Determination method for pre-splitting blasting pressure relief parameters of thick coal seam roadway roof

Abstract

The invention discloses a thick coal seam roadway roof presplitting blasting pressure relief parameter determination method which comprises the following steps: constructing a test system, and collecting stress distribution, sound wave propagation characteristics and blasting energy release values of roof strata through a geological stress monitoring device, a sound wave detector and a blasting energy analyzer; changing the explosive load, repeatedly testing for at least 15 times, and fitting a relation function between the stress value, the sound wave speed value and the energy release value and the explosive load; and carrying out coupling analysis by taking the stress relation function as a benchmark to obtain an optimal pressure relief parameter. The optimal pressure relief parameters of the thick coal seam roadway roof can be scientifically and reasonably determined, the roof pressure is effectively released, roadway deformation or collapse is avoided, and the method is suitable for complex geological conditions and has high practicability and popularization value.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mine exploitation and strata control, and particularly relates to a method for determining pre-splitting blasting pressure relief parameters of a thick coal seam roadway roof. BACKGROUND

[0002] With the continuous progress of coal mining technology, the mining efficiency of thick coal seam roadway has been significantly improved. However, in the process of mining thick coal seam roadway, the control of roof pressure becomes one of the key technical problems. The roof strata is prone to stress concentration under the influence of mining, and if pressure relief measures are not taken in time, it may lead to roof collapse or roadway deformation. In order to effectively release the roof pressure, pre-splitting blasting technology is widely used in the pressure relief treatment of roadway roof. However, for different geological conditions and roadway parameters, how to scientifically determine the pressure relief parameters of pre-splitting blasting still has certain challenges. The existing parameter determination methods mostly rely on empirical formula or simple simulation, which may have the problem of insufficient adaptability under complex geological conditions, resulting in that the pressure relief effect is difficult to reach the ideal state. SUMMARY

[0003] The purpose of the present application is to provide a method for determining pre-splitting blasting pressure relief parameters of a thick coal seam roadway roof, which solves the problems mentioned in the background.

[0004] The application is implemented by a method for determining roof pre-splitting blasting pressure relief parameters in thick coal seam roadway, comprising the following steps: constructing a test system, the test system comprising a geological stress monitoring device, a sound wave detector and a blasting energy analyzer, a pressure sensor in the geological stress monitoring device being embedded in the rock stratum inside the roadway roof, a probe of the sound wave detector being installed outside the pressure sensor, a signal receiver of the blasting energy analyzer being horizontally aligned with the probe of the sound wave detector, the geological stress monitoring device and the sound wave detector being used for real-time collection of stress distribution and sound wave propagation characteristics of the roof rock stratum; recording an initial stress value of the roof rock stratum measured by the geological stress monitoring device, a sound wave propagation speed value measured by the sound wave detector and a blasting energy release value measured by the blasting energy analyzer respectively; changing the charge amount of the blasting hole, and recording the stress value of the roof rock stratum measured by the geological stress monitoring device, the sound wave propagation speed value measured by the sound wave detector and the blasting energy release value measured by the blasting energy analyzer again respectively; repeating several times, fitting out a first relationship function of the stress value of the roof rock stratum measured by the geological stress monitoring device and the charge amount, a second relationship function of the sound wave propagation speed value measured by the sound wave detector and the charge amount and a third relationship function of the blasting energy release value measured by the blasting energy analyzer and the charge amount according to the measured stress value, sound wave propagation speed value and blasting energy release value respectively; taking the first relationship function as a reference, obtaining the optimal pressure relief parameters of the roof rock stratum by coupling analysis of the first relationship function, the second relationship function and the third relationship function. The number of repetitions is at least 15 times. The repeating steps include three cases, which are gradually increasing the charge amount, gradually reducing the charge amount or alternating the charge amount. The depth of the pressure sensor embedded in the roof rock stratum is between 1 / 3 and 1 / 2 of the thickness of the rock stratum. The probe of the sound wave detector is fixedly installed at the center position of the surface of the roof rock stratum. The adjustment amount is 5% of the total designed charge amount when changing the charge amount.

