Overlying strata multi-key layer composite pressure relief method and device, electronic equipment and storage medium

Abstract

The invention relates to the technical field of coal mining, and discloses an overlying strata multi-key layer composite pressure relief method and device, electronic equipment and a storage medium. Comprising the following steps: acquiring multi-mode rock stratum information of each overlying rock stratum of a target mining area; key strata in all the overlying strata are judged through the multi-mode strata information of all the overlying strata; based on the lithology and the mechanical property of each key layer, determining a pressure relief mode of each key layer; and determining pressure relief parameters of each key layer based on the pressure relief mode of each key layer. According to the method, the load distribution of each rock stratum is quantitatively calculated to judge the bearing capacity of each overlying rock stratum so as to preliminarily screen the key layer candidate layer, the fracture distance of the key layer candidate layer is further calculated to judge the fracture critical condition of each key layer candidate layer, and finally the key layer is screened out, so that the reliability of a key layer judgment result can be improved, and the judgment accuracy of the key layer is improved. It is ensured that the determined key layer is the optimal pressure relief layer position, and the economic benefit and efficiency of pressure relief construction can be improved.

Description

Technical Field

[0001] This invention relates to the field of coal mining technology, specifically to a composite pressure relief method for multiple key overburden layers, a composite pressure relief device for multiple key overburden layers, an electronic device, and a computer-readable storage medium. Background Technology

[0002] In coal mining, especially in areas with deep burial depths and complex surrounding rock stress environments, there are typically two or more critical layers in the overburden strata at the working face. If one of these critical layers migrates, it can affect the deformation and fracture of the adjacent roof, creating a complex effect between two or more layers. This manifests as synchronous movement of multiple layers, rather than a bottom-up transmission from the roof strata. However, the controlling effect of the complex roof on overburden movement is far greater than the linear superposition of single layers. The dynamic stress generated by the movement of the complex roof has a wide range and high speed, easily leading to large-scale deformation of the surrounding rock, spalling, and rockbursts due to large-amplitude fractures and high energy release, hindering safe and efficient coal mine production. Therefore, it is necessary to implement pressure relief and control measures for the overburden strata.

[0003] Currently, the decompression control methods for multiple key layers in overburden are mainly designed and constructed for low-level key layers or a single key layer, often ignoring the influence of high-level key layers or other key layers. The designed decompression key parameters are not reasonable enough, which can easily lead to poor decompression effect. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem of poor pressure relief effect in existing pressure relief control methods for multiple key overburden layers, and to provide a composite pressure relief method, device, electronic equipment and storage medium for multiple key overburden layers.

[0005] To achieve the above objectives, the present invention provides a composite depressurization method for multiple key overburden layers, mainly comprising: Obtain multimodal strata information of each overlying stratum in the target mining area; Key layers in all overburden strata are identified using multimodal strata information from each overburden stratum; Based on the lithology and mechanical properties of each key layer, the decompression method for each key layer is determined; Based on the depressurization method of each key layer, the depressurization parameters of each key layer are determined.

[0006] Optionally, the step of identifying key layers among all overburden layers using multimodal strata information of each overburden layer includes: Using multimodal rock strata information of each overburden layer, the load and fracture distance of each overburden layer are calculated; Based on the load and fracture distance of each overburden layer, the key layers in all overburden layers are identified.

[0007] Optionally, determining the decompression method for each key layer based on its lithology and mechanical properties includes: Based on the multimodal rock strata information, the cementation index, permeability coefficient, hardness coefficient and / or key layer spacing of each key layer are calculated respectively; Based on the cementation index, permeability coefficient, hardness coefficient and / or spacing of each key layer, the depressurization method of each key layer is determined.

[0008] Optionally, based on the cementation index, permeability coefficient, hardness coefficient, and / or spacing of each key layer, the depressurization method for each key layer is determined, including: If the cementation index of the key layer is less than the preset cementation index threshold and the permeability coefficient exceeds the preset permeability coefficient threshold, then the blasting depressurization method shall be adopted. If the permeability coefficient of the critical layer is less than the preset permeability coefficient threshold and the hardness coefficient is greater than the preset hardness coefficient threshold, then hydraulic fracturing and pressure relief shall be adopted.

[0009] Optionally, the key layers include upper overburden and lower overburden, and determining the decompression parameters of each key layer based on its decompression method includes: Numerical simulation methods were used to calculate the stress changes and load transfer patterns between key layers, and to determine the degree of stress relief influence of higher key layers on lower key layers. Based on the degree of pressure relief influence of the high-level critical layer on the low-level critical layer and the pressure relief method of each critical layer, the pressure relief parameters of each critical layer are determined.

[0010] Optionally, determining the depressurization parameters of each critical layer based on the degree of depressurization influence of the higher critical layer on the lower critical layer and the depressurization method of each critical layer includes: If the pressure relief method of the critical layer is blasting, the blasting borehole diameter, blasting hole spacing, blasting borehole angle and explosive amount of the corresponding critical layer are determined based on the degree of pressure relief influence of the higher critical layer on the lower critical layer. If the depressurization method of the critical layer is hydraulic fracturing, the hydraulic fracturing borehole diameter, hydraulic fracturing borehole spacing, hydraulic fracturing borehole inclination angle, hydraulic fracturing borehole depth and high-pressure water pressure of the corresponding critical layer are determined based on the degree of depressurization influence of the higher critical layer on the lower critical layer.

