Gas outburst pre-warning method using low-pressure water injection

Abstract

The present application relates to the field of safety devices in mines or tunnels or their own, especially relates to a kind of gas outburst prevention early warning method using low-pressure water injection. Including the construction of water pump, and to the front of the working face of several boreholes, water pump is configured as multiple, any the water pump is injected into the corresponding borehole with constant first pressure continuously;The first pressure is set to be lower than the original pressure of gas in coal seam;Monitoring and early warning system is constructed, the monitoring and early warning system is configured with multiple monitoring ends set for corresponding multiple boreholes, any the monitoring end is at least configured with flow sensor for monitoring water injection flow;The flow of the corresponding water pump when any the borehole is filled is set as reference flow, and the current flow of the water pump monitored by the monitoring end is set as actual flow;Compare the difference between the actual flow of all water injection boreholes and the reference flow, and execute corresponding countermeasures.

Description

Technical Field

[0001] This invention relates to the field of safety devices in mines or tunnels or in themselves, and more particularly to a gas outburst prevention and early warning method using low-pressure water injection. Background Technology

[0002] Gas outbursts are one of the most serious dynamic disasters in coal mining. Their occurrence is essentially the result of an imbalance between ground stress, gas pressure, and the physical properties of the coal seam. During the advance of the longwall face, the coal seam ahead is in a state of stress concentration, making it prone to deformation and damage. This leads to the development of fractures and a sharp increase in permeability, creating conditions for the rapid desorption, migration, and energy accumulation of gas, thus triggering an outburst accident.

[0003] Currently, the monitoring, early warning, and prevention technologies for gas outbursts in longwall mining faces have the following limitations:

[0004] Early warning methods are limited and delayed: Traditional early warning systems rely heavily on monitoring changes in methane concentration in the return airflow or using indirect methods such as microseismic activity and electromagnetic radiation. They cannot provide early warnings in the early stages of disaster development or at critical points where permeability changes occur within the coal seam.

[0005] Existing gas control measures, such as pre-extraction, pressure relief blasting, and high-pressure water injection, are mostly independent control processes or post-event remedial measures, lacking linkage with real-time monitoring and early warning systems. This makes it impossible to immediately initiate targeted control actions when early signs of risk are detected.

[0006] Conventional water injection measures for preventing gas outbursts or reducing dust often involve high-pressure, high-flow-rate water injection, which carries the risk of fracturing coal seams and artificially creating fissure channels, potentially exacerbating gas release.

[0007] Therefore, there is an urgent need for an integrated technology that can detect coal seam permeability changes in real time at low cost and combine early warning with proactive management, so as to effectively prevent and control the risk of gas outbursts in longwall mining faces. Summary of the Invention

[0008] The purpose of this invention is to provide a gas outburst prevention and early warning method using low-pressure water injection, so as to solve the problems of lack of early warning for gas outbursts and the lack of timely control measures when outbursts occur in the existing technology.

[0009] The technical solution of this invention is: a gas outburst prevention and early warning method using low-pressure water injection, comprising:

[0010] Construct water pumps and configure multiple water pumps for several boreholes in front of the longwall face. Any water pump continuously injects water into the corresponding borehole at a constant first pressure; the first pressure is set to be lower than the original pressure of the gas in the coal seam.

[0011] A monitoring and early warning system is constructed, wherein the monitoring and early warning system is configured with multiple monitoring terminals corresponding to multiple boreholes, and each monitoring terminal is configured with at least one flow sensor for monitoring water injection flow rate;

[0012] Set the flow rate of the water pump when any borehole is filled as the reference flow rate, and set the current flow rate of the water pump monitored by the monitoring terminal as the actual flow rate.

[0013] Comparing the actual flow rate of all currently injected boreholes with the reference flow rate reveals the following situations and corresponding countermeasures:

[0014] If at least half of the water-filled boreholes have an actual flow rate greater than 1.5 times the baseline flow rate, then measure A shall be implemented; measure A includes the monitoring and early warning system issuing a gas outburst early warning signal.

