Method for determining crossheading staggered distance of working faces of two coal seams of coal mine

Abstract

The invention relates to the technical field of mining engineering, and discloses a coal mine two-coal-seam working face crossheading staggering distance determination method, which comprises the following steps: firstly, constructing a key layer quantitative model to obtain a key layer thickness ratio coefficient, establishing a two-coal-seam mining numerical model, and screening a numerical simulation optimal staggering distance based on an energy-stress coupling evaluation index; inverting an equivalent pressure relief angle according to a simulation result, and calculating a theoretical protection range; correcting the basic weight by using the thickness ratio coefficient of the key layer to obtain a corrected simulation weight and a theoretical weight; and finally, calculating a target offset by combining an extreme working condition checking result, a correction weight and a theoretical maximum protection range, and comparing the target offset with a geometric constraint boundary to take a larger value to determine a final crossheading offset. According to the method, the shielding effect and the energy accumulation effect of the key layer are comprehensively considered, accurate determination of the staggered distance is achieved through a dynamic weight mechanism, and the stability of the roadway is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of mining engineering technology, specifically a method for determining the offset distance of the roadway in a coal mine working face between two coal seams. Background Technology

[0002] In the mining of closely spaced coal seams, a certain range of low-stress relief zone will be formed in the floor after the overlying coal seam is mined. The key to ensuring the safe mining of the lower coal seam is to reasonably arrange the position of the roadway of the working face so that it is located in this relief zone.

[0003] Currently, methods for determining roadway offset mainly rely on numerical simulations or empirical formulas. However, existing techniques typically use only the distribution characteristics of vertical stress as a single criterion, i.e., finding the trough of the vertical stress curve as the offset point. This method ignores the influence of the elastic energy accumulated in the surrounding rock on roadway stability. In deep mining environments with a tendency for rockbursts, a region of low vertical stress is not necessarily equivalent to a low-risk region, failing to effectively reveal the potential disaster risks under the coupling effect of stress and energy.

[0004] Furthermore, existing methods, when combining theoretical calculations and numerical simulation results, often employ simple arithmetic averaging or fixed weighting, lacking adaptive adjustment mechanisms tailored to specific geological structures. In particular, they fail to quantify the barrier and shielding effect of interlayer hard rock layers (key layers) on stress transmission. This results in the inability to dynamically adjust the reliability weights of numerical simulations and theoretical calculations based on the developmental degree of hard rock layers when there are significant differences in lithology between layers. Consequently, the determined offset is difficult to adapt to complex and variable rock structures.

[0005] Meanwhile, traditional design processes often rely on average geological parameters for calculations, lacking mechanisms to verify performance under extreme conditions such as variations in geological conditions (e.g., changes in interlayer spacing). Furthermore, they often fail to rigorously compare the calculation results with geometric constraints such as roadway width and coal pillars. This average-state-based design lacks necessary safety redundancy, making it highly susceptible to deviations from safe pressure relief ranges when actual geological conditions fluctuate adversely, posing safety hazards to engineering practices. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face in a coal mine. This method solves the problems of existing offset determination methods relying solely on a single vertical stress index, being unable to dynamically adjust the calculation weights based on the characteristics of key inter-layer layers, and lacking safety redundancy verification for fluctuations in geological conditions.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for determining the offset distance of the roadway between two coal seams in a coal mine, comprising the following steps: S1. Geological Characteristic Parameter Acquisition and Key Layer Quantification: Obtain the geological characteristic parameters of the target mine and calculate the average and maximum interlayer spacing between the two coal seams. Based on geological borehole data, identify the hard rock layers existing within the interlayer spacing between the two coal seams. Define rock layers with a single layer thickness greater than a preset thickness threshold and an elastic modulus greater than a preset modulus threshold as key layers.

[0008] To quantify the impact of hard rock layers, a key layer quantification model is constructed: the cumulative thickness of all rock layers marked as key layers within the interlayer spacing is statistically analyzed, the ratio of this cumulative thickness to the average interlayer spacing is calculated, and the obtained ratio is determined as the key layer thickness proportion coefficient.

[0009] S2. Energy-stress coupling analysis and numerical simulation optimization: A numerical model for mining two coal seams is constructed based on the average interlayer spacing. The model adopts either the Mohr-Coulomb constitutive model or the strain softening model, and corresponding displacement and load constraints are applied at the boundaries to simulate the real geological environment. The mining process under a set of preset roadway offset schemes is simulated, and the peak vertical stress and peak elastic energy density of the coal body in a preset range in front of the lower coal seam roadway are extracted.