[0011] Optional, also includes: After depressurization construction is carried out according to the depressurization method of each key layer, data on the development of internal cracks in the borehole before and after blasting of each key layer, energy data of microseismic events in the depressurization zone and non-depressurization zone, and stress distribution characteristics of the coal pillar in the section are obtained. The stress relief effect is evaluated using the borehole internal fracture development data, the microseismic event energy data, and the stress distribution characteristics of the coal pillar in the section, resulting in an evaluation result of the stress relief effect. A second aspect of this invention provides a composite stress relief device for multiple key overburden layers, mainly comprising: The data acquisition module is used to acquire multimodal strata information of each overlying stratum in the target mining area; The key layer identification module is used to identify key layers in all overburden layers by utilizing multimodal strata information from each overburden layer. The decompression method determination module is used to determine the decompression method for each key layer based on its lithology and mechanical properties. The pressure relief parameter design module is used to determine the pressure relief parameters of each key layer based on the pressure relief method of each key layer.

[0012] A third aspect of the present invention provides an electronic device, the electronic device comprising a memory for storing executable instructions; and a processor for calling and running the executable instructions in the memory to perform the steps of the above-described composite depressurization method for multiple key overburden layers.

[0013] A fourth aspect of the present invention provides a computer-readable storage medium storing program instructions that, when executed by a processor, implement the steps of the above-described composite depressurization method for multiple key overburden layers.

[0014] Compared with existing technologies, the beneficial effects of this solution are as follows: This invention determines the bearing capacity of each overburden layer by quantitatively calculating the load distribution of each rock layer, in order to initially screen rock layers that may be key layers (i.e., key layer candidate layers), and further calculates the fracture distance of the key layer candidate layers to determine the fracture critical conditions of each key layer candidate layer, and finally screens out the key layers. This can improve the reliability of the key layer identification results, ensure that the determined key layers are the optimal pressure relief layers, and help improve the economic benefits and efficiency of pressure relief construction.

[0015] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 Here is a simplified flowchart of the composite pressure relief method for multiple key overburden layers of the present invention; Figure 2 This is a detailed flowchart of the composite pressure relief method for multiple key overburden layers of the present invention; Figure 3 This is a schematic diagram of segmented deep-hole blasting and pressure relief of the high-level key layer and the low-level key layer of the present invention; Figure 4 This is a schematic diagram of the segmented hydraulic fracturing and depressurization of the high-level critical layer and the low-level critical layer of the present invention; Figure 5 This is a schematic diagram of deep-hole blasting and pressure relief in the high-level key layer of the present invention; Figure 6 This is a schematic diagram of the hydraulic depressurization of the high-level key layer of the present invention; Figure 7 This is a schematic diagram of deep-hole blasting pressure relief in the low-level key layer of the present invention; Figure 8 This is a schematic diagram of the hydraulic depressurization of the low-level key layer of the present invention; Figure 9 This is a schematic diagram of the composite pressure relief device module for multiple key overburden layers of the present invention; Figure 10 This is a schematic diagram of the electronic device structure of the present invention.

[0017] Explanation of reference numerals in the attached figures 1-Goaf; 2-Sectional protective coal pillar; 3-Return airway; 4-High-level key stratum; 5-Weak rock stratum; 6-Low-level key stratum; 7-First charging section of segmented deep-hole blasting pressure relief in high-level and low-level key strata; 8-First sealing section of segmented deep-hole blasting pressure relief in high-level and low-level key strata; 9-Second charging section of segmented deep-hole blasting pressure relief in high-level and low-level key strata; 10-Second sealing section of segmented deep-hole blasting pressure relief in high-level and low-level key strata; 11-High-level key... 12-Sectional hydraulic fracturing and pressure relief first fracturing zone for high and low key layers; 13-Deep hole blasting pressure relief charging section for high key layers; 14-Deep hole blasting pressure relief sealing section for high key layers; 15-Deep hole blasting pressure relief charging section for low key layers; 16-Deep hole blasting pressure relief sealing section for low key layers; 17-Hydraulic fracturing and pressure relief fracturing zone for high key layers; 18-Hydraulic fracturing and pressure relief fracturing zone for low key layers. Detailed Implementation

[0018] The technical solutions of 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 a part of the embodiments of the present invention, and not all of the 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.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Please refer to Figure 1 and Figure 2 This invention proposes a composite decompression method for multiple key overburden layers, comprising: Step 100: Obtain multimodal strata information of each overburden layer in the target mining area.

[0021] Specifically, by integrating coalfield exploration borehole data and working face mining data, multimodal strata information of each overlying stratum in the target mining area is obtained. This multimodal strata information includes stratigraphic mechanical parameters such as vertical thickness of the strata, unit weight of each stratum, Young's modulus, uniaxial compressive strength, and tensile strength; mining condition data such as the number of overlying strata and their vertical order; coal seam depth; stress environment; and historical pressure step distance of the working face; as well as surface characteristic parameters such as the thickness and density of the loose surface layer.

[0022] Step 200: Identify the key layers in all overburden layers using the strata information of each overburden layer.

[0023] Specifically, firstly, based on parameters such as Young's modulus and thickness of each rock stratum, the bearing capacity of each stratum is analyzed layer by layer using load calculation formulas to screen overburden strata that may be critical layers as candidate critical layers. Then, the theoretical failure distance of each candidate critical layer is calculated. By comparing the numerical relationship of failure distances of adjacent rock strata, the location of each critical layer is identified from the candidate critical layers, thereby identifying the critical layers among all overburden strata. This achieves critical layer identification using both load transfer and failure distance criteria.

