A combined pressure relief control method for lateral large coal pillars in roadways under hard roof

Abstract

This application discloses a method for combined pressure relief control of lateral large coal pillars in roadways under hard roofs. The method includes: acquiring geological parameters of the current working face and constructing a three-dimensional model based on the geological parameters, including the roadway under the goaf, the lateral large coal pillar, and adjacent goaf areas; performing numerical simulations on multiple preset combinations of coal pillar widths and cutting top positions using the three-dimensional model; selecting target combinations of coal pillar widths and cutting top positions that meet preset requirements based on the numerical simulation results; determining the optimal layer for roof cutting blasting based on the target combination scheme and corresponding geological parameters, and identifying high-stress zones inside the coal pillar based on the numerical simulation results corresponding to the target combination scheme; arranging roof cutting boreholes according to the optimal layer to carry out roof cutting blasting, and arranging pressure relief boreholes in the lateral large coal pillar according to the high-stress zones inside the coal pillar to carry out lateral large coal pillar blasting. This method can optimize blasting effects and achieve effective pressure relief.

Description

Technical Field

[0001] This application relates to the field of coal mine safety technology, and in particular to a method for combined pressure relief control of large lateral coal pillars in roadways under hard roofs. Background Technology

[0002] In deep and high-intensity concentrated mining of coal, large coal pillars are often left on the sides of roadways to isolate adjacent working faces or ensure safety. Under hard roof conditions, the span and stability of the roof are enhanced, and the lateral static load transmitted to the coal pillar is particularly enormous. Under the coupled effect of the aforementioned high ground stress and hard roof, roadways are prone to strong mine pressure manifestations such as coal wall spalling, floor heave, and roof collapse, and may even induce rockburst disasters, seriously threatening the safe production of the mine. In existing technologies, local treatment is carried out on a single aspect of the roof or coal pillar, and these measures are often based on experience-based design, resulting in poor controllability of the pressure relief range and intensity, making it difficult to achieve effective, reliable, and long-term pressure relief under complex geological and high-stress conditions.

[0003] Therefore, how to provide a combined pressure relief control method for large coal pillars on the side of roadways under hard roofs to optimize blasting effects and achieve effective pressure relief has become an urgent technical problem to be solved. Summary of the Invention

[0004] This application provides a method for combined pressure relief control of large lateral coal pillars in roadways under hard roofs to optimize blasting effects and achieve effective pressure relief.

[0005] This application provides a method for combined pressure relief control of large lateral coal pillars in roadways under hard roofs, including: Obtain the geological parameters of the current working face, and construct a three-dimensional model including the goaf roadway, lateral large coal pillars and adjacent goaf areas based on the geological parameters; The three-dimensional model is used to numerically simulate multiple preset combinations of coal pillar widths and top cutting positions. Based on the numerical simulation results, a target combination scheme of coal pillar width and cut-off top position that meets the preset requirements is selected; The optimal stratum for roof cutting blasting is determined based on the target combination scheme and the corresponding geological parameters, and the high-stress zone inside the coal pillar is identified based on the numerical simulation results corresponding to the target combination scheme. Roof cutting blasting is carried out by arranging top-cutting boreholes according to the optimal stratum, and lateral large coal pillar blasting is carried out by arranging pressure-relieving boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

[0006] The beneficial effects of this application are as follows: By constructing a three-dimensional model including the goaf roadway, lateral large coal pillars, and adjacent goaf areas, and conducting numerical simulations on multiple preset combinations of coal pillar widths and cutting top positions, this application selects target combinations of coal pillar widths and cutting top positions that meet preset requirements. Furthermore, based on the target combination schemes and corresponding geological parameters, the optimal layer for roof cutting blasting is determined, and high-stress zones within the coal pillars are identified based on the numerical simulation results corresponding to the target combination schemes. This achieves joint pressure relief of the roof and coal pillars, effectively cutting off the lateral high static load transfer of the roof and significantly weakening the high stress and elastic energy within the coal pillars. This fundamentally improves the stress environment of the roadway surrounding rock, reduces the risk of rockburst, and enhances the long-term stability of the roadway. This application, through constructing a three-dimensional model and conducting numerical simulations, provides a basis for the cutting and pressure relief ranges, constructs a predictable, controllable, and evaluable joint pressure relief system, and improves the accuracy of blasting.

[0007] In one embodiment, the numerical simulation results include the depth range of the plastic zone of the surrounding rock in the roadway and the peak value of the concentrated stress in the roof under each combination scheme. The step of selecting a target combination scheme with coal pillar width and cut-off roof position that meets preset requirements based on the numerical simulation results includes: Based on the numerical simulation results, the scheme that controls the plastic depth of the surrounding rock in the roadway after decompression within a first preset range and reduces the peak value of the concentrated stress in the roof after decompression within a second preset range is selected as the target combination scheme.

[0008] In one embodiment, determining the optimal stratum for roof-cutting blasting based on the selected target combination scheme and corresponding geological parameters includes: Identify coal pillars and high-stress concentration areas in accessible roadways based on the numerical simulation results corresponding to the target combination scheme; The treatment height of the roof and the critical fracture span of the roof rock beam are determined based on the geological parameters corresponding to the target combination scheme. The optimal stratum for roof cutting blasting is determined to be a hard rock stratum located above the high stress concentration zone of the coal pillar and the roadway, within the roof treatment height range, and with a post-blast roof overhang length less than the critical fracture span.

[0009] In one embodiment, the calculation process for the top plate treatment height includes: Obtain the current working face's mining height and roof strata fragmentation coefficient; Substitute the mining height and the roof strata fragmentation coefficient into the following formula to determine the roof treatment height: ; Among them, H ξ represents the roof treatment height; HC represents the mining height; and ξ represents the roof strata fragmentation coefficient.

[0010] In one embodiment, the calculation process for the critical fracture span of the roof rock beam includes: Obtain the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth; Substituting the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth into the following formula, the critical fracture span of the roof rock beam can be determined: ; Where Lcr is the critical fracture span of the roof rock beam, Rt is the tensile strength of the roof rock, h is the thickness of the roof rock strata under overall bending, γ is the average unit weight of the roof rock strata, H is the burial depth, and kL is an empirical coefficient related to the rock strata structure.

[0011] In one embodiment, the method further includes: During the implementation of roof cutting blasting and lateral large coal pillar blasting, on-site data including coal stress, microseismic event energy frequency, and roadway deformation are monitored. Based on the monitored field data, determine whether the combined pressure relief effect meets the standards.