[0005] The specific implementation of the above technical solution is as follows: first, a test hole is drilled in the rock stratum of the roadway roof, the diameter of the test hole is 50mm, the depth is 1 / 2 of the thickness of the rock stratum, and the axis of the test hole is perpendicular to the plane of the roadway roof. The pressure sensor of the geological stress monitoring device is fixed to the bottom of the test hole by epoxy resin glue, ensuring that the sensor is in close contact with the rock stratum. Then, the probe of the sound wave detector is installed outside the test hole, the probe is adsorbed to the surface of the roof rock stratum by a magnetic fixing bracket, and is horizontally aligned with the axis of the test hole. The signal receiver of the blasting energy analyzer is fixed on the sidewall of the roadway by bolts, and its receiving surface faces the direction of the probe of the sound wave detector, ensuring the stability of signal reception.

[0006] During the test, the initial stress value of the roof stratum measured by the geological stress monitoring device, the sound wave propagation speed value measured by the sound wave detector and the blasting energy release value measured by the blasting energy analyzer are recorded in the initial state. Then, the explosives with the designed charge amount are filled in the blasting hole, and the measurement values of the above three devices are recorded again after detonation. When the charge amount is changed each time, it is adjusted according to 5% of the total designed charge amount until all tests are completed. The specific value of each charge amount and the corresponding measurement data need to be recorded during the test for subsequent analysis.

[0007] In the data analysis stage, first, the first relationship function curve is drawn according to the relationship between the stress value of the roof stratum measured by the geological stress monitoring device and the charge amount. The curve reflects the trend of the stress of the roof stratum changing with the charge amount. Second, the second relationship function curve is drawn according to the relationship between the sound wave propagation speed value measured by the sound wave detector and the charge amount. The curve reflects the trend of the sound wave propagation speed changing with the charge amount. Finally, the third relationship function curve is drawn according to the relationship between the blasting energy release value measured by the blasting energy analyzer and the charge amount. The curve reflects the trend of the blasting energy release value changing with the charge amount.

[0008] In the coupling analysis stage, the first relationship function is taken as the benchmark, and the first relationship function, the second relationship function and the third relationship function are comprehensively analyzed. The specific method is: first, the correlation coefficient of the first relationship function and the second relationship function is calculated to determine the correlation between the two; then the correlation coefficient of the first relationship function and the third relationship function is calculated to further verify the synergy between the three; finally, the three are coupled through a mathematical model to obtain the optimal pressure relief parameters of the roof stratum. The parameters include the optimal charge amount, the optimal blasting hole spacing and the optimal blasting hole depth.

[0009] The technical effects produced by the above technical scheme are: the present application builds a test system by designing a thick coal seam roadway roof pre-splitting blasting pressure relief parameter determination method, tests the blasting of the roof stratum with different charge amounts, the geological stress monitoring device and the sound wave detector in the test system real-time collect the stress distribution and sound wave propagation characteristics of the roof stratum, and the blasting energy analyzer is used to evaluate the blasting energy release. After testing multiple groups of data, the first relationship function of the stress value of the roof stratum measured by the geological stress monitoring device and the charge amount, the second relationship function of the sound wave propagation speed value measured by the sound wave detector and the charge amount, and the third relationship function of the blasting energy release value measured by the blasting energy analyzer and the charge amount are fitted. Then, taking the first relationship function as the benchmark, the first relationship function, the second relationship function and the third relationship function are coupled and analyzed to obtain the optimal pressure relief parameters of the roof stratum. The pressure relief parameters determined by this method can effectively release the roof pressure, avoid roof collapse or roadway deformation, and are suitable for thick coal seam roadway mining under complex geological conditions.

