each explosion point propagating to the actively induced impact location. i The calculation formula is as follows:

[0043]

[0044] In the formula, A i Q represents the peak velocity of the particles propelled by the shock wave generated at each explosion point to the actively induced impact location, expressed in cm / s; i The charge amount at each blasting point, in kg; r i α represents the distance between each blast point and the location of the active induced impact, in meters; k is the blasting medium coefficient; α is the blast attenuation index.

[0045] (6) Calculate the peak particle velocity A of the vibration wave generated at all explosion points propagating to the actively induced impact location based on the superposition characteristics of signals in a linear system. s And according to A s ≥A c The final amount of explosives at each blasting point is determined using the following formula:

[0046]

[0047] In the formula, n is the number of detonation points; A c The critical particle vibration velocity that causes new cracks to form in rocks.

[0048] As a preferred embodiment, the step of determining the active induced impact location L0(x0,y0,z0) in step (1) is as follows: First, the deep stress concentration area in front of the working face is determined by the method of spatial prediction of the impact hazard area, such as seismic wave CT inversion, active CT inversion or impact deformation energy evolution; then, the active induced impact location L0(x0,y0,z0) that needs to be actively induced is determined.

[0049] In a preferred embodiment, in step (4), the detonation time t at each detonation point is... i The calculation method is as follows: according to the formula Calculate the propagation time t of the shock wave generated at each blast point to the actively induced impact location. i Taking the blasting point furthest from the actively induced impact location as the first blasting point, and denoting its detonation time as t1, the time it takes for the shock wave generated by each blasting point to propagate to the actively induced impact location is T = T1 = t1 + t1', and thus the detonation time t of each blasting point is... i It can be obtained through formula t i =Tt i 'Calculation; In step (4), the shock waves generated by the blasting at each blasting point propagate to the actively induced impact position at the same time, that is, T1 = T2 = ... = T n .

[0050] In a preferred embodiment, in step (5), the blasting medium coefficient k is taken as follows: when the blasting zone is hard rock, k is 50-150; when the blasting zone is medium-hard rock, k is 150-250; when the blasting zone is soft rock, k is 250-350; the blasting attenuation index α is taken as follows: when the blasting zone is hard rock, α is 1.3-1.5; when the blasting zone is medium-hard rock, α is 1.5-1.8; when the blasting zone is soft rock, α is 1.8-2.0; wherein, the method for classifying the hardness of rock is as follows: hard rock has a hardness coefficient f greater than 6; medium-hard rock has a hardness coefficient f between 3 and 6; soft rock has a hardness coefficient f less than 3; the formula for calculating the hardness coefficient f is:

[0051]

[0052] In the formula, R c It represents the uniaxial compressive strength of the rock.

[0053] In a preferred embodiment, in step (6), A c The value of A is: when the area where the active-induced impact occurs is hard rock. c =70cm / s; when the area where the active-induced impact occurs is medium-hard rock, A c =60cm / s; when the area where the actively induced impact occurs is soft rock, A c = 40cm / s.

[0054] Example:

[0055] This implementation case study describes the active induction of deep impact through superimposed blasting-induced seismic waves at the 7302 working face of a certain mine. The specific steps are as follows:

[0056] (1) Microseismic data from April 13, 2022 to April 20, 2022 were selected from the 7302 working face. Using impact deformation energy spatial detection technology, two stress concentration areas ahead of the working face were identified, such as... Figure 2 As shown;

[0057] In this area, the traditional blasting decompression method is used in area B, while the active induced shock decompression method of the present invention is used in area A. According to the mining engineering plan and the slice layer, the center position of area A is determined to be: L0 (20400592.96, 3916180.57, -812), located on the top of the coal seam.

[0058] (2) Figure 3 As shown, a row of blasting holes, 70m deep, 20m apart, and at an inclination angle of 20°, are drilled 170m ahead of the working face in both the transport roadway and the return air roadway. The opening positions of each blasting hole are listed in Table 1, and the closing positions of each blasting hole are listed in Table 2.

[0059] Table 1: Coordinates of the opening locations of each blast hole

[0060]

[0061]

[0062] Table 2: Coordinates of the final hole location for each blasting hole

[0063]

[0064] (3) Taking the final hole of each blasting hole as the blasting point, the distance of each blasting point from the center of area A can be calculated by the following formula:

[0065]

[0066] The calculated values ​​are r1, r2, ..., r 12 The m and r values ​​are 60.56m, 47.97m, 41.86m, 44.69m, 55.30m, 70.37m, 68.31m, 58.59m, 55.10m, 58.52m, 68.13m, and 82.02m respectively. Therefore, r... 12 The maximum value is L. 12 The location furthest from the center of area A is designated as the detonation point L. 12 As the first detonation point, its detonation time is set at time zero, i.e., t. 12 =0;

[0067] (4) Calculate the propagation time t of the shock wave generated at each blast point to the location of the active induced impact. i The calculation formula is as follows:

[0068]

[0069] In the formula, v is the propagation speed of the vibration wave, taken as 4100 m / s; t1', t2', ..., t are calculated. 12 The times are 14.77ms, 11.70ms, 10.21ms, 10.90ms, 13.49ms, 17.16ms, 16.66ms, 14.29ms, 13.44ms, 14.27ms, 16.62ms, and 20.00ms respectively; the time T = T_0.00 is obtained when the shock wave from each explosion point propagates to the actively induced impact location. 12 =t 12 +t 12 = 20ms;