[0024] Step 300: Determine the depressurization method for each key layer based on its lithology and mechanical properties.

[0025] Specifically, for overburden strata with multiple rock layers, there are usually at least two key layers. This embodiment employs differentiated decompression strategies based on the different lithologies and mechanical properties of each key layer to precisely control the decompression method and intensity, avoiding sudden large-scale roof impacts during coal seam mining. When the lithologies of different key layers are similar and the spacing is large, a segmented unified decompression method is used; when the lithologies of different key layers are different, a fracturing method matching the lithological characteristics and mechanical properties of each key layer is selected. For example, blasting decompression is suitable for poorly cemented rock layers, and interlayer isolation can be achieved through segmented charging; hydraulic fracturing is for hard rock layers with poor permeability, and segmented fracturing can be achieved through high-pressure water injection.

[0026] Step 400: Determine the depressurization parameters of each key layer based on the depressurization method of each key layer.

[0027] Specifically, in actual decompression construction, the decompression of high-level critical strata typically manifests as subsidence and stress release of the strata themselves and their controlling layers, while the decompression of low-level critical strata typically manifests as stress concentration and release. Stress concentration may lead to decreased stability and increased safety risks in low-level critical strata, while stress release allows for a certain degree of decompression relief. Furthermore, after decompression of the high-level critical strata, some of the load it bears will be transferred to the low-level critical strata. Therefore, this embodiment considers the impact of stress changes when determining the decompression parameters for each critical strata, and the setting of decompression parameters for the low-level critical strata considers the impact of factors such as the load transferred from the high-level critical strata. Simultaneously, in actual decompression construction, the high-level critical strata decompression is carried out first, followed by the low-level critical strata decompression, to minimize the impact of other rock layers on the decompression effect of the decompressed rock layers. Different decompression methods correspond to different types of decompression parameters. For example, the decompression parameters for blasting decompression include borehole diameter, charge quantity configured according to borehole diameter, borehole spacing, and borehole angle; while the decompression parameters for hydraulic fracturing decompression include borehole inclination angle, borehole depth, borehole spacing, and injection pressure.

[0028] In this embodiment, by utilizing the multimodal strata information of each overburden layer in the target mining area, the location of key layers in all overburden layers can be accurately identified. Based on the lithology and mechanical properties of each key layer, appropriate decompression methods are selected for the differences of each key layer, and the decompression parameters of the corresponding decompression methods are calculated. This enables customized decompression for each key layer, which can improve the effectiveness and comprehensiveness of composite decompression for each key layer, thereby improving the composite decompression control effect and efficiency of all key layers.

[0029] In a preferred embodiment, step 200, which utilizes multimodal strata information from each overburden layer to identify key layers among all overburden layers, includes: Step 210: Calculate the load and fracture distance of each overburden layer using the multimodal rock strata information of each overburden layer; Step 220: Based on the load and fracture distance of each overburden layer, identify the key layer in all overburden layers.

[0030] Specifically, the load on each overburden layer is calculated by using the thickness, unit weight, and Young's modulus of each overburden layer from the multimodal rock strata information. Based on the load magnitude of each overburden layer and the load transport between each overburden layer, the overburden layers that may be key layers are identified and screened as candidate key layers.

[0031] As a preferred example, if there are exactly two overburden layers, the first and the second... Layer 1 is a candidate layer for key layers, and layer 2 represents the lowest layer of overburden. The layer represents the uppermost overburden layer, located between layer 1 and layer 2. The overburden layer in the middle of the layer only deforms in tandem with the first key candidate layer. If the candidate key layer does not deform in tandem with the underlying rock strata, then the first candidate key layer (i.e., layer 1) will bear the weight of the overburden layer from layer 1 to layer 2. The load applied by the overlying rock strata can be expressed as: (1) in, The first to the second layer of the overlying rock strata The load formed by the rock strata; For the first The thickness of the rock strata; For the first The unit weight of the rock strata; E j For the first Young's modulus of the rock strata; , This indicates the total number of overburden layers in the target mining area.

[0032] Secondly, the second key layer candidate layer (i.e. The load of a layer on the first critical layer candidate layer below it can be expressed as: (2) Furthermore, due to the second key layer candidate layer (i.e., the first...) The mining intensity experienced by the (n+1)th layer is much less than that of the first critical stratum candidate layer (i.e., the 1st layer), and the deflection of the (n+1)th layer is less than that of the underlying overburden layer. Therefore, the (n+1)th layer and above no longer require the underlying rock layers to bear the load they bear. Thus, the second critical stratum candidate layer (i.e., the... If the overlying strata of the first key stratum can be ignored, then the load borne by the second key stratum candidate layer is less than that borne by the first key stratum candidate layer. Substituting into equations (1) and (2) and simplifying, we get: (3) By analogy, the magnitude of the load borne by each rock layer can be determined according to equations (1) to (3), and the location of each key candidate layer can be determined.

[0033] Furthermore, the failure distance of each key candidate layer is calculated. Among them, the... Break distance of key candidate layer It can be represented as: (4) in, For the first The fault distance of the candidate layer of the critical layer, The value can be 1 or n+1; For the first Tensile strength of the candidate layer of the key layer; For the first The load of the candidate critical layer is calculated using the following formula: (5) in, For the first The first key candidate layer controls the overlying rock mass Young's modulus of the layered rock mass; Indicates the first Young's modulus of the 0th rock layer in the overlying rock mass controlled by the candidate key layer; For the first The first in the overlying rock mass controlled by the candidate layer of the key layer Height of the rock mass layer; γ m，j For the first The first in the overlying rock mass controlled by the candidate layer of the key layer Density of rock layers.

