Deep mine rock burst and heat disaster comprehensive early warning method and system

Abstract

The present application relates to the technical field of mine safety monitoring and early warning, and discloses a deep mine rock burst and heat hazard comprehensive early warning method and system, which obtains mine mining engineering, lithology, original rock stress, rock mechanics, ground temperature, ventilation network, dynamic ground pressure, heat environment and operation state data, divides comprehensive early warning units according to geological boundaries, mining engineering boundaries, stress direction boundaries, ventilation branch boundaries and monitoring equipment coverage ranges, determines rock burst static risk, rock burst dynamic correction and heat hazard risk of each comprehensive early warning unit, and determines coupling correction according to the temperature rise of surrounding rock, high temperature duration and blasting or pressure relief operation state. The comprehensive risk grade is determined according to the rock burst risk, heat hazard risk and coupling correction, the rock burst dominant mode, heat hazard dominant mode or double high coupling mode is identified, and the pressure relief, support, ventilation, refrigeration, personnel control and operation permission instructions are generated accordingly.

Description

Technical Field

[0001] This invention relates to the field of mine safety monitoring and early warning technology, and more specifically, to a comprehensive early warning method and system for rock bursts and heat hazards in deep mines. Background Technology

[0002] As shallow mineral resources gradually decrease, the mining depth of metal mines continues to increase. Deep mines are typically characterized by high ground stress, high ground temperature, and strong mining disturbance. With increasing mining depth, the stress of the original rock and the temperature of the surrounding rock rise accordingly. Operations such as tunnel excavation, stope recovery, blasting, ore extraction, and backfilling can also cause stress redistribution and local temperature changes, increasing the likelihood of rockbursts and heat hazards.

[0003] Rockburst is a dynamic destructive phenomenon in which the elastic deformation energy accumulated in deep rock masses is suddenly released under conditions such as excavation disturbance, causing rock fracturing, spalling, or ejection. Existing rockburst evaluation methods typically determine the tendency of rockburst based on parameters such as burial depth, original rock stress, uniaxial compressive strength, tensile strength, elastic modulus, and Poisson's ratio, using criteria such as critical burial depth, strength brittleness, linear elastic energy, or strength-stress ratio. Some mines also use dynamic monitoring data such as microseismic activity, acoustic emission, surrounding rock strain, surrounding rock displacement, or drill cuttings volume to determine surrounding rock anomalies.

[0004] Different rockburst criteria consider different influencing factors, which may lead to differences in evaluation results. Using a single criterion makes it difficult to comprehensively reflect the stress state, brittleness, and energy storage characteristics of the surrounding rock. When using multiple criteria for evaluation, existing methods often employ fixed weights or simple weighting, failing to fully consider factors such as the distance between measuring points, the completeness of experimental data, sensor operating status, and the applicability of different criteria to specific lithologies. Furthermore, microseismic and acoustic emission data are easily affected by blasting, ore extraction, and the operation of mechanical equipment, potentially causing distortion in monitoring results.

[0005] Heat hazards in deep mines mainly originate from heat dissipation from the surrounding rock, self-compression of air entering the mine, heat release from mechanical equipment, heat release from blasting, and heat release from the hydration of backfill. Current heat hazard assessments typically determine the degree of heat hazard based on air temperature, air humidity, wind speed, air volume, or personnel heat exposure indicators, and reduce the temperature of the work area by increasing ventilation, shortening ventilation routes, installing insulation measures, or using refrigeration equipment.

[0006] Current thermal hazard assessments primarily focus on the working environment of underground personnel, typically neglecting the impact of surrounding rock temperature rise and its duration on rock mechanical properties, thermal stress, and anchoring support performance. Blasting or depressurization operations, while disturbing the rock mass, also generate heat and pollutants; ventilation and cooling conditions further affect the safety of depressurization, personnel evacuation, and recovery operations. Therefore, in deep mining operations, rockburst risk and thermal hazard risk may coexist and influence each other.

[0007] Currently, mine ground pressure monitoring systems and ventilation / heat hazard monitoring systems are typically set up separately. Ground pressure monitoring systems primarily process data on in-situ rock stress, microseismic activity, acoustic emission, and surrounding rock deformation, while ventilation / heat hazard monitoring systems primarily process temperature, humidity, wind speed, and air volume data. Even when some mine safety management platforms can display these data simultaneously, they often aggregate data and issue separate warnings, failing to uniformly divide the monitoring area according to lithology, mining engineering, stress direction, and ventilation network. Consequently, ground pressure warnings and heat hazard warnings are difficult to accurately correlate to the same stope or roadway area.

[0008] Furthermore, existing early warning systems typically propose separate measures such as pressure relief, support, ventilation, cooling, and personnel evacuation, lacking a unified assessment and execution sequence for situations where rockburst and heat hazards simultaneously reach a high risk level. For example, after blasting or pressure relief operations, timely ventilation and smoke extraction are necessary for heat dissipation. However, directly assigning personnel to pressure relief or support operations under high temperature and insufficient ventilation conditions increases operational risks. If operations are resumed based on only one type of risk, the other type of risk may not yet meet safety requirements.

[0009] Therefore, it is necessary to propose a comprehensive early warning method and system for rockbursts and heat hazards in deep mines to solve the above problems. Summary of the Invention

[0010] The purpose of this invention is to solve the technical problems mentioned in the background section and to provide a comprehensive early warning method for rockbursts and heat hazards in deep mines.