[0010] The pressure sensor of the geological stress monitoring device is embedded in the inside of the roof rock stratum, which ensures the accuracy and reliability of the stress data; the installation mode of the probe of the acoustic wave detector and the pressure sensor being horizontally aligned ensures the accurate measurement of the sound wave propagation characteristics; the signal receiver of the blasting energy analyzer is aligned with the direction of the probe of the acoustic wave detector, which further improves the measurement accuracy of the blasting energy release value. In addition, by gradually adjusting the charge amount and repeatedly testing, combined with fitting analysis of multiple groups of data, the finally obtained pressure relief parameters are more scientific and reasonable, and have high practicality and popularization value. DETAILED DESCRIPTION

[0011] The present application relates to a kind of thick coal seam roadway roof pre-splitting blasting pressure relief parameter determination method, and its specific implementation mode is as follows. First, test hole is drilled in the inside of the rock stratum of roadway roof, the diameter of test hole is 50mm, depth is 1 / 2 of rock stratum thickness, the axis of test hole is perpendicular to the plane of roadway roof. The position of test hole should be as close to roadway central region as possible and avoid known complex geological structure area to ensure the accuracy of data acquisition. Subsequently, the pressure sensor of geological stress monitoring device is fixed to the bottom of test hole by epoxy resin glue, and the depth of pressure sensor embedded in roof rock stratum is between 1 / 3 and 1 / 2 of rock stratum thickness, to ensure that sensor is in close contact with rock stratum to obtain accurate stress data. After the installation of pressure sensor is completed, the probe of acoustic wave detector is installed outside test hole, the probe is adsorbed on the surface of roof rock stratum by magnetic fixing support and installed at the center position of the surface of roof rock stratum, and the installation direction of probe needs to be horizontally aligned with pressure sensor to ensure the accurate measurement of sound wave propagation characteristics. Then the signal receiver of blasting energy analyzer is fixed on the sidewall of roadway by bolt, the receiving surface of signal receiver faces the direction of probe of acoustic wave detector, and signal receiver is horizontally aligned with probe of acoustic wave detector to improve the measurement accuracy of blasting energy release value. The installation position and connection relationship of the above-mentioned equipment ensure that the test system can collect the stress distribution of roof rock stratum, sound wave propagation characteristics and blasting energy release condition in real time.

[0012] After the test system is set up, data collection begins. The initial stress value of the roof stratum measured by the geological stress monitoring device, the sound wave propagation speed value measured by the sound wave detector, and the blasting energy release value measured by the blasting energy analyzer are recorded in the initial state. These initial data serve as the baseline values for subsequent data analysis. Then, explosives with the designed charge amount are loaded into the blasting hole, and after detonation, the measurement values of the above three devices are recorded again. Each time the charge amount is changed, it is adjusted by 5% of the total designed charge amount, and the adjustment methods include gradually increasing the charge amount, gradually reducing the charge amount, or alternating the charge amount. After each adjustment, the stress value of the roof stratum measured by the geological stress monitoring device, the sound wave propagation speed value measured by the sound wave detector, and the blasting energy release value measured by the blasting energy analyzer are recorded again. During the test, the specific values of each charge amount and the corresponding measurement data are recorded for subsequent analysis. The entire test process is repeated at least 15 times to ensure the sufficiency and reliability of the data.

[0013] After data collection is complete, the data analysis phase begins. First, a first relationship function curve is drawn based on the relationship between the stress value of the roof stratum measured by the geological stress monitoring device and the charge amount. This curve reflects the trend of the stress of the roof stratum changing with the charge amount. Second, a second relationship function curve is drawn based on the relationship between the sound wave propagation speed value measured by the sound wave detector and the charge amount. This curve reflects the trend of the sound wave propagation speed changing with the charge amount. Finally, a third relationship function curve is drawn based on the relationship between the blasting energy release value measured by the blasting energy analyzer and the charge amount. This curve reflects the trend of the blasting energy release value changing with the charge amount. When drawing each relationship function curve, the least squares method is used for data fitting to improve the accuracy of the curve. After fitting, the specific expressions of the first relationship function, the second relationship function, and the third relationship function are obtained.