[0012] In one embodiment, determining whether the combined pressure relief effect meets the standard based on monitored field data includes: If the stress level of the coal body decreases by more than the first preset value, high-energy micro-seismic events decrease, and the roadway deformation is less than the second preset value, then the joint pressure relief effect is deemed to have met the standard. Otherwise, readjust the blasting parameters and execute the procedure until the pressure relief effect meets the requirements.

[0013] This application also provides a combined pressure relief control device for lateral large coal pillars in roadways under hard roofs, comprising: The acquisition module is used to acquire the geological parameters of the current working face and construct a three-dimensional model including the goaf roadway, the lateral large coal pillar and the adjacent goaf based on the geological parameters; The simulation module is used to perform numerical simulations of multiple preset combinations of coal pillar widths and cut-off top positions using the three-dimensional model. The screening module is used to screen target combination schemes of coal pillar width and cutting top position that meet preset requirements based on the numerical simulation results; The determination module is used to determine the optimal layer for roof cutting blasting based on the target combination scheme and the corresponding geological parameters, and to identify the high-stress zone inside the coal pillar based on the numerical simulation results corresponding to the target combination scheme. The blasting module is used to carry out roof cutting blasting by arranging roof cutting boreholes according to the optimal stratum, and to carry out lateral large coal pillar blasting by arranging pressure relief boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

[0014] In one embodiment, the numerical simulation results include the plastic zone depth range of the surrounding rock in the roadway and the peak value of the concentrated stress in the roof under each combination scheme. The screening module is further used for: Based on the numerical simulation results, the scheme that controls the plastic depth of the surrounding rock in the roadway after decompression within a first preset range and reduces the peak value of the concentrated stress in the roof after decompression within a second preset range is selected as the target combination scheme.

[0015] In one embodiment, the determining module includes: The identification submodule is used to identify coal pillars and high-stress concentration areas in roadways with open spaces based on the numerical simulation results corresponding to the target combination scheme. The first determining submodule is used to determine the roof treatment height and the critical fracture span of the roof rock beam based on the geological parameters corresponding to the target combination scheme. The second determination submodule is used to determine the optimal stratum for roof cutting blasting for hard rock strata located above the high stress concentration zone of coal pillars and adjacent roadways, within the roof treatment height range, and with a post-blast roof overhang length less than the critical fracture span.

[0016] In one embodiment, the first determining submodule is further configured to: Obtain the current working face's mining height and roof strata fragmentation coefficient; Substitute the mining height and the roof strata fragmentation coefficient into the following formula to determine the roof treatment height: ; Among them, H H represents the height of the top slab treatment. C ξ represents the mining height; ξ is the coefficient of fragmentation of the roof strata.

[0017] In one embodiment, the first determining submodule is further configured to: Obtain the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth; Substituting the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth into the following formula, the critical fracture span of the roof rock beam can be determined: ; Where Lcr is the critical fracture span of the roof rock beam, Rt is the tensile strength of the roof rock, h is the thickness of the roof rock strata under overall bending, γ is the average unit weight of the roof rock strata, H is the burial depth, and kL is an empirical coefficient related to the rock strata structure.

[0018] In one embodiment, the apparatus further includes: The monitoring module is used to monitor field data, including coal stress, microseismic event energy frequency, and roadway deformation, during the implementation of roof cutting blasting and lateral large coal pillar blasting. The judgment module is used to determine whether the combined pressure relief effect meets the standard based on the monitored field data.

[0019] In one embodiment, the determining module is further configured to: If the stress level of the coal body decreases by more than the first preset value, high-energy micro-seismic events decrease, and the roadway deformation is less than the second preset value, then the joint pressure relief effect is deemed to have met the standard. Otherwise, readjust the blasting parameters and execute the procedure until the pressure relief effect meets the requirements.

[0020] This application also provides a combined pressure relief control system for lateral large coal pillars in roadways under hard roofs, including: At least one processor; and, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to implement the combined pressure relief control method for lateral large coal pillars in roadways under hard roofs as described in any of the above embodiments.

[0021] This application also provides a computer-readable storage medium, which, when the instructions in the storage medium are executed by the processor corresponding to the combined pressure relief control system for the lateral large coal pillar in the hard roof free-running roadway, enables the combined pressure relief control system for the lateral large coal pillar in the hard roof free-running roadway to realize the combined pressure relief control method for the lateral large coal pillar in the hard roof free-running roadway described in any of the above embodiments. Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0022] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0023] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the embodiments of the present application to explain the application and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart of a method for combined pressure relief control of lateral large coal pillars in an open roadway under a hard roof, according to one embodiment of this application. Figure 2 This is a schematic diagram of stress concentration partitioning obtained from numerical simulation in one embodiment of this application; Figure 3 This application provides an embodiment of a combined pressure relief control device for lateral large coal pillars in an open roadway under a hard roof. Figure 4 This is a schematic diagram of the hardware structure of a combined pressure relief control system for lateral large coal pillars in an open roadway under a hard roof, according to one embodiment of this application. Detailed Implementation

[0024] The preferred embodiments of this application are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit this application.

[0025] Figure 1 This is a flowchart of a method for combined pressure relief control of large lateral coal pillars in an open roadway under a hard roof, as described in one embodiment of this application. Figure 1 As shown, the method can be implemented as follows: S101-S105: In step S101, the geological parameters of the current working face are obtained, and a three-dimensional model including the goaf roadway, the lateral large coal pillar and the adjacent goaf area is constructed based on the geological parameters. In step S102, the three-dimensional model is used to numerically simulate the combination scheme of multiple sets of coal pillar widths and cutting top positions. In step S103, a target combination scheme of coal pillar width and cutting top position that meets the preset requirements is selected based on the numerical simulation results. In step S104, the optimal layer for roof cutting blasting is determined according to the target combination scheme and the corresponding geological parameters, and the high-stress zone inside the coal pillar is identified according to the numerical simulation results corresponding to the target combination scheme. In step S105, roof cutting blasting is carried out by arranging roof cutting boreholes according to the optimal stratum, and lateral large coal pillar blasting is carried out by arranging pressure relief boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

[0026] This application selects the most suitable pressure relief scheme by simulating the current geological and mining conditions of the working face.

[0027] First, the geological parameters of the current working face are obtained, and a three-dimensional model including the goaf roadway, lateral large coal pillars and adjacent goaf areas is constructed based on the geological parameters.