[0011] The above-mentioned objective of the present invention is achieved as follows: A comprehensive early warning method for rockburst and heat hazards in deep mines includes: Acquire mining engineering models, lithological distribution data, original rock stress data, rock mechanical parameters, geothermal data, ventilation network data, dynamic ground pressure monitoring data, thermal environment monitoring data, and mining operation status data for deep mines; Based on lithological boundaries, mining engineering boundaries, maximum principal stress direction change boundaries, ventilation branch boundaries, and monitoring equipment coverage, the mining area is divided into multiple comprehensive early warning units; For each integrated early warning unit, the static risk of rockburst is determined based on its burial depth, original rock stress data, rock mechanics parameters and spatial location relationship, and the dynamic correction amount of rockburst is determined based on the degree of deviation of the dynamic ground pressure monitoring data from the corresponding rolling time baseline, so as to obtain the rockburst risk value. The original rock temperature baseline is determined based on the burial depth and ground temperature data of the integrated early warning unit, and the heat hazard risk value is determined based on the thermal environment monitoring data, ventilation operation status, and local heat source status. Based on the surrounding rock temperature rise state, surrounding rock temperature gradient, high temperature duration, and blasting or decompression operation state, a coupling characteristic is generated to characterize the combined effect of thermal environment and rock mass disturbance, and a coupling correction amount is determined based on the coupling characteristic. The larger of the rockburst risk value and the heat hazard risk value is used as the basic comprehensive risk value. The basic comprehensive risk value is incrementally corrected using the coupling correction amount to determine the comprehensive risk level. Based on the rockburst risk value, heat hazard risk value, and comprehensive risk level, identify the rockburst-dominant mode, heat hazard-dominant mode, or dual-high-risk coupling mode, and generate corresponding decompression, support, ventilation, cooling, personnel management, and work permit linkage response strategies for the identified modes. The system acquires dynamic ground pressure monitoring data and thermal environment monitoring data after executing the aforementioned coordinated response strategy, and generates a recovery operation instruction when both rockburst recovery conditions and thermal hazard recovery conditions are simultaneously met.

[0012] Furthermore, the integrated early warning unit is determined to include: Geological boundaries are determined based on the location of lithological changes, faults, and lithological contact zones. The boundaries of the mining project are determined based on the location of the stope, roadway, pillar, goaf, and the area where the roof and sidewalls meet. The stress direction boundary is determined based on the change in the angle between the direction of the maximum principal stress and the direction of the roadway axis. The boundaries of ventilation branches are determined based on the effective range of air intake branches, return air branches, and local ventilation equipment. The mining area is divided into zones using the geological boundaries, mining engineering boundaries, stress direction boundaries, and ventilation branch boundaries, and each zone is assigned a unique comprehensive early warning unit identifier.

[0013] Furthermore, determining the static risk of rockburst includes: Based on the measurement results of multiple original rock stress measuring points set at different burial depths, a stress baseline model of the maximum principal stress varying with burial depth is established, and the maximum principal stress baseline of the integrated early warning unit is determined. Determine at least one stress intensity index, which includes at least one of the following: the relationship between the burial depth of the comprehensive early warning unit and the critical burial depth of rock eruption, and the relationship between the uniaxial compressive strength of rock and the maximum principal stress. Identify at least one brittle or energy-related indicator, which includes at least one of the following: the relationship between the uniaxial compressive strength and tensile strength of the rock, and the elastic energy storage level of the rock before reaching its peak strength. At least one spatial environment index is determined, which includes at least one of the following: the relationship between the roadway axis direction and the direction of the maximum principal stress, and the spatial relationship between the comprehensive early warning unit and faults, lithological contact zones, goafs, pillars, or stress concentration points. The stress intensity index, brittleness or energy index, and space environment index are converted into corresponding hazard levels and then fused to obtain the static risk of rockburst.

[0014] Furthermore, determining the rockburst dynamic correction amount includes: Extract at least two dynamic indicators from the dynamic ground pressure monitoring data, including microseismic event energy, microseismic event frequency, acoustic emission count, surrounding rock strain change rate, surrounding rock displacement change rate, and drill cuttings volume. Establish rolling time baselines for each dynamic indicator during periods without rock mass anomalies; Determine the degree of deviation of each dynamic indicator relative to the corresponding rolling time baseline; The reliability of each dynamic indicator is determined based on the online rate of monitoring equipment, data integrity, noise level, and the probability of interference caused by blasting, mining, and mechanical equipment operation. The dynamic correction amount for rockburst is determined based on the degree of deviation and the reliability of the data, and the dynamic correction amount for rockburst is used to correct the static risk of rockburst.

[0015] Furthermore, determining the heat hazard risk value includes: Based on the original rock temperature measurement results at different burial depths, a geothermal baseline model of the original rock temperature variation with burial depth is established, and the original rock temperature baseline of the comprehensive early warning unit is determined. Determine the risk of human heat exposure based on air temperature, air humidity, and wind speed; The risk of heat dissipation of the surrounding rock is determined based on the degree of deviation of the measured surrounding rock temperature from the baseline of the original rock temperature and the temperature difference between the surrounding rock and the airflow. The risk of insufficient ventilation is determined based on the relationship between the actual effective air volume and the required air volume of the integrated early warning unit. The transient heat source risk is determined based on the heat load generated by blasting operations, mechanical equipment operation, and the heat release from the hydration of the filling material within a preset time window. The heat hazard risk value is determined based on the personnel heat exposure risk, surrounding rock heat dissipation risk, insufficient ventilation risk, and transient heat source risk.

[0016] Further, determining the coupling correction amount includes: The degree of thermal stress influence is determined based on the surrounding rock temperature rise rate and surrounding rock temperature gradient. The degree of degradation of the surrounding rock or support performance is determined based on the duration of high temperature and the pre-established degradation relationship between temperature and rock mechanical properties or anchoring support performance. Based on the timing, location, and intensity of the blasting, decompression blasting, or decompression drilling operations, determine the degree of spatiotemporal superposition between rock mass disturbance and transient heat source within the same comprehensive early warning unit; The coupling correction amount is determined based on the degree of thermal stress influence, the degree of degradation of surrounding rock or support performance, and the degree of spatiotemporal superposition. Specifically, when both the rockburst risk value and the heat hazard risk value reach the corresponding early warning threshold, and the coupling correction amount reaches the preset coupling threshold, the integrated early warning unit is determined to be in a dual high coupling mode, and the integrated risk level is raised by at least one level.

