Multi-physical-field optical fiber sensing monitoring method for front frame and rear top plate of working face frame

Abstract

The invention discloses a working face frame front frame rear top plate multi-physics field optical fiber sensing monitoring method, which comprises the steps of collecting geological drilling data in and around a working face, and analyzing lithologic development conditions of a top plate and a surrounding rock stratum; according to an analysis result, designing an arrangement scheme of monitoring drill holes, and constructing the monitoring drill holes; selecting a multi-physical-field optical fiber and a sensor, installing the multi-physical-field optical fiber and the sensor in the monitoring drill hole, and protecting the optical fiber and the sensor; the grouting and hole sealing process is optimized, and grouting and hole sealing are conducted on the monitoring drill hole; a well up-down linkage online monitoring system platform is established, and real-time transmission and collection of data are achieved; and performing dynamic analysis on the monitoring data, and performing early warning and engineering application according to an analysis result. According to the invention, multi-physics field coupling monitoring can be realized, continuous spatial distribution data is provided, and the limitation of a traditional monitoring means is overcome.

Description

Technical Field

[0001] The invention belongs to the technical field of mine geotechnical engineering safety monitoring, and in particular relates to a multi-physical field optical fiber sensing monitoring method for a front frame and a rear top plate of a working face frame. Background Art

[0002] In the process of coal mining, the stability of the roof in the front and rear areas of the hydraulic support (before and after the support) is crucial to the safety and production efficiency of the mine. Traditional monitoring methods mainly include point sensors such as resistance strain gauges, displacement sensors, and pressure pillows. These sensors can measure physical quantities such as stress and displacement of the roof, providing certain technical support for roof stability monitoring. In addition, fiber optic sensing technology has gradually been applied in the field of mine monitoring, mainly for monitoring tunnel deformation or goaf settlement. These technologies have improved the efficiency and safety of coal mine roof monitoring to a certain extent.

[0003] However, existing monitoring technologies still have many shortcomings. Traditional point sensors measure a single physical quantity, making it difficult to synchronously obtain multi-physical field coupling data, and cannot achieve continuous spatial distribution monitoring. In the strong electromagnetic environment underground, these sensors have poor anti-interference capabilities and are easily interfered with, resulting in inaccurate monitoring data. In addition, most traditional monitoring methods require manual regular monitoring and cannot dynamically obtain monitoring parameter signal data in real time. Although fiber optic sensing technology has the advantages of inherent safety, anti-electromagnetic interference, and distributed measurement, existing fiber optic monitoring solutions are mostly used for tunnel deformation or goaf settlement monitoring, and the technical gap in multi-field coupling monitoring of the front and rear roofs of hydraulic supports has not yet been filled. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a multi-physical field optical fiber sensing monitoring method for the front frame and rear top plate of a working face frame to solve the problems existing in the above-mentioned prior art.

[0005] To achieve the above objectives, in a first aspect, the present invention provides a multi-physical field optical fiber sensing monitoring method for a front frame and a rear top plate of a working face frame, comprising:

[0006] Collect geological drilling data in and around the working face, and analyze the lithology development of the roof and surrounding rock formations;

[0007] Based on the analysis results, design the layout of monitoring boreholes and construct the monitoring boreholes;

[0008] Select multi-physics optical fiber and sensors, install them in the monitoring borehole, and protect the optical fiber and sensors;

[0009] Optimize the grouting and sealing process, and perform grouting and sealing on the monitoring boreholes;

[0010] Establish an online monitoring system platform for linkage between wells and underground areas to achieve real-time transmission and collection of data;

[0011] Conduct dynamic analysis on monitoring data and make early warning and engineering applications based on the analysis results.

[0012] Preferably, the step of analyzing the lithology development of the roof and surrounding rock formations comprises:

[0013] Collect existing geological drilling data in and around the working face to understand the lithology development of the working face roof and surrounding rock formations;

[0014] The lithology thickness data revealed by the drilling is interpolated to determine the location and range of the roof sand and mudstone development in the working face monitoring area.

