Optical fiber monitoring method for full-space supporting pressure transmission rule of working face

Abstract

The invention provides a working face total space supporting pressure transmission rule optical fiber monitoring method, which comprises the following steps that a monitored target rock stratum is determined, the target rock stratum comprises an immediate roof, a basic roof and an overlying strata part, and the immediate roof, the basic roof and the overlying strata part are sequentially arranged from bottom to top; a directional drilling field is arranged on a target rock stratum, according to a preset drilling track, drilling is conducted on the target rock stratum through a directional drilling machine, an optical fiber monitoring assembly is laid in a drilled hole, grouting and hole sealing are conducted on the drilled hole, the optical fiber monitoring assembly is connected with a monitor, and therefore the target rock stratum is monitored in real time, and a monitoring result is analyzed. And calculating the bearing pressure distribution condition of the target rock stratum. The optical fiber monitoring method for the whole-space supporting pressure transmission rule of the working face has the advantage of high monitoring precision.

Description

Technical Field

[0001] This invention relates to the field of fiber optic monitoring technology, specifically to a fiber optic monitoring method for the transmission law of pressure under full-space support on a working surface. Background Technology

[0002] During the mining process in underground coal mines, the stress in the surrounding rock is transferred and superimposed, generating support pressure. In some areas, the support pressure is higher than the original rock stress, while in others it is lower. The distribution pattern of support pressure in the surrounding rock of the working face directly affects the mine pressure management of the working face.

[0003] In related technologies, there is a lack of effective monitoring methods for the bearing pressure in the overlying rock strata of the entire working face. The installation location of traditional point sensors is limited, and they are greatly affected by environmental interference during the data acquisition process, making it impossible to achieve continuous and high-precision full-space monitoring. Summary of the Invention

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

[0005] Therefore, embodiments of the present invention propose an optical fiber monitoring method for the pressure transmission law of the working surface support in the entire space, which has the advantage of high monitoring accuracy.

[0006] The fiber optic monitoring method for the pressure transmission law of the working surface full-space support according to an embodiment of the present invention includes the following steps:

[0007] S1. Determine the target rock stratum for monitoring. The target rock stratum includes the immediate top, the main top, and the overburden, which are arranged sequentially from bottom to top.

[0008] S2. Deploy a directional drilling site in the target rock strata;

[0009] S3. Drill holes in the target rock strata using a directional drilling rig according to the preset drilling trajectory;

[0010] S4. Lay fiber optic monitoring components inside the borehole;

[0011] S5. Grout the borehole to seal it;

[0012] S6. Connect the fiber optic monitoring component to the monitoring instrument to monitor the target rock layer in real time;

[0013] S7. Analyze the monitoring results and estimate the distribution of the support pressure of the target rock strata.

[0014] The fiber optic monitoring method for the transmission law of support pressure in the working face in this embodiment of the invention involves drilling and deploying distributed fiber optic strain sensors in the direct roof, main roof, and overlying strata of the working face. In real time and continuously in the three-dimensional space of the mining area, the strain / stress changes of different layers in the overlying strata are monitored, and the fracture characteristics of the roof strata and the transmission law of support pressure are obtained during the mining process, providing basic data for the management of mine pressure in the working face.

[0015] In some embodiments, in step S3, the borehole includes a first segment, a second segment, and a third segment connected in sequence, the second segment being located above the first segment and the third segment and the extension direction of the second segment being consistent with the horizontal direction, and the extension directions of the first segment and the third segment being inclined toward the direction of the second segment.

[0016] In some embodiments, the system further includes a plurality of borehole groups, which are arranged at intervals along the extension direction of the roadway. Each borehole group includes a plurality of boreholes, which correspond one-to-one with the direct roof, the main roof, and the overburden.

[0017] In some embodiments, the fiber optic monitoring method for the pressure transmission law of the working face full-space support in this invention further includes the following steps: before step S4, flushing the borehole wall after drilling.

[0018] In some embodiments, the fiber optic monitoring assembly includes a fixing member and a monitoring fiber, the monitoring fiber being connected to the fixing member, and the extension direction of the fixing member being consistent with the extension direction of the borehole.

[0019] In some embodiments, the fiber optic monitoring assembly further includes a connector, a first end of which is connected to the fixing member, a second end of which is connected to the monitoring fiber, and the monitoring fiber is spaced apart from the fixing member.

