Roadway roof separation amount monitoring device and monitoring method based on optical sensing technology

Abstract

The invention discloses a roadway roof separation amount monitoring device and method based on an optical sensing technology. The roadway roof separation amount monitoring device comprises a bottom shell, an upper cover and an anchor rod pipe fixedly installed on the outer wall of the upper cover. An upper cover is detachably installed on the top of the bottom shell through a fixing base and an anti-loosening bolt, an installation base with a hexagonal clamping groove is integrally formed in the middle of the interior of the bottom shell, a connecting strip made of hollow aluminum alloy sleeves the installation base in an interference fit mode, a flange plate is welded to the tail end of the connecting strip, and positioning holes are evenly distributed in the surface of the flange plate. Four groups of lamp strip discs are fixed on the periphery of the outer wall of the connecting strip at equal intervals; and a lamp strip is wound in the lamp strip disc. According to the invention, high-precision and real-time dynamic monitoring of the separation amount of the roadway roof can be realized, underground complex environment interference can be effectively resisted, meanwhile, through an intelligent early warning function, the safety monitoring level of the mine roadway roof is remarkably improved, the risk of safety accidents is reduced, and reliable guarantee is provided for mine safety production.

Description

Technical Field

[0001] The present invention relates to the technical field of mine safety monitoring, and specifically to a roadway roof separation amount monitoring device and monitoring method based on optical sensing technology. Background Art

[0002] Traditional roadway roof separation monitoring technologies mainly include mechanical displacement gauges, resistance strain gauges, and early fiber Bragg grating sensors, etc.: Mechanical displacement gauges rely on manual reading, with a low monitoring frequency, an accuracy of only 1 mm, and are unable to adapt to the harsh underground environments of high dust and humidity, and are prone to mechanical component jamming. Although resistance strain gauge monitoring can achieve a certain degree of automation, the strain gauges are susceptible to temperature drift, and the underground vibration environment can cause the solder joints of the strain gauges to fall off, resulting in poor data reliability.

[0003] With the development of sensing technology, fiber Bragg grating sensors have begun to be applied to roof monitoring. It uses the wavelength encoding principle to measure displacement, and the theoretical accuracy can reach 0.01 mm, but there are the following technical bottlenecks: The fiber splicing process is complex, and the on-site maintenance difficulty underground is large. The single splicing takes about 30 minutes, is sensitive to the installation angle of the anchor rod. When the rock stratum dip angle exceeds 15°, the strain transfer efficiency of the fiber optic sensor drops by more than 20%. The cost is high, and the price of a single set of monitoring equipment is too high, making it difficult to promote on a large scale.

[0004] In addition, the complex underground environment poses a severe challenge to the reliability of the monitoring device: the dust concentration is high, and traditional optical components are easily contaminated, resulting in signal attenuation. The humidity is high, and electronic components are easily damaged by moisture. There is electromagnetic interference, affecting the stability of signal transmission.

[0005] The average trouble-free operation time of existing optical sensing monitoring devices in the above environment is less than 6 months, which cannot meet the requirements of long-term continuous monitoring in mines.

[0006] Therefore, how to provide a roadway roof separation amount monitoring device and monitoring method based on optical sensing technology is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] An object of the present invention is to provide a roadway roof separation amount monitoring device and monitoring method based on optical sensing technology. The present invention can achieve high-precision, real-time dynamic monitoring of the roadway roof separation amount, effectively resist the interference of complex underground environments, and at the same time, through the intelligent early warning function, significantly improve the safety monitoring level of mine roadway roofs, reduce the risk of safety accidents, and provide a reliable guarantee for mine safety production.