[0070] (5) Calculate the detonation time t of each of the other blasting points. i The calculation formula is as follows:

[0071] t i =T i -t i '=Tt i ',

[0072] In the formula, T i The time it takes for the shock waves generated by each blast point to propagate to the actively induced impact location is calculated as t1, t2, ..., t 11 The durations are 5.23ms, 8.30ms, 9.79ms, 9.10ms, 6.51ms, 2.84ms, 3.34ms, 5.71ms, 6.56ms, 5.73ms, and 3.38ms respectively; that is, from the explosion point L1 to L... 11 In L respectively 12 The detonation occurred 5.23ms, 8.30ms, 9.79ms, 9.10ms, 6.51ms, 2.84ms, 3.34ms, 5.71ms, 6.56ms, 5.73ms, and 3.38ms later to ensure that the 12 detonation points propagate to area A at the same time.

[0073] (6) The uniaxial compressive strength of the roof in area A is 42.5 MPa, and its firmness coefficient is 4.25, classifying it as medium-hard rock. Therefore, the blasting medium coefficient k is taken as 200, and the blasting attenuation index α is taken as 1.5. Substituting these values ​​into the following formula, the peak particle velocity A of the vibration wave generated at each blasting point propagating to the actively induced impact position is calculated. i :

[0074] Right now

[0075] In the formula, Q iThe charge amount at each blasting point is in kg.

[0076] (7) Calculate the peak particle velocity A of the vibration wave generated at all explosion points propagating to the actively induced impact location based on the superposition characteristics of signals in a linear system. s And A is required s With a speed >60cm / s, the explosive charge at each blasting point was finally determined using the following formula:

[0077] but Solving for Q, we get Q = 113.98 kg.

Claims

1. A method for actively inducing deep impact by superimposing blast-induced seismic waves, characterized in that, Includes the following steps: (1) Determine the deep location of the coal and rock mass where active impact induction is required. Multiple blasting points were selected based on geological conditions and mining conditions at the working face. ; (2) Calculate the distance between each blasting point and the location of the active induced impact. The calculation formula is as follows: ； (3) Calculate the propagation time of the shock wave generated at each blast point to the location of the active induced impact. The calculation formula is as follows: ， In the formula, v The speed of propagation of vibration waves is expressed in m / s. (4) Calculate the detonation time at each blasting point. t i The calculation formula is as follows: ， In the formula, T i The moment when the shock wave generated by the blasting at each blasting point propagates to the actively induced impact location; (5) Calculate the peak velocity of the particles from the vibration wave generated at each blast point to the actively induced impact location. A i The calculation formula is as follows: ， In the formula, The peak velocity of the particles as the shock wave generated at each explosion point propagates to the actively induced impact location, in cm / s; The charge amount at each blasting point is in kg. The distance between each blast point and the location of the actively induced impact is expressed in meters (m). The coefficient of the blasting medium; The blast attenuation index; (6) Calculate the peak particle velocity of the vibration wave generated at all explosion points propagating to the actively induced impact position based on the superposition characteristics of signals in a linear system. A s and according to The final amount of explosives at each blasting point is determined using the following formula: In the formula, n The number of detonation points; A c The critical particle vibration velocity that causes new cracks to form in rocks.

2. The method for actively inducing deep impact by superimposing blast-induced seismic waves according to claim 1, characterized in that, In step (1), the impact location is actively induced. The determination steps are as follows: First, the deep stress concentration area in front of the working face is determined by spatial prediction of the impact hazard area; then, the location of the active induced impact that needs to be actively induced is determined. .

3. The method for actively inducing deep impact by superimposing blast-induced seismic waves according to claim 1, characterized in that, In step (4), the detonation time of each blasting point t i The calculation method is as follows: according to the formula Calculate the propagation time of the shock wave generated at each blast point to the actively induced impact location. The detonation point furthest from the actively induced impact location is designated as the first detonation point, and its detonation time is recorded as _____. t 1. The time when the shock wave generated at each blast point propagates to the actively induced impact location. Therefore, the detonation time at each blasting point t i Through formula Calculation; in step (4), the shock waves generated by the blasting at each blasting point propagate to the actively induced impact position at the same time, that is .

4. The method for actively inducing deep impact by superimposing blast-induced seismic waves according to claim 1, characterized in that, In step (5), the blasting medium coefficient k The value of is: when the blasting zone is hard rock, k Take 50~150; when the blasting zone is medium-hard rock, k Take 150~250; when the blasting zone is soft rock, k Take 250~350; blast attenuation index α The value range is: when the blasting zone is hard rock, α Take 1.3~1.5; when the blasting zone is medium-hard rock, α Take a value of 1.5~1.8; when the blasting zone is soft rock, α The value is taken as 1.8~2.0; whereby, the method for classifying the rock hardness is: firmness coefficient. f Rocks with a strength coefficient greater than 6 are considered hard rocks; f Rocks with a hardness coefficient between 3 and 6 are considered medium-hard; f Rocks with a strength coefficient less than 3 are considered soft rocks. f The calculation formula is: ， In the formula, R c It represents the uniaxial compressive strength of the rock.

5. The method for actively inducing deep impact by superimposing blast-induced seismic waves according to claim 1, characterized in that, In step (6), A c The value is: when the area where the actively induced impact is located is hard rock. A c =70cm / s; When the area where the impact is actively induced is medium-hard rock. A c =60cm / s; When the area where the impact is actively induced is soft rock. A c =40cm / s.

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