[0020] In some embodiments, the monitoring optical fiber is a single fiber, and the single monitoring optical fiber is connected in series with multiple boreholes of the multiple borehole groups.

[0021] In some embodiments, there are multiple monitoring optical fibers, with at least one monitoring optical fiber arranged in one borehole.

[0022] In some embodiments, in step S5, the hole is sealed by segmented grouting.

[0023] In some embodiments, step S7 further includes fiber optic location calibration to determine the fiber optic location in the target rock layer and obtain the location information of the fiber optic monitoring component. Attached Figure Description

[0024] Figure 1This is a construction schematic diagram of the fiber optic monitoring method for the pressure transmission law of the working surface full-space support according to an embodiment of the present invention.

[0025] Figure 2 yes Figure 1 The diagram shown is AA-direction.

[0026] Figure 3 This is a top-view diagram illustrating the construction of the fiber optic monitoring method for the pressure transmission law of the working surface full-space support according to an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of the fiber optic monitoring component of the fiber optic monitoring method for monitoring the pressure transmission law of the working surface full-space support in an embodiment of the present invention.

[0028] Figure 5 This is a cross-sectional schematic diagram of the fiber optic monitoring component of the fiber optic monitoring method for monitoring the pressure transmission law of the working surface in the full space support according to an embodiment of the present invention.

[0029] Figure label:

[0030] 100. Working face mining area,

[0031] 11. Direct Top, 12. Basic Top, 13. Overburden,

[0032] 2. Drilling group, 21. Drilling, 211. First section, 212. Second section, 213. Third section.

[0033] 3. Fiber optic monitoring components; 31. Fixtures; 32. Monitoring fiber optic cable; 33. Connectors. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] like Figures 1-5 As shown, the fiber optic monitoring method for the pressure transmission law of the working surface full-space support in this embodiment of the invention includes the following steps:

[0036] S1. Determine the target rock strata for monitoring. The target rock strata include the immediate roof 11, the main roof 12, and the overburden 13, arranged sequentially from bottom to top. It can be understood that the immediate roof 11 refers to the rock strata closest to the working face, which is directly affected by mining activities; the main roof 12 refers to the hard rock strata above the immediate roof 11, which has a significant impact on the stability of the working face; and the overburden 13 refers to the deeper rock strata above the main roof 12. Exploration of the target rock strata can be carried out using geological exploration equipment, such as drilling rigs and rock strata analyzers. Identifying the target rock strata helps in the targeted placement of monitoring points, improving the efficiency and accuracy of monitoring.

[0037] S2. Deploy directional drilling sites in the target rock strata. This means designing and deploying directional drilling sites within the defined target rock strata. The location and number of drilling sites are determined based on monitoring requirements. Directional drilling sites can minimize interference with miner safety and the ore deposit while ensuring the accurate placement of monitoring points.

[0038] S3. Drill hole 21 in the target rock stratum using a directional drilling rig according to the preset borehole 21 trajectory. It is understood that the depth and direction of the borehole 21 need to be precisely controlled. The borehole 21 measuring device is a directional drilling rig; a precise borehole 21 trajectory helps in the accurate placement of the fiber optic monitoring component 3 and improves the quality of the monitoring data.

[0039] S4. Lay the fiber optic monitoring component 3 inside the borehole 21. It is understood that the fiber optic monitoring component 3 is laid inside the borehole 21 to ensure that it can cover the target rock layer.

[0040] S5. Grouting and sealing of borehole 21. After the fiber optic monitoring component 3 is installed, borehole 21 is grouted and sealed to protect the fiber optic sensor and prevent data interference. In other words, grouting and sealing ensures the long-term stability of the fiber optic monitoring component and the reliability of data transmission.

[0041] S6. Connect the fiber optic monitoring component 3 to the monitoring instrument for real-time monitoring of the target rock strata. This means connecting the fiber optic monitoring component 3 to the monitoring instrument allows for real-time data collection and analysis. The fiber optic monitoring instrument is used in the data acquisition and processing system; real-time monitoring enables rapid response to changes in rock strata stress, providing immediate information for mine pressure management.

[0042] S7. Analyze the monitoring results and estimate the distribution of the target rock strata bearing pressure.