[0017] Furthermore, generating the coordinated response strategy includes: In the rockburst-dominated mode, generate at least one of the following control commands: restrict personnel access, shorten mining advance, reduce single blast charge, implement pressure relief drilling, and strengthen surrounding rock support. In the heat hazard-dominated mode, generate at least one of the following control instructions: increase effective air volume, shorten ventilation path, start local cooling, limit the operation of high-heat equipment, and adjust the continuous working time of personnel. In the dual-high coupling mode, the following commands are generated: work stoppage and evacuation command, remote ventilation or pre-cooling command, depressurization or support operation permit command, and forced ventilation command after treatment. The control commands are sent to the corresponding devices or systems in the fan control equipment, refrigeration control equipment, audible and visual alarm equipment, personnel positioning system, and work permit system.

[0018] Furthermore, in the dual-high coupling mode, the coordinated handling strategy is executed in the following order: Stop mining operations within the target integrated early warning unit, evacuate non-response personnel, and set up an operational warning zone; Increase the effective airflow of the target integrated early warning unit or start the pre-cooling equipment through remote control; After the thermal environment reaches the preset short-term treatment conditions, at least one of the following operations shall be carried out by remote operation equipment or authorized personnel: pressure relief drilling, controlled blasting, and support reinforcement. Forced ventilation, smoke extraction, and heat dissipation should be implemented after depressurization or controlled blasting operations are completed; Dynamic ground pressure data and thermal environment data were re-measured within the preset observation period, and the status of surrounding rock and support was verified. When the dynamic ground pressure index is lower than the rockburst resumption threshold, the thermal environment index is lower than the heat hazard resumption threshold, and the surrounding rock and support conditions meet the preset safety conditions, the work warning is lifted and work resumes.

[0019] The present invention also provides a comprehensive early warning system for rockburst and heat hazards in deep mines, including an underground monitoring sensor group, a data communication gateway, an early warning server, and a linkage control interface; The downhole monitoring sensor group is used to collect original rock stress data, dynamic ground pressure monitoring data, surrounding rock temperature data, air temperature and humidity data, and wind speed or air volume data. The data communication gateway is used to send the data collected by the downhole monitoring sensor group and the mining operation status data to the early warning server; The early warning server includes: The early warning unit construction module is used to divide comprehensive early warning units according to lithological boundaries, mining engineering boundaries, maximum principal stress direction change boundaries, ventilation branch boundaries, and monitoring equipment coverage areas. The rockburst risk calculation module is used to determine the rockburst risk value based on the original rock stress data, rock mechanical parameters and dynamic ground pressure monitoring data. The heat hazard risk calculation module is used to determine the heat hazard risk value based on the original rock temperature baseline, air temperature and humidity data, wind speed or air volume data, and local heat source status. The coupling classification module is used to generate coupling characteristics that characterize the combined effect of thermal environment and rock mass disturbance, determine the coupling correction amount based on the coupling characteristics, and determine the comprehensive risk level based on rockburst risk value, thermal hazard risk value and coupling correction amount; The linkage decision-making module is used to generate depressurization, support, ventilation, cooling, personnel management and work permit control instructions based on the comprehensive risk level; The linkage control interface is communicatively connected to at least two of the fan control equipment, refrigeration control equipment, alarm equipment, personnel positioning system, and work permit system, and is used to send the control commands and receive the execution results.

[0020] Furthermore, the linkage control interface includes a fan control interface, a refrigeration equipment control interface, an alarm control interface, a personnel positioning interface, and a work permit control interface; The wind turbine control interface is used to adjust the operating status of the wind turbine corresponding to the target comprehensive early warning unit according to the comprehensive risk level; The refrigeration equipment control interface is used to start, stop, or adjust the refrigeration equipment corresponding to the target integrated early warning unit according to the heat hazard risk value. The alarm control interface is used to output graded alarm information according to the comprehensive risk level; The personnel positioning interface is used to determine the distribution of personnel within the target integrated early warning unit, and to generate evacuation information for the corresponding personnel when the integrated risk level reaches a preset level. The operation permission control interface is used to restrict the mining operations of the target integrated early warning unit, and the operation restriction is lifted when the conditions for rockburst resumption, heat hazard resumption, and surrounding rock and support safety are met simultaneously.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention divides comprehensive early warning units based on lithological boundaries, mining engineering boundaries, maximum principal stress direction change boundaries, ventilation branch boundaries, and monitoring equipment coverage areas, so that data such as original rock stress, rock mechanics, dynamic ground pressure, ground temperature, temperature and humidity, and air volume are mapped to specific mining areas, roadways, pillars, or stress concentration areas; compared with the method of evaluating according to fixed grids or separately according to ground pressure areas and ventilation areas, it can improve the positioning accuracy of risk areas.

[0022] 2. This invention comprehensively utilizes static rockburst indicators, dynamic ground pressure monitoring data, and thermal environment monitoring data, and corrects the risk results based on the surrounding rock temperature rise, the duration of high temperature, and the blasting or depressurization operation status; it uses the higher of rockburst risk and thermal hazard risk as the basis for comprehensive risk judgment, which can avoid the reduction of higher risks due to simple averaging; it determines the reliability of data based on the completeness of data, sensor operating status, and operational interference, which can reduce the impact of abnormal and missing data on early warning results.

[0023] 3. This invention generates depressurization, support, ventilation, cooling, personnel evacuation, and work permit instructions based on rockburst-dominant, heat hazard-dominant, and dual-high-pressure coupling modes, respectively. When the risks of rockburst and heat hazard increase simultaneously, work stoppage and personnel evacuation, increased ventilation or pre-cooling, depressurization or support, and post-treatment re-measurement are implemented sequentially. Work resumes only after the dynamic ground pressure index, thermal environment index, and surrounding rock support status all meet safety requirements, thereby reducing conflicts in the execution of different safety measures. Attached Figure Description

[0024] Figure 1 This is a flowchart of a comprehensive early warning method for rockburst and heat hazards in deep mines according to the present invention; Figure 2 This is a system block diagram of a comprehensive early warning system for rockburst and heat hazards in deep mines according to the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the following description is provided in conjunction with embodiments and appendices. Figure 1-2 The present invention will be further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] Example 1: This example provides the application of the integrated early warning method for rockburst and heat hazards in deep mines according to the implementation plan to a deep metal mine. The metal mine is equipped with a stope, transport roadway, return air roadway, pillar, goaf and local ventilation facilities. The deep area includes various lithologies, and some areas have faults, lithological contact zones and stress concentration areas formed by the intersection of the roof and sidewalls.