[0028] Drill holes are arranged along the strike and dip of the working face where the roadway is located. Geological parameters of the current working face, such as coal seam thickness, hard roof thickness, uniaxial compressive strength of the roof, coal pillar width, roadway width, and original in-situ stress, are obtained using methods such as drill cuttings recording, sonic logging, and core sampling. These parameters can be obtained through a combination of methods. Drill cuttings recording indirectly determines the integrity and stress state of the coal and rock mass by analyzing the amount of coal and rock cuttings discharged from the borehole. Sonic logging utilizes the propagation speed of sound waves in the rock strata to invert the integrity, fracture development, and mechanical properties of the strata. Core sampling directly obtains core samples, and precise mechanical parameters such as uniaxial compressive strength are measured in the laboratory. In practical applications, multiple methods can be combined. For example, after drilling is arranged at the working face of the roadway, drill cuttings recording and sonic logging can be used to quickly understand the overall geological conditions and stress anomaly zones; then, core sampling is performed at key strata (such as the silhouetted roof strata) to obtain core samples for laboratory core sampling tests to obtain precise mechanical parameters. Finally, the parameter values ​​of all preset parameters are obtained.

[0029] Based on the geological parameters of the current working face, a three-dimensional model including the goaf roadway, lateral large coal pillars, and goaf area is constructed. The goaf roadway is the excavated roadway; the lateral large coal pillar is the medium retained on one side of the roadway for support; and the goaf area is the area that has been mined out. After obtaining the geological parameters of the current working face, the professional geotechnical engineering parameter simulation software FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) is used. The collected geological parameters such as coal seam thickness, roof thickness, compressive strength, coal pillar size, and original in-situ stress are used as the set dimensions, material properties, and boundary conditions of the model and input into the software to establish a three-dimensional model including the goaf roadway, lateral large coal pillars, and goaf area.

[0030] Secondly, the three-dimensional model is used to numerically simulate the combination schemes of multiple preset coal pillar widths and cutting top positions.

[0031] In the model, by systematically changing certain key design variables, the software can automatically calculate the dynamic response of the rock mass surrounding the roadway under different scenarios. For example, it can analyze how stress, strain, displacement, and plastic zones within the rock mass redistribute and evolve, thereby identifying high-stress zones and plastic failure zones. Figure 2 As shown, this is a schematic diagram of stress concentration zoning obtained by numerical simulation in one embodiment of this application. Then, based on the evolution law of different schemes, the optimal combination of key design variables that can effectively control the plastic zone of the surrounding rock and reduce the stress peak can be selected.

[0032] For example, in order to determine how wide a coal pillar needs to be reserved to support the roadway and isolate the goaf, and at what depth and layer of rock to carry out blasting to ensure that the roof-cutting blasting is both safe and effective, it is necessary to simulate multiple pre-designed combinations of coal pillar widths and roof-cutting positions using the aforementioned three-dimensional model. By comparing the simulation results of different schemes, it is possible to analyze how the surrounding rock stress shifts, concentrates, or decreases as the coal pillar width narrows or the roof-cutting position changes.

[0033] Then, based on the numerical simulation results, a target combination scheme of coal pillar width and cutting top position that meets the preset requirements is selected.

[0034] Numerical simulation results were obtained by analyzing multiple combinations of coal pillar width and cut-off top position. The simulation results include the evolution law of surrounding rock stress under different combinations, the high-stress zone and plastic failure zone located according to the surrounding rock stress evolution law, and the peak value of concentrated roof stress and the depth range of plastic zone of the roadway surrounding rock under each combination. Among them, the high-stress zone is the area where the stress value is significantly higher than the original rock stress or rock strength, and it is the main area for the accumulation of rockburst energy, which requires decompression. The plastic failure zone is the area where the rock mass stress exceeds its yield strength, and plastic deformation, crack propagation or even rupture occurs. It can be used to determine whether the roadway surrounding rock is inclined to instability. It usually manifests as a plastic zone or a sudden displacement zone, and is a high-incidence area for roadway deformation, roof fall or spalling.

[0035] Based on the pre-set control objectives, the optimal stress relief combination scheme is selected. Specifically, by analyzing the high-stress zone and plastic failure zone corresponding to different schemes, and based on the numerical simulation results, the scheme that controls the plastic depth of the surrounding rock in the roadway after stress relief within a first preset range, and reduces the peak value of the concentrated stress in the roof after stress relief by a percentage within a second preset range, is selected as the target combination scheme. For example, the preferred scheme is a coal pillar width and roof cutting combination scheme that controls the plastic zone depth of the surrounding rock in the roadway to 2-5m and reduces the peak value of the concentrated stress in the roof by 20%-40% compared to the original arrangement.

[0036] Furthermore, the optimal stratum for roof cutting blasting is determined based on the target combination scheme and the corresponding geological parameters, and the high-stress zone inside the coal pillar is identified based on the numerical simulation results corresponding to the target combination scheme.

[0037] After determining the target combination scheme, the optimal layer for roof cutting blasting is determined based on the optimal coal pillar width for pressure relief and the roof cutting combination scheme.

[0038] On the one hand, based on the numerical simulation results corresponding to the target combination scheme, the high stress concentration areas of coal pillars and adjacent roadways are identified. On the other hand, in order to find an accurate, safe, and effective construction location for subsequent roof blasting, after determining the optimal roof cutting position and coal pillar decompression zone, it is necessary to further determine the roof treatment height and estimate the critical fracture span of the roof. The roof treatment height is used to determine the total thickness of the roof requiring blasting treatment. The critical fracture span (Lcr) of the roof rock beam is the maximum exposed length of the roof that can remain stable without natural fracture under its own weight and overlying load.

[0039] In this application, based on the principle that the volume expansion of the collapsed rock mass can basically fill the goaf, the expanded volume of the collapsed broken rock is designed to just fill the goaf below it. Specifically, the roof treatment height is calculated according to the following formula: ; Among them, H H represents the height of the top slab treatment. C ξ represents the mining height; ξ is the roof rock fragmentation coefficient, which refers to the multiple by which the volume of the roof rock increases compared to the original rock volume after it is blasted, broken, and collapses due to the gaps between the broken blocks.