[0043] Therefore, the fiber optic monitoring method for the transmission law of support pressure in the working face in this embodiment of the invention involves drilling and deploying distributed fiber optic strain sensors in the direct roof 11, basic roof 12, and overlying strata of the working face. In real time and continuously in the three-dimensional space of the mining area, the strain / stress changes of different layers in the overlying strata are monitored, and the fracture characteristics of the roof strata and the transmission law of support pressure are obtained during the mining process of the working face, providing basic data for the management of mine pressure in the working face.

[0044] In some embodiments, in step S3, the borehole 21 includes a first segment 211, a second segment 212 and a third segment 213 connected in sequence. The second segment 212 is located above the first segment 211 and the third segment 213 and the extension direction of the second segment 212 is consistent with the horizontal direction. The extension directions of the first segment 211 and the third segment 213 are inclined toward the direction of the second segment 212.

[0045] Specifically, such as Figures 1-5 As shown, boreholes 21 are provided in the immediate roof 11, the main roof 12, and the overburden 13, and the starting and ending ends of the boreholes 21 in each rock stratum are located within the roadway. That is to say, when drilling the immediate roof 11, the main roof 12, and the overburden 13, the drilling 21 is carried out from the working face mining area 100 of the roadway obliquely upward until the corresponding rock stratum is reached and the drilling is maintained horizontally. Then, the drilling proceeds obliquely downward to the rock stratum, so that each borehole 21 is arranged by a first section 211, a second section 212, and a third section 213 connected in sequence.

[0046] Optionally, the lengths of the first segment 211, the second segment 212, and the third segment 213 are approximately equal. That is, during the drilling process 21, the lengths of the first segment 211, the second segment 212, and the third segment 213 are kept as equal as possible, i.e., the first segment 211, the second segment 212, and the third segment 213 are approximately "three equal segments", in order to facilitate the subsequent laying of optical fibers.

[0047] In some embodiments, a plurality of borehole groups 2 are further included, the plurality of borehole groups 2 being along the extension direction of the roadway (e.g., Figure 2 The boreholes are arranged at intervals in the left and right directions. A borehole group 2 includes multiple boreholes 21, and the multiple boreholes 21 correspond one-to-one with the direct top 11, the main top 12 and the overlying part 13.

[0048] Specifically, such as Figures 1-5 As shown, in the vertical direction, a borehole group 2 includes multiple vertically spaced boreholes 21, and each borehole 21 is arranged on both sides of the working face mining area 100 in the horizontal direction. It can be understood that, as... Figures 1-5As shown, taking the bottommost borehole 21 as an example, the opening of the first section 211 of borehole 21 is located on the left side of the working face mining area 100, the opening of the third section 213 of borehole 21 is located on the right side of the working face mining area 100, and the second section 212 is located in the rock strata of the direct roof 11.

[0049] In other words, multiple borehole groups 2 can provide more comprehensive monitoring coverage, helping to capture stress changes in the rock strata above the entire working face. Furthermore, data from different borehole groups 2 can be compared and analyzed to identify and assess differences in rock strata stress in different areas.

[0050] In some embodiments, the fiber optic monitoring method for the pressure transmission law of the working face full space support in this invention further includes the following steps: before step S4, the borehole wall is flushed after drilling 21.

[0051] Understandably, after drilling hole 21 is completed, flushing equipment, such as high-pressure water guns and flushing pumps, should be prepared. High-pressure water should be used to flush the borehole wall to ensure that rock cuttings and debris are flushed out. After flushing, check the cleanliness of the borehole. If necessary, repeat the flushing operation until the borehole wall is clean. After confirming that the borehole wall is clean, necessary borehole wall treatments can be performed, such as applying anti-corrosion material to protect the fiber optic monitoring component 3.

[0052] In other words, removing rock cuttings and debris generated during the drilling process can ensure the cleanliness of the borehole wall, reduce impurities between the borehole wall and the fiber optic monitoring component 3, improve data accuracy, and prevent rock cuttings and impurities from damaging the fiber optic monitoring component 3.

[0053] In some embodiments, the fiber optic monitoring component 3 includes a fixing member 31 and a monitoring fiber 32, the monitoring fiber 32 being connected to the fixing member 31, and the extension direction of the fixing member 31 being consistent with the extension direction of the borehole 21.