[0015] Preferably, the arrangement scheme of the monitoring boreholes includes:

[0016] The fiber optic sensor in front of the rack monitors the drilling hole, which is arranged in the return air lane of the working face with a hole diameter of Φ113mm;

[0017] The optical fiber strain monitoring drilling holes in front of the rack are arranged in the return air lane of the working face, with a hole diameter of Φ113mm and an elevation angle.

[0018] The optical fiber sensor behind the frame monitors the drilling hole. The drilling hole is arranged behind the end bracket of the transport lane of the working face, with a hole diameter of Φ113mm and is constructed at an elevation angle.

[0019] Preferably, the steps of selecting a multi-physics field optical fiber and a sensor, installing them in a monitoring borehole, and protecting the optical fiber and the sensor include:

[0020] Select distributed strain optical fiber, soil pressure sensor, permeate water pressure sensor and humidity sensor;

[0021] The strain optical fiber is laid in the whole hole section to monitor the strain generated when the roof rock formation breaks;

[0022] The permeable water pressure sensor is installed in the middle section of the sandstone layer in the borehole to monitor the water pressure changes in the sandstone aquifer;

[0023] The humidity sensor is installed in the middle section of the mudstone layer in the borehole to monitor the change in moisture content of the mudstone layer after it absorbs cement;

[0024] The geotechnical pressure sensor is buried in the roof of the goaf behind the frame to monitor the overlying pressure of the rock in the collapse zone;

[0025] The optical fiber and sensor were tied and fixed to the PVC tube using nylon tie, and the sensor surface was protected with nylon gauze wrapped with coarse sand.

[0026] Preferably, the step of optimizing the grouting and sealing process and performing grouting and sealing on the monitoring borehole comprises:

[0027] Use a PVC plug-in tube with a diameter of Φ50mm and a single length of 2m to bind and fix the optical fiber and sensor, and send them to the final hole position together with the PVC tube. At the same time, make eyelets on the surface of the PVC tube near the bottom of the hole to serve as a channel for exhaust and grouting when grouting and sealing the hole;

[0028] Use single / double bag plugging method to inject grout into the sensor buried in the hole;

[0029] A hole is drilled in the PVC pipe at the bottom of the deep bag. When the space in the middle of the bag is filled with cement slurry, the slurry flows from the hole of the PVC pipe into the inner wall of the pipe and the drilling is completed.

[0030] Preferably, the steps of establishing an online monitoring system platform for linkage between the well and the bottom to achieve real-time transmission and collection of data include:

[0031] Connect the strain optical fiber and the sensor lead wires at the hole mouth with a communication optical cable, and connect the other end of the communication optical cable to the fiber grating demodulator downhole;

[0032] Install the demodulator at the location of the underground LAN switch near the monitoring borehole;

[0033] Connect the demodulator to the underground LAN and assign it an IP address so that the collected data can be obtained on the ground later.

[0034] Preferably, the steps of dynamically analyzing the monitoring data and carrying out early warning and engineering application according to the analysis results include:

[0035] Dynamically analyze monitoring data and monitor the strain, pressure, seepage and humidity changes of roof rock in real time;

[0036] According to the set warning threshold, the system automatically triggers the warning;

[0037] According to the real-time monitoring data, the timing of support withdrawal is adjusted to prevent accidents such as pumping in front of the support and mud protrusion behind the support.

[0038] Preferably, the process of dynamically analyzing the monitoring data also includes:

[0039] Analyze the tensile strain at the top coal position, the water pressure change of the coarse sandstone layer, and the pressure change of the caving zone in the goaf;

[0040] According to the analysis results, the working face mining plan is adjusted and the support layout and support parameters are optimized.

[0041] In a second aspect, the present invention further discloses a computer device, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described in the first aspect.

[0042] In a third aspect, the present invention further discloses a computer-readable storage medium having a computer program stored thereon, which implements the steps of the method described in the first aspect when executed by a processor.

