Longwall coal mining system for controlling coal wall spalling at large mining height working face

Abstract

This application discloses a longwall mining system for controlling coal face spalling in high-extraction working faces, relating to the field of fully mechanized coal mining equipment and intelligent mining. In this system, a hydrological sensing module is used to collect hydrological data of the working face; a stress monitoring module is used to collect stress data of the working face; a water-retaining and injection module is used to inject water into the coal face; an adaptive support and control module is used to actively support the coal face; and an intelligent central control module incorporates a spalling risk coupling model. This model calculates the comprehensive risk index of coal face spalling based on hydrological and stress data, classifies risk levels according to the comprehensive risk index, and outputs corresponding control commands to dynamically adjust the injection parameters of the water-retaining and injection module and / or the support parameters of the adaptive support and control module. This application enables closed-loop intelligent operation of hydrological control, coal body reinforcement, condition monitoring, and adaptive parameter control.

Description

Technical Field

[0001] This application relates to the field of coal mine fully mechanized mining equipment and intelligent mining, and in particular to a longwall mining system for controlling coal wall spalling in high-mining-height working faces. Background Technology

[0002] Rib spalling in coal mines refers to the geological and safety accident phenomenon in which the sidewalls (coal face / coal wall) of underground coal mining faces or roadways deform, break, and suddenly detach or collapse under the influence of factors such as mining pressure, geological conditions, or human operation.

[0003] High-extraction longwall mining is a core technology for efficient mining of thick coal seams, boasting advantages such as high output and high mining efficiency. However, in actual mining operations, factors such as high extraction height, concentrated stress in the surrounding rock, well-developed coal seam fissures, and complex hydrological environment have led to widespread instability and spalling of the coal face, which has become a core challenge restricting the safe and efficient production of high-extraction longwall faces.

[0004] Existing high-extraction coal mining technology suffers from the following problems: after the coal body loses water, the fissures expand and the brittleness intensifies, the overall integrity of the coal wall decreases significantly, and the combined effect of mining-induced stress makes it very easy for vertical splitting, large-area spalling, and rock falling to occur. In severe cases, this can lead to safety accidents such as roof leakage, equipment damage, and casualties.

[0005] Existing methods for preventing coal wall spalling are relatively simplistic, relying heavily on traditional approaches such as passive support with hydraulic supports, manual grouting reinforcement, and pre-emptive pressure relief. These methods lack intelligent closed-loop control capabilities. Traditional methods suffer from significant delays, poor adaptability, and low precision, failing to dynamically adjust control parameters in real time based on coal seam moisture content, surrounding rock stress, and mining progress. This makes them ill-suited for the stability control needs of coal walls under complex geological conditions. Furthermore, current technologies fail to achieve coordinated water conservation and control with coal wall spalling prevention, thus failing to address the dual requirements of safe mining and water resource protection.

[0006] Therefore, in order to solve the above problems, there is an urgent need to provide an integrated, intelligent, and water-retaining coal mining system for preventing coal wall spalling in high-mining areas. Summary of the Invention

[0007] The purpose of this application is to provide a longwall mining system for controlling coal wall spalling in high-extraction working faces, which can realize closed-loop intelligent operation of hydrological regulation, coal body reinforcement, condition monitoring, and adaptive parameter control.

[0008] To achieve the above objectives, this application provides the following solution: This application provides a longwall mining system for controlling coal wall spalling in high-extraction working faces, comprising: The hydrological sensing module is used to collect hydrological data from the working face. The stress monitoring module is used to collect stress data from the working surface; The water-retaining and water-injection module is used for water injection into the coal face. The adaptive support control module includes a support actuator for actively supporting the coal face; The intelligent central control module is communicatively connected to the hydrological sensing module, stress monitoring module, water retention and injection module, and adaptive side protection and control module, respectively. The intelligent central control module incorporates a coal wall spalling risk coupling model. This model calculates the comprehensive risk index of coal wall spalling based on the hydrological and stress data, classifies risk levels according to the comprehensive risk index, and outputs corresponding control commands to dynamically adjust the water injection parameters of the water retention and injection module and / or the support parameters of the adaptive rock protection control module. The comprehensive risk index of coal wall spalling is obtained by weighted calculation based on the coal body water content stability coefficient and the surrounding rock stress hazard coefficient.

[0009] Optionally, the hydrological sensing module includes: Distributed coal moisture content sensors are evenly embedded in the shallow layer of the coal face to be mined in high mining faces to collect real-time, layered data on moisture content and wet / dry changes inside the coal body of the working face. The working face water spray sensor is installed below the hydraulic support or the exposed area of ​​the working face top plate to collect real-time data on water volume and water flow fluctuations from cracks in the working face top plate and local seepage. The roof aquifer water pressure sensor is drilled and embedded in the aquifer rock stratum above the working face roof, deeply fitting the interface between the coal seam roof aquifer and the aquifer, and is used to collect data on the changes in the original water pressure and seepage pressure of the roof aquifer of the working face. The signal acquisition terminal is located in the electrical control box at the end of the working face and is used to collect and transmit hydrological data.