[0040] In another embodiment, when determining the roof treatment height based on the geological parameters, the method further includes: obtaining the goaf volume (V). 空 The parameters are: 1) the preset goaf filling rate (η), 2) the horizontal projected area of ​​the roof treatment zone (A), and 3) the coefficient of rock fragmentation of the roof (ξ); 4) the minimum filling volume (V=V) to be filled by collapsed rock is calculated based on the goaf volume and the preset goaf filling rate. 空 ×η); The roof treatment height (H) is determined based on the minimum filling volume, the horizontal projected area of ​​the roof treatment zone, and the fragmentation coefficient of the roof rock. Specifically, the treatment height of the roof slab is calculated using the following formula:

[0041] Among them, H V represents the roof treatment height; η represents the preset goaf filling rate; V 空 ξ represents the volume of the goaf; A represents the horizontal projected area of ​​the roof treatment area; ξ represents the roof rock strata fragmentation coefficient.

[0042] Meanwhile, to prevent uncontrollable, large-scale sudden collapse of the roof slab, the critical fracture span (L) of the roof slab rock beam is calculated according to the following formula. cr ): ; Among them, L cr R is the critical fracture span of the top rock beam. tγ is the tensile strength of the roof rock, h is the thickness of the roof rock strata considered as a whole under bending, γ is the average unit weight of the roof rock strata, H is the burial depth, and K is the tensile strength of the roof rock. L This is an empirical coefficient related to the rock strata structure, which can be obtained by fitting experimental or engineering empirical data.

[0043] The overhang length (L) refers to the length of the hard roof that remains suspended like a "beam" after the formation of a goaf, without collapsing. The longer the overhang, the greater the energy accumulated in the roof, and the greater the pressure on the coal pillars and roadways below, making it more prone to sudden fracture (rockburst). The critical fracture span of the roof represents the maximum overhang length at which the roof strata are about to fracture under their own weight and overlying pressure.

[0044] Based on the numerical simulation results and the calculated roof treatment height and critical fracture span, the optimal stratum for roof cutting blasting is determined to be a hard rock layer located above the high stress concentration zone of the coal pillar and the adjacent roadway, within the roof treatment height range, and with a post-blast overhang length less than the critical fracture span. In other words, the optimal stratum for roof cutting blasting is selected where the actual overhang length L above the coal pillar can be controlled within the range of L≤Lcr, and within the roof treatment height H. Within the specified range, and above the high stress concentration zone of the coal pillar and the adjacent roadway, the hard rock strata are considered the optimal strata for roof cutting blasting. Furthermore, the hard rock strata within a predetermined range above the high stress concentration zone can be designated as the roof cutting strata, such as hard and brittle rock strata 0.5–3.0 m from the coal seam roof with a total thickness of 1.0–3.0 m.

[0045] Finally, roof cutting blasting is carried out by arranging roof cutting boreholes according to the optimal stratum, and lateral large coal pillar blasting is carried out by arranging pressure relief boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

[0046] In one embodiment, the roof cutting blasting adopts a directional and decoupled charging process; the lateral large coal pillar blasting adopts a medium-to-large diameter, segmented charging process, wherein the pressure relief boreholes are arranged within the elastic core range inside the coal pillar.

[0047] When conducting roof-cutting blasting based on the optimal stratigraphic arrangement of the boreholes, the corresponding blasting condition type can be determined by combining blasting condition parameters. These parameters include overburden pressure, tensile strength of the roof strata, uniaxial compressive strength, degree of joint and fracture development, expected fracture expansion radius, and allowable blasting disturbance range. A correspondence table between blasting condition parameters and blasting conditions can be pre-observed using historical data through cluster analysis and mechanical analysis. The current blasting condition can be determined by querying this table based on the real-time collected blasting condition parameters. Table 1 lists seven typical blasting conditions and provides their corresponding borehole parameters, charge structure, and reference charge level, along with explanations. Furthermore, based on Table 1, the borehole diameter, depth, spacing, charge structure, and reference charge range for the roof-cutting blasting boreholes can be selected as initial parameters.

[0048] In this application, the working conditions targeted are three types: deep hole pre-fracturing and anti-impact blasting of hard thick roof (adjacent roadway / above large coal pillar), pressure relief blasting of coal body / coal pillar in high stress zone (local anti-impact blasting), and shallow hole pre-fracturing and roof cutting of hard roof. For these three working conditions, this application selects a decoupled charging method.

[0049] Directional blasting boreholes are arranged along the cut line at the determined cut-off location. A segmented delayed blasting method is used to cut the roof, causing it to collapse directionally along the cut line. The directional pre-splitting blasting structure of the cut-off boreholes employs a decoupled charge method, leaving a gap between the explosive charge and the borehole wall. This allows the detonation products to expand and impact the air cushion layer surrounding the explosive charge, thereby weakening the peak impact pressure acting on the borehole wall. Simultaneously, segmented charges are used in conjunction with millisecond delayed detonators to control the propagation speed and direction of the blast cracks, ensuring the formation of a substantially continuous cut fracture zone at the target cut-off location, penetrating adjacent boreholes. This precisely induces the roof to fracture and collapse along a predetermined path.

[0050] For example, along the roadway direction, cut-off boreholes are arranged in the middle of the roof or on the side of the goaf, using boreholes with a diameter of 42 to 75 mm, and hard and brittle rock strata with a total thickness of 1.0 to 3.0 m from the roof of the coal seam are selected as the cut-off top.

[0051] Because the specifications of explosive cartridges are often fixed during on-site construction, the charge diameter cannot be arbitrarily selected. Furthermore, when used for pressure relief blasting of coal seams / coal pillars in hazardous areas, the decoupling coefficient is preferably no greater than 1.5. Based on the aforementioned initial parameters, the target decoupling coefficient can be determined according to the borehole diameter, roof rock strength, target fracture propagation range, and allowable blasting disturbance range, and the charge diameter can be determined accordingly. Alternatively, if the charge diameter is already determined by the permitted explosive cartridge specifications or charging tube specifications for the coal mine, the decoupling coefficient can be checked based on the borehole diameter and charge diameter. Specifically, the decoupling coefficient can be calculated using the following first formula based on the borehole diameter and charge diameter: ; Among them, K d D is the decoupling coefficient; b D is the borehole diameter; e This refers to the diameter of the propellant charge.

[0052] The linear charge amount is determined using the following second formula based on the charge diameter, explosive density, and charge structure correction factor: ; in, D represents the amount of drug packed into the line. e The diameter of the propellant charge; Density of the explosive; This is the charge structure correction coefficient, which is used to correct the influence of the actual charge structure (such as decoupling, segmentation, air gap) on the blast energy utilization rate. It can be determined in advance according to the charge structure.

[0053] Then, based on the charge quantity and charge section length, the charge quantity per orifice is obtained using the following third formula: ; in, This refers to the charge amount per hole; This refers to the amount of drug in the line; This refers to the length of the charge section.