[0008] A tunnel roof separation monitoring device based on optical sensing technology according to an embodiment of the present invention comprises a bottom shell, an upper cover, and an anchor rod pipe fixedly installed on the outer wall of the upper cover; The top of the bottom shell is detachably mounted with an upper cover through a fixing seat and anti-loosening bolts. A mounting seat with a hexagonal slot is integrally formed in the center of the bottom shell. A hollow aluminum alloy connecting strip is sleeved on the mounting seat through an interference fit. A flange is welded at the end of the connecting strip. Positioning holes are evenly distributed on the surface of the flange, which is used to fix four sets of light strips at equal distances around the outer wall of the connecting strip. A light strip is wound inside the light strip reel, and four groups of ambient light sensors are distributed in a ring shape at 90° intervals with the mounting seat as the center on the inner wall of the bottom shell, and the center of the probe of each group of ambient light sensors is at the same height as the axis of the light strip reel and faces the light-emitting surface of the light strip; An anchor rod tube is fixedly installed in the center of the outer side of the upper cover, and an anchor plate for dispersing radial load is sleeved on the outer wall of the anchor rod tube. An inverted cone anchor head is fixedly installed on the other end of the anchor rod tube. One end of the four groups of light strips away from the light strip plate is fixedly connected to a steel wire rope through a copper crimping terminal. The steel wire rope runs through the anchor rod tube and the anchor head, and an angle-adjustable anchor claw is fixedly installed on the end; The outer wall of the light belt disk is provided with a spring seat, and the spring seat has a built-in spring. The spring spring is used to provide a constant tension of 6±0.3N for the light belt to ensure the position detection accuracy when the light belt moves with the wire rope. The tension calculation formula of the spring spring is: Spring torque ,in is the spring rotation angle, which is converted into linear tension T=M / r, where r is the radius of the light strip reel, so T=( ) / r, which ensures =0.75rad, T=6N, meeting the requirement of 6±0.3N constant tension, avoiding the light strip from loosening or over-stretching.

[0009] Furthermore, an aviation plug is embedded on the top of the bottom shell, and the aviation plug integrates a two-core 24V power line and a four-core shielded signal line, which is used to realize power supply and data transmission between the light strip and the ambient light sensor and the external power supply and signal processing module; The model of the ambient light sensor is APDS-9960, with a 525nm bandpass filter and a 20dB gain amplifier circuit integrated at the front end, and the half-bandwidth of the bandpass filter is ≤10nm, and the amplifier noise density is ≤1nV / √Hz, so that the sensor can detect the position of the light source with a resolution of 0.03mm. Most underground lighting sources are 400-500nm blue light and 600-700nm red light. 525nm is in the middle band, which can effectively filter out ambient light interference. The 20dB gain amplifier circuit amplifies the weak light signal to the detectable range, and cooperates with an amplifier with a noise density of ≤1nV / √Hz to ensure a signal-to-noise ratio of ≥30dB.

[0010] Furthermore, the docking edge of the bottom case and the upper cover is integrally formed with an annular fixing seat, which is connected by four groups of anti-loosening bolts. The anti-loosening bolts adopt a double-nut insert structure and are coated with thread locking agent. Together with a silicone rubber seal ring with a cross-sectional diameter of 3 mm, an IP66-level dustproof and waterproof sealing structure is formed. The sealing structure is tested under a positive pressure of 1.5 kPa, and the pressure decay within two hours is ≤5%.

[0011] Furthermore, the anchor claw adopts an X-shaped four-claw structure. A locking mechanism composed of a hinge joint and a locking bolt is provided at the end of a single claw, and the adjustable angle range is ±15°, which can meet the anchoring requirements for rock layer dip angles of 0° to 30°; Tungsten carbide alloy teeth are welded on the surface of the anchor claw body. The pulling resistance in the sandstone formation is ≥55 kN. The hardness of the tungsten carbide alloy teeth is ≥HV1500, and the tooth spacing is evenly distributed at 2 mm to enhance the biting ability of the rock layer.

[0012] When the angle of the anchor claw is adjusted to 15° and the tooth spacing is 2 mm, the contact stress distribution with the sandstone hole wall is uniform, the maximum stress is 120 MPa, and the simulated pulling resistance value is 58 kN.