[0010] Optionally, the stress monitoring module includes: The working face surrounding rock stress sensor is installed inside the rock strata of the roadway or the top and bottom plate of the working face to collect real-time data on the original stress, stress increment and stress concentration factor of the surrounding rock of the roadway and working face under the influence of mining. Coal wall pressure sensors are deployed on the surface of the coal wall and in areas with shallow fractures in the working face to collect data on the vertical compressive stress and horizontal extrusion pressure of the solid coal in the working face. The hydraulic support column pressure sensor is installed on the hydraulic support column to collect data on the working resistance and support pressure fluctuation of the support column. The data transmission sub-terminal, integrated within the support electrical control system, is used to aggregate and transmit stress data.

[0011] Optionally, the water-retaining and water-injecting module includes: The adjustable pressure intelligent water injection pump station is fixedly installed at the equipment train position at the end of the working face to provide a high-pressure water source for water injection into the coal face. The coal mining machine is equipped with a multi-point water injection nozzle, which is installed on the coal mining machine and connected to the adjustable pressure intelligent water injection pump station. A high-precision flow regulating valve is installed in series in the inlet pipeline of the multi-point water injection nozzle on the coal mining machine to independently control the water injection flow of a single set of nozzles. The goaf water filtration and recycling component is arranged in the low-level water accumulation area of ​​the working face goaf and at the end of the roadway drainage ditch. It is used to collect the accumulated water and filter it back to the adjustable pressure intelligent water injection pump station.

[0012] Optionally, the adaptive support adjustment module further includes: Side guard plate stroke detection sensor, used to collect the extension and retraction stroke data of the side guard plate; An electro-hydraulic regulating valve is installed in series in the hydraulic pipeline of the side guard actuator to regulate the pressure and flow of the hydraulic oil circuit; The support pressure feedback component is installed on the contact surface between the support plate and the coal face to collect actual support pressure data.

[0013] Optionally, the process for determining the water content stability coefficient of the coal body is as follows: Real-time moisture content is obtained based on the optimal stable moisture content range of the coal seam. When the real-time moisture content is within the optimal stable moisture content range, the moisture content stability coefficient of the coal body is 0. When the real-time moisture content is lower than the lower limit of the optimal stable moisture content range, the difference between the real-time moisture content and the drying limit moisture content is calculated and divided by the difference between the lower limit and the drying limit moisture content to obtain the first deviation normalized value as the moisture content stability coefficient of the coal body. When the real-time moisture content is higher than the upper limit of the optimal stable moisture content range, the difference between the real-time moisture content and the upper limit is calculated and divided by the difference between the immersion limit moisture content and the upper limit to obtain a second deviation normalized value as the moisture content stability coefficient of the coal body.

[0014] Optionally, the process for determining the surrounding rock stress hazard factor is as follows: The comprehensive real-time stress is obtained by integrating the surrounding rock stress, coal wall bearing pressure, and support column resistance. When the comprehensive real-time stress is less than or equal to the safe stress threshold calibrated at the working face, the surrounding rock stress hazard factor is 0; When the comprehensive real-time stress is greater than the safe stress threshold and less than or equal to the coal wall shear failure limit stress, the difference between the comprehensive real-time stress and the safe stress threshold is calculated and divided by the difference between the coal wall shear failure limit stress and the safe stress threshold to obtain a third normalized value as the surrounding rock stress hazard coefficient. When the comprehensive real-time stress is greater than the shear failure limit stress of the coal wall, the stress hazard factor of the surrounding rock is 1.

[0015] Optionally, the risk levels classified by the intelligent central control module according to the comprehensive risk index of the film include safety level, early warning level and danger level; When the safety level is maintained, standard water injection parameters, conventional coal mining traction speed, and standard support pressure are maintained. When the warning level is reached, fine-tune the water injection parameters, reduce the coal mining traction speed, and appropriately increase the support pressure. When the situation is at the aforementioned danger level, the water injection parameters are increased, the coal mining traction speed is significantly reduced, and the support actuator is controlled to extend throughout its full stroke and lock the support pressure.

[0016] Optionally, the intelligent central control module is further used for: After outputting control commands, real-time updates of hydrological data, stress data, and support status feedback data are collected. The risk coupling model for the slope support is dynamically modified based on hydrological data, stress data, and support status feedback data.

[0017] Optionally, the intelligent central control module is deployed inside the explosion-proof electrical control cabinet at the working face end, and establishes bidirectional communication connections with the hydrological sensing module, stress monitoring module, water retention and injection module, and adaptive side protection control module via underground industrial Ethernet.