[0027] The integrated early warning system includes a downhole monitoring sensor group, a data communication gateway, an early warning server, and a linkage control interface. The downhole monitoring sensor group includes microseismic sensors, acoustic emission sensors, strain sensors, displacement sensors, surrounding rock temperature sensors, air temperature and humidity sensors, and wind speed or air volume sensors. Depending on the monitoring conditions of different areas, at least some of these sensors can be selected for combined use.

[0028] The data communication gateway receives data collected by each sensor and configures the collection time, spatial coordinates, sensor identifier, and data quality mark for each data item. The data communication gateway also receives data on blasting, ore release, backfilling, equipment operation, personnel distribution, and mining progress provided by the mine production management system, and sends the processed data to the early warning server.

[0029] The linkage control interface includes a fan control interface, a refrigeration equipment control interface, an alarm control interface, a personnel positioning interface, and a work permit control interface. The fan control interface communicates with the local fan or ventilation control system; the refrigeration equipment control interface communicates with the local refrigeration equipment; the alarm control interface communicates with the audible and visual alarm equipment; the personnel positioning interface communicates with the underground personnel positioning system; and the work permit control interface communicates with the blasting, mining, and maintenance work permit system.

[0030] Before the system runs, the three-dimensional mining engineering model, lithological distribution data, fault and lithological contact zone data, original rock stress measurement results, rock mechanics test results, ground temperature measurement results, ventilation network data, and monitoring equipment layout data of the mine are imported into the early warning server.

[0031] The early warning server first divides the comprehensive early warning units. In the process of dividing, the geological boundaries are the location of lithological changes, faults and lithological contact zones, the mining engineering boundaries are the mining area, roadways, pillars, goaf and the area where the roof and sidewalls meet, the stress direction boundaries are the changes in the direction of the maximum principal stress and the changes in the angle between the roadway axis and the direction of the maximum principal stress, the ventilation boundaries are the intake air branch, return air branch and the effective range of local ventilation equipment, and the final unit boundaries are determined by combining the effective coverage of each monitoring device.

[0032] When the same mining area spans different lithologies or is supplied with air by different ventilation branches, it is divided into different comprehensive early warning units. When the lithology, stress state, ventilation conditions, and mining conditions of adjacent areas are basically the same, they can be merged into the same comprehensive early warning unit. Each comprehensive early warning unit has a unique identifier and is associated with its burial depth, lithology, original rock stress, rock mechanical parameters, direction of maximum principal stress, original rock temperature baseline, normal air volume range, adjacent units, and current operating status.

[0033] The static risk of rockburst is determined from three aspects: stress intensity, brittleness or energy, and spatial environment. Regarding stress intensity, at least the burial depth of the integrated early warning unit should be considered whether it exceeds the critical rockburst depth for the corresponding lithology, and the relative relationship between the uniaxial compressive strength of the rock and the maximum principal stress at its location. Regarding brittleness or energy, at least the relationship between the uniaxial compressive strength and tensile strength of the rock should be considered, and the level of elastic energy stored in the rock before reaching its peak strength. Regarding the spatial environment, at least the angle between the roadway axis and the direction of the maximum principal stress should be considered, as well as the distance between the integrated early warning unit and faults, lithological contact zones, goafs, pillars, or other stress concentration points.

[0034] The above indicators are converted into low, moderate, relatively high, or high risk levels, respectively. The early warning server also determines the data reliability of each indicator based on the distance of the original rock stress measurement points, the number of rock test samples, the completeness of the data, and the applicability of the corresponding indicator to the current lithology. When the risk levels obtained from different static indicators are inconsistent, the results of indicators with higher risk levels and higher data reliability are retained first to avoid diluting high-risk information due to simple averaging.

[0035] After determining the static risk of rockburst, the early warning server extracts at least two dynamic indicators from the dynamic ground pressure monitoring data, including microseismic event energy, microseismic event frequency, acoustic emission count, surrounding rock strain change rate, surrounding rock displacement change rate, and drill cuttings volume.

[0036] The early warning server selects historical periods with no obvious rock mass fracturing and stable mining activities, establishes a rolling time baseline for each dynamic indicator, and compares the real-time monitoring results with the corresponding rolling time baseline. When the frequency of microseismic events, the energy of microseismic events, the acoustic emission count, or the deformation rate of the surrounding rock continues to increase, the dynamic correction amount for rockburst is increased, and the static risk of rockburst is corrected using this correction amount to obtain the rockburst risk value.

[0037] For interference caused by blasting, mining, and mechanical equipment operation, the early warning server determines the probability of interference based on the operation time, event location, signal waveform, and equipment operation records. Data with a high probability of interference has reduced reliability but is retained. When monitoring equipment is offline, data is missing, or sensors drift, the uncertainty of the early warning result is increased, and missing data is not directly considered as low risk.

[0038] The risk of heat damage is determined by comprehensively considering the original rock temperature baseline, human heat exposure, surrounding rock heat dissipation, ventilation capacity, and local heat sources. The early warning server establishes the ground temperature baseline based on the original rock temperature measurement results at different burial depths and determines the original rock temperature benchmark for each comprehensive early warning unit at the current burial depth.

[0039] Personnel heat exposure risk is determined based on air temperature, air humidity, and wind speed; surrounding rock heat dissipation risk is determined based on the deviation of the measured temperature of the surrounding rock from the baseline temperature of the original rock and the temperature difference between the surrounding rock and the airflow; insufficient ventilation risk is determined based on whether the actual effective air volume can meet the current number of personnel, equipment load, and work mode; local heat source risk is determined based on the thermal impact of blasting, mechanical equipment operation, and hydration heat release of the filling material within a preset time.

[0040] The early warning server generates coupled characteristics representing the combined effects of the thermal environment and rock mass disturbance based on the surrounding rock temperature rise rate, surrounding rock temperature gradient, duration of high temperature, and blasting or decompression operation status. The impact of the duration of high temperature on rock mechanical properties or anchoring support performance can be determined based on a pre-established temperature-performance degradation relationship. If corresponding experimental data is not yet available, this item is marked as insufficient data and the uncertainty is increased; unknown states are not considered as having no degradation.

