Working face advance bearing pressure distribution optical fiber monitoring method

Abstract

The invention discloses a working face advance bearing pressure distribution optical fiber monitoring method, which comprises the following steps of S1, laying a drilling route on the side part of a roadway in front of a working face; S2, constructing a plurality of drill holes in a coal seam along the drilling route, and enabling the drill holes to extend along the length direction of the working face; s3, arranging a monitoring optical fiber in each drill hole, and connecting the monitoring optical fibers in each drill hole in series; s4, the drill hole is filled with slurry, and the slurry is solidified; s5, connecting the monitoring optical fiber in the drill hole farthest from the working surface with a strain demodulator to monitor strain data of the monitoring optical fiber; and S6, performing inversion according to the acquired monitoring optical fiber strain data to obtain the advanced bearing pressure distribution of the working face. The monitoring method provided by the invention not only can realize high-precision pressure measurement of a plurality of sensing points in a long-distance range, but also can provide more continuous and detailed pressure distribution information, and realizes continuous and high-precision monitoring of the advanced section of the coal mine working face.

Description

Technical Field

[0001] The invention relates to the technical field of working face advance support pressure monitoring, and in particular to an optical fiber monitoring method for working face advance support pressure distribution. Background Art

[0002] In the process of coal mining, the influence of advance support pressure on the spalling and deformation of the leading section of the working face is particularly important. Especially when the coal rock mass has developed joints and fissures and is weak and broken, the advance support pressure under the influence of mining will significantly aggravate the problem of surrounding rock stability. Therefore, it is of vital importance to monitor and grasp the stress concentration degree and influence range of the advance support pressure of the working face in the front coal body in advance to determine reasonable support parameters and optimize mining deployment.

[0003] At present, the main monitoring methods used in the industry, such as drilling stress gauges and hydraulic pillows, are all point-based monitoring methods and cannot perform continuous overall measurements. In addition, the monitoring results of these methods are greatly affected by the layout and depth of the monitoring points, resulting in low measurement accuracy. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, an embodiment of the present invention proposes a method for optical fiber monitoring of the advance support pressure distribution of a working surface.

[0006] The optical fiber monitoring method for the advanced support pressure distribution of a working surface according to an embodiment of the present invention comprises the following steps:

[0007] S1. Arrange the drilling route on the side of the tunnel in front of the working face;

[0008] S2, constructing a plurality of boreholes on the coal seam along the drilling route, and extending the boreholes along the length direction of the working face;

[0009] S3, arranging monitoring optical fibers in each borehole, and connecting the monitoring optical fibers in each borehole in series;

[0010] S4, filling the borehole with slurry and allowing the slurry to solidify;

[0011] S5, connecting the monitoring optical fiber in the borehole farthest from the working surface to the strain demodulator to monitor the strain data of the monitoring optical fiber;

[0012] S6. Inversion is performed based on the collected monitoring optical fiber strain data to obtain the leading support pressure distribution of the working face.

[0013] In some embodiments, in step S1 , the drilling route extends along the inclination direction of the working surface.

[0014] In some embodiments, in step S2, the borehole penetrates the entire coal seam along the length direction of the working face, and after the drilling construction is completed, the coal blocks and debris in the borehole are removed.

[0015] In some embodiments, in step S3, the monitoring optical fibers in two adjacent boreholes are connected via a connecting optical fiber, and the monitoring optical fiber and the connecting optical fiber are arranged in a serpentine shape along the inclination direction of the working surface.

[0016] In some embodiments, in step S3, a groove is opened on the side of the lane, and the connecting optical fiber is placed in the groove on the side.

[0017] In some embodiments, in step S3, the connecting optical fiber is placed in a tensioned state in the groove, the groove is filled with slurry, and the slurry is solidified.

[0018] In some embodiments, in step S3, the monitoring optical fiber is bundled on a plastic tube, and the monitoring optical fiber is sent into the borehole using the plastic tube.

[0019] In some embodiments, in step S3, the monitoring optical fiber is bundled on the plastic tube by a cable tie, and the head of the monitoring optical fiber is wrapped to protect the monitoring optical fiber.