[0054] Specifically, such as Figures 1-5 As shown, the extension direction of the fastener 31 is consistent with the extension direction of the drill hole 21, so that the fastener 31 can be adapted to the drill hole 21. The monitoring fiber optic cable 32 and the fastener 31 can be connected by straps, buckles, etc., so as to quickly fix the fastener 31 and the monitoring fiber optic cable 32 together.

[0055] Understandably, the optical fiber is effectively fixed within the borehole 21 by the fixing component 31, reducing fiber displacement caused by rock movement or external interference and improving the stability of the monitoring system. Connecting the fixing component 31 to the monitoring optical fiber 32 can improve the reliability of the optical fiber monitoring assembly 3 and extend its service life in harsh environments.

[0056] In some embodiments, the fiber optic monitoring component 3 further includes a connector 33, the first end of which is connected to the fixing member 31, and the second end of which is connected to the monitoring fiber 32, with the monitoring fiber 32 spaced apart from the fixing member 31.

[0057] It is understandable that, such as Figures 1-5 As shown, the connector 33 provides a certain gap between the fixing member 31 and the monitoring optical fiber 32, thus reducing the direct pressure of the fixing member 31 on the optical fiber and protecting it from damage. The size and shape of the connector 33 are designed according to the size of the borehole 21 and the specifications of the monitoring optical fiber 32 to ensure compatibility with both the fixing member 31 and the monitoring optical fiber 32. Furthermore, the connector 33 sets the gap between the monitoring optical fiber 32 and the fixing member 31; this gap can be adjusted as needed to ensure that the optical fiber is not damaged by rock movement.

[0058] In other words, connector 33 provides additional protection for the optical fiber, reducing direct damage caused by rock movement or external interference. The spacing effect of connector 33 improves the stability of the optical fiber within borehole 21, helping to maintain the accuracy of monitoring data.

[0059] It should be noted that the fastener 31 can be a strip that can undergo flexible deformation, such as a steel strip, or it can be other objects with a certain degree of rigidity, such as a PVC pipe.

[0060] In some embodiments, the monitoring fiber 32 is a single fiber, and the single monitoring fiber 32 is connected in series with multiple boreholes 21 of multiple borehole groups 2. It is understood that, as Figures 1-5 As shown, a monitoring optical fiber 32 is sequentially threaded through multiple boreholes 21 in multiple borehole groups 2 so that the monitoring optical fiber 32 runs through the entire monitoring area. That is, based on the geological conditions of the working face and the layout of the borehole groups 2, a path for the monitoring optical fiber 32 is designed to ensure that the optical fiber can sequentially pass through each borehole 21.

[0061] In other words, a single monitoring fiber optic cable 32 is used in series with multiple boreholes 21, reducing the amount of fiber used and improving the installation efficiency of the monitoring system. This design significantly reduces the cost of the monitoring system by decreasing the number of fibers and installation work. Furthermore, the continuity of the fiber optic cables ensures the continuity and consistency of the monitoring data, which helps to analyze rock stress changes more accurately.

[0062] Of course, multiple monitoring optical fibers 32 can also be connected in series to form a monitoring optical fiber 32 that can be arranged in all boreholes 21. By using the series connection design of the monitoring optical fibers 32, the maintenance and troubleshooting of the monitoring system can be made simpler, and problems can be quickly located and repaired.

[0063] In other embodiments, there are multiple monitoring optical fibers 32, with at least one monitoring optical fiber 32 arranged within a borehole 21. It is understood that at least one monitoring optical fiber 32 is arranged within each borehole 21. These monitoring optical fibers 32 can be individual fibers or a bundle of fibers, depending on the monitoring requirements and the size of the borehole 21. The appropriate fiber type and quantity are selected based on the monitoring objectives and geological conditions. The fiber layout within the borehole 21 is designed to ensure coverage of different areas of the rock strata.

[0064] In other words, the arrangement of multiple monitoring optical fibers 32 can provide multiple monitoring points within a single borehole 21, improving the spatial resolution of monitoring. Furthermore, if one monitoring optical fiber 32 fails, the others can still provide data, increasing monitoring reliability. In addition, the data collected through multiple optical fibers is more comprehensive, contributing to a more accurate analysis of the stress state of the rock strata.