[0018] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a longwall mining system for controlling coal wall spalling in high-extraction longwall faces. By integrating a hydrological sensing module, stress monitoring module, intelligent central control module, water conservation and injection module, and adaptive support control module, a closed-loop control system of "sensing-analysis-decision-execution-feedback" is formed. It integrates water-conserving mining technology with an adaptive intelligent control system to achieve precise underground water resource management, active coal body structure reinforcement, and dynamic adjustment of mining support parameters. This fundamentally suppresses coal wall spalling hazards while simultaneously solving the problems of water waste and ecological damage associated with traditional mining methods. It achieves the triple technical goals of safe and stable mining, green water conservation, and intelligent management in high-extraction longwall faces. This application is an integrated hardware and software intelligent mining system that, relying on longwall mining equipment, realizes closed-loop intelligent operation of hydrological control, coal body reinforcement, condition monitoring, and adaptive parameter control. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a longwall mining system for controlling coal wall spalling in a high-mining face according to one embodiment of this application; Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] In one exemplary embodiment, such as Figure 1 As shown, a longwall mining system for controlling coal wall spalling in high-extraction longwall faces is provided. It is suitable for active prevention and control of coal wall spalling, surrounding rock stability control, and protective mining of underground water resources in high-extraction longwall faces in thick coal seams. The system includes: a hydrological sensing module, a stress monitoring module, a water retention and injection module, an adaptive side protection control module, and an intelligent central control module. The hydrological sensing module is used to collect hydrological data from the working face; The stress monitoring module is used to collect stress data from the working surface; The water-retaining and water-injection module is used for water injection into the coal face; The adaptive support control module includes a support actuator for active support of the coal face; The intelligent central control module is communicatively connected to the hydrological sensing module, stress monitoring module, water retention and injection module, and adaptive side protection and control module, respectively. The intelligent central control module incorporates a coal wall spalling risk coupling model. This model calculates the comprehensive risk index of coal wall spalling based on the hydrological and stress data, classifies risk levels according to the comprehensive risk index, and outputs corresponding control commands to dynamically adjust the water injection parameters of the water retention and injection module and / or the support parameters of the adaptive rock protection control module. The comprehensive risk index of coal wall spalling is obtained by weighted calculation based on the coal body water content stability coefficient and the surrounding rock stress hazard coefficient.

[0024] As a specific embodiment, the hydrological sensing module includes: a distributed coal seam moisture content sensor (GUY5 mine-use submersible liquid level sensor), a working face water seepage sensor (GUCS10 mine-use ultrasonic liquid level sensor), a roof aquifer water pressure sensor (GPD40 mine-use intrinsically safe pressure sensor), and a signal acquisition terminal; the data collected by the above three types of sensors serve as the hydrological data of the working face, and their specific placement and acquisition functions are defined as follows: Distributed coal moisture content sensors are uniformly embedded in the shallow layer of the coal wall to be mined in the high-mining face to collect real-time, layered data on the moisture content and wet / dry changes inside the coal body of the working face. Specifically, the distributed coal moisture content sensors are deployed to cover key layers at 1 / 3, 1 / 2, and 2 / 3 of the working face mining height, and to comprehensively cover the vertical areas of the coal face prone to spalling; they accurately monitor the state of coal body dehydration and cracking or softening due to water immersion during mining, providing core coal body hydrological data for coal body stability assessment and precise adjustment of water injection and water retention parameters.

[0025] The working face water spray sensor is installed below the hydraulic support or the exposed area of ​​the working face top plate to collect real-time data on water volume and water flow fluctuations from cracks in the working face top plate and local seepage. Specifically, the water spray sensors are fixedly installed below the top beam of each hydraulic support, above the support side plate, and below the exposed area of ​​the working face roof; to monitor the dynamic water spray conditions of the working face, predict the risk of local coal wall softening due to water immersion, and avoid sudden spalling caused by local water accumulation infiltrating the coal body. The roof aquifer water pressure sensor is drilled and embedded inside the aquifer rock stratum above the working face roof, deeply fitting the interface between the coal seam roof aquifer and the aquifer. It is used to collect data on changes in the original water pressure and seepage pressure of the roof aquifer; monitor the leakage and pressure relief of the roof aquifer; determine the integrity of the roof aquifer structure; and provide hydrological data for roof water retention, seepage prevention, and water control.