[0013] Furthermore, the surface of the steel wire rope is coated with a polytetrafluoroethylene wear-resistant coating with a thickness of 0.3 mm, the diameter is 0.5 - 1.5 mm, and the tensile strength is not less than 2000 MPa. The steel wire rope adopts a stainless steel wire stranded structure. The steel wire rope adopts a 19-strand stainless steel wire stranded structure, with 7 Φ0.15 mm steel wires in each strand. The surface is coated with a polytetrafluoroethylene wear-resistant coating with a thickness of 0.3 mm, the diameter is 1.2 mm, the tensile strength is 2300 MPa, the elongation at break is ≤1.5%, and after 500,000 reciprocating friction tests, the coating thickness reduction is ≤10%.

[0014] Furthermore, the connecting bar is a hollow aluminum alloy rod with a length of 80 mm, and its inner wall is anodized. The flange and the connecting bar are welded by friction stir welding process, and the tensile strength of the weld is ≥300 MPa, ensuring that the coaxiality error of the installation of the four groups of lamp belt discs is ≤0.1 mm.

[0015] Furthermore, the width of the lamp belt is 8 mm, and its surface is covered with a temperature-resistant silicone layer. The minimum bending radius is 15 mm. The light-emitting surface of the lamp belt adopts diffuse reflection treatment, and the light-emitting angle is ≥120°, ensuring the full-angle detection of the light source position by the ambient light sensor.

[0016] Furthermore, the hexagonal card slot of the mounting seat is in interference fit with the connecting bar, and the fit tolerance is H7 / g6 to prevent the circumferential rotation of the connecting bar. Four groups of ambient light sensors are annularly distributed at 90° intervals centered on the mounting seat on the inner wall of the bottom case to form an X-Y plane rectangular coordinate system.

[0017] A monitoring method for the separation amount of the roadway roof based on optical sensing technology, comprising the following steps: S1. Device installation: Use an anchor drill to construct a hole in the roof, insert the anchor claw into the hole, adjust the locking mechanism to make the claw body fit the hole wall, inject a quick-hardening resin anchoring agent, and after curing, embed the connecting strip connected with the lamp belt reel into the mounting seat of the bottom shell, fasten the upper cover, and tighten the anti-loosening bolts in diagonal order to ensure that the sealing ring is evenly compressed to achieve IP66-level sealing; Use an anchor drill to construct a Φ32mm hole in the roof, determine the depth according to the monitoring layer, insert the anchor claw into the hole, adjust the articulated joint to make the claw body fit the hole wall, inject a quick-hardening resin anchoring agent, embed the connecting strip connected with the lamp belt reel into the hexagonal card slot of the bottom shell, fasten the upper cover, and tighten the anti-loosening bolts in diagonal order to ensure that the sealing ring is evenly compressed; S2. Connect to a 24V DC power supply through an aviation plug, light up the lamp belt for 5 minutes stably, the ambient light sensor collects the initial light intensity data at a frequency of 100Hz, fits the light source center position based on the least squares method, and establishes polar coordinate reference data; The method for establishing the polar coordinate reference data is: Take the center of the bottom shell as the origin O(0,0), and through the formula Calculate the initial center coordinates of the light source to eliminate the initial installation deviation, where Is the real-time detection coordinate of the sensor, eliminate the initial installation deviation, establish polar coordinate reference data, n is the number of sampling points, and n≥2000; S3. Real-time monitoring of the separation amount: When the roof rock formation displaces, the anchor claw drives the steel wire rope to move, the lamp belt is pulled out from the lamp belt reel or retracted under the action of the clockwork spring, the ambient light sensor captures the light source displacement signal at a frequency of 100Hz and converts it into an electrical signal, and transmits it to the external PLC through the RS485 bus; According to Lambert-Beer's law (k is the light source intensity constant, Is the distance from the light source to the sensor), establish an overdetermined system of equations, and solve the real-time coordinates of the light source through the least squares method , the separation amount ; S4. Dynamic warning and maintenance: The data processing unit presets three-level safety thresholds. When the separation amount Reaches the yellow warning 5mm≤ <10mm, trigger local audible and visual alarms and group text message notifications. When the orange warning 10mm≤ <15mm, link the voice broadcast with the data interaction of the dispatching center. When the red warning ≥15mm, cut off the non-safe power supply in the area and encrypt and upload it to the group monitoring platform, and at the same time regularly check the wear of the steel wire rope and the locking state of the anchor claw.