[0020] In some embodiments, in step S4, one end of the plastic tube is placed in the borehole, and the other end of the plastic tube is placed outside the borehole, and the slurry is filled into the borehole through the plastic tube.

[0021] In some embodiments, the monitoring optical fiber is a steel strand optical fiber.

[0022] Compared with the traditional point-type monitoring method, the optical fiber monitoring method for the advanced support pressure distribution of the working face of the embodiment of the present invention can not only realize the high-precision pressure measurement of multiple sensing points within a long distance, but also provide more continuous and detailed pressure distribution information, and realize continuous and high-precision monitoring of the advanced section of the coal mine working face. By setting multiple monitoring points on the monitoring optical fiber, a point-line-surface three-dimensional distributed sensing network is formed to capture the slight deformation and stress changes of the coal seam, providing a new method and technical means for the study of the deformation law of the coal seam.

[0023] In addition, by burying multiple monitoring optical fibers in the coal seam, we can further construct distribution models of the support pressure of the working face. These models can reflect the change process of the support pressure as the working face advances. The high precision and spatial resolution of the monitoring optical fiber enable it to accurately capture subtle pressure changes under complex geological conditions, provide real-time data support for mine safety production, and timely warn of potential geological disaster risks to ensure the safety of miners' lives and production. Monitoring optical fibers can not only monitor pressure, but also monitor other physical quantities such as temperature and displacement, and realize synchronous monitoring of multiple physical quantities, which makes it possible to comprehensively evaluate the stability of the working face. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a side view of a monitoring optical fiber according to an embodiment of the present invention.

[0025] Figure 2 4 is a top view of the monitoring optical fiber according to an embodiment of the present invention.

[0026] Figure 3 4 is a front view of a monitoring optical fiber according to an embodiment of the present invention.

[0027] Figure 4 It is a schematic diagram of the connection between the optical fiber and the plastic tube according to an embodiment of the present invention.

[0028] Figure 5 It is a schematic diagram of the connection between the optical fiber and the plastic tube according to an embodiment of the present invention.

[0029] Reference numerals:

[0030] 1. Working face; 2. Tunnel; 201. Gangway; 3. Drilling hole; 4. Coal seam; 5. Monitoring optical fiber; 6. Connecting optical fiber; 7. Plastic pipe; 8. Cable tie. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0032] like Figures 1 to 5 As shown, the optical fiber monitoring method for the advanced support pressure distribution of the working surface 1 according to the embodiment of the present invention comprises the following steps:

[0033] S1, laying out a drilling route on the side 201 of the tunnel 2 in front of the working face 1;

[0034] S2, constructing a plurality of boreholes 3 on the coal seam 4 along the drilling route, and extending the boreholes 3 along the length direction of the working face 1;

[0035] S3, arranging a monitoring optical fiber 5 in each borehole 3, and connecting the monitoring optical fibers 5 in each borehole 3 in series;

[0036] S4, filling the borehole 3 with slurry and allowing the slurry to solidify;

[0037] S5, connecting the monitoring optical fiber 5 in the borehole 3 farthest from the working surface 1 to the strain demodulator to monitor the strain data of the monitoring optical fiber 5;

[0038] S6. Inversion is performed based on the collected strain data of the monitoring optical fiber 5 to obtain the leading support pressure distribution of the working face 1.

[0039] The optical fiber monitoring method for the distribution of the advance support pressure of the working face 1 of the embodiment of the present invention provides a basis for subsequent optical fiber monitoring by laying a drilling route on the side 201 of the tunnel 2 in front of the working face 1. A plurality of boreholes 3 are constructed along the pre-laid drilling route, and these boreholes 3 will extend into the coal seam 4 to monitor the advance support pressure. A monitoring optical fiber 5 is arranged in each borehole 3, and they are connected in series to form a continuous optical fiber monitoring line. The slurry is filled into the borehole 3 and solidified, so that the optical fiber can be fixed and the stress changes of the coal rock mass can be transmitted to the optical fiber. The monitoring optical fiber 5 in the borehole 3 farthest from the working face 1 is connected to the strain demodulator to monitor the strain data of the optical fiber 5 in real time. The monitoring optical fiber 5 is calibrated by the modem to obtain accurate information on the position of the monitoring data of the monitoring optical fiber 5, and then the monitoring data is fed back to the intelligent analysis terminal to perform support pressure inversion. By analyzing the strain data of the monitoring optical fiber 5, the distribution of the advance support pressure of the working face 1 is inverted.