[0041] The early warning server uses the higher of rockburst risk and heat hazard risk as the base comprehensive risk, and increases the comprehensive risk based on the coupling correction amount corresponding to the coupling characteristics. When both rockburst risk and heat hazard risk reach the corresponding early warning threshold, and blasting, decompression or other disturbances are superimposed with high temperature and insufficient ventilation in the same comprehensive early warning unit and within the same time range, the unit is identified as a dual-high coupling mode, and the comprehensive risk level is increased by at least one level.

[0042] In this embodiment, a comprehensive early warning unit for the footwall of a certain mining area is located in a biotite-quartz schist region, buried at a depth of approximately 900 meters, and adjacent to the angle between the roof and the footwall. Static evaluation indicates that this unit has a high risk of rockburst. During the monitoring process, the frequency of microseismic events, acoustic emission counts, and the rate of change of surrounding rock strain continuously increased, and the early warning server accordingly increased the rockburst risk level.

[0043] Meanwhile, the air temperature and humidity in the area continue to rise, the actual effective air volume is lower than the air volume required for the current equipment and personnel operations, and blasting operations are about to be carried out in the area. Based on this, the early warning server increases the risk of heat damage and the coupling correction amount, and identifies the area as a dual high coupling mode.

[0044] The early warning server suspends blasting and mining operations in the area through the work permit control interface, determines the distribution of personnel in the area through the personnel positioning interface, generates evacuation information through the alarm control interface, and evacuates non-response personnel.

[0045] After personnel evacuation, the early warning server increases the operating speed of the corresponding fan via the fan control interface. If increasing the air volume is still insufficient to meet the thermal environment requirements for handling, localized cooling or pre-cooling equipment is activated via the cooling equipment control interface.

[0046] Once the thermal environment reaches the preset short-term treatment conditions, pressure relief drilling and support reinforcement will be carried out by remote operation equipment or authorized personnel. Pressure relief boreholes will be preferentially located at the angle between the roof and footwall, near pillars, and other stress concentration areas. The borehole depth can be set to two to five meters depending on the integrity of the surrounding rock and construction conditions. Support can be provided using a combination of resin anchors and metal mesh. The anchor length and spacing will be determined based on the integrity of the surrounding rock, the rockburst risk level, and the existing support design.

[0047] After depressurization or controlled blasting is completed, the early warning server controls the fans to perform forced ventilation, smoke extraction, and heat dissipation. During the preset observation period, the system continuously collects data on microseismic activity, acoustic emission, surrounding rock strain, air temperature and humidity, wind speed, and air volume, and verifies the status of surrounding rock cracks, loose rocks, and anchored support.

[0048] The work permit control interface will only lift the work restriction when the dynamic ground pressure index is below the rockburst resumption threshold, the thermal environment index is below the heat hazard resumption threshold, and the surrounding rock and support conditions meet the preset safety conditions. If any condition is not met, the system will remain on alert and will again implement ventilation, cooling, depressurization, or support measures.

[0049] When only the rockburst risk reaches the high-risk level, the system enters the rockburst-dominated mode and implements at least one of the following measures: restricting personnel access, shortening the mining advance, reducing the amount of explosives per blast, implementing pressure relief drilling, and strengthening the surrounding rock support; when only the heat hazard risk reaches the high-risk level, the system enters the heat hazard-dominated mode and implements at least one of the following measures: increasing the effective air volume, shortening the ventilation path, starting local cooling, restricting the operation of high-heat equipment, and adjusting the continuous working time of personnel.

[0050] The early warning server records early warning units, monitoring data, risk levels, control commands, execution results, and risk changes after handling. For confirmed rock mass fracturing events or thermal hazard events, the weights of corresponding indicators are adjusted based on changes in each indicator before the event. For verified and effective decompression, support, ventilation, and cooling measures, their applicable rock types, burial depths, and operating conditions are recorded for subsequent handling decisions of similar integrated early warning units.

[0051] Example 2: This example is based on measured data of in-situ rock stress, rock mechanics, and geothermal temperature from deep metal mines. It explains the calculation process for rockburst risk, thermal hazard risk, coupling correction, and overall risk using formulas. The burial depth of the comprehensive early warning unit is assumed to be... , burial depth The maximum principal stress, intermediate principal stress, and vertical stress components at the location are respectively , and The uniaxial compressive strength of the rock is The tensile strength of the rock is The tangential elastic modulus of the rock unloading is Poisson's ratio is The density of the rock is The critical burial depth for rock bursts is The strength brittleness coefficient is The linear elastic performance index is The strength-stress ratio is .

[0052] Based on the measured results of three original rock stress measuring points located at different burial depths, a regression relationship between principal stress and burial depth was established: ; In the formula, The unit is meters, and the unit for each stress is megapascal. Field measurements show that the average direction of the maximum principal stress is approximately 5.68 degrees north of northwest, generally close to a north-south direction, and the maximum principal stress is mainly manifested as horizontal tectonic stress.

[0053] For the integrated early warning unit with a burial depth of 900 meters, we can obtain the following from equation (1): ; From equations (2) and (3), the intermediate principal stress is approximately 29.64 MPa and the vertical stress component is approximately 23.93 MPa.

[0054] When the roadway axis is basically parallel to the direction of the maximum principal stress, the direction correction value is small; when the angle between the roadway axis and the direction of the maximum principal stress increases, or when the comprehensive early warning unit is located at the intersection of the roof, floor, sidewalls and adjacent areas of the pillar, the spatial environment hazard level increases.

[0055] The critical burial depth for rock bursts is determined by the following formula: (4); In the formula, the uniaxial compressive strength is converted to Pascals when substituted into the calculation, and the rock density is expressed as Newtons per cubic meter.

[0056] The uniaxial compressive strength of the two mica quartz schist is taken as 144.61 MPa, the Poisson's ratio as 0.22, and the density as 2.74 g / cm³; the uniaxial compressive strength of the biotite quartz schist is taken as 93.05 MPa, the Poisson's ratio as 0.27, the density as 2.75 g / cm³, and the gravitational acceleration as 10 m / s².