[0018] Further, the PLC calculates the separation amount through a triangulation algorithm combined with Kalman filtering, specifically as follows: Establish a mathematical model of the distance from the light source to the sensor and the light intensity according to Lambert-Beer's law , and solve the real-time coordinates of the light source by the least squares method , the separation amount , and improve the positioning accuracy to the 0.05 mm level through Kalman filtering.

[0019] The beneficial effects of the present invention are as follows: 1. In the present invention, four groups of ambient light sensors are distributed in a 90° ring, and cooperate with the light strip disk structure integrated with a spring. The position change of the light source of the light strip can be captured in real time. Among them, under the action of a constant tension of 6±0.3 N, the position change of the light strip when moving with the steel wire rope can be accurately sensed by the sensor. Combined with the triangulation algorithm, the detection accuracy of the light source position of 0.05 mm level is achieved, ensuring the effective monitoring of the 0.1 mm level fine separation displacement of the roof rock stratum, and cooperating with the IP66 level dust and waterproof sealing structure, significantly suppressing the interference of underground dust, moisture and stray light; 2. The monitoring method in the present invention integrates functions of dynamic calibration, real-time calculation and multi-level early warning, constructs a full-process intelligent monitoring system, establishes polar coordinate reference data by the least squares method during the installation stage to eliminate the initial installation deviation, and in the monitoring process, the light intensity signal is collected in real time at a sampling frequency of 100 Hz, transmitted to the PLC through the RS485 bus for triangulation operation, realizing the dynamic display of the separation amount curve once per second and the traceability of 365-day historical data. The three-level safety threshold mechanism constructs a gradient risk response system. The yellow early warning triggers local audible and visual alarms and team text message notifications, the orange early warning is linked with voice broadcasts and data interactions with the dispatching center, and the red early warning directly cuts off the non-safe power supply in the area and encrypts and uploads it to the group monitoring platform, forming a three-dimensional safety protection from local early warning to global control. Description of the Drawings

[0020] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention, and do not constitute a limitation to the present invention. In the drawings: Figure 1 is a schematic diagram of the overall structure of a roadway roof separation amount monitoring device based on optical sensing technology proposed by the present invention; Figure 2 is a split structure diagram of a roadway roof separation amount monitoring device based on optical sensing technology proposed by the present invention; Figure 3 is a connection structure diagram of the light strip and the steel wire rope of a roadway roof separation amount monitoring device based on optical sensing technology proposed by the present invention; Figure 4Flowchart of the usage method of a roadway roof separation monitoring device based on optical sensing technology proposed by the present invention.

[0021] In the figure: 1. Bottom shell; 2. Upper cover; 3. Anchor rod tube; 4. Anchor tube grid; 5. Anchor head; 6. Anchor plate; 7. Connecting bar; 8. Spring seat; 9. Light strip disc; 10. Light strip; 11. Aviation plug; 12. Anchor claw; 13. Flange plate; 14. Ambient light sensor; 15. Steel wire rope; 16. Fixed seat; 17. Anti-loosening bolt; 18. Mounting seat. Detailed implementation manners

[0022] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0023] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. If there is any inconsistency, it shall be based on the meaning described in this specification or the meaning obtained according to the content recorded in this specification. In addition, the terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0024] The following will describe the implementation manners of the present invention in detail with reference to the drawings.

[0025] As Figures 1 - 3 shown, a roadway roof separation monitoring device based on optical sensing technology includes a bottom shell 1, an upper cover 2 and an anchor rod tube 3; The bottom shell 1 is made of high-strength aluminum alloy material, and the inner wall is anodized with a thickness of 20 μm. The docking edge between the bottom shell 1 and the upper cover 2 is integrally formed with an annular fixing seat 16. The upper cover 2 and the bottom shell 1 are connected by 4 groups of M8 anti-loosening bolts 17. The bolts adopt a double-nut insert structure, and the thread surface is coated with Loctite 243 locking agent. Cooperating with a silicone rubber seal ring with a cross-sectional diameter of 3 mm, an IP66-level dustproof and waterproof sealing structure is formed. In the center of the bottom shell 1, a cylindrical mounting seat 18 is injection-molded, and a hexagonal card slot is opened at the top, which is in interference fit with the connecting strip 7 to prevent circumferential rotation.