[0040] Compared with the traditional point monitoring method, the optical fiber monitoring method for the leading support pressure distribution of the working face 1 of the embodiment of the present invention can not only realize the high-precision pressure measurement of multiple sensing points within a long distance range, but also provide more continuous and detailed pressure distribution information, and realize continuous and high-precision monitoring of the leading section of the coal mine working face. By setting multiple monitoring points on the monitoring optical fiber 5, a point-line-surface three-dimensional distributed sensing network is formed to capture the slight deformation and stress changes of the coal seam, which provides a new method and technical means for the study of the deformation law of the coal seam. In addition, by burying multiple monitoring optical fibers 5 in the coal seam, a distribution model of the support pressure of the working face can be further constructed, and these models can reflect the change process of the support pressure as the working face advances. The high precision and spatial resolution of the monitoring optical fiber 5 enable it to accurately capture subtle pressure changes under complex geological conditions, provide real-time data support for mine safety production, timely warn of potential geological disaster risks, and ensure the life safety and production safety of miners. The monitoring optical fiber 5 can not only monitor pressure, but also realize the monitoring of other physical quantities such as temperature and displacement, realize the synchronous monitoring of multiple physical quantities, and provide the possibility for comprehensive evaluation of the stability of the working face.

[0041] In some embodiments, in step S1 , the drilling route extends along the inclination direction of the working surface 1 .

[0042] The drilling route in the dip direction can better monitor the stress distribution of the coal body in the direction perpendicular to the working face 1, which helps to understand the stress changes in the dip direction of the coal body during mining. The data in the dip direction can reflect the changes in the vertical stress inside the coal seam 4, which helps to evaluate the stability of the coal seam 4 in the dip direction.

[0043] In some embodiments, in step S2, the borehole 3 penetrates the entire coal seam 4 along the length direction of the working face 1, and after the construction of the borehole 3 is completed, the coal blocks and debris in the borehole 3 are removed.

[0044] Removing the coal debris in the borehole 3 can ensure that the monitoring optical fiber 5 is in close contact with the surface of the coal seam 4, reducing the monitoring data error caused by the presence of debris. The removal of debris helps the optical fiber to more accurately sense the stress changes in the coal seam 4, thereby improving the reliability of the monitoring data. The debris in the borehole 3 may affect the installation of the optical fiber, resulting in the optical fiber and the surface of the coal seam 4 not being completely attached, affecting the collection of monitoring data. After removing the debris, a clean and smooth surface can be provided for the installation of the optical fiber, which is conducive to the fixation of the optical fiber and the stable transmission of data.

[0045] In some embodiments, in step S3 , the monitoring optical fibers 5 in two adjacent boreholes 3 are connected via a connecting optical fiber 6 , and the monitoring optical fibers 5 and the connecting optical fibers 6 are arranged in a serpentine shape along the inclination direction of the working surface 1 .

[0046] The serpentine arrangement enables the monitoring optical fiber 5 to cover a larger range in the dip direction of the working face 1, so that the stress changes at different positions inside the coal body can be continuously monitored. This layout helps to capture the stress gradient changes of the coal body in the dip direction and provide more comprehensive stress distribution data. By connecting the monitoring optical fibers 5 in adjacent boreholes 3 by connecting optical fibers 6, a more stable data transmission network can be formed, reducing the impact of single-point failures on the entire monitoring system. The serpentine arrangement can effectively disperse the potential damage to the optical fiber due to coal body movement or ground pressure changes, and improve the anti-interference ability of the monitoring system.

[0047] In some embodiments, in step S3 , a groove is opened on the side portion 201 of the lane 2 , and the connecting optical fiber 6 is placed in the groove on the side portion 201 .