[0015] If at least half of the water-filled boreholes do not have an actual flow rate greater than 1.5 times the baseline flow rate, but at least half of the water-filled boreholes have an actual flow rate greater than or equal to 1.2 times the baseline flow rate, then measure B shall be implemented; measure B includes the monitoring and early warning system marking the corresponding water-filled boreholes as abnormal and issuing a primary early warning signal, and the water pump responding to the primary early warning signal by increasing the water injection flow rate or extending the water injection time for the abnormally water-filled boreholes;

[0016] If at least half of the injected boreholes do not have an actual flow rate greater than 1.2 times the baseline flow rate, then measure C shall be implemented, which includes normal mining operations.

[0017] Preferably, any of the monitoring terminals is equipped with a pressure sensor for monitoring water injection pressure;

[0018] The pressure output by the water pump when any borehole is filled with water is set as the reference pressure, and the current pressure of the water pump monitored by the monitoring terminal is set as the actual pressure; and the following situations and corresponding countermeasures exist:

[0019] If at least half of the water-filled boreholes have an actual pressure less than 85% of the reference pressure, then implement measure A.

[0020] If at least half of the boreholes filled with water do not have an actual pressure less than 85% of the reference pressure, but at least half of the boreholes filled with water have an actual pressure less than 90% of the reference pressure, then implement measure B.

[0021] If at least half of the boreholes filled with water do not have an actual pressure less than 90% of the reference pressure, and at least half of the boreholes filled with water do not have an actual flow rate greater than 1.2 times the reference flow rate, then implement measure C.

[0022] Preferably, if there are at least two adjacent water-filled boreholes marked as abnormal, the monitoring and early warning system performs trend analysis and targeted response.

[0023] The trend extrapolation includes inferring the dominant direction of fracture development based on the spatial distribution of each anomalous water injection borehole and the time sequence in which they were marked as anomalous.

[0024] The targeted response includes action B for at least one water-injected borehole located in the dominant direction.

[0025] Preferably, the targeted response includes enhanced gas extraction in the dominant direction.

[0026] Preferably, the actual distance between any monitoring terminal and the longwall face in the mining direction is obtained and compared with a preset value;

[0027] When the actual distance is less than the preset value, stop the water injection and monitoring operations of the borehole corresponding to the monitoring terminal, and move the water pump and monitoring terminal to the borehole that is furthest from the mining face and adjacent to the monitoring terminal.

[0028] Preferably, if the following conditions are met: the actual pressure in at least half of the water-filled boreholes is less than the reference pressure, and the actual flow rate in at least half of the water-filled boreholes is greater than the reference flow rate, the monitoring terminal records the water injection flow rate and water injection pressure of the corresponding borehole at a first frequency.

[0029] If the conditions are not met, the monitoring terminal records the water injection flow rate and water injection pressure of the corresponding borehole at a second frequency, which is higher than the first frequency.

[0030] Preferably, the preset value is set to 1 meter.

[0031] Preferably, when the monitoring and early warning system issues a gas outburst warning signal, an emergency plan is executed, which includes notifying underground personnel, instructing the coal mining machine to reduce its traction speed, or organizing personnel to evacuate through the transport roadway and return airway.

[0032] Preferably, the first pressure is set to between 0.2 and 0.4 MPa.

[0033] Compared with the prior art, the advantages of the present invention are:

[0034] (1) This invention uses the constant low-pressure water injection process itself as a direct means of sensing changes in coal seam permeability. By monitoring and comparing the water injection flow rate of each borehole in real time, it can sensitively capture abnormal seepage fields caused by the development of fractures in the coal seam ahead, thereby achieving risk warning in the early stages of gas outbursts. Furthermore, the warning signal directly triggers a graded response mechanism: in the case of a primary warning, water injection is automatically strengthened in abnormal boreholes to preemptively seal fractures; in the case of a high-level warning, an alarm is immediately triggered and an emergency procedure is initiated, fundamentally changing the traditional passive mode of post-event remediation.

[0035] (2) Based on flow monitoring, pressure monitoring is added and a flow-pressure dual-parameter criterion is established. The pressure parameter is more sensitive and faster to coal seam deformation and can effectively identify hidden risks with insignificant flow changes. The dual-parameter fusion judgment mechanism overcomes the problem of false alarms or missed alarms that may be caused by the dynamic changes of fractures in single flow monitoring, making the early warning conclusions more scientific and reliable, and significantly improving the system's anti-interference ability and early warning accuracy.