[0014] In the coupling analysis stage, the first relationship function, the second relationship function, and the third relationship function are analyzed comprehensively based on the first relationship function. The specific method is to first calculate the correlation coefficient between the first relationship function and the second relationship function to determine the correlation between the two, and then calculate the correlation coefficient between the first relationship function and the third relationship function to further verify the synergy between the three. The Pearson correlation coefficient formula is used to calculate the correlation coefficient to ensure the scientificity of the results. Finally, the three are coupled through a mathematical model to obtain the optimal pressure relief parameters of the roof stratum. This mathematical model uses multivariate regression analysis method combined with actual geological conditions to set constraints to ensure the rationality of the final parameters. The optimal pressure relief parameters include the optimal charge amount, the optimal blasting hole spacing, and the optimal blasting hole depth, which can effectively release the roof pressure to avoid roof collapse or roadway deformation.

[0015] It is necessary to pay attention to the installation depth and fixing method of the pressure sensor during the whole implementation process, which directly affects the accuracy of stress data, so it must be strictly operated according to the design requirements. The installation position and direction of the probe of the acoustic wave detector need to be horizontally aligned with the pressure sensor to ensure the accurate measurement of the acoustic wave propagation characteristics. The direction alignment of the signal receiver of the blasting energy analyzer with the probe of the acoustic wave detector and the fixing stability of the signal receiver also need to be paid special attention to improve the measurement accuracy of the blasting energy release value. In addition, the adjustment amount of each charge amount during the test process is 5% of the total designed charge amount, which can ensure the continuity of the data and avoid the data deviation caused by the large adjustment amplitude. The requirement of at least 15 repeated tests ensures the sufficiency and reliability of the data, thereby providing a solid foundation for subsequent analysis.

[0016] In practical application, the method of the present application is suitable for thick coal seam roadway mining under complex geological conditions. For example, in the thick coal seam roadway of a certain coal mine, there is a risk of roadway deformation and roof collapse due to the large pressure of the roof rock layer. By using the method of the present application, first, a test hole is drilled in the rock layer of the roadway roof, and the geological stress monitoring device, the acoustic wave detector and the blasting energy analyzer are installed in place according to the foregoing method. Then, a plurality of blasting tests with different charge amounts are carried out to record the stress value, acoustic wave propagation speed value and blasting energy release value of each test. Through data analysis and coupling analysis, the optimal pressure relief parameters of the roadway roof are finally obtained, including the optimal charge amount of 1.5 kg per meter of blasting hole, the optimal blasting hole spacing of 1.2 m, and the optimal blasting hole depth of 1 / 2 of the rock layer thickness. The application of these parameters significantly reduces the roof pressure and improves the stability of the roadway, providing a strong guarantee for the safe and efficient mining of the coal mine.

[0017] In order to better enable the relevant persons in the technical field to fully understand and implement the present application, the specific implementation principles of the present application are further described below in conjunction with a specific application scenario.

[0018] In the actual mining of a thick coal seam roadway in a certain coal mine, due to the large roof strata pressure and complex geological conditions, there is a risk of roadway deformation and roof collapse. In order to solve this problem, according to the technical scheme of the present application, first, a test hole is drilled in the roof strata of the roadway. The diameter of the test hole is 50mm, the depth is 1 / 2 of the thickness of the strata, and the axis is perpendicular to the plane of the roof of the roadway. The position of the test hole is selected close to the center area of the roadway and avoids the area with complex geological structure to ensure the accuracy of data collection. Then, the pressure sensor of the geological stress monitoring device is embedded at the bottom of the test hole, the embedding depth is between 1 / 3 and 1 / 2 of the thickness of the strata, and the sensor is fixed with epoxy resin to ensure that the sensor is in close contact with the strata, so that the stress distribution data of the roof strata can be accurately obtained. At the same time, the probe of the acoustic wave detector is installed outside the test hole, the probe is adsorbed on the surface of the roof strata by a magnetic fixing bracket, and is horizontally aligned with the pressure sensor to ensure accurate measurement of the acoustic wave propagation characteristics. Then, the signal receiver of the blasting energy analyzer is fixed on the side wall of the roadway by bolts, the receiving surface faces the direction of the probe of the acoustic wave detector, and is horizontally aligned with the probe to improve the measurement accuracy of the blasting energy release value.