[0065] In some embodiments, in step S5, the borehole is sealed using a segmented grouting method. Optionally, if the fixing member 31 is a PVC pipe, the monitoring optical fiber 32 is fixed to the PVC pipe via the connector 33. During segmented grouting, firstly, the end of the PVC pipe is sealed and fixed to the borehole 21 to prevent the gap between the PVC pipe and the wall of the borehole 21 from changing during the grouting process. Secondly, using the PVC pipe as a grouting pipe, the gap between the PVC pipe and the side wall of the borehole 21 can be grouted before grouting the PVC pipe, thereby completing the grouting of the entire borehole 21.

[0066] In other words, segmented grouting ensures that each gap is fully filled, improving the overall quality of the borehole sealing. Segmented grouting also reduces the impact and pressure on the optical fiber during the grouting process, protecting it from damage. Furthermore, the location and number of grouting segments can be adjusted according to the specific conditions of borehole 21 to adapt to different geological conditions and monitoring needs.

[0067] In some embodiments, step S7 further includes fiber optic position calibration to determine the fiber optic position in the target rock layer and obtain the position information of the fiber optic monitoring component 3.

[0068] Understandably, the position of the monitoring fiber 32 can be calibrated using a demodulator to obtain the position information of the fiber monitoring component 3, so as to provide data support for subsequent inversion.

[0069] Support pressure inversion. The pressure distribution of the direct top 11, the basic top 12, and the overlying strata is inverted. The optical fiber is coupled to the overlying strata. When the overlying strata deform, the optical fiber generates strain. Based on the strain data measured by the optical fiber, Hooke's law is used to calculate the stress of the monitoring unit, i.e.:

[0070] σ 轴向 =ε轴向 E

[0071] Where, σ 轴向 It is the stress on the optical fiber along the axial direction, ε 轴向 E is the strain of the optical fiber along the axial direction, and E is the Young's modulus of the optical fiber material. Thus, the stress components in other directions can be calculated based on the spatial relationship of the optical fiber, providing basic data for mine pressure management at the working face.

[0072] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0073] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0074] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0075] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0076] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0077] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for optical fiber monitoring of the full-space support pressure transmission law of a working surface, characterized in that: The steps include: S1. Determine a target rock layer to be monitored, wherein the target rock layer includes a direct top, a basic top and an overburden portion, and the direct top, the basic top and the overburden portion are arranged in sequence from bottom to top; S2. Arrange a directional drilling site in the target rock formation; S3, drilling in the target rock formation using a directional drill according to a preset drilling trajectory; S4, laying optical fiber monitoring components in the borehole; S5, grouting and sealing the drilled hole; S6, connecting the optical fiber monitoring assembly to the monitoring instrument to perform real-time monitoring of the target rock formation; S7. Analyze the monitoring results and calculate the distribution of the support pressure of the target rock formation.

2. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 1 is characterized in that: In step S3, the borehole includes a first section, a second section and a third section connected in sequence, the second section is located above the first section and the third section and the extension direction of the second section is consistent with the horizontal direction, and the extension directions of the first section and the third section are inclined toward the direction of the second section.

3. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 2 is characterized in that: It also includes a plurality of drilling groups, which are arranged at intervals along the extension direction of the tunnel, and one drilling group includes a plurality of boreholes, which correspond one-to-one to the direct top, the basic top and the overburden part.

4. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 3 is characterized in that: The following steps are also included: Before step S4, the hole wall is flushed after the drilling construction.

5. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 4 is characterized in that: The optical fiber monitoring assembly includes a fixing member and a monitoring optical fiber. The monitoring optical fiber is connected to the fixing member. The extending direction of the fixing member is consistent with the extending direction of the drill hole.

6. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 5 is characterized in that: The optical fiber monitoring assembly further comprises a connecting member, a first end of the connecting member is connected to the fixing member, a second end of the connecting member is connected to the monitoring optical fiber, and the monitoring optical fiber is spaced apart from the fixing member.

7. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 6 is characterized in that: The monitoring optical fiber is one, and the monitoring optical fiber is sequentially connected in series to the multiple boreholes in the multiple borehole groups.

8. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 6 is characterized in that: There are multiple monitoring optical fibers, and at least one monitoring optical fiber is arranged in one borehole.

9. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to any one of claims 1 to 8, characterized in that: In step S5, the hole is sealed by segmented grouting.

10. The optical fiber monitoring method for the full-space support pressure transmission law of a working surface according to claim 9 is characterized in that: In step S7, it also includes optical fiber position calibration to locate the optical fiber position in the target rock formation and obtain the position information of the optical fiber monitoring component.

Images