[0034] Assuming the thickness of the loose surface layer is The density is Then the load of the highest critical candidate layer is: (6) in, For the first Young's modulus of key candidate layers; For the first Thickness of key candidate layers; The thickness of the loose surface layer; Density of the loose surface layer; Indicates the first The first key candidate layer controls the overlying rock mass Young's modulus of the layered rock mass; For the first The first in the overlying rock mass controlled by the candidate layer of the key layer Height of the rock mass layer; For the first The first in the overlying rock mass controlled by the candidate layer of the key layer Density of rock layers.

[0035] Based on the fracture distance of the key layer candidate layer calculated using formula (4), the key layer is identified, specifically including: assuming the m-th key layer candidate layer is a key layer, then theoretically the fracture distance of the m-th key layer candidate layer should be smaller than the fracture distance of the overburden layer above it; if there is a fracture distance of the m-th key layer candidate layer that is greater than the fracture distance of at least one overburden layer above it, then the fracture distance of the m-th key layer candidate layer needs to be reconfirmed, and the fracture distances of the m-th layer and the overburden layer above it are superimposed; according to the formula... In a bottom-up order, the fracture distance of each key candidate layer is compared with the fracture distance of the overburden layer above it. If the fracture distance of the m-th key candidate layer is smaller than the fracture distance of any overburden layer above it, then the m-th key candidate layer is a key layer. If the fracture distance of the m-th key candidate layer is greater than the fracture distance of at least one overburden layer above it, then the fracture distance of the m-th key candidate layer is corrected to ensure that the fracture distance of the m-th key candidate layer is less than the fracture distance of any overburden layer above it.

[0036] In this embodiment, the bearing capacity of each overburden stratum is determined by quantitatively calculating the load distribution of each stratum, so as to initially screen the strata that may be key strata (i.e., key stratum candidate strata). Furthermore, the fracture distance of the key stratum candidate strata is calculated to determine the fracture critical conditions of each key stratum candidate strata, and finally the key strata are screened out. This can improve the reliability of the key strata identification results, ensure that the determined key strata are the best pressure relief strata, and help improve the economic benefits and efficiency of pressure relief construction.

[0037] In a preferred embodiment, step 300, based on the lithology and mechanical properties of each key layer, determines the decompression method for each key layer, including: Step 310: Based on the multimodal rock strata information, calculate the cementation index, permeability coefficient, hardness coefficient and / or key layer spacing for each key layer; Step 320: Determine the depressurization method for each key layer based on the bonding index, permeability coefficient, hardness coefficient and / or key layer spacing of each key layer.

[0038] Specifically, this embodiment calculates the cementation index, permeability coefficient, hardness coefficient, and / or interlayer spacing of each key layer based on multimodal rock strata information. The cementation index reflects the cementation strength between rock particles; poorly cemented strata (such as loose sandstone) are easily propagated through blasting to relieve pressure, while strongly cemented strata require higher energy intervention. The permeability coefficient characterizes the water permeability of the rock mass and is a key indicator for judging the suitability of hydraulic fracturing; highly permeable strata (such as fractured limestone) are suitable for hydraulic fracturing, while low-permeability strata require blasting to relieve pressure. The hardness coefficient distinguishes the mechanical properties of the rock strata (medium-hard / hard rock); hard rock strata require higher explosive charges or fracturing pressures to effectively induce fracturing.

[0039] Then, the cementation index, permeability coefficient, and hardness coefficient of each key layer are combined with the distance between key layers (i.e., the vertical distance between high and low layers) to determine the appropriate decompression method for each key layer. For example, if the lithology of each key layer is similar and the distance between them is large, a segmented unified decompression method is adopted, and high and low layers are independently controlled by segmented isolation within the borehole; if the lithology of each key layer is significantly different, construction is prioritized on the high layer, and lithology is used as the main consideration when matching the decompression method; at the same time, if the key layers are close together, the safety redundancy of the decompression parameters is increased by reducing the borehole spacing or increasing the fracturing pressure to control interlayer influence and avoid stress superposition disturbance; if the key layers are close together, decompression construction of the key layers is carried out by segmented decompression to ensure that each key layer is fully decompressed. Preferably, the selection principle for the fracturing method is as follows: if the cementation index of the key layer is less than a preset cementation index threshold and the permeability coefficient exceeds a preset permeability coefficient threshold, then blasting is used for pressure relief. The preset cementation index threshold represents the critical value for judging the good or bad cementation of the overburden, and the preset permeability coefficient threshold represents the critical value for judging the strength of water permeability of the overburden. If the permeability coefficient of the key layer is less than a preset permeability coefficient threshold and the hardness coefficient is greater than a preset hardness coefficient threshold, then hydraulic fracturing is used for pressure relief. The preset hardness coefficient threshold represents the critical value for judging that the hardness of the overburden has reached moderate hardness. That is, for poorly cemented and highly permeable rock layers, deep-hole blasting is used to expand the fractures, while for hard rock layers with poor permeability, hydraulic fracturing is used to induce fractures by wedging high-pressure water into the rock mass.

[0040] As can be seen, this embodiment achieves precise and flexible selection of decompression methods for each key layer based on the intelligent matching of multiple parameters related to lithology and mechanical properties with interlayer spacing. This not only effectively solves the shortcomings of insufficient adaptability of a single method, but also reduces the risk of interlayer interference through high-level priority construction.