[0043] Compared with the prior art, the present invention has the following advantages and technical effects:

[0044] The present invention provides a multi-physical field optical fiber sensing monitoring method for the front and rear roof of a working face frame. First, geological drilling data in and around the working face are collected, and the lithology development of the roof and surrounding rock formations is analyzed; secondly, according to the analysis results, a layout plan for monitoring boreholes is designed, and monitoring boreholes are constructed; then, multi-physical field optical fibers and sensors are selected, installed in the monitoring boreholes, and the optical fibers and sensors are protected; further, the grouting and sealing process is optimized, and the monitoring boreholes are grout-sealed; thirdly, an online monitoring system platform for linkage between the upper and lower wells is established to realize real-time transmission and collection of data; finally, the monitoring data is dynamically analyzed, and early warning and engineering applications are carried out according to the analysis results.

[0045] The present invention can realize multi-physical field coupling monitoring, provide continuous spatial distribution data, and overcome the limitations of traditional monitoring methods. The present invention resists electromagnetic interference through optical fiber sensing technology, and sensor protection measures improve durability to ensure stable and reliable monitoring data. The present invention realizes real-time data transmission and dynamic analysis through an online monitoring system, reduces manual inspections, and reduces safety risks. The monitoring data is of great significance for the prevention and control of accidents such as roof pumping in front of the frame and mud outburst accidents caused by the suspension of mining on the working face, and for ensuring the safe recovery of mines. In addition, the real-time data of the present invention supports dynamic analysis and early warning, providing a scientific basis for working face mining design and accident prevention. The technical solution of the present invention has strong scalability, reduces duplication of construction, and reduces labor costs and maintenance workload.

[0046] The present invention innovates the sensor network configuration, multi-physical field coupling analysis and engineering installation technology, realizing the leap from "single-point static" to "global dynamic" in multi-physical field monitoring of roof rock strata, significantly improving the timeliness and accuracy of roof disaster warning in coal mine working faces, while reducing manual maintenance costs, and has outstanding engineering application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0048] Figure 1 A histogram of geological drilling holes in the monitoring area according to an embodiment of the present invention;

[0049] Figure 2 It is a schematic diagram of the arrangement of monitoring drilling holes before and after the rack according to an embodiment of the present invention;

[0050] Figure 3 Schematic diagram of strain before and after the rack and sensor optical fiber monitoring drilling according to an embodiment of the present invention;

[0051] Figure 4 A schematic diagram of a well top-bottom linkage monitoring system according to an embodiment of the present invention;

[0052] Figure 5 It is a schematic diagram of the monitoring curve of the multi-field optical fiber strain and sensor in front of the rack according to an embodiment of the present invention;

[0053] Figure 6 It is a schematic diagram of the monitoring curve of the optical fiber sensor behind the rack (caving zone in the goaf area) according to an embodiment of the present invention;

[0054] Among them, 1. MKS strain optical fiber; 2. PVC pipe; 3. Pressure-resistant grouting hose; 4. Woven bag; 5. Bag one-way grouting valve; 6. Middle section one-way grouting valve; 7. Orifice lead; 8. Nylon cable tie; 9. PVC eyelet; 10. Nylon mesh; 11. Coarse sand; 12. Seepage pressure sensor; 13. Humidity sensor; 14. Pressure sensor; 15. Fiber optic sensor monitoring drilling hole behind the frame (caving zone in the goaf); 16. Fiber optic sensor monitoring drilling hole in front of the frame; 17. Fiber optic strain monitoring drilling hole in front of the frame; 18. Multi-core communication optical cable; 19. Downhole demodulator; 20. Downhole LAN switch; 21. Downhole substation; 22. Ground dispatch room switch; 23. Ground monitoring server. DETAILED DESCRIPTION

[0055] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0056] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0057] Embodiment 1

[0058] like Figure 1 As shown, in this embodiment, a multi-physical field optical fiber sensing monitoring method for the front frame and rear top plate of a working face frame is provided, comprising:

[0059] S1. Collect geological drilling data in and around the working face and analyze the lithology development of the roof and surrounding rock formations;

[0060] Further, the steps of analyzing the lithology development of the roof and surrounding rock formations include:

[0061] Collect existing geological drilling data in and around the working face to understand the lithology development of the working face roof and surrounding rock formations;

[0062] The lithology thickness data revealed by the drilling is interpolated to determine the location and range of the roof sand and mudstone development in the working face monitoring area.