[0036] (3) When multiple anomalies occur, this method can deduce the dominant direction and expansion trend of fracture development based on the spatial location and temporal sequence of the abnormal boreholes. Based on this situational assessment, precise targeted responses can be implemented: enhanced water injection is carried out in the direction of fracture expansion to construct a water film barrier, and gas extraction is enhanced in that direction. This differentiated prevention and control strategy based on spatial intelligent analysis achieves precise intervention in the disaster gestation process, greatly improving governance efficiency and safety.

[0037] (4) An intelligent trigger storage strategy is adopted, in which the system automatically switches the data recording frequency according to the monitoring status. Under normal circumstances, low-frequency recording is used to save storage resources, and when parameters are abnormal, it automatically switches to high-frequency recording to capture the complete change process. This design not only ensures the accuracy of early warning, but also greatly optimizes the system memory usage and retains a complete data chain for in-depth post-event analysis, thereby enhancing the value of the data. Attached Figure Description

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0039] Figure 1 This is a flowchart of a gas outburst prevention and early warning method using low-pressure water injection as described in this invention;

[0040] Figure 2 This is a layout diagram of a gas outburst prevention and early warning method using low-pressure water injection as described in this invention;

[0041] Figure 3 This is a schematic diagram illustrating the distribution of the fractures in the coal seam as described in this invention;

[0042] Figure 4 For the present invention Figure 3 A magnified view of part A in the middle;

[0043] Figure 5 This is a schematic diagram illustrating the low-pressure water injection anti-burst principle described in this invention;

[0044] Among them: 1. Transport roadway, 2. Return airway, 3. Longwall face, 4. Flow sensor, 5. Pressure sensor, 6. Water pump, 7. Borehole, 8. Fracture, 9. Water film, 10. Goaf, 11. Coal seam, 12. Gas. Detailed Implementation

[0045] To facilitate understanding of the problem solved by this method and the means employed, the application scenario of this application will be described first before introducing the specific implementation method:

[0046] like Figure 2 As shown, during the mining of coal seam 11, the mine shaft forms a U-shaped structure, including two parallel roadways. One roadway is the transport roadway 1, used for coal transportation and air intake, and the other is the return air roadway 2, used for pedestrians and return air. Connecting the two roadways is the longwall face 3 of coal seam 11. Mining equipment and workers are mainly concentrated on the longwall face 3, and the longwall face 3 dynamically moves forward along the length of the transport roadway 1 and the return air roadway 2 as coal seam 11 is mined. Figure 2 Advance from the left side of the middle. And behind the third longwall face ( Figure 2 The right side of the area forms goaf 10.

[0047] Combination Figures 2-4 As shown, gas 12 is an associated gas within coal seam 11, typically contained within the fractures 8 of coal seam 11. Multiple parallel boreholes 7 are laid in front of the longwall face 3 in the direction of travel. These boreholes 7 are used to simultaneously extract gas 12 contained within the fractures 8 of coal seam 11 in front of the longwall face 3, in conjunction with extraction equipment. This method is implemented based on these boreholes 7.

[0048] The present invention will be further described in detail below with reference to specific embodiments:

[0049] This application provides a gas outburst prevention and early warning method using low-pressure water injection, such as... Figure 1 As shown, it includes:

[0050] A water pump 6 is constructed, and multiple water pumps 6 are configured corresponding to several boreholes 7 in front of the longwall face 3. Water is continuously injected into any borehole 7 at a constant first pressure through the water pump 6. It should be noted that the first pressure is set lower than the original pressure of gas 12 in the coal seam 11, hence the term low-pressure water injection. In the specific implementation, the first pressure will be set between 0.2 and 0.4 MPa, which is lower than the measured original pressure of most of the gas 12. The phrase "multiple water pumps 6 are configured corresponding to several boreholes 7 in front of the longwall face 3" can also be achieved by connecting a single water pump 6 to water pipes and valves corresponding to several boreholes 7 in the specific implementation.

[0051] Combination Figure 5As shown, the purpose of this is to fill the pore space of the coal seam 11 with low-pressure water injection, thereby squeezing out the storage space of free gas 12 and reducing the energy of the free gas 12. Simultaneously, it alters the connectivity of the pores and fractures 8, isolating the channels between multiple fractures 8 in the coal seam 11 through a water film 9, thus blocking the gas 12 migration channels, inhibiting gas desorption and release, and weakening the gas outburst hazard at its source. However, if the water injection pressure is too high, the water pressure will actively break down the fractures 8 in the coal seam 11, causing gas 12 to be released, thus having the opposite effect.