[0010] To comprehensively evaluate the stability of the surrounding rock, an energy-stress coupling evaluation index is introduced. First, the maximum vertical stress and maximum elastic energy density from the entire set of offset schemes are obtained as benchmark values. The peak vertical stress and peak elastic energy density of each scheme are then normalized. Subsequently, using preset stress and energy weighting coefficients, the normalized vertical stress and normalized elastic energy density values ​​are linearly weighted and summed to obtain the energy-stress coupling evaluation index. The offset value corresponding to the minimum value of this index is selected as the optimal offset for numerical simulation.

[0011] S3. Theoretical protection range inversion: Extract the vertical stress distribution data corresponding to the optimal misalignment in the numerical simulation, and perform differential processing on the vertical stress distribution curve to calculate the horizontal stress gradient function. Identify the extreme points of the horizontal stress gradient function or the locations where the vertical stress recovers to the preset proportion of the original rock stress as abrupt change points, and measure the horizontal projection distance from the abrupt change point to the edge of the upper coal seam goaf as the effective stress relief radius.

[0012] Based on the geometric tangent relationship between the average interlayer spacing and the effective pressure relief radius, the equivalent pressure relief angle is derived in reverse. By multiplying the cotangent of the equivalent pressure relief angle by the maximum and average interlayer spacing values, the theoretical maximum protection range and the theoretical average protection range are calculated.

[0013] S4. Dynamic correction based on geological weights: To balance the local accuracy of numerical simulation with the geometric universality of theoretical calculations, a dynamic weight correction system is constructed.

[0014] First, calculate the basic weights: use the sum of the numerical simulation optimal offset and the theoretical average protection range as the denominator, and the numerical simulation optimal offset as the numerator, and calculate the ratio between the two to determine the basic weights.

[0015] The basic weights are then corrected using the critical layer thickness ratio coefficient: the numerator is calculated as the product of the basic weight and the sum of the numerical value and the critical layer thickness ratio coefficient; the denominator is calculated as the sum of the numerical value and the product of the basic weight and the critical layer thickness ratio coefficient; the ratio of the numerator to the denominator is calculated to obtain the corrected simulated weights. The difference between the numerical value and the corrected simulated weights is calculated to obtain the corrected theoretical weights.

[0016] S5. Extreme working condition verification and final offset determination: The numerical model is reconstructed based on the maximum interlayer spacing for verification under extreme working conditions. The surrounding rock response under different offset schemes is simulated, and the offset corresponding to the minimum energy-stress coupling evaluation index is selected as the optimal offset for energy-stress coupling under extreme working conditions.

[0017] The target misalignment is calculated by combining the aforementioned weights and parameters: the product of the corrected simulated weights and the optimal misalignment under extreme conditions of energy-stress coupling is calculated, as well as the product of the corrected theoretical weights and the theoretical maximum protection range is calculated. The target misalignment is obtained by adding these two products together.

[0018] Finally, the design width of the roadway in the lower coal seam working face and the design width of the section support pillar are obtained. The sum of the theoretical maximum protection range, the design width of the roadway, and the design width of the section support pillar are calculated to construct a geometric constraint boundary. The target offset is numerically compared with the geometric constraint boundary, and the larger value is selected as the final roadway offset.

[0019] This invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine. It has the following beneficial effects: 1. This invention overcomes the limitations of traditional methods that only consider vertical stress distribution by constructing an energy-stress coupling evaluation index. This method comprehensively calculates the peak vertical stress and the peak elastic energy density, enabling more accurate identification of composite hazardous areas of stress concentration and energy accumulation. This allows for the selection of the optimal numerical simulation offset that combines low stress and low energy characteristics, effectively improving the prevention and control capabilities against dynamic disasters such as rockbursts.

[0020] 2. This invention introduces a key layer thickness ratio coefficient to correct the basic weights, establishing a dynamic correlation between geological conditions and calculation weights. When a thick, hard key layer exists within the interlayer spacing, the algorithm automatically increases the weight of the numerical simulation results, thus objectively reflecting the barrier effect of hard rock layers on stress transmission; conversely, it refers more to theoretical calculation results. This dynamic correction mechanism makes the offset determination results more adaptable to the complex and varied rock strata structures of different mines.