[0063] S2. Design the layout of monitoring boreholes based on the analysis results and construct the monitoring boreholes;

[0064] Furthermore, the arrangement scheme of the monitoring boreholes includes:

[0065] The optical fiber sensor in front of the rack monitors the drilling hole 16, which is arranged in the return air lane of the working face, with a hole diameter of Φ113mm;

[0066] The optical fiber strain monitoring drilling hole 17 in front of the rack is arranged in the return air lane of the working face, with a hole diameter of Φ113mm and an elevation angle;

[0067] The optical fiber sensor monitors the borehole 15 behind the frame (caving zone in the goaf area). The borehole is arranged behind the end bracket of the transport lane of the working face, with a hole diameter of Φ113mm and is constructed at an elevation angle.

[0068] Specifically, monitoring holes are constructed in the area before and after the working face frame: the holes are upward holes with a hole diameter of Φ113mm, and the final hole layer is within the collapsed zone of the working face roof. The collapsed zone height H = mining height h × collapsed mining ratio α; based on the lithology of the coal seam roof revealed by geological drilling holes in and around the working face, the lithology development of the roof strata in the monitoring area is predicted, and the fiber optic sensing design scheme is preliminarily determined.

[0069] S3, select a multi-physics field optical fiber and a sensor, install them in the monitoring borehole, and protect the optical fiber and the sensor;

[0070] Furthermore, the steps of selecting a multi-physics field optical fiber and a sensor, installing them in a monitoring borehole, and protecting the optical fiber and the sensor include:

[0071] Select distributed strain optical fiber, soil pressure sensor, permeate water pressure sensor and humidity sensor;

[0072] The strain optical fiber is laid in the whole hole section to monitor the strain generated when the roof rock formation breaks;

[0073] The permeable water pressure sensor is installed in the middle section of the sandstone layer in the borehole to monitor the water pressure changes in the sandstone aquifer;

[0074] The humidity sensor is installed in the middle section of the mudstone layer in the borehole to monitor the change in moisture content of the mudstone layer after it absorbs cement;

[0075] The geotechnical pressure sensor is buried in the roof of the goaf behind the frame to monitor the overlying pressure of the rock in the collapse zone;

[0076] The optical fiber and sensor were tied and fixed to the PVC tube using nylon tie, and the sensor surface was protected with nylon gauze wrapped with coarse sand.

[0077] Specifically, determine the installation locations of strain optical fiber, soil pressure, seepage water pressure, and humidity sensors: During the drilling process, record the true rock properties of the entire hole section. On this basis, timely adjust the preliminary design of the fiber optic sensing scheme; according to different monitoring objects, the borehole is divided into strain optical fiber monitoring holes before the frame and sensor optical fiber monitoring holes before and after the frame. The strain optical fiber is buried in the entire hole section to dynamically monitor the strain of the rock formation under the influence of mining; water pressure and humidity sensors are buried in the medium-coarse sandstone layer and mudstone layer in the seepage water pressure and humidity sensor optical fiber monitoring holes, respectively, to monitor the water pressure of the sandstone aquifer and the changes in the water content of the mudstone. A pressure sensor is buried in the borehole behind the hydraulic support of the working face to monitor the changing laws of the overburden pressure in the goaf area.

[0078] S4. Optimize the grouting and sealing process, and perform grouting and sealing on the monitoring boreholes;

[0079] As an innovative implementation method, the grouting and sealing process is optimized, and the steps of grouting and sealing the monitoring borehole include:

[0080] Use a PVC plug-in tube with a diameter of Φ50mm and a single length of 2m to bind and fix the optical fiber and sensor, and send it to the final hole position together with the PVC tube. At the same time, it serves as a channel for exhaust and grouting during grouting and sealing.

[0081] Use single / double bag plugging method to inject grout into the sensor buried in the hole;

[0082] A hole is drilled at the bottom of the deep bag on the PVC pipe. When the space in the middle of the bag is filled with cement slurry, the slurry flows from the hole of the PVC pipe into the inner wall of the pipe and the drilling is completed.

[0083] Specifically, optimize the fiber optic monitoring drilling grouting backfill process:

[0084] The strain optical fiber and various sensors are fixed on the PVC tube (diameter Φ50mm, 2.0m / root) with nylon cable ties. The sensor surface is protected with a nylon mesh wrapped with coarse sand and sent into the hole together with the casing.