[0041] As a preferred example, when the lithology and mechanical properties of the high-level and low-level key strata are the same and the distance between the two strata is relatively large, the same decompression method is selected to decompress the high-level and low-level key strata in stages. Preferably, if the lithology of both the high-level and low-level key strata is poorly cemented and highly permeable, then staged blasting decompression is selected; if the lithology of both the high-level and low-level key strata is poorly permeable medium-hard or hard rock, then staged hydraulic fracturing decompression is selected. When the lithology and mechanical properties of the high-level and low-level key strata are different, different decompression methods are selected to decompress the high-level and low-level key strata respectively. Preferably, if the lithology of the high-level or low-level key layer is a poorly cemented and highly permeable rock layer, then the blasting decompression method is selected for decompression construction of the key layer; if the lithology of the high-level or low-level key layer is a medium-hard or hard rock layer with poor permeability, then the hydraulic fracturing decompression method is selected for decompression construction of the key layer.

[0042] In a preferred embodiment, to simplify the number of depressurization methods used for depressurizing different critical layers and reduce the difficulty of depressurization operations, this embodiment considers the case of having only two critical layers, namely, a high-level critical layer and a low-level critical layer. Therefore, in step 400, based on the depressurization method of each critical layer, the depressurization parameters for each critical layer are determined, including: Step 410: Use numerical simulation methods to calculate the stress changes and load transfer patterns between key layers, and determine the degree of stress relief influence of the higher key layer on the lower key layer.

[0043] Specifically, due to the greater thickness and stronger bearing capacity of the upper critical layer, it can typically bear larger loads and transfer them to the lower critical layers or other rock strata below. However, the load distribution within the rock strata is usually uneven and susceptible to factors such as the physical properties of the rock strata. After decompression, the upper critical layer releases stress in the rock strata it controls, forming a decompression zone. The load transferred through this layer is then transferred to other rock strata, including the lower critical layer. The extent and degree of the decompression zone depend on the physical and mechanical properties of the upper critical layer itself. Simultaneously, the decompression of the upper critical layer typically manifests as subsidence and stress release in itself and the rock strata it controls, while the lower critical layer typically exhibits stress concentration and release. Stress concentration may lead to decreased stability and increased safety risks in the lower critical layer, while stress release provides a certain degree of decompression relief. For example, assuming the loads borne by the upper and lower critical layers are respectively located at... and ,definition η The pressure relief efficiency coefficient for high-level critical layers (0.5~0.8 for explosive pressure relief and 0.3~0.6 for hydraulic fracturing) represents the load released after pressure relief of the high-level critical layers. It can be represented as: The load released from the higher critical layer will be transferred to the lower critical layer, and the load change borne by the lower critical layer is as follows: .

[0044] Therefore, after determining the decompression method for each key layer, this embodiment determines the degree of decompression influence of the high-level key layer on the low-level key layer based on the stress changes between each key layer and the influence of load transfer between each rock layer. Decompression construction is then carried out in the order of first the high-level key layer and then the low-level key layer to control the influence of load transfer between rock layers during the decompression construction process.

[0045] Step 420: Based on the degree of pressure relief influence of the high-level critical layer on the low-level critical layer and the pressure relief method of each critical layer, determine the pressure relief parameters of each critical layer.

[0046] Specifically, if the decompression method for the critical layer is blasting, the diameter, spacing, angle, and explosive charge of the blasting boreholes for the corresponding critical layer are determined based on the degree of influence of the higher critical layer on the lower critical layer. If the decompression method for the critical layer is hydraulic fracturing, the diameter, spacing, inclination, depth, and high-pressure water pressure of the hydraulic fracturing boreholes for the corresponding critical layer are determined based on the degree of influence of the higher critical layer on the lower critical layer. For example, for blasting decompression, if stress concentration is detected in the lower critical layer after decompression of the higher critical layer, resulting in a sudden increase in microseismic energy, the blasting intensity is increased first. For hydraulic fracturing decompression, if the wave velocity in the lower critical layer is abnormal after decompression of the higher critical layer, the hydraulic fracturing parameters are adjusted first.

[0047] As a preferred example, for the blasting pressure relief method, the deep-hole blasting pressure relief parameters designed for actual fracturing operations include: The preferred diameter for blasting boreholes is 65mm, 75mm, or 89mm. Parameters influencing the explosive charge include explosive diameter, borehole diameter, explosive detonation velocity, explosive density, and the uniaxial compressive strength of the coal and rock mass. In this example, the preferred charge per meter for blasting boreholes with diameters of 65mm, 75mm, and 89mm are 0.23kg, 0.84kg, and 2.58kg, respectively. L f In particular, considering that the accuracy of the measurement may be affected by human factors, this example is corrected by simulation verification based on actual on-site engineering scenarios after theoretical calculations.

[0048] Since the choice of blast hole spacing directly affects whether the fracture zone can be penetrated, if decoupled charges are used, the initial impact pressure after blasting is calculated based on the blast stress wave. and the range of single-hole blasting fracturing zone ， The calculation expressions are as follows: (7) (8) in, For the density of the explosive, ; For the detonation velocity of the explosive, ; The diameter of the propellant charge is in meters (m). The borehole diameter is in meters (m). Energy transfer efficiency factor; This is a proportionality coefficient related to the failure characteristics of the rock mass; The tensile strength of the rock mass; The decay index; Let be the radius of the charge, in meters (m).