[0021] 3. This invention employs a dual-protection strategy combining extreme working condition verification and geometric constraint boundaries. By simulating extreme working conditions under maximum interlayer spacing and calculating the target offset, a geometric constraint boundary is constructed by combining the roadway width and the width of the coal pillar supporting the roadway, ultimately selecting the larger of the two values. This approach ensures that the roadway offset not only meets the low-energy and low-pressure requirements under conventional mining conditions but also reserves a safety redundancy to cope with geological deviations, guaranteeing the stability of the roadway during the mining of the lower coal seam. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the system structure of the present invention; Figure 2 This is a schematic diagram of the overall process of the method of the present invention.

[0023] Among them, 10 is the parameter acquisition module; 20 is the simulation calculation module; 30 is the parameter correction module; 40 is the weight allocation module; and 50 is the offset determination module. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] See attached document Figure 1 The coal mine two-coal-seam working face roadway misalignment determination system provided by the present invention mainly includes a parameter acquisition module 10, a simulation calculation module 20, a parameter correction module 30, a weight allocation module 40, and a misalignment determination module 50.

[0026] The parameter acquisition module 10 is used to establish a geological feature quantification model. The parameter acquisition module 10 is configured to receive input coal mine geological borehole data, rock mechanical parameters, and geostress test data, and calculate the average and maximum interlayer spacing between the two coal seams accordingly. The parameter acquisition module 10 further includes a key layer identification unit. This unit identifies key layers within the interlayer spacing between the two coal seams based on preset rock layer thickness and elastic modulus thresholds, calculates the ratio of the cumulative thickness of all key layers to the average interlayer spacing, and outputs the key layer thickness proportion coefficient.

[0027] The simulation calculation module 20 is connected to the parameter acquisition module 10 and is used to perform multiphysics numerical calculations. The simulation calculation module 20 is configured to construct a numerical model including the main roadway and the working faces of the two coal seams, and to simulate the mining process under different roadway offset conditions. The simulation calculation module 20 integrates a data extraction unit to extract the peak vertical stress and peak elastic energy density of the coal body ahead of the lower coal seam roadway. The simulation calculation module 20 also includes a coupling index calculation unit, used to normalize the vertical stress and elastic energy density, calculate the energy-stress coupling evaluation index, and select the offset value corresponding to the minimum index, outputting the optimal offset for numerical simulation.

[0028] The parameter correction module 30 is connected to the simulation calculation module 20 and is used to correct theoretical calculation parameters. The parameter correction module 30 is configured to receive stress distribution data generated by the simulation calculation module 20 and calculate the horizontal stress gradient along the dip of the lower coal seam. The parameter correction module 30 determines the effective stress relief radius by identifying abrupt changes in the horizontal stress gradient curve and inverts the equivalent stress relief angle by combining the average interlayer spacing. Using this equivalent stress relief angle and the maximum interlayer spacing, the parameter correction module 30 calculates the corrected theoretical maximum protection range.

[0029] The weight allocation module 40 is connected to the parameter acquisition module 10, the simulation calculation module 20, and the parameter correction module 30, respectively, and is used to dynamically calculate the decision weights. The weight allocation module 40 is configured to calculate the basic weights based on the optimal misalignment distance in numerical simulation and the theoretical protection range. The weight allocation module 40 further uses the critical layer thickness ratio coefficient output by the parameter acquisition module 10 to correct the basic weights, and outputs the corrected simulated weights and the corrected theoretical weights.

[0030] The offset determination module 50 is connected to the weight allocation module 40 and is used to output the final roadway layout parameters. The offset determination module 50 is configured to call the simulation calculation module 20 to perform verification calculations under the maximum interlayer spacing condition to obtain the optimal offset for energy-stress coupling under extreme conditions. The offset determination module 50 combines the corrected weights with the simulation and theoretical results under the maximum interlayer spacing to calculate the target offset. The offset determination module 50 is also configured to determine the geometric constraint boundary based on the width of the lower coal seam roadway and the width of the protective coal pillar, compare the target offset with the geometric constraint boundary, and output the larger of the two values ​​as the final roadway offset.

[0031] See attached document Figure 2 This invention provides a method for determining the offset distance of the roadway between two coal seams in a coal mine, the method comprising the following steps: S1. Obtain the geological characteristic parameters of the target mine and construct a quantitative model of the key layers. Specifically, this step involves first collecting geological borehole columnar sections, rock mechanics parameter test reports, and geostress test data from the coal mine. The interlayer spacing data between upper and lower coal seams within the mining area is then statistically analyzed, and the average and maximum interlayer spacing values ​​are calculated. Subsequently, based on the borehole data, hard rock layers existing within the interlayer spacing between the two coal seams are identified. Layers with a single-layer thickness greater than a preset thickness threshold and an elastic modulus greater than a preset modulus threshold are defined as key layers. The cumulative thickness of all key layers is statistically analyzed, and the ratio of this cumulative thickness to the average interlayer spacing value is calculated to obtain the key layer thickness proportion coefficient.