[0054] The single-hole charge amount was verified by considering the roof rock strength, original rock stress, and the maximum allowable charge per section in the mine, ensuring that the blasting action could induce tensile fractures in the roof strata while avoiding excessive crushing and non-directional damage around the borehole. The effective fracture propagation radius R along the target cut direction of the single hole was determined through numerical simulation or field test blasts. f The spacing between adjacent top-cutting boreholes is determined or corrected according to the following formula:

[0055] Where S is the distance between adjacent top-cutting boreholes. Let be the crack overlap coefficient, and By making the effective fracture expansion range of adjacent top-cutting boreholes overlap with each other in the direction of the inter-hole connection, and by modifying the hole spacing, charge structure and charge amount, the explosive fractures of adjacent boreholes are basically connected, forming a continuous or nearly continuous top-cutting fracture zone.

[0056] The optimal spacing between the top-cutting holes is 1.0–2.0 m, the row spacing is 1.2–2.5 m, and the hole depth is 6–20 m. This must meet the constraints of a minimum 70% filling rate of the goaf after blasting and a minimum 3.0 m thickness of intact rock strata remaining beneath the roadway roof. The bottom of the holes is filled with emulsion explosives or permitted emulsion explosives for coal mines, with a preferred charge density of 1.0–1.3 kg / m³. This is combined with directional cavity, hollow hole, or segmented detonation methods to create a nearly continuous cut-and-break zone along the designed strata. This ensures that the hard roof breaks and collapses at a predetermined location after mining, fully filling the goaf and transferring the concentrated overlying stress to the goaf. Table 1 shows the parameter selection and explanation for different working conditions.

[0057] Table 1. Parameter Selection and Explanation under Different Working Conditions

[0058] According to the high stress zone inside the coal pillar, when lateral coal pillar blasting is carried out by arranging pressure relief boreholes in the lateral coal pillar, pressure relief boreholes are arranged along the roadway direction inside the coal pillar, and deep hole pre-splitting blasting is used to relieve pressure on the coal pillar and reduce the stress concentration inside the coal pillar.

[0059] Based on the width of the coal pillar, the location of the goaf roadway, and the spatial relationship of the goaf, and following the principle of "zoning management and classified prevention," the layout area, depth, spacing, and direction of the coal pillar stress relief boreholes are determined based on the stress distribution, high stress concentration area, elastic core area, and impact hazard area of ​​the coal pillar obtained from numerical simulation, combined with the results of on-site stress monitoring, drill cuttings monitoring, and microseismic monitoring. Several coal body stress relief boreholes are directionally arranged along the roadway direction inside the lateral large coal pillar on the goaf side of the goaf roadway, so that the borehole axis points to the high stress area in the middle of the coal pillar or the side opposite to the goaf, and the bottom of the borehole and the charging section are located in or cover the high stress concentration area, elastic core area, or impact hazard area inside the coal pillar. The boreholes are preferably located within the high-stress zone of the coal pillar's elastic core, ensuring their influence covers the lateral high-stress concentration zone of the coal pillar. The borehole diameter, spacing, elevation angle, and depth are determined based on the impact hazard assessment results, the physical and mechanical properties of the coal and rock, mining layout conditions, numerical simulation results, and on-site stress monitoring results. Specifically, the borehole depth and charging section location are determined according to the extent of the high-stress concentration zone and elastic core zone of the coal pillar, ensuring the borehole bottom and charging section are located within or cover the high-stress zone inside the coal pillar. The borehole spacing is determined based on the effective pressure relief range after a single borehole blast, ensuring the pressure relief influence ranges of adjacent boreholes overlap along the roadway direction. The elevation angle is determined based on the spatial relationship between the coal wall of the goaf roadway and the center of the high-stress zone of the coal pillar, ensuring the borehole axis points towards the high-stress zone inside the coal pillar. The borehole diameter is determined based on the coal strength, target pressure relief range, charging diameter, drilling rig capacity, and blasting safety requirements. The preferred borehole diameter is medium to large diameter, the borehole spacing is on the order of several meters, and the borehole depth extends to the middle of the coal pillar and the high-stress zone on the side adjacent to the goaf. Each pressure relief borehole uses permitted emulsion or expanded explosives for coal mines, with segmented charging and millisecond-delayed detonation at the bottom section. The middle and orifice sections are sealed with inert materials, ensuring that the charging sections are mainly concentrated within the high-stress zone of the coal pillar. After blasting, fracture zones and loosening zones are formed inside the coal pillar, weakening the overall stiffness and bearing capacity of the coal body, reducing the peak stress and elastic energy accumulation within the coal pillar, and transforming the coal pillar from concentrated bearing to dispersed bearing. This reduces the lateral support pressure of the coal pillar on the goaf roadway, providing conditions for the long-term stability of the goaf roadway.

[0060] In addition, this application also includes a process for monitoring the pressure relief effect and dynamically adjusting the pressure relief parameters.

[0061] Stress monitoring points, microseismic monitoring points, and roadway deformation monitoring points are set up around the access roadway and large coal pillar to obtain data on changes in coal stress, microseismic activity, and roadway surrounding rock deformation over time and as the working face advances. Coal stress data includes internal stress of the coal pillar, stress in the roadway sidewalls, peak stress, peak stress location, and stress reduction. Microseismic activity data includes the frequency of microseismic events, total energy, maximum energy, number of high-energy events, and spatial distribution. Roadway surrounding rock deformation data includes roof subsidence, floor heave, sidewall convergence, sidewall bulge, roof and floor approach, and deformation rate. Based on the monitored field data, it is determined whether the combined pressure relief effect meets the standards.

[0062] In one embodiment, if it is determined that the combined pressure relief effect is not up to standard, then based on the pressure relief effect deviation reflected by the stress, micro-vibration and roadway deformation monitoring data, at least one of the following parameters is readjusted and the corresponding blasting is performed again: the spacing and / or charging structure of the top-cutting boreholes; the arrangement position, elevation angle and / or the amount of explosives in the segmented charging of the pressure relief boreholes inside the coal pillar; and the sealing length of the pressure relief boreholes.