[0057] According to equation (4), the critical burial depth of two mica quartz schist is approximately 617.50 meters, and the critical burial depth of biotite quartz schist is approximately 409.10 meters. Therefore, when the burial depth of the integrated early warning unit reaches 900 meters, both lithologies exceed their corresponding critical burial depths, and there is a possibility of rockburst.

[0058] The strength-brittleness coefficient is determined by the following formula: (5); The uniaxial compressive strength of the two-mica quartz schist was taken as 144.61 MPa, and the tensile strength as 9.00 MPa, resulting in a strength-brittleness coefficient of approximately 16.07. The strength-brittleness coefficient of the biotite quartz schist was taken as 15.59. Based on the discrimination range of 14.5 to 26.7 corresponding to a moderate rockburst tendency, both lithologies exhibit a moderate rockburst tendency.

[0059] The linear elastic performance index is determined by the following formula: (6); when and When all units are in megapascals, the calculation result corresponds to megajoules per cubic meter, which is then converted to kilojoules per cubic meter.

[0060] The elastic modulus of the two-mica quartz schist is taken as 58.25 GPa, and the calculated linear elastic performance index is approximately 179.50 kJ / m³. The linear elastic performance index of the biotite quartz schist is taken as 110.59 kJ / m³. Based on the discrimination range of 100 to 200 kJ / m³ corresponding to moderate rockburst tendency, both lithologies exhibit moderate rockburst tendency.

[0061] The strength-stress ratio is determined by the following formula: (7); At a depth of 900 meters, the strength-stress ratio of the two-mica quartz schist is: ; This result falls within the range of moderate rockburst tendency. The strength-stress ratio of biotite-quartz schist is: ; The result is below 2.5, placing it within the strong rockburst tendency range. Therefore, the biotite-quartz schist area at a depth of approximately 900 meters is designated as a key rockburst early warning area. For indicators with higher values ​​indicating higher risk, the following method is used to convert them to a risk level between zero and one: (8); In the formula, Indicators to be converted As a low-risk boundary, As a high-risk boundary, This represents the degree of danger. For indicators such as the strength-stress ratio, the smaller the value, the higher the degree of danger; an inverse conversion is used: (9); Critical burial depth index, strength-brittleness index, linear elastic performance index, strength-stress ratio index, and space environment index are respectively converted into hazard levels. Static risk of rockburst Determined according to the following formula: (10); In the formula, For the first The weight of each static rockburst index, The corresponding data reliability is determined based on the distance between measurement points, the number of test samples, the completeness of the data, and the applicability of the indicators.

[0062] The weights can be adjusted based on the correlation between each indicator and the confirmed rock mass fracture events within the historical monitoring period. If the denominator of equation (10) is zero, it indicates a lack of effective static data. In this case, a low-risk result is not output, but the comprehensive early warning unit is marked as having insufficient data and the data uncertainty is increased.

[0063] Select at least two of the following from the dynamic ground pressure monitoring data: microseismic event energy, microseismic event frequency, acoustic emission count, surrounding rock strain change rate, surrounding rock displacement change rate, and drill cuttings volume. Let the first... The degree of deviation of each dynamic indicator from the rolling time baseline is The corresponding weights and credibility are respectively and Then the dynamic correction amount for rockburst for: (11); Rockburst risk value for: (12); In the formula, For dynamic correction coefficients, This is the direction correction factor. To calculate the thermal hazard risk corresponding to the angle between the roadway axis and the direction of maximum principal stress, a baseline of the original rock temperature is first established. Let the baseline depth be... The original rock temperature at the reference depth is The geothermal gradient is Then the burial depth The original rock temperature baseline at that location for: (13); In this embodiment, the geothermal gradient ranges from 2.01 to 2.43 degrees Celsius per 100 meters, with an average of 2.256 degrees Celsius per 100 meters. The measured original rock temperature at 900 meters was 27.73 degrees Celsius, and at 1200 meters it was 34.81 degrees Celsius.

[0064] The degree of human thermal exposure hazard is determined based on air temperature, wet-bulb temperature, relative humidity, and wind speed; the degree of heat dissipation hazard from the surrounding rock is determined based on the deviation between the measured temperature of the surrounding rock and the baseline temperature of the original rock; and the degree of transient heat source hazard is determined based on the heat release from blasting, mechanical equipment operation, and hydration of the filling material.

[0065] Let the actual effective air volume be The required air volume is Inadequate ventilation poses a significant risk. for: (14); When the actual effective air volume reaches or exceeds the required air volume, the danger of insufficient ventilation is zero; the lower the actual effective air volume is than the required air volume, the higher the danger of insufficient ventilation.

[0066] Let the first The degree of danger, weight, and reliability of each heat hazard indicator are as follows: , and Heat damage risk value for: (15); The coupling correction takes into account the surrounding rock temperature rise rate, surrounding rock temperature gradient, the performance degradation of surrounding rock or support caused by high temperature, and the spatiotemporal superposition of blasting or decompression disturbance and heat source in the same comprehensive early warning unit.

[0067] Let the risk level of the surrounding rock temperature rise rate be . The hazard level of the surrounding rock temperature gradient is: The degree of degradation of the surrounding rock or support performance is The disturbance level of blasting or depressurization operations is The corresponding coupling coefficient is to Then the coupling correction amount for: (16); The degree of degradation in the performance of the surrounding rock or support is determined based on a pre-established correlation between temperature, duration, and rock mechanical properties or anchoring performance. If relevant experimental data has not yet been obtained, this item will not be used as a deterministic input, and the data uncertainty will be increased. Let the data uncertainty be... The coupling correction factor and the uncertainty correction factor are respectively and Overall risk value for: (17); Using the larger of the rockburst risk value and the heat hazard risk value as the basic comprehensive risk value can prevent the dilution of the other high risk by the low risk of one.

[0068] When both the rockburst risk value and the heat hazard risk value reach the corresponding early warning threshold, and the coupling repair amount reaches the preset coupling inverse value, the comprehensive early warning unit will be identified as a dual high coupling mode, and the comprehensive risk level will be raised by at least one level.