[0052] Meanwhile, injecting water into borehole 7 can also moisten the coal seam, thereby helping to reduce the emission of dust inside the borehole and optimizing the mining environment.

[0053] After constructing the water pump 6, a monitoring and early warning system is further constructed. The monitoring and early warning system is equipped with multiple monitoring terminals corresponding to multiple boreholes. Each monitoring terminal is equipped with a flow sensor 4 for monitoring the water injection flow of the water pump 6. The change in the actual water injection flow of the water pump 6 monitored by the flow sensor 4 can reflect the development of the fracture 8 in the current borehole 7, and thus provide an early warning of the gas outburst 12.

[0054] The specific principle is as follows: After the water pump 6 fills the borehole 7 and the fracture 8 connected to the borehole 7 with water, the current water injection flow rate is set as the reference flow rate. If the coal seam 11 is completely stable, the water pressure in the borehole 7 will be balanced with the water injection pressure of the water pump 6, so water injection will stop, and the actual flow rate will not change and will be equal to the reference flow rate. If the fracture 8 in the coal seam 11 develops as the mining work progresses and connects with the fracture 8 that was not originally connected to the borehole 7, then the water in the borehole 7 will rush into this new space, thereby increasing the actual flow rate.

[0055] Based on this monitoring result, the development status of fracture 8 is inferred, and corresponding implementation measures are formulated according to the development status of fracture 8:

[0056] If the actual flow rate in at least half of the water-filled boreholes 7 is greater than 1.5 times the reference flow rate, it indicates that the development of fracture 8 is poor and there is a significant risk of gas 12 outburst. In this case, measure A shall be implemented, which includes the monitoring and early warning system issuing a gas 12 outburst early warning signal.

[0057] If at least half of the water-filled boreholes 7 do not have an actual flow rate greater than 1.5 times the baseline flow rate, but at least half of the water-filled boreholes 7 have an actual flow rate greater than or equal to 1.2 times the baseline flow rate, it indicates that although fracture 8 has developed, its development is relatively slow and unlikely to cause gas 12 to escape. The corresponding measure B should be implemented. Measure B includes the monitoring and early warning system marking the corresponding water-filled boreholes 7 as abnormal and issuing a primary early warning signal. The water pump 6 responds to the primary early warning signal by increasing the water injection flow rate or extending the water injection time in the abnormally water-filled boreholes 7. This method seals the initially developed fracture 8, making it difficult for gas 12 within the fracture 8 to escape.

[0058] If at least half of the water-injected boreholes 7 do not have an actual flow rate greater than 1.2 times the benchmark flow rate, then the current coal seam 11 is stable and there is no risk of gas outburst 12. Implement measure C, which includes normal mining operations.

[0059] Monitoring a single variable like water injection flow rate may lead to inaccurate monitoring. This problem mainly stems from the fact that when coal seam 11 deforms, the change in fissure 8 is also a dynamic process, which may manifest as: opening-closing-reopening, resulting in a possible lag or insignificance in flow rate changes.

[0060] Therefore, in a preferred embodiment of this application, any monitoring terminal is further equipped with a pressure sensor 5 for monitoring the water injection pressure of the water pump 6. Compared to the changes in water flow rate in the aforementioned problem, changes in water pressure are more sensitive and rapid. Thus, this application achieves more accurate monitoring of the development of the crack 8 by combining flow rate monitoring with pressure monitoring.

[0061] Specifically, the pressure output by the water pump 6 when any drill hole 7 is filled with water is set as the reference pressure, and the current pressure of the water pump 6 monitored by the monitoring terminal is set as the actual pressure. The following situations and corresponding countermeasures exist:

[0062] If at least half of the water-filled boreholes 7 have an actual pressure less than 85% of the reference pressure, then implement measure A.

[0063] If at least half of the boreholes 7 filled with water do not have an actual pressure less than 85% of the reference pressure, but at least half of the boreholes 7 filled with water have an actual pressure less than 90% of the reference pressure, then measure B shall be implemented.