[0063] In another embodiment, if the combined pressure relief effect does not meet the preset requirements, the blasting parameters are adjusted according to the type of the non-compliant index: when the peak stress of the coal pillar is still higher than the warning threshold or the high stress concentration area and the elastic core range have not significantly decreased, the spacing of the coal pillar pressure relief boreholes is reduced, the hole depth is increased, the elevation angle is adjusted, or the length of the charging section is increased so that the charging section further covers the high stress area inside the coal pillar; when the total energy, frequency, or number of high-energy events of microseismic events is still higher than the warning threshold, the source of energy concentration is determined according to the spatial distribution of microseismic events, if it is concentrated in the roof. If the blasting is concentrated on the side of the coal pillar, adjust the top cutting position, the distance between the top cutting holes, the hole depth, or the charging structure. If the blasting is concentrated on the side of the coal pillar, adjust the distance between the coal pillar pressure relief boreholes, the amount of charge, or the detonation sequence. When the amount of roof subsidence, side bulging, or bottom bulging exceeds the preset safety allowable range, adjust the roof cutting blasting parameters, coal pillar pressure relief blasting parameters, and / or support parameters according to the deformed part. When the degree of rock fragmentation in the roadway increases or the disturbance is too strong after blasting, reduce the single hole charge or linear charge density, increase the sealing length, increase the decoupling coefficient, or use segmented small charge delayed detonation.

[0064] If the stress level of the coal body is significantly reduced, high-energy micro-seismic events are reduced, and the roadway deformation does not exceed the preset safety threshold, then the joint pressure relief effect is deemed to be up to standard; otherwise, the blasting parameters are readjusted and executed until the pressure relief effect is up to standard.

[0065] Stress monitoring points, microseismic monitoring points, and roadway deformation monitoring points were set up in the access roadway and around the large coal pillar to obtain data on coal stress, microseismic event energy and frequency, and the changes in roof, floor, and sidewall convergence deformation over time and as the working face advanced. The monitoring data before and after roof-cutting blasting and coal pillar decompression blasting were compared and analyzed. The results showed a significant decrease in the stress level of the coal pillar and surrounding rock compared to before blasting, a reduction in the high-stress concentration area and elastic core range of the coal pillar, a decrease in the total energy and frequency of microseismic events, and a reduction in high-energy events. The criteria for determining whether the combined pressure relief effect is met are that the roof subsidence, sidewall bulge, and floor bulge in the access roadway are controlled within the preset safety allowable range and no signs of dynamic disasters such as rockbursts appear within the set advance distance. If the preset evaluation indicators are not met, at least one parameter of the drilling layout, hole depth, spacing, elevation angle, charge structure, and charge amount of the roof cutting blast and coal pillar pressure relief blast should be adjusted, and the roof cutting blast and coal pillar pressure relief blast should be re-implemented, and monitoring and evaluation should be repeated until the pressure relief effect meets the preset requirements.

[0066] The beneficial effects of this application are as follows: By constructing a three-dimensional model including the goaf roadway, lateral large coal pillars, and adjacent goaf areas, and conducting numerical simulations on multiple preset combinations of coal pillar widths and cutting top positions, this application selects target combinations of coal pillar widths and cutting top positions that meet preset requirements. Furthermore, based on the target combination schemes and corresponding geological parameters, the optimal layer for roof cutting blasting is determined, and high-stress zones within the coal pillars are identified based on the numerical simulation results corresponding to the target combination schemes. This achieves joint pressure relief of the roof and coal pillars, effectively cutting off the lateral high static load transfer of the roof and significantly weakening the high stress and elastic energy within the coal pillars. This fundamentally improves the stress environment of the roadway surrounding rock, reduces the risk of rockburst, and enhances the long-term stability of the roadway. This application, through constructing a three-dimensional model and conducting numerical simulations, provides a basis for the cutting and pressure relief ranges, constructs a predictable, controllable, and evaluable joint pressure relief system, and improves the accuracy of blasting.

[0067] In one embodiment, the numerical simulation results include the depth range of the plastic zone of the surrounding rock in the roadway and the peak value of the concentrated stress in the roof under each combination scheme. The above step S103 can be implemented as follows: Based on the numerical simulation results, the scheme that controls the plastic depth of the surrounding rock in the roadway after decompression within a first preset range and reduces the peak value of the concentrated stress in the roof after decompression within a second preset range is selected as the target combination scheme.

[0068] In one embodiment, the step S104 above, which involves determining the optimal stratum for roof-cutting blasting based on the selected target combination scheme and corresponding geological parameters, can be implemented as follows: steps A1-A3: In step A1, the coal pillar and the high stress concentration area of ​​the roadway are identified based on the numerical simulation results corresponding to the target combination scheme; In step A2, the roof treatment height and the critical fracture span of the roof rock beam are determined according to the geological parameters corresponding to the target combination scheme. In step A3, the optimal stratum for roof cutting blasting is determined to be the hard rock stratum located above the high stress concentration zone of the coal pillar and the roadway, within the roof treatment height range, and with a suspended roof length less than the critical fracture span after blasting.

[0069] In one embodiment, the calculation process for the top plate treatment height can be implemented as follows: steps B1-B2: In step B1, the current working face mining height and roof rock strata swelling coefficient are obtained; In step B2, the mining height and the roof strata swelling coefficient are substituted into the following formula to determine the roof treatment height: ; Among them, H ξ represents the roof treatment height; HC represents the mining height; and ξ represents the roof strata fragmentation coefficient.

[0070] In one embodiment, the calculation process for the critical fracture span of the top rock beam can be implemented as follows: steps C1-C2: In step C1, the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth are obtained. In step C2, the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth are substituted into the following formula to determine the critical fracture span of the roof rock beam: ; Where Lcr is the critical fracture span of the roof rock beam, Rt is the tensile strength of the roof rock, h is the thickness of the roof rock strata under overall bending, γ is the average unit weight of the roof rock strata, H is the burial depth, and kL is an empirical coefficient related to the rock strata structure.

[0071] In one embodiment, the method may also be implemented as steps D1-D3: In step D1, data on surrounding rock stress, microseismic energy, and tunnel deformation are monitored and acquired. In step D2, the monitoring data before and after the roof cutting blast and the lateral large coal pillar blast are compared; In step D3, based on the comparison results, it is determined whether the combined pressure relief effect meets the standard.

[0072] In one embodiment, step D3 above can be implemented as steps D31-D32 as follows: In step D31, if the coal stress level decreases by more than the first preset value, high-energy micro-vibration events decrease, and the roadway deformation is less than the second preset value, then the combined pressure relief effect is determined to be satisfactory. In step D32, otherwise, readjust the blasting parameters and execute until the pressure relief effect meets the requirements.