[0069] In this embodiment, the biotite-quartz schist comprehensive early warning unit with a burial depth of 900 meters is identified as a key rockburst monitoring unit because its strength-stress ratio enters the strong rockburst tendency range. When the frequency of microseismic events, the energy of microseismic events, and the rate of change of surrounding rock strain all increase simultaneously in this unit, the rockburst risk value is increased by equations (11) and (12).

[0070] When the unit simultaneously experiences increased air temperature and humidity, insufficient effective airflow, and is in the blasting preparation stage, the heat hazard risk value is increased using equation (15), and the coupling correction is increased using equation (16). The early warning server determines the comprehensive risk level according to equation (17) and sends corresponding control commands to the fan, refrigeration equipment, alarm equipment, personnel positioning system, and work permit system.

[0071] In the dual-high coupling mode, the system first stops mining operations and evacuates non-response personnel, then performs remote ventilation or pre-cooling. After the thermal environment meets the short-term response conditions, remote operating equipment or authorized personnel carry out pressure relief drilling, controlled blasting, or support reinforcement. Forced ventilation is performed after the response, and rockburst risk and heat hazard risk values ​​are recalculated within the observation period.

[0072] Only when the rockburst risk is below the rockburst resumption threshold, the heat hazard risk is below the heat hazard resumption threshold, and the surrounding rock and support conditions are verified as qualified, will the work permit control interface remove the work restrictions of the target integrated early warning unit.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A comprehensive early warning method for rockburst and heat hazards in deep mines, characterized in that, include: Acquire mining engineering models, lithological distribution data, original rock stress data, rock mechanical parameters, geothermal data, ventilation network data, dynamic ground pressure monitoring data, thermal environment monitoring data, and mining operation status data for deep mines; Based on lithological boundaries, mining engineering boundaries, maximum principal stress direction change boundaries, ventilation branch boundaries, and monitoring equipment coverage, the mining area is divided into multiple comprehensive early warning units; For each integrated early warning unit, the static risk of rockburst is determined based on its burial depth, original rock stress data, rock mechanics parameters and spatial location relationship, and the dynamic correction amount of rockburst is determined based on the degree of deviation of the dynamic ground pressure monitoring data from the corresponding rolling time baseline, so as to obtain the rockburst risk value. The original rock temperature baseline is determined based on the burial depth and ground temperature data of the integrated early warning unit, and the heat hazard risk value is determined based on the thermal environment monitoring data, ventilation operation status, and local heat source status. Based on the surrounding rock temperature rise state, surrounding rock temperature gradient, high temperature duration, and blasting or depressurization operation state, a coupling characteristic is generated to characterize the combined effect of thermal environment and rock mass disturbance, and a coupling correction amount is determined based on the coupling characteristic. The larger of the rockburst risk value and the heat hazard risk value is used as the basic comprehensive risk value. The basic comprehensive risk value is incrementally corrected using the coupling correction amount to determine the comprehensive risk level. Based on the rockburst risk value, heat hazard risk value, and comprehensive risk level, identify the rockburst-dominant mode, heat hazard-dominant mode, or dual-high-risk coupling mode, and generate corresponding decompression, support, ventilation, cooling, personnel management, and work permit linkage response strategies for the identified modes. The system acquires dynamic ground pressure monitoring data and thermal environment monitoring data after executing the aforementioned coordinated response strategy, and generates a recovery operation instruction when both rockburst recovery conditions and thermal hazard recovery conditions are simultaneously met.

2. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 1, characterized in that, The integrated early warning unit is defined as including: Geological boundaries are determined based on the location of lithological changes, faults, and lithological contact zones. The boundaries of the mining project are determined based on the location of the stope, roadway, pillar, goaf, and the area where the roof and sidewalls meet. The stress direction boundary is determined based on the change in the angle between the direction of the maximum principal stress and the direction of the roadway axis. The boundaries of ventilation branches are determined based on the effective range of air intake branches, return air branches, and local ventilation equipment. The mining area is divided into zones using the geological boundaries, mining engineering boundaries, stress direction boundaries, and ventilation branch boundaries, and each zone is assigned a unique comprehensive early warning unit identifier.

3. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 1, characterized in that, Determining the static risk of rockburst includes: Based on the measurement results of multiple original rock stress measuring points set at different burial depths, a stress baseline model of the maximum principal stress varying with burial depth is established, and the maximum principal stress baseline of the integrated early warning unit is determined. Determine at least one stress intensity index, which includes at least one of the following: the relationship between the burial depth of the comprehensive early warning unit and the critical burial depth of rock eruption, and the relationship between the uniaxial compressive strength of rock and the maximum principal stress. Identify at least one brittle or energy-related indicator, which includes at least one of the following: the relationship between the uniaxial compressive strength and tensile strength of the rock, and the elastic energy storage level of the rock before reaching its peak strength. At least one spatial environment index is determined, which includes at least one of the following: the relationship between the roadway axis direction and the direction of the maximum principal stress, and the spatial relationship between the comprehensive early warning unit and faults, lithological contact zones, goaf areas, pillars, or stress concentration points. The stress intensity index, brittleness or energy index, and space environment index are converted into corresponding hazard levels and then fused to obtain the static risk of rockburst.

4. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 1, characterized in that, Determining the dynamic correction amount for rockburst includes: Extract at least two dynamic indicators from the dynamic ground pressure monitoring data, including microseismic event energy, microseismic event frequency, acoustic emission count, surrounding rock strain change rate, surrounding rock displacement change rate, and drill cuttings volume. Establish rolling time baselines for each dynamic indicator during periods without rock mass anomalies; Determine the degree of deviation of each dynamic indicator relative to the corresponding rolling time baseline; The reliability of each dynamic indicator is determined based on the online rate of monitoring equipment, data integrity, noise level, and the probability of interference caused by blasting, mining, and mechanical equipment operation. The dynamic correction amount for rockburst is determined based on the degree of deviation and the reliability of the data, and the dynamic correction amount for rockburst is used to correct the static risk of rockburst.

5. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 1, characterized in that, Determining the heat hazard risk value includes: Based on the original rock temperature measurement results at different burial depths, a geothermal baseline model of the original rock temperature variation with burial depth is established, and the original rock temperature baseline of the comprehensive early warning unit is determined. Determine the risk of human heat exposure based on air temperature, air humidity, and wind speed; The risk of heat dissipation of the surrounding rock is determined based on the degree of deviation of the measured surrounding rock temperature from the baseline of the original rock temperature and the temperature difference between the surrounding rock and the airflow. The risk of insufficient ventilation is determined based on the relationship between the actual effective air volume and the required air volume of the integrated early warning unit. The transient heat source risk is determined based on the heat load generated by blasting operations, mechanical equipment operation, and the heat release from the hydration of the filling material within a preset time window. The heat hazard risk value is determined based on the personnel heat exposure risk, surrounding rock heat dissipation risk, insufficient ventilation risk, and transient heat source risk.

6. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 1, characterized in that, Determining the coupling correction amount includes: The degree of thermal stress influence is determined based on the surrounding rock temperature rise rate and surrounding rock temperature gradient. The degree of degradation of the surrounding rock or support performance is determined based on the duration of high temperature and the pre-established degradation relationship between temperature and rock mechanical properties or anchoring support performance. Based on the timing, location, and intensity of the blasting, decompression blasting, or decompression drilling operations, determine the degree of spatiotemporal superposition between rock mass disturbance and transient heat source within the same comprehensive early warning unit; The coupling correction amount is determined based on the degree of thermal stress influence, the degree of degradation of surrounding rock or support performance, and the degree of spatiotemporal superposition. Specifically, when both the rockburst risk value and the heat hazard risk value reach the corresponding early warning threshold, and the coupling correction amount reaches the preset coupling threshold, the integrated early warning unit is determined to be in a dual high coupling mode, and the integrated risk level is raised by at least one level.

7. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 1, characterized in that, The generation of the coordinated response strategy includes: In the rockburst-dominated mode, generate at least one of the following control commands: restrict personnel access, shorten mining advance, reduce single blast charge, implement pressure relief drilling, and strengthen surrounding rock support. In the heat hazard-dominated mode, generate at least one of the following control instructions: increase effective air volume, shorten ventilation path, start local cooling, limit the operation of high-heat equipment, and adjust the continuous working time of personnel. In the dual-high coupling mode, the following commands are generated: work stoppage and evacuation command, remote ventilation or pre-cooling command, depressurization or support operation permit command, and forced ventilation command after treatment. The control commands are sent to the corresponding devices or systems in the fan control equipment, refrigeration control equipment, audible and visual alarm equipment, personnel positioning system, and work permit system.

8. The integrated early warning method for rockburst and heat hazards in deep mines according to claim 7, characterized in that, In the dual-high coupling mode, the linkage handling strategy is executed in the following order: Stop mining operations within the target integrated early warning unit, evacuate non-response personnel, and set up an operational warning zone; Increase the effective airflow of the target integrated early warning unit or start the pre-cooling equipment through remote control; After the thermal environment reaches the preset short-term treatment conditions, at least one of the following operations shall be carried out by remote operation equipment or authorized personnel: pressure relief drilling, controlled blasting, and support reinforcement. Forced ventilation, smoke extraction, and heat dissipation should be implemented after depressurization or controlled blasting operations are completed; Dynamic ground pressure data and thermal environment data were re-measured within the preset observation period, and the status of surrounding rock and support was verified. When the dynamic ground pressure index is lower than the rockburst resumption threshold, the thermal environment index is lower than the heat hazard resumption threshold, and the surrounding rock and support conditions meet the preset safety conditions, the work warning is lifted and work resumes.

9. A comprehensive early warning system for rockburst and heat hazards in deep mines, characterized in that, This includes downhole monitoring sensor arrays, data communication gateways, early warning servers, and linkage control interfaces; The downhole monitoring sensor group is used to collect original rock stress data, dynamic ground pressure monitoring data, surrounding rock temperature data, air temperature and humidity data, and wind speed or air volume data. The data communication gateway is used to send the data collected by the downhole monitoring sensor group and the mining operation status data to the early warning server; The early warning server includes: The early warning unit construction module is used to divide comprehensive early warning units according to lithological boundaries, mining engineering boundaries, maximum principal stress direction change boundaries, ventilation branch boundaries, and monitoring equipment coverage areas. The rockburst risk calculation module is used to determine the rockburst risk value based on the original rock stress data, rock mechanical parameters and dynamic ground pressure monitoring data. The heat hazard risk calculation module is used to determine the heat hazard risk value based on the original rock temperature baseline, air temperature and humidity data, wind speed or air volume data, and local heat source status. The coupling classification module is used to generate coupling characteristics that characterize the combined effect of thermal environment and rock mass disturbance, determine the coupling correction amount based on the coupling characteristics, and determine the comprehensive risk level based on rockburst risk value, thermal hazard risk value and coupling correction amount; The linkage decision-making module is used to generate depressurization, support, ventilation, cooling, personnel management and work permit control instructions based on the comprehensive risk level; The linkage control interface is communicatively connected to at least two of the fan control equipment, refrigeration control equipment, alarm equipment, personnel positioning system, and work permit system, and is used to send the control commands and receive the execution results.

10. The integrated early warning system for rockburst and heat hazards in deep mines according to claim 9, characterized in that, The linkage control interface includes a fan control interface, a refrigeration equipment control interface, an alarm control interface, a personnel positioning interface, and a work permit control interface; The wind turbine control interface is used to adjust the operating status of the wind turbine corresponding to the target comprehensive early warning unit according to the comprehensive risk level; The refrigeration equipment control interface is used to start, stop, or adjust the refrigeration equipment corresponding to the target integrated early warning unit according to the heat hazard risk value. The alarm control interface is used to output graded alarm information according to the comprehensive risk level; The personnel positioning interface is used to determine the distribution of personnel within the target integrated early warning unit, and to generate evacuation information for the corresponding personnel when the integrated risk level reaches a preset level. The operation permission control interface is used to restrict the mining operations of the target integrated early warning unit, and the operation restriction is lifted when the conditions for rockburst resumption, heat hazard resumption, and surrounding rock and support safety are met simultaneously.

Images