[0085] The "two blocking and one injection" method of woven bags is used for grouting and plugging. The two bags are connected by a high-pressure hose to form a complete set of sealing materials. Grouting valves I and II are installed at the connection between the grouting hose and the two bags, and grouting valve III is also installed in the middle section. The opening pressure of the grouting valve in the middle section is greater than that of grouting valves I and II. In the early stage of slurry, grouting valves I and II of the bag are opened first, and then enter the bag through the high-pressure hose. After the bag expands, it can effectively block both ends of the borehole. As the grouting pressure increases, grouting valve III in the middle section opens, and slurry is filled between the two bags.

[0086] It is worth noting that in order to reduce a return slurry pipeline in the borehole, three eyelets are drilled on the PVC pipe, and the eyelets are located below the bag in the hole.

[0087] The woven bag and the grouting hose are fixed on the PVC pipe together, and the two bags are fixed below the hole mouth and the sensor in the hole.

[0088] S5. Establish an online monitoring system platform for linkage between wells and underground areas to achieve real-time transmission and collection of data;

[0089] As an innovative implementation method, the steps of establishing an online monitoring system platform above and below the well to realize real-time transmission and collection of data include:

[0090] Connect the strain optical fiber and the sensor lead wires at the hole mouth with a communication optical cable, and connect the other end of the communication optical cable to the fiber grating demodulator downhole;

[0091] Install the demodulator at the location of the underground LAN switch near the monitoring borehole;

[0092] Connect the demodulator to the underground LAN and assign it an IP address to obtain the collected data on the ground.

[0093] Specifically, establish communication between the downhole fiber demodulator and the fiber strain and sensor: the strain fiber and sensor in the hole are led to the outside of the hole with fiber leads, and the leads outside the hole are connected using multi-core communication optical cables. After the connection is completed, test whether there is signal data output. The other end of the communication optical cable is connected to the fiber demodulator. The downhole demodulator is installed near the LAN switch near the monitoring borehole to shorten the length of the communication optical cable, reduce optical loss, and ensure data accuracy. The fiber demodulator device connected to the downhole LAN switch is assigned an enterprise LAN IP address.

[0094] S6. Conduct dynamic analysis on monitoring data and make early warning and engineering applications based on the analysis results.

[0095] Furthermore, the steps of dynamically analyzing the monitoring data and making early warning and engineering applications based on the analysis results include:

[0096] Dynamically analyze monitoring data and monitor the strain, pressure, seepage and humidity changes of roof rock in real time;

[0097] According to the set warning threshold, the system automatically triggers the warning;

[0098] According to the real-time monitoring data, the timing of support withdrawal is adjusted to prevent accidents such as pumping in front of the support and mud protrusion behind the support.

[0099] Furthermore, the process of dynamic analysis of monitoring data also includes:

[0100] Analyze the tensile strain at the top coal position, the water pressure change of the coarse sandstone layer, and the pressure change of the caving zone in the goaf;

[0101] According to the analysis results, the working face mining plan is adjusted and the support layout and support parameters are optimized.

[0102] Specifically, a real-time automated multi-physics field optical fiber monitoring system platform is established. After the communication between the underground demodulator and the sensors for monitoring borehole strain and the sensors is completed, a server device with large storage capacity is installed in the computer room of the mine ground dispatch room. An IP address is assigned to the ground server and connected to the switch in the computer room. The IP address is configured through the local connection of the server and connected to the same local area network as the underground demodulator. At the same time, the strain and sensor monitoring application is installed on the server, and the program operation parameters (monitoring cycle, optical loss threshold, etc.) are configured to enable the underground demodulator data to be consulted on the ground server.

[0103] Example:

[0104] Taking the 11702 working face of Xinjiang Hami Dananhu No. 7 Coal Mine as an example, the working face tunnel height is 3.2m, and the top coal mining method is adopted. The inner section (0-1000m) of the working face is 310m long, and the outer section (1000-2400m) is 260m long. When the width of the mining area becomes narrower, the working face needs to stop production and remove some fully mechanized mining supports. In order to do a good job in roof safety management during the removal of the support, multi-physical field fiber optic sensing monitoring is carried out on the roof before and after the working face support.