[0073] Figure 3 This application provides an embodiment of a combined pressure relief control device for lateral large coal pillars in an open roadway under a hard roof, such as... Figure 3 As shown, it includes: The acquisition module 301 is used to acquire the geological parameters of the current working face and construct a three-dimensional model including the goaf roadway, the lateral large coal pillar and the adjacent goaf based on the geological parameters. Simulation module 302 is used to perform numerical simulation of multiple preset combinations of coal pillar width and cutting top position using the three-dimensional model; The screening module 303 is used to screen target combination schemes of coal pillar width and cutting top position that meet preset requirements based on the numerical simulation results. The determination module 304 is used to determine the optimal layer for roof cutting blasting based on the target combination scheme and the corresponding geological parameters, and to identify the high-stress zone inside the coal pillar based on the numerical simulation results corresponding to the target combination scheme. The blasting module 305 is used to carry out roof cutting blasting by arranging roof cutting boreholes according to the optimal layer position, and to carry out lateral large coal pillar blasting by arranging pressure relief boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

[0074] In one embodiment, the numerical simulation results include the plastic zone depth range of the surrounding rock in the roadway and the peak value of the concentrated stress in the roof under each combination scheme. The screening module is further used for: Based on the numerical simulation results, the scheme that controls the plastic depth of the surrounding rock in the roadway after decompression within a first preset range and reduces the peak value of the concentrated stress in the roof after decompression within a second preset range is selected as the target combination scheme.

[0075] In one embodiment, the determining module includes: The identification submodule is used to identify coal pillars and high-stress concentration areas in roadways with open spaces based on the numerical simulation results corresponding to the target combination scheme. The first determining submodule is used to determine the roof treatment height and the critical fracture span of the roof rock beam based on the geological parameters corresponding to the target combination scheme. The second determination submodule is used to determine the optimal stratum for roof cutting blasting for hard rock strata located above the high stress concentration zone of coal pillars and adjacent roadways, within the roof treatment height range, and with a post-blast roof overhang length less than the critical fracture span.

[0076] In one embodiment, the first determining submodule is further configured to: Obtain the current working face's mining height and roof strata fragmentation coefficient; Substitute the mining height and the roof strata fragmentation coefficient into the following formula to determine the roof treatment height: ; Among them, H H represents the height of the top slab treatment. C ξ represents the mining height; ξ is the coefficient of fragmentation of the roof strata.

[0077] In one embodiment, the first determining submodule is further configured to: Obtain the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth; Substituting the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth into the following formula, the critical fracture span of the roof rock beam can be determined: ; Where Lcr is the critical fracture span of the roof rock beam, Rt is the tensile strength of the roof rock, h is the thickness of the roof rock strata under overall bending, γ is the average unit weight of the roof rock strata, H is the burial depth, and kL is an empirical coefficient related to the rock strata structure.

[0078] In one embodiment, the apparatus further includes: The monitoring module is used to monitor field data, including coal stress, microseismic event energy frequency, and roadway deformation, during the implementation of roof cutting blasting and lateral large coal pillar blasting. The judgment module is used to determine whether the combined pressure relief effect meets the standard based on the monitored field data.

[0079] In one embodiment, the determining module is further configured to: If the stress level of the coal body decreases by more than the first preset value, high-energy micro-seismic events decrease, and the roadway deformation is less than the second preset value, then the joint pressure relief effect is deemed to have met the standard. Otherwise, readjust the blasting parameters and execute the procedure until the pressure relief effect meets the requirements.

[0080] Figure 4 This is a schematic diagram of the hardware structure of a combined pressure relief control system for lateral large coal pillars in an open roadway under a hard roof, according to one embodiment of this application. Figure 4 As shown, the combined pressure relief control system for the large lateral coal pillar in the roadway under the hard roof includes: At least one processor 420; and, Memory 404 communicatively connected to the at least one processor 420; wherein, The memory 404 stores instructions that can be executed by the at least one processor 420 to implement the combined pressure relief control method for lateral large coal pillars in roadways under hard roof as described in any of the above embodiments.

[0081] Reference Figure 4 The combined pressure relief control system 400 for the large coal pillars on the side of the roadway under the hard roof may include one or more of the following components: processing component 402, memory 404, power supply component 406, input / output (I / O) interface 408, sensor component 410, and communication component 412.

[0082] The processing component 402 typically controls the overall operation of the combined pressure relief control system 400 for lateral large coal pillars in roadways under hard roof. The processing component 402 may include one or more processors 420 to execute instructions to complete all or part of the steps described above. Furthermore, the processing component 402 may include one or more modules to facilitate interaction between the processing component 402 and other components. The processor 420 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor.

[0083] Memory 404 is configured to store various types of data to support the operation of the combined pressure relief control system 400 for lateral large coal pillars in hard roof free-running roadways. Examples of this data include instructions for any application or method used to operate on the combined pressure relief control system 400 for lateral large coal pillars in hard roof free-running roadways. Memory 404 can be an internal storage unit of the terminal device, such as a hard disk or memory of the terminal device. Memory 404 can also be an external storage device of the terminal device, such as a plug-in hard disk equipped on the terminal device. Memory 404 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. Memory 404 is used to store programs and data required by this application. Memory 404 can also be used to temporarily store data that has been output or will be output.

[0084] Power supply assembly 406 provides power to various components of the combined pressure relief control system 400 for lateral large coal pillars in roadways under hard roof. Power supply assembly 406 may include a power management system, one or more power sources, and other components associated with generating, managing, and distributing power to the combined pressure relief control system 400 for lateral large coal pillars in roadways under hard roof.

[0085] I / O interface 408 provides an interface between processing component 402 and peripheral interface modules, such as keyboards, click wheels, buttons, etc.

[0086] Sensor assembly 410 includes one or more sensors for providing various aspects of the status assessment of the combined pressure relief control system 400 for lateral large coal pillars in the hard roof free-running roadway. Additionally, sensor assembly 410 can detect the on / off state of the combined pressure relief control system 400 for lateral large coal pillars in the hard roof free-running roadway, the relative positioning of components, and the operating status of the combined pressure relief control system 400 for lateral large coal pillars in the hard roof free-running roadway or one of its components. In some embodiments, sensor assembly 410 may include accelerometers, gyroscopes, magnetometers, pressure sensors, or temperature sensors, etc.