[0026] The signal acquisition terminal is located in the electrical control box at the end of the working face and is used to collect and transmit hydrological data; Specifically, the signal acquisition terminal aggregates the hydrological data collected by the three types of sensors across the entire region, completes signal conversion and transmission, and provides accurate and comprehensive basic data support for subsequent water retention parameter adjustment and coal wall stability determination; As a specific embodiment, the stress monitoring module includes: a working face surrounding rock stress sensor (GZY30W intrinsically safe mining stress sensor), a coal wall pressure sensor (GMY30 mining strain gauge coal body pressure sensor), a hydraulic support column pressure sensor (GPD60 pressure transmitter), and a data transmission sub-terminal; the data collected by the above three types of sensors serve as the stress data of the working face; the specific arrangement and monitoring functions are as follows: The working face surrounding rock stress sensor is installed inside the rock strata of the roadway or the top and bottom plate of the working face to collect real-time data on the original stress, stress increment and stress concentration factor of the roadway and working face surrounding rock under the influence of mining. Specifically, the working face surrounding rock stress sensor is drilled and embedded in the surrounding rock of the upper and lower roadways of the working face and the key rock strata of the top and bottom plates of the working face, and is evenly distributed along the strike of the working face; it is mainly used to collect data on the original stress, stress increment and stress concentration coefficient of the roadway and the surrounding rock of the working face under the influence of mining in real time, monitor the stress transfer and superposition change law of the surrounding rock during mining, and predict the risk of high stress extrusion causing spalling.

[0027] Coal wall pressure sensors are deployed on the surface of the coal wall and in areas with shallow fractures in the working face to collect data on the vertical compressive stress and horizontal extrusion pressure of the solid coal in the working face. Specifically, the coal wall pressure sensor is embedded in the surface layer and shallow crack development area of ​​the coal wall in the working face, and is deployed in conjunction with the moisture content sensor; it is mainly used to collect the vertical compressive stress and horizontal extrusion pressure data of the coal body in real time, capture the local stress change and stress imbalance characteristics of the coal wall, and identify the early mechanical precursors of coal wall cracking and peeling.

[0028] The hydraulic support column pressure sensor is installed on the hydraulic support column to collect data on the working resistance and support pressure fluctuation of the support column. Specifically, the hydraulic support column pressure sensor is coaxially fixedly installed on the pressure-bearing end of the cylinder body of each hydraulic support column; it is mainly used to collect data on the working resistance and support pressure fluctuation of the support column in real time, monitor the actual support status and pressure stability of the support, determine whether the support system matches the mining pressure of the surrounding rock, and provide a mechanical basis for dynamic control of the support pressure.

[0029] The data transmission sub-terminal is integrated into the support's electrical control system and is used to aggregate and transmit stress data. Before transmission, the data undergoes noise reduction and packaging, and is then transmitted to the intelligent central control module, providing precise mechanical data support for the assessment of slab risk mechanics and the adaptive adjustment of support parameters.

[0030] As a specific embodiment, the water retention and injection module includes: an adjustable pressure intelligent water injection pump station, a coal mining machine-mounted multi-point water injection nozzle, a high-precision flow regulating valve, and a goaf water filtration, circulation, and recovery assembly; the various devices are deployed in conjunction and operate collaboratively, and their specific locations and functions are as follows: The adjustable pressure intelligent water injection pump station is fixedly installed at the equipment train position at the end of the working face. It is connected to the water injection nozzles of the entire working face through a high-pressure water supply pipeline. It is used to provide an adjustable and stable high-pressure water source for water injection into the coal face. The overall water injection pressure is dynamically adjusted according to the central control command to adapt to the water injection reinforcement requirements corresponding to different coal body moisture contents, so as to achieve stable pressure and water retention operation.

[0031] The multi-point water injection nozzles on the coal mining machine are installed on the coal mining machine and connected to the adjustable pressure intelligent water injection pump station. Specifically, the multi-point water injection nozzles on the coal mining machine are symmetrically embedded and fixed on both sides of the coal mining machine drum and the front and rear ends of the machine body traction unit, and move synchronously with the coal mining machine. They are mainly used to carry out full-coverage, micro-volume, uniform high-pressure water injection on the coal wall to be mined in front of the coal cutting operation, accurately fill the shallow micro-cracks on the surface of the coal body, improve the cohesion and integrity of the coal body, and solidify the coal wall from the physical structure to inhibit the expansion of cracks.

[0032] A high-precision flow regulating valve is installed in series in the inlet pipeline of the multi-point water injection nozzle on the coal mining machine to independently control the water injection flow of a single set of nozzles. Specifically, high-precision flow regulating valves are installed in series one-to-one in the inlet pipeline of each group of water injection nozzles; they are mainly used to independently control the water injection flow of a single group of nozzles, realize differentiated water injection in different zones, increase the water injection flow in dry areas of the coal body and reduce the flow in water-saturated areas, avoid excessive immersion and softening or dehydration and cracking, and accurately maintain the optimal stable moisture content of the coal body.

[0033] The goaf water filtration and recycling component is arranged in the low-level water accumulation area of ​​the working face goaf and at the end of the roadway drainage ditch. It is used to collect water (water from the working face, seepage from the roof, and water from the goaf) and filter it back to the adjustable pressure intelligent water injection pump station, so as to prevent the disorderly loss of underground water resources and achieve two-way synergy between water conservation and coal body reinforcement.