[0105] S1. Geological analysis and drilling design of monitoring area;

[0106] According to the formation conditions revealed by drilling holes in and around the 11702 working face, as shown in Table 1;

[0107] Table 1

[0108]

[0109] The roof rock in this area is mainly composed of weakly cemented siltstone and gravel-bearing coarse sandstone. The lithology of the roof rock was initially understood and the location of the monitoring borehole was determined ( Figure 2 )as follows:

[0110] S101. Sensor monitoring holes before and after the rack (1#~6#): The holes are arranged in the return air lane of the working face, with a hole diameter of Φ113mm. The final hole layer of holes 1#~3# is located in the 7th coal roof rock layer, 12.3m away from the wall and 17.8m away from the top; holes 4#~6# are arranged in the 6th coal bottom rock layer, 21.0m away from the wall and 17.8m away from the top.

[0111] S102. Pre-frame strain monitoring holes (7#~9#): Holes 7#~9# are arranged in the return air lane of the working face, with a hole diameter of Φ113mm and an elevation angle of construction. The final hole layer is the coarse sandstone of the 5 coal roof, 26.3m from the wall and 44.8m from the top.

[0112] S103. Monitoring hole for the caving zone in the goaf (10#): The drilling hole is arranged behind the end support of the transport tunnel of the working face, with a hole diameter of Φ113mm and an elevation angle. The final hole reaches the direct roof rock layer of the 7 coal.

[0113] S2.Optical fiber and sensor selection and installation;

[0114] S201. Strain fiber selection: Distributed MKS strain fiber 1 has a spatial resolution of 1m and a strain range of ±15000με. It is used to monitor the strain generated when the rock formation in the entire hole section of the roof is broken.

[0115] S202. Sensor selection: The fiber Bragg grating seepage pressure sensor 12 has a range of 0 to 0.5 MPa and an accuracy of ±0.5% FS, and is used to monitor the water pressure of sandstone aquifers; the fiber Bragg grating humidity sensor 13 has a range of 0 to 100% RH and an accuracy of ±2% RH, and is used to monitor the moisture content of mudstone layers; the fiber Bragg grating soil pressure sensor 14 has a range of 0 to 10 MPa and an accuracy of ±1% FS, and is buried in the direct top to monitor the overlying pressure of rocks in the collapse zone and reflect its degree of compaction.

[0116] S203. Fixing and protecting monitoring elements: tie the strain optical fiber 1 and the sensor to the outer wall of the PVC pipe 2 and fix them with nylon tie 8. Wrap the sensor with an eight-mesh nylon gauze 10 and fill the sensor with coarse sand 11 with a particle size of 5 to 10 mm to prevent it from being affected by the slurry. Open three flower holes 9 at the bottom of the PVC pipe as a grouting return channel.

[0117] S3. Grouting and sealing process optimization;

[0118] Adopting the "two blocking and one injection" woven bag grouting process ( Figure 3 ): Two woven bags 4 are fixed at the hole mouth and below the sensor in the hole respectively, and connected by a pressure-resistant grouting hose 3.

[0119] At the beginning of grouting, open the one-way grouting valve 5 of the bag, inject cement-water glass double slurry (water-cement ratio 1:1, accelerator dosage 3%), and seal the two ends of the borehole after the bag expands. When the grouting pressure reaches 1.5MPa, open the one-way grouting valve 6 in the middle section to fill the gap between the two bags until the PVC pipe returns to slurry and the borehole is closed.

[0120] S4. Monitoring system networking and data transmission;

[0121] By establishing an online monitoring system platform up and down the well ( Figure 4 ) to realize intelligent data monitoring.

[0122] S401. Downhole networking: The optical fiber in the hole and the sensor hole lead 7 are connected to the fiber grating downhole demodulator 19 through the multi-core communication optical cable 18. The downhole demodulator 19 is installed near the downhole LAN switch 20 in the downhole substation 21 in the mining area, and the LAN IP address is allocated.