[0049] Specifically, the determined blasting parameters are substituted into equations (7) and (8) to calculate the range of the single-hole blasting fracturing zone. Furthermore, considering the pre-cracking amplification factor... The furthest fracture development range of a single-hole blasted rock mass can be expressed as: Therefore, the optimal range for the spacing between blasting holes is determined. to .

[0050] Regarding the arrangement of boreholes, the angle of blasting boreholes The calculation expression is: (9) In the formula, This refers to the vertical distance from the bottom of the charging section of the borehole to the coal seam. This refers to the horizontal distance from the bottom of the charging section hole to the return airway / ventilation roadway of the working face.

[0051] Based on equations (7) to (9), this example preferably uses uncoupled charges to reduce the duration of the blasting compression wave and increase the radius of the fracture zone. The hole spacing is determined according to the width of the crushing zone and the fracture zone so that the fracture zones of two adjacent blast holes can be connected. The charge length of each borehole is 1 / 3 to 1 / 2 of the borehole depth, and the corresponding sealing length is 1 / 2 to 2 / 3 of the borehole depth.

[0052] As another preferred example, for hydraulic fracturing depressurization methods, the hydraulic fracturing depressurization parameters designed for actual fracturing operations include: Regarding the arrangement of boreholes, the angle of hydraulic drilling... The calculation expression is: (10) In the formula, The vertical distance from the hydraulic borehole to the coal seam; This refers to the horizontal distance between the hydraulic borehole and the coal seam.

[0053] The depth of hydraulic fracturing boreholes is determined based on historical experience from previous mining operations or similar geological conditions in coal mines, combined with the initial fracturing step distance and the periodic fracturing step distance of the key strata.

[0054] Drilling spacing b The calculation expression is: (11) in, The borehole diameter is in mm and is determined based on the lithology of each key layer. Where is the coal seam thickness, in meters (m). The coefficient of strength of the top plate; The depth of the coal seam in the working face is used as a reference. The preferred range for borehole spacing is 10 to 15 meters.

[0055] High pressure water pressure The calculation expression is: (12) in, This is an estimated pressure required for hydraulic fracturing, in MPa; The maximum principal stress in the fracturing zone is expressed in MPa. The minimum principal stress in the fracturing zone, MPa: denoted as σ0, where σ0 is the tensile strength of the top strata in the fracturing zone, expressed in MPa.

[0056] In this embodiment, the pressure relief parameters of different pressure relief methods are flexibly adjusted by combining theoretical calculations with dynamic adjustments based on field verification. This ensures the pressure relief effect while avoiding rock instability caused by excessive construction, thereby significantly improving the safety of coal mining.

[0057] In a preferred embodiment, the step of performing decompression construction on the high-level key strata and the low-level key strata according to their lithology and mechanical properties specifically includes: 1) If the lithology and mechanical properties of the high-level key layer and the low-level key layer are the same and the distance between the two layers is far, the same decompression method shall be selected to decompress the high-level and low-level key layers in stages.

[0058] As a preferred example, if the two key layers are poorly cemented and highly permeable rock strata, a segmented blasting decompression method is chosen for decompression construction. Preferably, segmented deep-hole blasting employs an in-hole segmented charging method, dividing the entire deep-hole blasting into two segments, with a blocking section as the boundary. Both segments use continuous charges, each detonated with a different time-delay detonator, proceeding from shallow to deep holes. For example, as... Figure 3 As shown, the high-level key overburden layer 4 and the low-level key overburden layer 6 are located above the section coal pillar 2 and roadway 3. Blasting holes are constructed along one side of the goaf 1 for the high-level key overburden layer 4 and the low-level key overburden layer 6. The blasting holes are charged in sections 7 and 9 inside the hole, and sections 8 and 10 are the sealing sections. Different time-delay detonators are installed in each section for detonation, and blasting proceeds from the low level to the high level. The angle of the blasting borehole for decompression is shown. This is the high-level critical layer depressurization and charging section. This is the pressure relief section of the low-lying critical layer. This is a high-level critical layer pressure relief and sealing section. This is the pressure relief and sealing section of the low-level critical layer.

[0059] As another preferred example, if the two key layers are medium-hard or hard rock layers with poor permeability, a segmented hydraulic fracturing depressurization method is selected for depressurization construction. Preferably, the segmented hydraulic fracturing depressurization is divided into two segments with the barrier segment as the boundary, and hydraulic fracturing depressurization is carried out sequentially from the high position to the low position.

[0060] For example, such as Figure 4 As shown, the high-level key overburden strata 4 and the low-level key overburden strata 6 are located above the section coal pillar 2 and roadway 3. Hydraulic fracturing holes are constructed along one side of the goaf 1 for the high-level key overburden strata 4 and the low-level key overburden strata 6. The hydraulic fracturing and pressure relief are carried out in sections, with the weak rock strata as the boundary. The entire hydraulic fracturing area is divided into two sections, 11 and 12. This indicates the drilling angle for segmented hydraulic fracturing and depressurization, with hydraulic fracturing and depressurization performed sequentially from the highest to the lowest position.

[0061] 2) If the lithology and mechanical properties of the high-level key layer and the low-level key layer are different, different pressure relief methods shall be selected according to the lithology and mechanical properties of each key layer, and pressure relief construction shall be carried out according to the principle of prioritizing the high-level key layer.