[0032] S2. Construct a numerical model for mining two coal seams and determine the optimal offset for basic simulation based on the energy-stress coupling index. This step constructs a numerical model under the condition of average inter-layer spacing to simulate the mining process of a set of preset offset schemes for different roadways. For each offset scheme, after the model calculation reaches equilibrium, the peak vertical stress and peak elastic energy density of the coal body within a preset range in front of the lower coal seam roadway are extracted. The stress and energy data are normalized respectively, and the energy-stress coupling evaluation index is calculated using preset weighting coefficients. The coupling evaluation indices of each scheme are compared, and the offset scheme corresponding to the minimum value is selected as the optimal offset for numerical simulation under the condition of average inter-layer spacing.

[0033] In this embodiment, the numerical model employs either the Mohr-Coulomb constitutive model or the strain softening model. Horizontal displacement constraints are applied to the left and right boundaries of the model, vertical displacement constraints to the bottom boundary, and an equivalent load is applied to the top boundary to simulate the weight of the overlying strata. The physical and mechanical parameters of the coal and rock strata in the model (such as cohesion and internal friction angle) are engineered based on rock mechanics test reports and within a preset strength reduction factor (e.g., 0.6-0.8).

[0034] S3. Calculate the equivalent stress relief angle and correct the theoretical protection range based on the stress gradient variation characteristics. This step extracts the vertical stress distribution data of the lower coal seam working face corresponding to the optimal offset in the numerical simulation of step S2, and calculates the horizontal stress gradient. The abrupt transition point from the stress relief zone to the original rock stress zone in the horizontal stress gradient curve is identified, and the horizontal distance from this abrupt transition point to the edge of the upper coal seam goaf is measured as the effective stress relief radius. Using the geometric tangent relationship between the effective stress relief radius and the average interlayer spacing, the equivalent stress relief angle is calculated in reverse. Based on this equivalent stress relief angle and the maximum interlayer spacing obtained in step S1, the maximum protection range under the theoretical system is calculated.

[0035] S4. Establish a dynamic weight allocation model incorporating lithological characteristics. This step first calculates the basic weights based on the theoretical protection range under the optimal offset and mean conditions of numerical simulation. Then, the basic weights are corrected using the key layer thickness proportion coefficient obtained in step S1. When the key layer thickness proportion coefficient increases, the weight proportion of the numerical simulation method is increased through a correction formula, while the weight proportion of the theoretical calculation method is correspondingly decreased, thus obtaining the corrected simulation weights and the corrected theoretical weights.

[0036] S5. Determining the final roadway offset based on extreme working condition verification and engineering geometric constraints. This step first reconstructs the numerical model under the maximum inter-layer spacing condition and repeats the calculation process of step S2 to obtain the optimal offset for energy-stress coupling under this extreme working condition. Combining the corrected simulation weights, corrected theoretical weights, the optimal offset for energy-stress coupling under extreme conditions, and the theoretical maximum protection range, the target offset is calculated. Simultaneously, the geometric constraint boundary, including the roadway width and the width of the coal pillar, is calculated based on the design parameters of the lower coal seam roadway. The target offset is numerically compared with the geometric constraint boundary, and the larger value is selected as the final offset of the roadway layout in the lower coal seam working face.

[0037] This invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine, wherein step S1 is executed by the parameter acquisition module 10, and specifically includes the following: The parameter acquisition module 10 first reads the geological database of the target mine. The database contains geological borehole columnar sections, rock mechanics parameter test reports, and geostress test data within the mining area. The parameter acquisition module 10 parses this data to extract the spatial location information of the upper and lower coal seams. By traversing all valid borehole data within the mining area, the parameter acquisition module 10 calculates the arithmetic mean of the vertical distance between the two coal seams, defining it as the average interlayer distance. Meanwhile, the parameter acquisition module 10 filters out the maximum vertical distance between the two coal seams and defines it as the maximum interlayer distance. .

[0038] The parameter acquisition module 10 then executes the interlayer lithological characteristic identification procedure. Based on the geological borehole columnar section and the corresponding rock mechanics parameters, the parameter acquisition module 10 scans the rock strata located between the upper coal seam floor and the lower coal seam roof layer by layer. The parameter acquisition module 10 has built-in key layer discrimination thresholds, including a thickness threshold and an elastic modulus threshold. In this embodiment, the thickness threshold is set to 10 meters, and the elastic modulus threshold is set to 60 GPa.