[0123] S402. Ground platform construction: Connect the large-capacity ground monitoring server 23 (storage ≥ 10TB) to the ground dispatch room switch 22 in the ground dispatch room, configure the IP address, and use the same network segment as the underground equipment. Install the data acquisition software, set the sampling interval to 10 minutes, and receive monitoring data in real time.

[0124] S5. Dynamic analysis and application of monitoring data;

[0125] S501. Multi-field monitoring of the roof in front of the frame: The opening of the #11 strain optical cable is located about 7m in front of the working face frame. Similar to the other two optical fiber monitoring holes, a large tensile strain concentration area appears near the top coal position, indicating that cracks are developed in the top coal position, and the top coal and the fine sandstone above are compressive strain. As the working face continues to advance, the compressive strain gradually increases. Going deeper, the position where the coarse sandstone and the siltstone above it are layered, the optical fiber strain gradually transforms into tensile strain, the upper siltstone layer is tensile strain, and the coarse sandstone layer and the siltstone layer above it form a local tensile separation. As the working face advances, the water pressure in the coarse sandstone layer gradually increases, the local separation layer is gradually filled with water, and the seepage pressure sensor data gradually increases, with a peak value of about 0.1MPa. Figure 5 shown.

[0126] S502. Post-frame (caving zone in goaf) monitoring: The overburden pressure in the caving zone shows a trend of first increasing briefly and then slowly increasing. The main reason is that in the early stage of monitoring, the crushed rocks falling from the top of the goaf squeezed the sensor, causing a sudden increase in pressure, which then decreased and remained stable. As time went by, the rock in the caving zone in the goaf continued to collapse, and the pressure gradually increased to 1.4MPa. There was a certain fluctuation in the seepage water pressure, but the overall change was small, and the seepage pressure was stable at around 0.12MPa. Figure 6 shown.

[0127] S6. Early warning and engineering effects.

[0128] By analyzing data in real time on the ground server, the system triggers an early warning when the seepage water pressure of the sandstone aquifer is greater than 0.2MPa or the tensile strain of the top coal is greater than 1000με. The 11702 working face adjusted the timing of the support withdrawal accordingly, successfully avoiding the pumping accident in front of the support and the mud outburst accident behind the support, verifying the engineering effectiveness of this method.

[0129] Beneficial effects of this embodiment:

[0130] The present invention realizes the synchronous collection and fusion analysis of multiple physical field data such as stress field, seepage field, humidity field, etc. by integrating strain optical fiber, soil pressure sensor, osmotic water pressure sensor and humidity sensor. It overcomes the limitation that traditional point sensors (such as resistance strain gauges) can only obtain a single physical quantity; optical fiber sensing technology has no electrical signal transmission, strong resistance to underground electromagnetic interference, and avoids signal distortion caused by electromagnetic noise; nylon gauze wrapped in coarse sand is used to protect the sensor, combined with the "two blocking and one injection" grouting process (woven bag blocking, high-pressure hose grouting) to improve the durability of the sensor in complex geological environments; based on the enterprise LAN IP address configuration, the ground dispatch room can directly retrieve monitoring data, reduce the frequency of manual inspections, and reduce safety risks. The monitoring system platform supports parallel access of multiple sensors, which is convenient for the later expansion of monitoring parameters or coverage.

[0131] The present invention realizes the leap from "single-point static" to "global dynamic" in multi-physical field monitoring of roof rock strata through innovative sensor network configuration, multi-physical field coupling analysis and engineering installation technology, significantly improving the timeliness and accuracy of roof disaster warning for coal mine working faces, while reducing manual maintenance costs, and has outstanding engineering application value.

[0132] Embodiment 2

[0133] This embodiment further discloses a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method described in the first embodiment.

[0134] Embodiment 3

[0135] This embodiment further discloses a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the method described in the first embodiment are implemented.

[0136] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A multi-physical field optical fiber sensing monitoring method for the front frame and rear top plate of a working face frame, characterized in that: The following steps are involved: Collect geological drilling data in and around the working face, and analyze the lithology development of the roof and surrounding rock formations; Based on the analysis results, design the layout of monitoring boreholes and construct the monitoring boreholes; Select multi-physics optical fiber and sensors, install them in the monitoring borehole, and protect the optical fiber and sensors; Optimize the grouting and sealing process, and perform grouting and sealing on the monitoring boreholes; Establish an online monitoring system platform for linkage between wells and underground areas to achieve real-time transmission and collection of data; Conduct dynamic analysis on monitoring data and make early warning and engineering applications based on the analysis results.