[0062] If the high-level critical stratum is a poorly cemented and highly permeable rock layer, deep-hole blasting pre-splitting and decompression methods should be selected for decompression construction of the high-level critical stratum. For example, Figure 5 As shown, the high-level key overburden layer 4 is located above the section coal pillar 2 and roadway 3. Deep-hole pre-splitting blasting holes are constructed along one side of the goaf 1 for the high-level key overburden layer 4. The deep-hole pre-splitting blasting holes are then loaded with explosives and sealed. The loading section is 13 and the sealing section is 14. This indicates the angle of the blasting and decompression drilling in the high-level key layer. For the explosive loading section, For the sealing section, after the charging and sealing are completed, deep hole blasting is carried out. After the construction of the high-level key layer is completed and the top plate is stabilized, the pressure relief construction is carried out on the low-level key layer.

[0063] If the high-level critical stratum is composed of medium-hard or hard rock with poor permeability, hydraulic fracturing should be used to depressurize the high-level critical stratum. For example, Figure 6 As shown, the high-level key overburden layer 4 is located above the section coal pillar 2 and roadway 3. Hydraulic fracturing holes were designed and constructed along one side of the goaf 1 according to the hydraulic fracturing parameters in step 52. High-pressure water injection was performed on the hydraulic fracturing holes using water injection equipment. The hydraulic fracturing section is 15. The angle of the hydraulic fracturing and depressurization borehole in the high-level key layer is indicated. When water seeps out from the roof and sidewalls of roadway 1, the hydraulic pre-fracturing is completed. After the construction of the high-level key layer is completed and the roof is stabilized, the depressurization construction of the low-level key layer is carried out.

[0064] If the lithology of the lower-level critical stratum is poorly cemented and highly permeable, deep-hole blasting pre-splitting decompression method should be selected for decompression construction of the lower-level critical stratum. For example, Figure 7As shown, the low-lying key overburden layer 6 is located above the section coal pillar 2 and roadway 3. Deep-hole pre-splitting blasting holes were constructed along one side of the goaf 4 according to the design parameters for deep-hole blasting pre-splitting and pressure relief in step 51. The deep-hole pre-splitting blasting holes were then loaded and sealed. The loading section is 16, and the sealing section is 17. This indicates the drilling angle for blasting and decompression of the low-level key layer. After the charging and sealing of the hole are completed, deep-hole blasting and decompression construction will be carried out.

[0065] If the lithology of the lower critical layer is a medium-hard or hard rock layer with poor permeability, hydraulic fracturing should be used to depressurize the lower critical layer. For example, Figure 8 As shown, the low-lying key overburden layer 6 is located above the coal pillar 2 and roadway 3 in the section. Hydraulic fracturing holes were designed and constructed along one side of the goaf 1 according to the hydraulic fracturing parameters in step 52. High-pressure water injection was performed on the hydraulic fracturing holes using water injection equipment. The hydraulic fracturing section is 18. This indicates the angle of the hydraulic fracturing and pressure relief drilling in the low-level key layer. When water seeps out from the roof and sidewalls of tunnel 1, the hydraulic pre-fracturing construction is completed.

[0066] In a preferred embodiment, after the depressurization construction is carried out according to the depressurization method of each key layer, and after the top slab is stabilized, step 500 is performed, as follows: After depressurization construction according to the depressurization methods of each key layer, data on the development of internal cracks in the boreholes before and after blasting, energy data of microseismic events in the depressurization and non-depressurization zones, and stress distribution characteristics of the coal pillar in each section are obtained. Using the data on internal crack development in the boreholes, energy data of microseismic events, and stress distribution characteristics of the coal pillar in each section, three depressurization effect evaluation indicators—borehole inspection, microseismic monitoring, and channel wave imaging—are calculated respectively. These three depressurization effect evaluation indicators are then weighted and summed according to preset weights to obtain the comprehensive depressurization effect evaluation index K. Wherein, if K < 0.3, it indicates that the depressurization effect is insufficient and depressurization needs to be carried out again; if 0.3 ≤ K < 0.7, it indicates that the depressurization effect is sufficient; if K ≥ 0.7, it indicates that the depressurization effect is significant. Preferably, the weights of the three depressurization effect evaluation indicators—borehole inspection, microseismic monitoring, and channel wave imaging—are 0.30, 0.35, and 0.35, respectively.

[0067] Furthermore, based on the comprehensive pressure relief effect evaluation index K, the pressure relief parameters for the corresponding pressure relief methods are optimized. Preferably, for the blasting pressure relief method, when K < 0.4, the charge amount is increased by 20% and the hole spacing is reduced to 80% of the original hole spacing; when 0.4 ≤ K < 0.7, the charge amount is increased by 10% and the hole spacing is reduced to 90% of the original hole spacing; when K ≥ 0.7, the initial blasting parameters are maintained unchanged. For the hydraulic fracturing pressure relief method, when K < 0.4, the injection pressure is increased by 25% and the fracturing time is extended by 40%; when 0.4 ≤ K < 0.7, the injection pressure is increased by 15% and the fracturing time is extended by 20%; when K ≥ 0.7, the initial hydraulic fracturing parameters are maintained unchanged.

[0068] Please refer to Figure 9 This invention provides a composite pressure relief device for multiple key overburden layers, comprising: Data acquisition module 901 is used to acquire multimodal strata information of each overburden layer in the target mining area; The key layer identification module 902 is used to identify key layers in all overburden layers by utilizing the multimodal strata information of each overburden layer; The decompression method determination module 903 is used to determine the decompression method of each key layer based on the lithology and mechanical properties of each key layer; The pressure relief parameter design module 904 is used to determine the pressure relief parameters of each key layer based on the pressure relief method of each key layer.