[0026] The connecting strip 7 is a hollow aluminum alloy rod with a length of 80 mm. A circular flange 13 is welded at the end, and 4 groups of positioning holes are evenly distributed on the surface. 4 groups of lamp belt reels 9 are fixed by M5 bolts. The lamp belt reel 9 is a cylindrical reel with a diameter of Φ50 mm × 30 mm. A spring seat 8 is sleeved on the outer wall, and a clockwork spring is integrated inside to provide a constant tension of T = 6 N ( = 0.75 rad); One end of the spring is fixed to the inner wall of the spring seat by a pin, and the other end is key-connected to the reel shaft to provide a constant tension of 6 ± 0.3 N for the lamp belt 10. The lamp belt 10 uses a flexible LED light source, with a width of 8 mm, and the surface is covered with a heat-resistant silicone layer. The minimum bending radius is 15 mm, and it can withstand 100,000 times of tensile fatigue tests when wound on the reel.

[0027] Taking the mounting seat as the center, 4 groups of ambient light sensors 14 are annularly distributed at 90° intervals on the inner wall of the bottom shell 1. Taking the center of the bottom shell as the origin O(0, 0), the direction of one group of sensors is the positive direction of the X-axis, and the direction of the other group of sensors perpendicular to it is the positive direction of the Y-axis, thus forming a rectangular coordinate system in the X-Y plane. This coordinate system is used for subsequent precise calculation of the position coordinates of the light source in the plane. The detection range of the ambient light sensor 14 is 0.01 - 188000 lx, the resolution is 0.01 lx, the response time ≤ 15 ms, the center of the sensor probe is at the same height as the axis of the lamp belt reel 9, and it is directly opposite to the light-emitting surface of the lamp belt 10. The sensor communicates with an external signal processing module through the RS485 bus, with a sampling frequency of 100 Hz, and the detection accuracy of the light source position change can reach 0.05 mm. An M12 waterproof aviation plug is embedded on the side of the bottom shell 1 as the aviation plug 11, and 2-core 24V power lines and 4-core shielded signal lines are integrated inside. The plug is equipped with a metal locking nut to ensure reliable connection in the downhole vibration environment; Among them, the four groups of ambient light sensors 14 are of the model APDS-9960, integrating an infrared filter, ambient light sensing and proximity detection functions, with a detection range of 0.01 - 188000 lx, a resolution of 0.01 lx, and a response time ≤ 15 ms.

[0028] Specifically, a rectangular coordinate system in the X-Y plane is formed by the four groups of sensors, and the coordinates of the four groups of sensors are respectively: (50, 0), (0, 50), (-50, 0), (0, -50) (unit: mm). At the same time, taking the center of the bottom shell as the origin O(0, 0), through the formula: ;

[0029] (n≥2000) to calculate the initial center coordinates of the light source, establish the polar coordinate reference data, which is used to eliminate the initial installation deviation and provide a reference for subsequent separation monitoring.

[0030] The center of the top surface of the upper cover 2 is welded with a bolt pipe 3, and the inner wall is plated with hard chromium to reduce the friction of the wire rope. A circular anchor plate 6 is sleeved on the outer wall of the bolt pipe, and is positioned by the shaft shoulder to disperse the radial load during anchoring. The end of the bolt pipe is welded with an anchor head 5, which is in an inverted conical shape and has an interference fit with the bolt pipe. A diversion groove is provided in the internal rope-passing hole to guide the wire rope 15 to pass through smoothly.