[0039] When the thickness of a single layer of a certain rock layer between layers The rock layer has an elastic modulus greater than or equal to the thickness threshold. When the elastic modulus is greater than or equal to the threshold value, the parameter acquisition module 10 marks the rock layer as a key layer. The parameter acquisition module 10 then counts the number of rock layers marked as key layers within the interlayer spacing. And extract the thickness of each key layer. ,in Representing the Key layer.

[0040] The parameter acquisition module 10 then calculates the key layer thickness ratio coefficient. This coefficient is used to quantify the shielding effect of the interlayer hard rock layer on the movement and stress transmission of the overlying rock layer, and is the physical basis for subsequent weight correction. Parameter acquisition module 10 sums the thicknesses of all key layers to obtain the cumulative thickness of the key layers, and calculates the ratio of this cumulative thickness to the average interlayer spacing. Key layer thickness proportion coefficient. The calculation formula is as follows: ; After completing the key layer quantization, the parameter acquisition module 10 uses the average interlayer spacing as a basis. A geometric framework for a two-dimensional numerical calculation model is established. Based on rock mechanics parameter test reports, parameter acquisition module 10 assigns strength-reduced values ​​to the physical and mechanical parameters of each rock layer in the model. Simultaneously, based on geostress test data, parameter acquisition module 10 applies horizontal and vertical stresses to the model boundaries to recreate the initial geostress environment of the mine, providing an initial state model for subsequent simulation calculations by module 20.

[0041] This invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine, wherein step S2 is executed by the simulation calculation module 20, and specifically includes the following: The simulation calculation module 20 receives the average value based on the interlayer spacing output by the parameter acquisition module 10. The initial numerical model is constructed. The simulation module 20 sets the simulation time step sequence according to the preset mining plan. This sequence follows the time logic of main roadway excavation, upper coal seam face mining, and lower coal seam face mining. During the simulation, the simulation module 20 keeps the spatial coordinates of the main roadway and upper coal seam face unchanged, and sets the horizontal offset of the lower coal seam face roadway relative to the upper coal seam face roadway as a variable. The standard defines a positive offset (internal offset) as the deviation of the lower coal seam from the goaf upwards along the coal seam roadway, and a negative offset (external offset) as the deviation from the upper coal seam solid pillar. Simulation module 20 pre-sets a set of offset schemes. This set covers a predetermined range from inner staggered arrangements to outer staggered arrangements, for example, a set of staggered distance schemes. The value range is set to 0 meters to 40 meters, and the sampling step size is set to 5 meters, i.e. .

[0042] Simulation Calculation Module 20 for Sets Each staggered scheme Numerical calculations are performed sequentially. In each simulation, the simulation module 20 first excavates the main roadway and calculates it to a stress equilibrium state, then excavates the upper coal seam working face and calculates it to a stress equilibrium state, and finally calculates it according to the offset distance. The lower coal seam working face is excavated at the determined location and calculated to a stress equilibrium state. After the lower coal seam working face reaches a stable state during mining, the simulation calculation module 20 delineates the data extraction area in the model. This data extraction area is located within a preset distance range directly in front of the roadway of the lower coal seam working face. In this embodiment, this range is set to the coal body area within 20 meters in front of the roadway.

[0043] The simulation module 20 monitors and records the vertical stress distribution data and elastic energy density distribution data within the data extraction area. The simulation module 20 extracts the peak vertical stress within this area, denoted as... Simultaneously, the peak elastic energy density in this region is extracted and denoted as... The simulation calculation module iterates through the set 20 times. For all offset schemes, obtain the maximum vertical stress value in the entire scheme set. and maximum elastic energy density This serves as the baseline value for subsequent normalization processing.

[0044] Simulation module 20 uses the extracted data to calculate the energy-stress coupling evaluation index. This index combines the stress concentration and energy accumulation in the surrounding rock using a linear weighting method to quantitatively characterize the risk of rockburst. The simulation module 20 is equipped with stress weighting coefficients. and energy weighting coefficient And meet the conditions In this embodiment, and All values ​​are taken as 0.5. The simulation calculation module 20 calculates the first value according to the following formula. Energy-stress coupling evaluation index for each staggered scheme: ; Simulation calculation module 20 calculates all the results. The values ​​are compared numerically. The simulation calculation module 20 selects the offset scheme corresponding to the minimum energy-stress coupling evaluation index, and defines the horizontal offset value corresponding to this scheme as the optimal offset in numerical simulation under the condition of average interlayer spacing. The simulation module 20 will use this numerical simulation to determine the optimal shift. The corresponding vertical stress distribution data is transmitted to the parameter correction module 30 and the weight allocation module 40 for subsequent parameter inversion and weight calculation.