[0069] Specifically, in this embodiment, the specific functions of the above-mentioned composite pressure relief device for multiple key overburden layers can be referred to the corresponding description in the above-mentioned composite pressure relief method for multiple key overburden layers, and will not be repeated here.

[0070] Based on the above embodiments, the present invention also provides an electronic device, the schematic diagram of which can be as follows: Figure 10 As shown. This electronic device can be used to execute the composite depressurization method for multiple key overburden layers provided in the above embodiments, which will not be described in detail here for the sake of simplicity. The electronic device includes: a processor coupled to a memory, the memory for storing computer programs or instructions, and the processor for executing the computer programs or instructions stored in the memory, so that the method in the above method embodiments is executed.

[0071] The present invention also provides a computer-readable storage medium having stored thereon computer instructions for implementing the methods in the above-described method embodiments.

[0072] For example, when the computer program is executed by a computer, it enables the computer to implement the methods described in the above method embodiments.

[0073] This application also provides a computer program product containing instructions that, when executed by a computer, cause the computer to implement the methods described in the above method embodiments.

[0074] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0075] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0076] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0077] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0078] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0079] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A composite depressurization method for multiple key overburden layers, characterized in that, The method includes: Obtain multimodal strata information of each overlying stratum in the target mining area; Key layers in all overburden strata are identified using multimodal strata information from each overburden stratum; Based on the lithology and mechanical properties of each key layer, the decompression method for each key layer is determined; Based on the depressurization method of each key layer, the depressurization parameters of each key layer are determined.

2. The composite depressurization method for multiple key overburden layers according to claim 1, characterized in that, The method of identifying key layers in all overburden layers using multimodal strata information includes: Using multimodal rock strata information of each overburden layer, the load and fracture distance of each overburden layer are calculated; Based on the load and fracture distance of each overburden layer, the key layers in all overburden layers are identified.

3. The composite pressure relief method for multiple key overburden layers according to claim 1, characterized in that, The determination of the decompression method for each key layer based on its lithology and mechanical properties includes: Based on the multimodal rock strata information, the cementation index, permeability coefficient, hardness coefficient and / or key layer spacing of each key layer are calculated respectively; Based on the cementation index, permeability coefficient, hardness coefficient and / or spacing of each key layer, the depressurization method of each key layer is determined.

4. The composite pressure relief method for multiple key overburden layers according to claim 3, characterized in that, Based on the cementation index, permeability coefficient, hardness coefficient, and / or spacing of each critical layer, the depressurization method for each critical layer is determined, including: If the cementation index of the key layer is less than the preset cementation index threshold and the permeability coefficient exceeds the preset permeability coefficient threshold, then the blasting depressurization method shall be adopted. If the permeability coefficient of the critical layer is less than the preset permeability coefficient threshold and the hardness coefficient is greater than the preset hardness coefficient threshold, then hydraulic fracturing and pressure relief shall be adopted.

5. The composite depressurization method for multiple key overburden layers according to claim 1, characterized in that, The key layers include upper overburden and lower overburden. The determination of decompression parameters for each key layer based on its decompression method includes: Numerical simulation methods were used to calculate the stress changes and load transfer patterns between key layers, and to determine the degree of stress relief influence of higher key layers on lower key layers. Based on the degree of pressure relief influence of the high-level critical layer on the low-level critical layer and the pressure relief method of each critical layer, the pressure relief parameters of each critical layer are determined.

6. The composite depressurization method for multiple key overburden layers according to claim 5, characterized in that, The decompression parameters for each critical layer are determined based on the degree of decompression impact of the higher critical layer on the lower critical layer and the decompression method of each critical layer, including: If the pressure relief method of the critical layer is blasting, the blasting borehole diameter, blasting hole spacing, blasting borehole angle and explosive amount of the corresponding critical layer are determined based on the degree of pressure relief influence of the higher critical layer on the lower critical layer. If the depressurization method of the critical layer is hydraulic fracturing, the hydraulic fracturing borehole diameter, hydraulic fracturing borehole spacing, hydraulic fracturing borehole inclination angle, hydraulic fracturing borehole depth and high-pressure water pressure of the corresponding critical layer are determined based on the degree of depressurization influence of the higher critical layer on the lower critical layer.

7. The composite pressure relief method for multiple key overburden layers according to claim 1, characterized in that, Also includes: After depressurization construction is carried out according to the depressurization method of each key layer, data on the development of internal cracks in the borehole before and after blasting of each key layer, energy data of microseismic events in the depressurization zone and non-depressurization zone, and stress distribution characteristics of the coal pillar in the section are obtained. The pressure relief effect is evaluated using the borehole internal fracture development data, the microseismic event energy data, and the stress distribution characteristics of the coal pillar in the section, and the pressure relief effect evaluation results are obtained.

8. A composite pressure relief device for multiple key overburden layers, characterized in that, include: The data acquisition module is used to acquire multimodal strata information of each overlying stratum in the target mining area; The key layer identification module is used to identify key layers in all overburden layers by utilizing multimodal strata information from each overburden layer. The decompression method determination module is used to determine the decompression method for each key layer based on its lithology and mechanical properties. The pressure relief parameter design module is used to determine the pressure relief parameters of each key layer based on the pressure relief method of each key layer.

9. An electronic device, characterized in that, include: Memory, used to store executable instructions; A processor is configured to invoke and run the executable instructions in the memory to perform the steps of the composite decompression method for multiple key overburden layers as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores program instructions that, when executed by a processor, implement the steps of the composite depressurization method for multiple key overburden layers as described in any one of claims 1-7.

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