[0034] As a specific embodiment, the water-retaining and water-injection module adopts a non-hydrophobic water-retaining process, which maintains the optimal water content of the coal body and inhibits the expansion of coal wall cracks through roof water-blocking, micro-precise water injection, and water resource recycling. As a specific embodiment, the support mechanism is a hydraulic support cylinder; the hydraulic support cylinder is built into the back of each high-extraction hydraulic support support mechanism, providing a power source for the extension and compression of the support plate; it is mainly used to perform the actions of extending the support plate, fitting against the coal wall, stabilizing support, and retracting and resetting, so as to achieve active fitting and protection of the outer side of the coal wall and restrain the deformation and fall of the coal wall.

[0035] The adaptive side support control module also includes: a side support plate stroke detection sensor (GUD960 intrinsically safe hydraulic support stroke sensor for mining), an electro-hydraulic regulating valve, and a side support pressure feedback component. The entire set of equipment is integrated inside the side support mechanism of the high-extraction hydraulic support. The specific layout and control functions are as follows: The side guard plate stroke detection sensor is used to collect the extension and retraction stroke data of the side guard plate; Specifically, the side protection plate stroke detection sensor is fixedly installed at the end of the piston rod of the side protection cylinder; it is mainly used to collect data on the extension and retraction stroke and contact distance of the side protection plate in real time, accurately reflect the position of the side protection support, and determine whether the support coverage meets the protection requirements of the high-mining coal wall. An electro-hydraulic regulating valve is connected in series in the hydraulic pipeline of the support actuator. It is used to receive intelligent central control commands and dynamically adjust the hydraulic oil pressure and flow to achieve adaptive and precise control of the support pressure, extension speed and support stroke. The support pressure feedback component is installed on the contact surface between the support plate and the coal face to collect actual support pressure data.

[0036] Specifically, the support pressure feedback component is fitted and installed on the inner side of the contact pressure surface between the support plate and the coal wall; it is mainly used to collect the actual support pressure of the support plate on the coal wall in real time, and to provide feedback on the support stress state, so as to avoid the protection failure due to insufficient pressure or the secondary crushing caused by excessive pressure squeezing the coal wall, and to achieve precise matching of the support to the stable state of the coal wall. As a specific implementation, the core of the intelligent central control module is deployed inside the explosion-proof electrical control cabinet at the working face end. It establishes bidirectional communication connections with the hydrological sensing module, stress monitoring module, water retention and injection module, and adaptive support control module through underground industrial Ethernet and explosion-proof signal cables, respectively. It has full-process functions of data reception, fusion analysis, risk assessment, intelligent decision-making, command output, and closed-loop feedback correction. The intelligent central control module has a built-in panel risk coupling model, which can dynamically classify risk levels and link and control water injection parameters, coal mining traction speed, and hydraulic support support parameters to achieve closed-loop prevention and control. It is the core decision-making kernel of the system, realizing the model principle, data processing, hierarchical judgment, and adaptive control. High-extraction coal face spalling is not caused by a single factor, but rather by a two-way coupling effect of the weakening effect of coal moisture content and the stress concentration effect of mining: if the coal moisture content is too low, the coal body becomes more brittle and fractures expand; if the moisture content is too high, the coal body softens and its cohesion decreases; at the same time, the greater the surrounding rock stress, the stronger the tendency for coal face compression failure. The spalling risk coupling model abandons the traditional single threshold judgment method and constructs a three-dimensional coupling calculation relationship of "moisture content deterioration coefficient + stress concentration coefficient + spalling sensitivity weight". By fusing multi-source parameters, it quantifies the probability of coal face instability, realizes accurate quantitative assessment of spalling risk, and solves the technical defects of misjudgment and omission by single monitoring parameters.

[0037] Before processing, the hydrological and stress data are preprocessed by noise reduction, filtering, outlier removal and mean smoothing to eliminate numerical distortion caused by downhole dust, electromagnetic interference and sensor jitter, and output a stable and effective standardized dataset. Specifically, the process for determining the water content stability coefficient of the coal body is as follows: Real-time moisture content is obtained based on the optimal stable moisture content range of the coal seam. When the real-time moisture content is within the optimal stable moisture content range, the moisture content stability coefficient of the coal body is 0. When the real-time moisture content is lower than the lower limit of the optimal stable moisture content range, the difference between the real-time moisture content and the drying limit moisture content is calculated and divided by the difference between the lower limit and the drying limit moisture content to obtain the first deviation normalized value as the moisture content stability coefficient of the coal body. When the real-time moisture content is higher than the upper limit of the optimal stable moisture content range, the difference between the real-time moisture content and the upper limit is calculated and divided by the difference between the immersion limit moisture content and the upper limit to obtain a second deviation normalized value as the moisture content stability coefficient of the coal body.