2. The method according to claim 1, characterized in that The steps to analyze the lithology of the roof and surrounding rock formations include: Collect existing geological drilling data in and around the working face to understand the lithology development of the working face roof and surrounding rock formations; The lithology thickness data revealed by the drilling is interpolated to determine the location and range of the roof sand and mudstone development in the working face monitoring area.

3. The method according to claim 1, characterized in that The arrangement scheme of the monitoring boreholes includes: The fiber optic sensor in front of the rack monitors the drilling hole, which is arranged in the return air lane of the working face with a hole diameter of Φ113mm; The optical fiber strain monitoring drilling holes in front of the rack are arranged in the return air lane of the working face, with a hole diameter of Φ113mm and an elevation angle. The optical fiber sensor behind the frame monitors the drilling hole. The drilling hole is arranged behind the end bracket of the transport lane of the working face, with a hole diameter of Φ113mm and is constructed at an elevation angle.

4. The method according to claim 1, characterized in that: The steps of selecting a multi-physics field optical fiber and a sensor, installing them in a monitoring borehole, and protecting the optical fiber and the sensor include: Select distributed strain optical fiber, soil pressure sensor, permeate water pressure sensor and humidity sensor; The strain optical fiber is laid in the whole hole section to monitor the strain generated when the roof rock formation breaks; The permeable water pressure sensor is installed in the middle section of the sandstone layer in the borehole to monitor the water pressure changes in the sandstone aquifer; The humidity sensor is installed in the middle section of the mudstone layer in the borehole to monitor the change in moisture content of the mudstone layer after it absorbs cement; The geotechnical pressure sensor is buried in the roof of the goaf behind the frame to monitor the overlying pressure of the rock in the collapse zone; The optical fiber and sensor were tied and fixed to the PVC tube using nylon tie, and the sensor surface was protected with nylon gauze wrapped with coarse sand.

5. The method according to claim 1, characterized in that The step of optimizing the grouting and sealing process and performing grouting and sealing on the monitoring borehole comprises: Use a PVC plug-in tube with a diameter of Φ50mm and a single length of 2m to bind and fix the optical fiber and sensor, and send them to the final hole position together with the PVC tube. At the same time, make eyelets on the surface of the PVC tube near the bottom of the hole to serve as a channel for exhaust and grouting when grouting and sealing the hole; Use single / double bag plugging method to inject grout into the sensor buried in the hole; A hole is drilled in the PVC pipe at the bottom of the deep bag. When the space between the two bags is filled with cement slurry, the slurry flows from the hole of the PVC pipe into the inner wall of the pipe and the drilling is completed.

6. The method according to claim 1, characterized in that The steps of establishing an online monitoring system platform for linking the well and the well to realize real-time transmission and collection of data include: Connect the strain optical fiber and the sensor lead wires at the hole mouth with a communication optical cable, and connect the other end of the communication optical cable to the fiber grating demodulator downhole; Install the demodulator at the location of the underground LAN switch near the monitoring borehole; Connect the demodulator to the underground LAN and assign it an IP address so that the collected data can be obtained on the ground later.

7. The method according to claim 1, characterized in that The steps of dynamically analyzing the monitoring data and carrying out early warning and engineering application according to the analysis results include: Dynamically analyze monitoring data and monitor the strain, pressure, seepage and humidity changes of roof rock in real time; According to the set warning threshold, the system automatically triggers the warning; According to the real-time monitoring data, the timing of support withdrawal is adjusted to prevent accidents such as pumping in front of the support and mud protrusion behind the support.

8. The method according to claim 7, characterized in that The process of dynamic analysis of monitoring data also includes: Analyze the tensile strain at the top coal position, the water pressure change of the coarse sandstone layer, and the pressure change of the caving zone in the goaf; According to the analysis results, the working face mining plan is adjusted and the support layout and support parameters are optimized.

9. A computer device comprising a memory, a processor and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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