[0087] Communication component 412 is configured to enable the combined pressure relief control system 400 for lateral large coal pillars in a hard roof free-running roadway to provide wired or wireless communication capabilities with other devices and a cloud platform. The combined pressure relief control system 400 for lateral large coal pillars in a hard roof free-running roadway can access wireless networks based on communication standards, such as WiFi, 2G, or 3G, or combinations thereof. In one exemplary embodiment, communication component 412 receives broadcast signals or broadcast-related information from an external broadcast management system via a broadcast channel. In one exemplary embodiment, communication component 412 also includes a near-field communication (NFC) module to facilitate short-range communication. For example, the NFC module may be implemented based on radio frequency identification (RFID) technology, Infrared Data Association (IrDA) technology, ultra-wideband (UWB) technology, Bluetooth (BT) technology, and other technologies.

[0088] In an exemplary embodiment, the combined pressure relief control system 400 for lateral large coal pillars in a roadway under a hard roof can be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the combined pressure relief control method for lateral large coal pillars in a roadway under a hard roof as described in any of the above embodiments.

[0089] This application also provides a computer-readable storage medium, which, when the instructions in the storage medium are executed by the processor corresponding to the combined pressure relief control system for the lateral large coal pillar in the hard roof free-running roadway, enables the combined pressure relief control system for the lateral large coal pillar in the hard roof free-running roadway to realize the combined pressure relief control method for the lateral large coal pillar in the hard roof free-running roadway described in any of the above embodiments. Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0090] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0091] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0092] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0093] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A method for combined pressure relief control of lateral large coal pillars in a roadway under a hard roof, characterized in that, include: Obtain the geological parameters of the current working face, and construct a three-dimensional model including the goaf roadway, lateral large coal pillars and adjacent goaf areas based on the geological parameters; The three-dimensional model is used to numerically simulate multiple preset combinations of coal pillar widths and top cutting positions. Based on the numerical simulation results, a target combination scheme of coal pillar width and cut-off top position that meets the preset requirements is selected; The optimal stratum for roof cutting blasting is determined based on the target combination scheme and the corresponding geological parameters, and the high-stress zone inside the coal pillar is identified based on the numerical simulation results corresponding to the target combination scheme. Roof cutting blasting is carried out by arranging top-cutting boreholes according to the optimal stratum, and lateral large coal pillar blasting is carried out by arranging pressure-relieving boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

2. The method as described in claim 1, characterized in that, The numerical simulation results include the depth range of the plastic zone of the surrounding rock in the roadway and the peak value of the concentrated stress in the roof under each combination scheme. The step of selecting the target combination scheme of coal pillar width and cut-off roof position that meets the preset requirements based on the numerical simulation results includes: Based on the numerical simulation results, the scheme that controls the plastic depth of the surrounding rock in the roadway after decompression within a first preset range and reduces the peak value of the concentrated stress in the roof after decompression within a second preset range is selected as the target combination scheme.

3. The method as described in claim 1, characterized in that, The step of determining the optimal stratum for roof-cutting blasting based on the selected target combination scheme and corresponding geological parameters includes: Identify coal pillars and high-stress concentration areas in accessible roadways based on the numerical simulation results corresponding to the target combination scheme; The treatment height of the roof and the critical fracture span of the roof rock beam are determined based on the geological parameters corresponding to the target combination scheme. The optimal stratum for roof cutting blasting is determined to be a hard rock stratum located above the high stress concentration zone of the coal pillar and the roadway, within the roof treatment height range, and with a post-blast roof overhang length less than the critical fracture span.

4. The method as described in claim 3, characterized in that, The calculation process for the top plate treatment height includes: Obtain the current working face's mining height and roof strata fragmentation coefficient; Substitute the mining height and the roof strata fragmentation coefficient into the following formula to determine the roof treatment height: ； Among them, H ξ represents the roof treatment height; HC represents the mining height; and ξ represents the roof strata fragmentation coefficient.

5. The method as described in claim 3, characterized in that, The calculation process for the critical fracture span of the top rock beam includes: Obtain the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth; Substituting the tensile strength of the roof rock, the thickness of the roof rock strata under overall bending, the average unit weight of the roof rock strata, and the burial depth into the following formula, the critical fracture span of the roof rock beam can be determined: ； Where Lcr is the critical fracture span of the roof rock beam, Rt is the tensile strength of the roof rock, h is the thickness of the roof rock strata under overall bending, γ is the average unit weight of the roof rock strata, H is the burial depth, and kL is an empirical coefficient related to the rock strata structure.

6. The method as described in claim 1, characterized in that, The method further includes: Monitoring and acquiring data on surrounding rock stress, microseismic energy, and tunnel deformation; Compare the monitoring data before and after the implementation of roof cutting blasting and lateral large coal pillar blasting; Based on the comparison results, determine whether the combined pressure relief effect meets the standard.

7. The method as described in claim 6, characterized in that, The step of determining whether the combined pressure relief effect meets the standard based on the comparison results includes: If the stress level of the coal body decreases by more than the first preset value, the frequency of high-energy micro-seismic events decreases, and the roadway deformation is less than the second preset value, then the joint pressure relief effect is deemed to meet the standard. Otherwise, readjust the blasting parameters and execute the procedure until the pressure relief effect meets the requirements.

8. A combined pressure relief control device for lateral large coal pillars in a roadway under a hard roof, characterized in that, include: The acquisition module is used to acquire the geological parameters of the current working face and construct a three-dimensional model including the goaf roadway, the lateral large coal pillar and the adjacent goaf based on the geological parameters; The simulation module is used to perform numerical simulations of multiple preset combinations of coal pillar widths and cut-off top positions using the three-dimensional model. The screening module is used to screen target combination schemes of coal pillar width and cutting top position that meet preset requirements based on the numerical simulation results; The determination module is used to determine the optimal layer for roof cutting blasting based on the target combination scheme and the corresponding geological parameters, and to identify the high-stress zone inside the coal pillar based on the numerical simulation results corresponding to the target combination scheme. The blasting module is used to carry out roof cutting blasting by arranging roof cutting boreholes according to the optimal stratum, and to carry out lateral large coal pillar blasting by arranging pressure relief boreholes in the lateral large coal pillar according to the high stress zone inside the coal pillar.

9. A combined pressure relief control system for lateral large coal pillars in a roadway under a hard roof, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to implement the combined pressure relief control method for lateral large coal pillars in roadways under hard roof as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, When the instructions in the storage medium are executed by the processor corresponding to the joint pressure relief control system for the large coal pillar on the side of the roadway under hard roof, the joint pressure relief control system for the large coal pillar on the side of the roadway under hard roof can realize the joint pressure relief control method for the large coal pillar on the side of the roadway under hard roof as described in any one of claims 1-7.

Images