[0048] Placing the connecting optical fiber 6 in the groove can provide physical protection to prevent the optical fiber from being damaged by the external environment, such as being squeezed or hit by rocks or covered by coal dust. The groove can fix the position of the connecting optical fiber 6 to ensure that the connecting optical fiber 6 will not be displaced due to environmental changes (such as wind flow, vibration, etc.) inside the tunnel 2, thereby ensuring data stability. The setting of the groove helps to reduce signal loss caused by bending, stretching or compression of the optical fiber, and improve the quality and efficiency of optical fiber data transmission.

[0049] In some embodiments, in step S3, the connecting optical fiber 6 is placed in a tensioned state in the groove, and the groove is filled with slurry and the slurry is solidified.

[0050] When installing the connecting optical fiber 6 in the groove, it is placed in a tensioned state. This ensures that the optical fiber maintains a straight line or a predetermined curved shape in the groove, and reduces the displacement or deformation of the optical fiber caused by changes in the internal environment of the lane 2 (such as temperature changes, vibrations, etc.). The groove is filled with slurry, which can be cement slurry, resin or other suitable filling materials. The filling of slurry can fix the position of the optical fiber and prevent the optical fiber from moving in the groove. After the filled slurry solidifies, the optical fiber is firmly fixed in the groove and an additional protective layer is provided to prevent the optical fiber from being physically damaged.

[0051] In some embodiments, in step S3 , the monitoring optical fiber 5 is bundled onto a plastic tube 7 , and the monitoring optical fiber 5 is sent into the borehole 3 using the plastic tube 7 .

[0052] By bundling the optical fiber on the plastic tube 7, it is easier to feed the optical fiber into the borehole 3, reducing the complexity and time of installation. The plastic tube 7 helps to maintain the shape and position of the optical fiber, and prevents the optical fiber from being twisted or folded during feeding into the borehole 3.

[0053] In some embodiments, in step S3 , the monitoring optical fiber 5 is bundled on the plastic tube 7 by a cable tie 8 , and the head of the monitoring optical fiber 5 is wrapped to protect the monitoring optical fiber 5 .

[0054] The cable tie 8 can fix the position of the optical fiber on the plastic tube 7 to prevent the optical fiber from being displaced or twisted during transportation and installation. The wrapping of the optical fiber head can provide an additional layer of protection to prevent the optical fiber end from being hit or worn. The use of the cable tie 8 and the plastic tube 7 can simplify the installation process of the optical fiber and improve the installation efficiency. By fixing and wrapping, the stability of the optical fiber in the borehole 3 is improved, reducing the risk of damage caused by geological activities or mining operations. For different geological conditions and borehole 3 diameters, the tightness of the cable tie 8 and the type of plastic tube 7 can be adjusted to adapt. Protective measures can reduce damage and failure of the optical fiber, thereby extending its service life and reducing maintenance and replacement costs.

[0055] In some embodiments, in step S4 , one end of the plastic tube 7 is placed inside the borehole 3 , and the other end of the plastic tube 7 is placed outside the borehole 3 , and the slurry is filled into the borehole 3 through the plastic tube 7 .

[0056] Specifically, a plastic tube 7 of appropriate length and diameter is selected to ensure that one end of the plastic tube 7 can be smoothly inserted into the borehole 3, and the other end is left outside the borehole 3 for operation. One end of the plastic tube 7 is inserted into the borehole 3, and the other end is left outside the borehole 3. Ensure that the plastic tube 7 is correctly positioned in the borehole 3 and does not block the borehole 3 channel. Fill the borehole 3 with slurry through the end of the plastic tube 7 that remains outside the borehole 3. A pump or other conveying equipment can be used to control the flow rate and pressure of the slurry. During the filling process, monitor the filling of the slurry to ensure that the slurry is evenly distributed inside the borehole 3. Before the slurry is about to solidify, ensure that the optical fiber is correctly positioned and fixed to avoid unnecessary pressure on the optical fiber caused by the solidified slurry.