[0019] After the test system is completed, data collection begins. In the initial state, the initial stress value of the roof strata measured by the geological stress monitoring device, the acoustic wave propagation speed value measured by the acoustic wave detector, and the blasting energy release value measured by the blasting energy analyzer are recorded, which are used as the baseline values for subsequent analysis. Then, the designed amount of explosive is loaded into the blasting hole and detonated, and the measurement values of the above three devices are recorded again. Each time the charge amount is adjusted, the change is 5% of the total designed charge amount, and the adjustment method includes gradually increasing the charge amount, gradually reducing the charge amount, or alternating the charge amount. After each adjustment, the measurement data is recorded again, and the specific value of each charge amount and its corresponding measurement result are recorded. The whole test process is repeated at least 15 times to ensure the sufficiency and reliability of the data.

[0020] In the data analysis stage, a first relationship function curve is drawn according to the relationship between the stress value of the roof strata measured by the geological stress monitoring device and the charge amount, which reflects the trend of the stress of the roof strata changing with the charge amount. At the same time, a second relationship function curve is drawn according to the relationship between the acoustic wave propagation speed value measured by the acoustic wave detector and the charge amount, which reflects the trend of the acoustic wave propagation speed changing with the charge amount. In addition, a third relationship function curve is drawn according to the relationship between the blasting energy release value measured by the blasting energy analyzer and the charge amount, which reflects the trend of the blasting energy release value changing with the charge amount. When drawing each relationship function curve, the least squares method is used for data fitting to improve the accuracy of the curve. After fitting, the specific expressions of the first relationship function, the second relationship function and the third relationship function are obtained.

[0021] In the coupling analysis stage, the first relationship function, the second relationship function and the third relationship function are comprehensively analyzed based on the first relationship function. First, the correlation coefficient of the first relationship function and the second relationship function is calculated to determine the correlation between the two; then the correlation coefficient of the first relationship function and the third relationship function is calculated to further verify the synergy between the three. The calculation of the correlation coefficient adopts the Pearson correlation coefficient formula to ensure the scientificity of the result. Finally, the three are coupled by a mathematical model to obtain the optimal pressure relief parameter of the roof stratum. The mathematical model adopts a multivariate regression analysis method and sets constraint conditions in combination with actual geological conditions to ensure the rationality of the final parameter. The optimal pressure relief parameter includes the optimal charge amount, the optimal blast hole spacing and the optimal blast hole depth.

[0022] In actual application, through data analysis and coupling analysis, the optimal pressure relief parameters of the roadway roof are finally obtained as follows: the charge amount of each meter of blast hole is 1.5 kg, the optimal blast hole spacing is 1.2 m, and the optimal blast hole depth is 1 / 2 of the thickness of the stratum. The application of these parameters significantly reduces the roof pressure and improves the stability of the roadway, providing a strong guarantee for the safe and efficient mining of coal mines.

[0023] During the entire implementation process, the installation depth and fixing method of the pressure sensor directly affect the accuracy of the stress data, so it must be operated strictly in accordance with the design requirements. The installation position and direction of the probe of the acoustic wave detector need to be horizontally aligned with the pressure sensor to ensure the accurate measurement of the acoustic wave propagation characteristics. The direction alignment of the signal receiver of the blasting energy analyzer with the probe of the acoustic wave detector and the fixing stability of the signal receiver also need special attention to improve the measurement accuracy of the blasting energy release value. In addition, during the test process, the adjustment amount of each charge is 5% of the total designed charge, and this proportion can not only ensure the continuity of the data, but also avoid the data deviation caused by the large adjustment amplitude. The number of repeated tests is at least 15 times, which ensures the sufficiency and reliability of the data, thereby providing a solid foundation for subsequent analysis.

[0024] Through the combination of the above steps and principles, the method of the present application can effectively determine the pressure relief parameters of the pre-splitting blasting of the roadway roof in thick coal seam under complex geological conditions, significantly reduce the roof pressure, avoid roadway deformation and roof collapse, and provide technical support for the safe and efficient mining of coal mines.