[0064] If at least half of the boreholes 7 filled with water do not have an actual pressure less than 90% of the reference pressure, and at least half of the boreholes 7 filled with water do not have an actual flow rate greater than 1.2 times the reference flow rate, then measure C shall be implemented.

[0065] Based on the precise monitoring of fracture 8 development achieved through a combination of flow and pressure monitoring, in the preferred embodiment of this application, the development of fracture 8 can also be limited by the following means. Specifically:

[0066] If at least two adjacent boreholes 7 marked as anomalous and undergoing water injection are identified, the monitoring and early warning system performs trend deduction and targeted response. Trend deduction involves inferring the dominant direction of fracture development 8 based on the spatial distribution of the anomalous boreholes 7 and the temporal sequence in which they were marked as anomalous. For example, if adjacent boreholes 3 and 4 are both marked as anomalous, and borehole 5, adjacent to borehole 4, is subsequently also marked as anomalous, it can be determined that at least one fracture 8 develops along the direction from borehole 4 to borehole 5. Simultaneously, borehole 2, adjacent to borehole 3, is also monitored.

[0067] The targeted response includes implementing measure B on at least one water-filled borehole 7 located in the dominant direction. Based on the results of the above trend deduction, the water film 9 in the borehole 7 in the direction of fracture 8 development is strengthened, thereby inhibiting the development of fracture 8.

[0068] Furthermore, the extraction of gas 12 can be enhanced by drilling 7 in the dominant direction, thereby reducing the concentration of gas 12 in the direction of fracture development 8, which can also play a role in preventing gas 12 outbursts.

[0069] As the longwall face 3 advances, the distance between the longwall face and each monitoring borehole 7 is calculated in real time. When the distance between a monitoring borehole 7 and the longwall face 3 decreases to less than a preset value, the significance of its anti-outburst warning will be significantly reduced. Typically, this preset value is set to 1 meter. At this point, water injection and monitoring operations for the corresponding borehole 7 are stopped, and the water pipe, valve, and monitoring terminal for that borehole 7 are moved to the borehole 7 furthest from the longwall face 3 and adjacent to a monitoring terminal. This achieves cyclical and continuous monitoring of the risks at the longwall face 3.

[0070] Furthermore, the monitoring terminals used to monitor water injection flow and pressure are configured with both low-frequency and high-frequency operating modes, which reduces system memory usage while ensuring timely and accurate early warnings. Specifically:

[0071] If the condition that the actual pressure in at least half of the boreholes 7 that are not filled with water is less than the reference pressure and the actual flow rate in at least half of the boreholes 7 that are filled with water is greater than the reference flow rate is met, then it is proven that the current state of coal seam 11 is stable. The monitoring terminal records the water injection flow rate and water injection pressure of the corresponding borehole 7 at a lower first frequency to save memory usage on the system.

[0072] If, in half of the water-filled boreholes 7, the actual pressure is greater than the reference pressure, or the actual flow rate is greater than the reference flow rate, although the requirements of Implementation Measure B are not met, as a precaution, the monitoring terminal records the water injection flow rate and water injection pressure of the corresponding borehole 7 at a second frequency higher than the first frequency, so that the pressure and flow rate change values ​​are more precise and convenient for data analysis and reference.

[0073] When the monitoring and early warning system issues a gas outburst warning signal of 12, the emergency plan is executed. The emergency plan includes notifying underground personnel, instructing the coal mining machine to reduce its traction speed, or organizing personnel to evacuate through transport roadway 1 and return airway 2.

[0074] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more, unless otherwise expressly defined.