[0038] The process for determining the surrounding rock stress hazard factor is as follows: The comprehensive real-time stress is obtained by integrating the surrounding rock stress, coal wall bearing pressure, and support column resistance. When the comprehensive real-time stress is less than or equal to the safe stress threshold calibrated at the working face, the surrounding rock stress hazard factor is 0; When the comprehensive real-time stress is greater than the safe stress threshold and less than or equal to the coal wall shear failure limit stress, the difference between the comprehensive real-time stress and the safe stress threshold is calculated and divided by the difference between the coal wall shear failure limit stress and the safe stress threshold to obtain a third normalized value as the surrounding rock stress hazard coefficient. When the comprehensive real-time stress is greater than the shear failure limit stress of the coal wall, the stress hazard factor of the surrounding rock is 1.

[0039] As a specific example, the coal body water content stability coefficient is based on the optimal stable water content range of the coal seam (18% to 22%). The real-time water content deviation is calculated. Both excessively high and low water content will generate a negative weakening coefficient, which quantifies the structural integrity of the coal body itself. Coal body water content stability coefficient The specific calculation method is as follows: The average value collected by the multi-layer moisture content sensor is taken as the real-time moisture content. Midpoint of the optimal moisture content range Maximum permissible deviation for unilateral safety ; Calculate the moisture content deviation under three working conditions : 1) The coal has a good moisture content. ; 2) (Dehydration) The lower the moisture content, the greater the deviation, and the more severe the brittle damage to the coal body. 3) (Soak in water to soften). The higher the moisture content, the more significant the decrease in coal strength and cohesion.

[0040] Water stability coefficient Segmented normalized calculation: 1) , There is no risk of water-induced weakening. 2) , The drying limit moisture content is 12%, and the immersion limit moisture content is 28%. 3) ( or ), The coal body structure is completely deteriorated. value range The larger the value, the worse the integrity of the coal body itself.

[0041] Surrounding rock stress hazard factor: Based on the working face safety stress threshold, the real-time stress relative concentration ratio is calculated. The closer the stress is to or exceeds the threshold, the higher the stress hazard factor, and the quantification of the external force crushing failure intensity. The comprehensive real-time stress is obtained by integrating the surrounding rock stress, coal wall bearing pressure, and support column resistance. ; To calibrate the safe stress threshold for the working face, The shear failure limit stress of the coal wall; stress concentration ratio. Ultimate stress ratio .

[0042] Surrounding rock stress hazard factor Segmented normalized calculation: 1) , No risk of stress compression; 2) , ; 3) , High stress can easily induce sheet fracture.

[0043] 4) value range The higher the value, the higher the risk of mining-induced crushing and damage.

[0044] Dynamically assign weights based on working face geological conditions (Water content weight) (Stress weight) Soft and fractured coal seams High-stress hard coal seams conventional coal seams By weighting and fusing the two sets of coefficients, the comprehensive risk index of coal wall spalling is obtained. This enables quantitative evaluation with multi-parameter coupling.

[0045] As a specific embodiment, the risk levels classified by the intelligent central control module according to the comprehensive risk index of the film include safety level, early warning level and danger level; When the safety level is reached (risk index is in the low range), the coal body has a moderate moisture content, no stress concentration, and a stable coal wall condition, with no risk of spalling. When the warning level is reached (risk index is in the middle range), the coal body is severely dehydrated and cracked or softened by water immersion, stress is highly concentrated, coal wall fissures expand and deformation is obvious, and there is an immediate risk of collapse. When the coal body is in the aforementioned danger level (high range), it is severely dehydrated and cracked or softened by water immersion, with high stress concentration, coal wall fissures expanding and deformation obvious, posing an immediate risk of collapse.

[0046] For different risk levels, the system matches corresponding water retention parameters, coal mining parameters, and support parameters from the operating parameter database to implement a coordinated control strategy, and outputs closed-loop control commands with a single click. ① Safety level operating conditions: Maintain the system's baseline parameters, keep the standard micro-injection water pressure and flow rate, the conventional coal mining traction speed, and the standard side support pressure and stroke to ensure the normal and efficient advancement of the working face; ② Warning Level Operating Conditions: Initiate mild optimization and control, fine-tune the water injection flow rate and pressure according to the moisture content deviation, and correct the water content state of the coal body; slightly reduce the coal mining traction speed and extend the coal wall water injection wetting and consolidation time; moderately increase the support pressure of the side protection plate to restrain the micro deformation of the coal wall in advance and eliminate potential risks; ③ Hazardous working conditions: Activate the emergency anti-slab protection mode, instantly increase the precise water injection parameters to repair coal body cracks and solidify the coal body structure; significantly reduce the coal mining advance speed to avoid strong mining stress disturbance; extend the side protection plate throughout the entire stroke to lock the support pressure, implement full-coverage pressure stabilization and strong support for the coal wall, and quickly suppress the expansion of coal wall cracks and spalling collapse.