[0045] This invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine, wherein step S3 is executed by the parameter correction module 30, and specifically includes the following: The parameter correction module 30 receives the numerical simulation optimal error output by the simulation calculation module 20. The corresponding model calculation results. Parameter correction module 30 establishes a data extraction path along the dip direction of the lower coal seam working face. This path extends perpendicular to the strike of the working face, covering the area below the goaf of the upper coal seam and the unmined area. Parameter correction module 30 extracts vertical stress distribution data along this path, generating a distribution curve of vertical stress varying with dip position. ,in Indicates the coordinates of the inclined position.

[0046] The parameter correction module 30 performs differential processing on the extracted vertical stress distribution curve and calculates the horizontal stress gradient function. This function characterizes the rate of change of vertical stress along the dip direction and is used to identify the spatial evolution of the stress field. The formula for calculating the horizontal stress gradient is as follows: ; Parameter correction module 30 for horizontal stress gradient function A scanning analysis is performed to identify abrupt changes in the function curve. Specifically, the horizontal stress gradient curve is analyzed. The extreme point is defined as the abrupt change point; or, the vertical stress is defined as... The location where the stress recovers to a certain proportion (e.g., 1.05 times) of the original rock stress is defined as the abrupt change point. This abrupt change point corresponds to the spatial location where the vertical stress rapidly transitions from the low-stress state of the stress relief zone to the high-stress state of the support pressure zone, characterizing the boundary of the stress relief range formed by the mining of the upper coal seam. The parameter correction module 30 measures the horizontal projection distance on the geological plane from this abrupt change point to the edge of the upper coal seam goaf, and defines this distance as the effective stress relief radius. .

[0047] Parameter correction module 30 utilizes effective pressure relief radius The average interlayer spacing provided by parameter acquisition module 10 Perform inverse calculations of theoretical parameters. Parameter correction module 30, based on geometric tangent, derives the equivalent stress relief angle applicable to the current geological and lithological conditions. This corrects the bias in traditional theoretical calculations that rely solely on empirical table lookups. The inversion formula for the equivalent pressure relief angle is as follows: ; The parameter correction module 30 is based on the equivalent pressure relief angle obtained by inversion. Combined with the maximum interlayer spacing provided by parameter acquisition module 10 The maximum protection range under the theoretical framework is calculated. Parameter correction module 30 calculates the theoretical pressure relief boundary when the distance between the two coal seams is at its maximum value, denoted as the theoretical maximum protection range. Meanwhile, parameter correction module 30 calculates the theoretical average protection range when the interlayer spacing is the average value. This is used for subsequent weight benchmark calculations. The above calculation process follows the formula: ; ; The parameter correction module 30 will calculate the theoretical maximum protection range. and theoretical average protection range The data is transmitted to the weight allocation module 40 and the misalignment determination module 50.

[0048] This invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine, wherein step S4 is executed by the weight allocation module 40, and specifically includes the following: The weight allocation module 40 first calls the numerical simulation of the optimal misalignment output by the simulation calculation module 20. and the theoretical average protection range output by parameter correction module 30 The weight allocation module 40 calculates the basic weights of the numerical simulation method based on the distance proportion principle. The basic weights characterize the initial confidence level of the numerical simulation results in the decision-making system without considering specific differences in rock strata structure. The basic weights are calculated according to the following formula: ; The weight allocation module 40 then incorporates geological heterogeneity characteristics to correct the basic weights. The weight allocation module 40 reads the key layer thickness ratio coefficient calculated by the parameter acquisition module 10. The weight allocation module 40 uses this coefficient to construct a dynamic correction model to reflect the impact of the critical interlayer on the applicability of the theoretical calculation model. When the critical layer thickness accounts for a certain percentage of the coefficient... When the weight increases, it indicates a high degree of development of hard rock layers between layers, leading to increased errors in traditional empirical theoretical formulas. Therefore, the weight allocation module 40 increases the weight ratio of the numerical simulation results through a correction algorithm. The corrected simulation weights are shown below. The calculation formula is as follows: ; The weight allocation module 40 determines the corrected theoretical weights based on the normalization principle. The weight allocation module 40 calculates the numerical value 1 and the corrected simulated weights. The difference is defined as the corrected theoretical weight. The revised formula for calculating theoretical weights is as follows: ; After completing the above calculations, the weight allocation module 40 will assign the corrected simulated weights. and the revised theoretical weights The values ​​are transmitted to the offset determination module 50 as weighting coefficients for the final offset synthesis.