[0025] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for determining the parameters of pre-splitting blasting for pressure relief of a thick coal seam roadway roof, characterized in that, The method comprises the following steps: (1) setting up a test system, which comprises a geological stress monitoring device (1), an acoustic wave detector (2) and a blasting energy analyzer (3), the pressure sensor in the geological stress monitoring device (1) is embedded in the rock stratum of the roadway roof, the embedding depth is between 1 / 3 and 1 / 2 of the thickness of the rock stratum, the probe of the acoustic wave detector (2) is installed outside the pressure sensor and fixed to the central position of the rock stratum surface of the roof, the signal receiver of the blasting energy analyzer (3) is horizontally aligned with the probe of the acoustic wave detector (2); (2) recording the initial stress value of the roof rock stratum measured by the geological stress monitoring device (1), the acoustic wave propagation speed value measured by the acoustic wave detector (2) and the blasting energy release value measured by the blasting energy analyzer (3) respectively; (3) changing the charge amount of the blasting hole, and recording the stress value of the roof rock stratum measured by the geological stress monitoring device (1), the acoustic wave propagation speed value measured by the acoustic wave detector (2) and the blasting energy release value measured by the blasting energy analyzer (3) again respectively; (4) repeating step (3) several times, and fitting the first relationship function of the stress value of the roof rock stratum measured by the geological stress monitoring device (1) and the charge amount, the second relationship function of the acoustic wave propagation speed value measured by the acoustic wave detector (2) and the charge amount and the third relationship function of the blasting energy release value measured by the blasting energy analyzer (3) and the charge amount according to the measured stress value, acoustic wave propagation speed value and blasting energy release value respectively; (5) taking the first relationship function as the reference, coupling analysis is performed on the first relationship function, the second relationship function and the third relationship function to obtain the optimal pressure relief parameter of the roof rock stratum.

2. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The number of times of repeating step (3) in step (4) is at least 15.

3. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The repeating step (3) in step (4) includes three cases, which are gradually increasing the charge amount, gradually reducing the charge amount or alternately increasing and reducing the charge amount.

4. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The adjustment amount of the charge amount in step (3) is 5% of the total designed charge amount.

5. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The setting up of the test system comprises the following steps: (1) drilling a test hole in the rock stratum of the roadway roof, the diameter of the test hole is 50 mm, the depth is 1 / 2 of the thickness of the rock stratum, and the axis of the test hole is perpendicular to the plane of the roadway roof; (2) fixing the pressure sensor of the geological stress monitoring device (1) to the bottom of the test hole by epoxy resin glue; (3) installing the probe of the acoustic wave detector (2) outside the test hole, the probe is adsorbed to the rock stratum surface of the roof by a magnetic fixing support and is horizontally aligned with the pressure sensor; (4) fixing the signal receiver of the blasting energy analyzer (3) on the sidewall of the roadway by bolts, and the receiving surface faces the direction of the probe of the acoustic wave detector (2).

6. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The specific method of coupling analysis in step (5) comprises: (1) calculating the correlation coefficient of the first relationship function and the second relationship function to determine the correlation between the two functions; (2) calculating the correlation coefficient of the first relationship function and the third relationship function, and further verifying the synergy among the three; (3) coupling the first relationship function, the second relationship function and the third relationship function through a mathematical model to obtain the optimal pressure relief parameter of the roof stratum.

7. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 6, characterized in that, The mathematical model adopts a multiple regression analysis method and sets a constraint condition in combination with an actual geological condition.

8. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The optimal pressure relief parameter includes an optimal charge weight, an optimal blast hole spacing and an optimal blast hole depth.

9. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, In the step (4), the least square method is used for data fitting when fitting the relationship function curve.

10. The method for determining the pre-splitting blasting pressure relief parameters of the thick seam roadway roof according to claim 1, characterized in that, The correlation coefficient is calculated by using a Pearson correlation coefficient formula.