[0047] The intelligent central control module is also used to: collect updated hydrological data, stress data, and support status feedback data in real time after outputting control commands; and dynamically correct the slope risk coupling model based on the hydrological data, stress data, and support status feedback data.

[0048] After each adjustment is completed, the system collects and updates data on coal moisture content, stress values, coal wall deformation, and support status in real time, dynamically corrects the algorithm weight coefficients and threshold ranges, and enables the model to adapt to different coal seam hardness, fracture development degree, and hydrogeological conditions. This continuously improves the accuracy of risk assessment and the matching degree of adjustment, realizes intelligent closed-loop management of the entire process, and ultimately achieves proactive, precise, and intelligent prevention and control of coal wall spalling in high-extraction working faces.

[0049] Compared with existing technologies, this application is adapted to the high-extraction, single-pass full-height longwall retreat mining process, achieving deep coupling of active coal wall spalling control and water-conserving green mining. It has four core advantages: safety and practicality, green energy saving, and intelligent advancement. The specific beneficial effects are as follows: (1) Solve the problem of coal wall spalling at the root of the problem: By using water-conserving mining technology to precisely control the water content of the coal body, fill the coal body cracks, improve the coal body cohesion and overall strength, and cooperate with intelligent adaptive support control, the drawbacks of passive prevention and delayed treatment of traditional technology can be completely solved, the incidence of coal wall spalling, rock falling and roof leakage accidents can be greatly reduced, and the safety and efficiency of mining face can be improved.

[0050] (2) Achieve green water-conserving mining and protect the ecology of the mining area: Abandon the traditional water-draining mining mode, and retain underground groundwater resources to the maximum extent through water isolation, water control and water recycling technologies, reduce water loss and hydrological structure damage, achieve synergy between coal mining and water resource protection, and meet the standards for green mine construction.

[0051] (3) Intelligent closed-loop control with strong adaptability: Relying on multi-source sensing and intelligent algorithms, it can dynamically adjust water retention, coal mining and support parameters according to different geological conditions and mining conditions. No manual intervention is required. It has high control accuracy and fast response speed, and is suitable for various high-extraction thick coal seam working faces. It has strong versatility.

[0052] (4) Reduce mining costs and improve production efficiency: Reduce the cost of manual reinforcement and post-repair operations, reduce the probability of equipment damage and production stoppage, and at the same time, reduce water supply energy consumption through water resource recycling, significantly improve the overall production efficiency of the working face, and have extremely high engineering promotion value.

[0053] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0054] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A longwall mining system for controlling coal wall spalling in high-extraction working faces, characterized in that, include: The hydrological sensing module is used to collect hydrological data from the working face. The stress monitoring module is used to collect stress data from the working surface; The water-retaining and water-injection module is used for water injection into the coal face. The adaptive support control module includes a support actuator for actively supporting the coal face; The intelligent central control module is communicatively connected to the hydrological sensing module, stress monitoring module, water retention and injection module, and adaptive side protection and control module, respectively. The intelligent central control module has a built-in coal wall spalling risk coupling model. The coal wall spalling risk coupling model is used to calculate the comprehensive risk index of coal wall spalling based on the hydrological data and stress data, and to classify the risk level according to the comprehensive risk index of coal wall spalling, and output corresponding control commands to dynamically adjust the water injection parameters of the water retention and injection module and / or the support parameters of the adaptive support control module. The risk coupling model for rock spalling is based on a weighted calculation of the coal body water content stability coefficient and the surrounding rock stress hazard coefficient to obtain the comprehensive risk index for rock spalling.

2. The longwall mining system for controlling coal wall spalling in high-seam working faces according to claim 1, characterized in that, The hydrological sensing module includes: Distributed coal moisture content sensors are evenly embedded in the shallow layer of the coal face to be mined in high mining faces to collect real-time, layered data on moisture content and wet / dry changes inside the coal body of the working face. The working face water spray sensor is installed below the hydraulic support or the exposed area of ​​the working face top plate to collect real-time data on water volume and water flow fluctuations from cracks in the working face top plate and local seepage. The roof aquifer water pressure sensor is drilled and embedded in the aquifer rock stratum above the working face roof, deeply fitting the interface between the coal seam roof aquifer and the aquifer, and is used to collect data on the changes in the original water pressure and seepage pressure of the roof aquifer of the working face. The signal acquisition terminal is located in the electrical control box at the end of the working face and is used to collect and transmit hydrological data.