[0057] The plastic tube 7, as a channel for conveying slurry, can help the operator control the flow of slurry and ensure that the slurry can evenly fill each part of the borehole 3. Filling the slurry through the plastic tube 7 can prevent the slurry from directly contacting the optical fiber, reducing the potential damage of the slurry to the optical fiber.

[0058] In some embodiments, the monitoring optical fiber 5 is a steel strand optical fiber.

[0059] The steel stranded optical fiber is made of multiple tiny optical fibers twisted around a central reinforcing steel wire. It has high tensile strength and can withstand large tensile loads. It is suitable for use in mine environments that may be subjected to tension or compression. The outer layer of the steel stranded optical fiber is usually made of a protective material with good wear resistance, which can resist the wear of hard objects such as coal dust and rocks in the mine. The material selection and surface treatment of the steel stranded optical fiber can make it have good corrosion resistance and can adapt to the moist and corrosive gas environment in the mine. The steel stranded optical fiber is designed with flexibility in mind, and it is not easily damaged even when bent or twisted, which helps the optical fiber to be smoothly arranged in the borehole 3. The strength and flexibility of the steel stranded optical fiber make it easier to install in the borehole 3, reducing the difficulty and risk during the installation process.

[0060] Optionally, the diameter of the stranded optical fiber is 5 mm.

[0061] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0062] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0063] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0065] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0066] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for optical fiber monitoring of the advanced support pressure distribution of a working surface, characterized in that: The following steps are involved: S1. Arrange the drilling route on the side of the tunnel in front of the working face; S2, constructing a plurality of boreholes on the coal seam along the drilling route, and extending the boreholes along the length direction of the working face; S3, arranging monitoring optical fibers in each borehole, and connecting the monitoring optical fibers in each borehole in series; S4, filling the borehole with slurry and allowing the slurry to solidify; S5, connecting the monitoring optical fiber in the borehole farthest from the working surface to the strain demodulator to monitor the strain data of the monitoring optical fiber; S6. Inversion is performed based on the collected monitoring optical fiber strain data to obtain the leading support pressure distribution of the working face.

2. According to the optical fiber monitoring method for the advance support pressure distribution of the working face as described in claim 1, in step S1, the drilling route extends along the inclination direction of the working face.

3. According to the optical fiber monitoring method for the advance support pressure distribution of the working face as described in claim 2, in step S2, the borehole is drilled through the entire coal seam along the length direction of the working face, and after the drilling construction is completed, the coal blocks and debris in the borehole are removed.

4. According to the optical fiber monitoring method for the advance support pressure distribution of the working face as described in claim 3, in step S3, the monitoring optical fibers in two adjacent boreholes are connected by a connecting optical fiber, and the monitoring optical fiber and the connecting optical fiber are arranged in a serpentine shape along the inclination direction of the working face.

5. The optical fiber monitoring method for the advanced support pressure distribution of the working surface according to claim 4 is characterized in that: In step S3, a groove is formed on the side of the lane, and the connecting optical fiber is placed in the groove on the side.

6. The optical fiber monitoring method for advanced support pressure distribution of a working surface according to claim 5 is characterized in that: In step S3, the connecting optical fiber is placed in a tensioned state in the groove, and the groove is filled with slurry and solidified.

7. The optical fiber monitoring method for advanced support pressure distribution of a working surface according to claim 1, characterized in that: In step S3, the monitoring optical fiber is bundled on a plastic tube, and the monitoring optical fiber is sent into the borehole by using the plastic tube.

8. The optical fiber monitoring method for advanced support pressure distribution of a working surface according to claim 7, characterized in that: In step S3, the monitoring optical fiber is bundled on the plastic tube by a cable tie, and the head of the monitoring optical fiber is wrapped to protect the monitoring optical fiber.

9. The optical fiber monitoring method for advanced support pressure distribution of a working surface according to claim 6, characterized in that: In step S4, one end of the plastic tube is placed in the borehole, and the other end of the plastic tube is placed outside the borehole, and slurry is filled into the borehole through the plastic tube.

10. The optical fiber monitoring method for advanced support pressure distribution of a working surface according to claim 1, characterized in that: The monitoring optical fiber is a steel strand optical fiber.

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