[0075] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. A gas outburst prevention and early warning method using low-pressure water injection, characterized in that, include: Construct water pumps (6) and configure multiple water pumps (6) in relation to several boreholes (7) in front of the longwall face (3). Any water pump (6) continuously injects water into the corresponding borehole (7) at a constant first pressure. The first pressure is set to be lower than the original pressure of the gas (12) in the coal seam (11). A monitoring and early warning system is constructed, which is equipped with multiple monitoring terminals corresponding to multiple boreholes (7), and each monitoring terminal is equipped with at least one flow sensor (4) for monitoring water injection flow. The flow rate output by the water pump (6) when any borehole (7) is filled is set as the reference flow rate, and the current flow rate of the water pump (6) monitored by the monitoring terminal is set as the actual flow rate. Comparing the actual flow rate of all currently injected boreholes (7) with the reference flow rate, the following situations and corresponding countermeasures exist: If at least half of the water-filled boreholes (7) have an actual flow rate greater than 1.5 times the reference flow rate, then measure A shall be implemented; measure A includes the monitoring and early warning system issuing a gas (12) outburst early warning signal; If at least half of the water-filled boreholes (7) do not have an actual flow rate greater than 1.5 times the reference flow rate, but at least half of the water-filled boreholes (7) have an actual flow rate greater than or equal to 1.2 times the reference flow rate, then measure B shall be implemented; measure B includes the monitoring and early warning system marking the corresponding water-filled boreholes (7) as abnormal and issuing a primary early warning signal, and the water pump (6) responding to the primary early warning signal to increase the water flow rate or extend the water filling time of the abnormally water-filled boreholes (7); If there is no actual flow rate greater than 1.2 times the reference flow rate in at least half of the boreholes (7) that are filled with water, then measure C shall be implemented, which includes normal mining operations.

2. The gas outburst prevention and early warning method using low-pressure water injection according to claim 1, characterized in that, Any of the monitoring terminals is equipped with a pressure sensor (5) for monitoring water injection pressure; The pressure output by the water pump (6) when any water-filled borehole (7) is filled is set as the reference pressure, and the current pressure of the water pump (6) monitored by the monitoring terminal is set as the actual pressure; and the following situations and corresponding countermeasures exist: If at least half of the boreholes (7) that are filled with water have an actual pressure less than 85% of the reference pressure, then measure A shall be implemented. If at least half of the boreholes (7) filled with water do not have an actual pressure less than 85% of the reference pressure, but at least half of the boreholes (7) filled with water have an actual pressure less than 90% of the reference pressure, then measure B shall be implemented. If the actual pressure in at least half of the boreholes (7) that are not filled with water is less than 90% of the reference pressure, and the actual flow rate in at least half of the boreholes (7) that are not filled with water is greater than 1.2 times the reference flow rate, then measure C shall be implemented.

3. A gas outburst prevention and early warning method using low-pressure water injection according to claim 2, characterized in that, If there are at least two adjacent water-filled boreholes marked as abnormal (7), the monitoring and early warning system performs trend deduction and targeted response; The trend deduction includes inferring the dominant direction of fracture (8) development based on the spatial distribution of each anomalous water injection borehole (7) and the time sequence in which they were marked as anomalous. The targeted response includes implementing measure B on at least one water-filled borehole (7) located in the dominant direction.

4. A gas outburst prevention and early warning method using low-pressure water injection according to claim 3, characterized in that, The targeted response includes enhanced gas (12) extraction in the dominant direction.

5. A gas outburst prevention and early warning method using low-pressure water injection according to claim 4, characterized in that, Obtain the actual distance between any monitoring terminal and the longwall face (3) in the mining direction, and compare it with the preset value; When the actual distance is less than the preset value, stop the water injection and monitoring operation of the borehole (7) corresponding to the monitoring end, and move the water pump (6) and the monitoring end to the borehole (7) that is furthest from the mining face (3) and adjacent to the monitoring end.

6. A gas outburst prevention and early warning method using low-pressure water injection according to claim 3, characterized in that, If the following conditions are met: the actual pressure in at least half of the water-filled boreholes (7) is less than the reference pressure, and the actual flow rate in at least half of the water-filled boreholes (7) is greater than the reference flow rate, the monitoring terminal records the water injection flow rate and water injection pressure of the corresponding borehole (7) at the first frequency. If the conditions are not met, the monitoring terminal records the water injection flow rate and water injection pressure of the corresponding borehole (7) at a second frequency, which is higher than the first frequency.

7. A gas outburst prevention and early warning method using low-pressure water injection according to claim 5, characterized in that, The preset value is set to 1 meter.

8. A gas outburst prevention and early warning method using low-pressure water injection according to claim 2, characterized in that, When the monitoring and early warning system issues a gas (12) outburst warning signal, the emergency plan is executed. The emergency plan includes notifying underground personnel, instructing the coal mining machine to reduce its traction speed, or organizing personnel to evacuate through the transport roadway (1) and return airway (2).

9. A gas outburst prevention and early warning method using low-pressure water injection according to claim 2, characterized in that, The first pressure is set between 0.2 and 0.4 MPa.

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