3. The longwall mining system for controlling coal wall spalling in high-mining faces according to claim 1, characterized in that, The stress monitoring module includes: The working face surrounding rock stress sensor is installed inside the rock strata of the roadway or the top and bottom plate of the working face to collect real-time data on the original stress, stress increment and stress concentration factor of the surrounding rock of the roadway and working face under the influence of mining. Coal wall pressure sensors are deployed on the surface of the coal wall and in areas with shallow fractures in the working face to collect data on the vertical compressive stress and horizontal extrusion pressure of the solid coal in the working face. The hydraulic support column pressure sensor is installed on the hydraulic support column to collect data on the working resistance and support pressure fluctuation of the support column. The data transmission sub-terminal, integrated within the support electrical control system, is used to aggregate and transmit stress data.

4. The longwall mining system for controlling coal wall spalling in high-seam working faces according to claim 1, characterized in that, The water retention and injection module includes: The adjustable pressure intelligent water injection pump station is fixedly installed at the equipment train position at the end of the working face to provide a high-pressure water source for water injection into the coal face. The coal mining machine is equipped with a multi-point water injection nozzle, which is installed on the coal mining machine and connected to the adjustable pressure intelligent water injection pump station. A high-precision flow regulating valve is installed in series in the inlet pipeline of the multi-point water injection nozzle on the coal mining machine to independently control the water injection flow of a single set of nozzles. The goaf water filtration and recycling component is arranged in the low-level water accumulation area of ​​the working face goaf and at the end of the roadway drainage ditch. It is used to collect the accumulated water and filter it back to the adjustable pressure intelligent water injection pump station.

5. The longwall mining system for controlling coal wall spalling in high-mining faces according to claim 1, characterized in that, The adaptive support and control module also includes: Side guard plate stroke detection sensor, used to collect the extension and retraction stroke data of the side guard plate; An electro-hydraulic regulating valve is installed in series in the hydraulic pipeline of the side guard actuator to regulate the pressure and flow of the hydraulic oil circuit; The support pressure feedback component is installed on the contact surface between the support plate and the coal face to collect actual support pressure data.

6. The longwall mining system for controlling coal wall spalling in high-seam working faces according to claim 1, characterized in that, The process for determining the water content stability coefficient of the coal body is as follows: Real-time moisture content is obtained based on the optimal stable moisture content range of the coal seam. When the real-time moisture content is within the optimal stable moisture content range, the moisture content stability coefficient of the coal body is 0. When the real-time moisture content is lower than the lower limit of the optimal stable moisture content range, the difference between the real-time moisture content and the drying limit moisture content is calculated and divided by the difference between the lower limit and the drying limit moisture content to obtain the first deviation normalized value as the moisture content stability coefficient of the coal body. When the real-time moisture content is higher than the upper limit of the optimal stable moisture content range, the difference between the real-time moisture content and the upper limit is calculated and divided by the difference between the immersion limit moisture content and the upper limit to obtain a second deviation normalized value as the moisture content stability coefficient of the coal body.

7. The longwall mining system for controlling coal wall spalling in high-seam working faces according to claim 1, characterized in that, The process for determining the surrounding rock stress hazard factor is as follows: The comprehensive real-time stress is obtained by integrating the surrounding rock stress, coal wall bearing pressure, and support column resistance. When the comprehensive real-time stress is less than or equal to the safe stress threshold calibrated at the working face, the surrounding rock stress hazard factor is 0; When the comprehensive real-time stress is greater than the safe stress threshold and less than or equal to the coal wall shear failure limit stress, the difference between the comprehensive real-time stress and the safe stress threshold is calculated and divided by the difference between the coal wall shear failure limit stress and the safe stress threshold to obtain a third normalized value as the surrounding rock stress hazard coefficient. When the comprehensive real-time stress is greater than the shear failure limit stress of the coal wall, the stress hazard factor of the surrounding rock is 1.

8. The longwall mining system for controlling coal wall spalling in high-seam working faces according to claim 1, characterized in that, The intelligent central control module classifies risk levels based on the comprehensive risk index of the film and television industry, including safety level, early warning level and danger level; When the safety level is maintained, standard water injection parameters, conventional coal mining traction speed, and standard support pressure are maintained. When the warning level is reached, fine-tune the water injection parameters, reduce the coal mining traction speed, and appropriately increase the support pressure. When the situation is at the aforementioned danger level, the water injection parameters are increased, the coal mining traction speed is significantly reduced, and the support actuator is controlled to extend throughout its full stroke and lock the support pressure.

9. The longwall mining system for controlling coal wall spalling in high-seam working faces according to claim 1, characterized in that, The intelligent central control module is also used for: After outputting control commands, real-time updates of hydrological data, stress data, and support status feedback data are collected. The risk coupling model for the slope support is dynamically modified based on hydrological data, stress data, and support status feedback data.

10. The longwall mining system for controlling coal wall spalling in high-mining faces according to claim 1, characterized in that, The intelligent central control module is deployed inside the explosion-proof electrical control cabinet at the working face end, and establishes bidirectional communication connections with the hydrological sensing module, stress monitoring module, water retention and injection module and adaptive side protection control module through the underground industrial Ethernet.

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