[0049] This invention provides a method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine, wherein step S5 is executed by the offset determination module 50, and specifically includes the following: The misalignment determination module 50 first sends a command to the simulation calculation module 20 to perform numerical simulation verification under extreme conditions. The simulation calculation module 20 receives the maximum interlayer spacing provided by the parameter acquisition module 10. The numerical model for mining the two coal seams is reconstructed based on the maximum interlayer spacing. The simulation module 20 repeats the calculation process in step S200 to simulate the surrounding rock response under different offset schemes. The simulation module 20 extracts the vertical stress data and elastic energy density data under this condition, calculates the energy-stress coupling evaluation index, and selects the offset corresponding to the minimum value of the coupling evaluation index. The offset determination module 50 receives this offset value and defines it as the optimal energy-stress coupling offset under extreme conditions. .

[0050] The offset determination module 50 then calls the corrected simulated weights output by the weight allocation module 40. and the revised theoretical weights And the theoretical maximum protection range output by parameter correction module 30. The offset determination module 50 uses a weighted algorithm to calculate the target offset. This calculation process integrates weighting coefficients considering geological heterogeneity, numerical simulation results under extreme interlayer spacing conditions, and corrected theoretical calculation results. The formula for calculating the target offset is as follows: ; The offset determination module 50 then introduces the engineering geometric constraints of the lower coal seam roadway. The offset determination module 50 reads the roadway design parameters of the lower coal seam working face and determines the design width of the roadway in the next stage working face. and the design width of the coal pillars in the section of the roadway. The offset determination module 50 calculates the sum of the theoretical maximum protection range, the width of the roadway, and the width of the coal pillar in the roadway protection, and constructs the geometric constraint boundary values.

[0051] The offset determination module 50 calculates the target offset. A numerical comparison was performed with the geometric constraint boundary values. Considering that the roadway must be arranged within the theoretical protection range to achieve pressure relief, and that space must be reserved for roadways and coal pillars, the geometric constraint boundary was set as follows: Final shift in the roadway The determination logic follows the following formula: ; If the calculation result is negative, it indicates that a completely internal displacement pressure relief arrangement cannot be achieved under these geological conditions.

[0052] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0054] Any process or method description in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0055] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0056] It should be understood that various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0057] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0058] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0059] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for determining the offset distance of the roadway in a two-coal-seam working face of a coal mine, characterized in that, Includes the following steps: S1. Obtain the geological characteristic parameters of the target mine, calculate the average and maximum interlayer spacing between the two coal seams, and construct a key layer quantitative model based on the hard rock layer characteristics within the interlayer spacing between the two coal seams, and output the key layer thickness ratio coefficient. S2. Based on the average interlayer spacing, construct a numerical model for mining two coal seams, simulate the mining process under a set of preset different roadway offset schemes, calculate the energy stress coupling evaluation index based on vertical stress and elastic energy density, screen out the offset value corresponding to the minimum value of the energy stress coupling evaluation index, and determine the offset value as the optimal offset for numerical simulation. S3. Extract the vertical stress distribution data corresponding to the optimal misalignment in the numerical simulation, calculate the horizontal stress gradient, invert the equivalent stress relief angle by identifying the abrupt change point of the horizontal stress gradient, calculate the theoretical maximum protection range based on the maximum value of the interlayer spacing, and calculate the theoretical average protection range based on the average value of the interlayer spacing. S4. Calculate the basic weight based on the optimal misalignment distance in the numerical simulation and the theoretical average protection range, and correct the basic weight using the key layer thickness ratio coefficient to obtain the corrected simulation weight and the corrected theoretical weight. S5. Perform numerical simulation verification under extreme conditions based on the maximum interlayer spacing to obtain the optimal energy-stress coupling offset under extreme conditions; calculate the target offset by combining the corrected simulation weights, the corrected theoretical weights, the optimal energy-stress coupling offset under extreme conditions, and the theoretical maximum protection range. The target offset is compared with the geometric constraint boundary determined by the combined geometric parameters of the coal seam roadway to determine the final roadway offset.

2. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific method for calculating the critical layer thickness ratio coefficient in step S1 includes: Based on geological borehole data, the hard rock layers existing between the two coal seams are identified, and the rock layers with a single layer thickness greater than a preset thickness threshold and an elastic modulus greater than a preset modulus threshold are defined as key layers. Calculate the cumulative thickness of all rock layers marked as key layers; Calculate the ratio of the cumulative thickness to the average interlayer spacing, and determine the ratio as the critical layer thickness ratio coefficient.

3. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific method for calculating the energy-stress coupling evaluation index in step S2 includes: Extract the peak vertical stress and peak elastic energy density of the coal body within a preset range ahead of the lower coal seam roadway; The maximum vertical stress and the maximum elastic energy density in the entire set of offset schemes are obtained as reference values, and the peak vertical stress and the peak elastic energy density are normalized respectively. By using preset stress weighting coefficients and energy weighting coefficients, the normalized vertical stress value and the normalized elastic energy density value are linearly weighted and summed to obtain the energy-stress coupling evaluation index.

4. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, When constructing the numerical model for mining two coal seams in step S2: The numerical model adopts either the Mohr-Coulomb constitutive model or the strain softening model. The numerical model is subject to horizontal displacement constraints on the left and right boundaries, vertical displacement constraints on the bottom boundary, and an equivalent load on the top boundary to simulate the weight of the overlying rock strata. The physical and mechanical parameters of the coal and rock strata in the numerical model are based on rock mechanics test reports and are modified in an engineering manner within a preset strength reduction coefficient range.

5. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific methods for inverting the equivalent pressure relief angle and calculating the theoretical protection range in step S3 include: The horizontal stress gradient function is calculated by differentiating the vertical stress distribution curve. The extreme points of the horizontal stress gradient function or the locations where the vertical stress recovers to a preset proportion of the original rock stress are identified as abrupt change points. The horizontal projection distance from the abrupt change point to the edge of the upper coal seam goaf is determined as the effective pressure relief radius. Based on the geometric tangent relationship between the average interlayer spacing and the effective pressure relief radius, the equivalent pressure relief angle is derived in reverse. The theoretical maximum protection range and the theoretical average protection range are calculated by multiplying the cotangent value of the equivalent pressure relief angle by the maximum interlayer spacing and the average interlayer spacing, respectively.

6. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific method for calculating the basic weights in step S4 includes: The sum of the numerical simulation optimal error distance and the theoretical average protection range is calculated as the denominator, and the numerical simulation optimal error distance is determined as the numerator. The ratio of the numerator to the denominator is calculated and determined as the basic weight.

7. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 6, characterized in that, The specific methods for calculating the corrected simulated weights and the corrected theoretical weights in step S4 include: Calculate the product of the basic weight and the sum of the numerical value and the key layer thickness ratio coefficient, and determine the product as the numerator; Calculate the sum of the product of the numerical value and the basic weight multiplied by the critical layer thickness ratio coefficient, and use the sum as the denominator; Calculate the ratio of the numerator to the denominator to obtain the corrected simulated weights; The difference between the numerical value and the corrected simulated weight is calculated to obtain the corrected theoretical weight.

8. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific methods for obtaining the optimal energy-stress coupling offset under extreme conditions in step S5 include: A numerical model for mining two coal seams is reconstructed based on the maximum interlayer spacing. Simulate the surrounding rock response under different offset schemes and calculate the energy-stress coupling evaluation index for each scheme. The offset corresponding to the minimum value of the energy-stress coupling evaluation index is selected as the optimal offset of energy-stress coupling under the extreme working condition.

9. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific method for calculating the target offset in step S5 includes: Calculate the product of the corrected simulation weights and the optimal energy-stress coupling offset under the extreme conditions; Calculate the product of the corrected theoretical weight and the theoretical maximum protection range; The target misalignment is obtained by adding the product of the modified simulated weights and the optimal misalignment distance under the extreme conditions, and the product of the modified theoretical weights and the theoretical maximum protection range.

10. The method for determining the offset distance of the working face of two coal seams in a coal mine according to claim 1, characterized in that, The specific methods for determining the final roadway offset in step S5 include: Obtain the design width of the roadway in the lower coal seam working face and the design width of the coal pillars for the section roadway protection; Calculate the sum of the theoretical maximum protection range, the design width of the roadway, and the design width of the coal pillar of the section roadway protection, and construct the geometric constraint boundary; The target offset is numerically compared with the geometric constraint boundary, and the larger value between the target offset and the geometric constraint boundary is selected as the final roadway offset.

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