[0031] The wire rope 15 is a 19-strand stainless steel wire rope with a diameter of 1.2 mm, and the surface is coated with a 0.3-mm polytetrafluoroethylene wear-resistant coating. The tensile strength is 2300 MPa, and it can withstand 500,000 reciprocating frictions without wire breakage after underground simulation tests. One end of the wire rope is fixed to the lamp strip 10 through a copper crimping terminal, and the other end passes through the anchor head 5 and then connects to the anchor claw 12. The anchor claw 12 adopts an "X"-shaped four-claw structure, the single-claw length is 70 mm, and a hinge joint is provided at the end, which is fixed by an M8 locking bolt, and can adapt to the rock stratum dip angle of 0° to 30°. Tungsten carbide alloy teeth are welded on the surface of the claw body, and the pull-out resistance in the sandstone stratum is ≥55 kN.

[0032] Specifically, in the soft rock stratum, the angle of the anchor claw can be adjusted to 0°, a wire rope with a diameter of 1.5 mm is used, and the thickness of the anchor plate 6 is increased to 15 mm to disperse the load; in the hard rock stratum, the angle of the anchor claw can be adjusted to 30°, the tooth pitch is reduced to 1.5 mm, and a quick-setting cement anchor agent is injected to improve the initial anchoring force.

[0033] As Figure 4 shown, the monitoring method of the roadway roof separation monitoring device based on the optical sensing technology is as follows: S1. Device installation: First, use a rock bolt drill to construct a Φ32-mm hole in the roof, and the depth is determined according to the monitoring horizon. For example, for 2-m and 4-m stratified monitoring, insert the anchor claw 12 into the hole through the bolt pipe 3, adjust the hinge joint so that the claw body fits the hole wall, inject a quick-hardening resin anchor agent, and the curing time ≤90 s. After the anchor head 5 forms a mechanical bite with the rock stratum, embed the connecting strip 7 connected with the lamp strip disc 9 into the mounting seat 18 of the bottom shell 1, close the upper cover 2 and tighten the anti-loosening bolts 17 in the diagonal order to ensure that the sealing ring is evenly compressed; S2. Calibration of the light strip and the sensor: Connect to a 24V DC power supply through a aviation plug, light up the light strip for 10 minutes and stabilize for 5 minutes. The ambient light sensor collects 2000 initial light intensity data in the X-Y plane rectangular coordinate system at a frequency of 100Hz. Based on these data, use the formula: , ; where, ( , ) represent the estimated values or means of x and y respectively, is the real-time detection coordinate of the sensor, is the number of sampling points (n = 2000). Using this formula, the center position of the light source is fitted by the least squares method, the initial center coordinates of the light source are calculated, and the polar coordinate reference data is established to eliminate the initial installation deviation. At this time, the polar coordinate reference data can be calculated based on the light intensity data in the X-Y plane rectangular coordinate system and is used to calibrate the monitoring starting point and calculate the zero-point offset , , if or exceeds 0.1mm, the automatic calibration program is triggered until the offset is less than the threshold. The reference data is stored in the external PLC controller as the reference for subsequent monitoring; S3. Real-time monitoring of the separation amount: When the roof rock stratum undergoes relative displacement, the anchor claw drives the steel wire rope to be pulled outwards or retracts under the tension of the hairspring. The light strip 10 moves synchronously with the steel wire rope, and the position of the light source generates a radial displacement relative to the sensor array in the X-Y plane rectangular coordinate system . The ambient light sensor collects the light intensity signal at a frequency of 100Hz and transmits it to the PLC through the RS485 bus. The PLC calculates the light source displacement in the X-Y plane rectangular coordinate system based on the triangulation algorithm. The specific steps are as follows: ① Establish the sensor array coordinate system. The coordinates of the four groups of sensors are (50, 0), (0, 50), (-50, 0), (0, -50) (unit: mm); ② Real-time detect the light intensity values of each sensor . According to the Lambert-Beer law, the light intensity is inversely proportional to the square of the distance, that is , where, is the light intensity value detected by the i-th group of sensors, k is the light source intensity constant, is the distance from the light source to the i-th group of sensors; ③ Through the light intensity values detected by the four groups of sensors, combined with the positions of the sensors in the X-Y plane rectangular coordinate system, construct the equations: ; Solve the above equations by the least squares method to obtain the real-time coordinates of the light source , so as to calculate the amount of separated strata , after 2000 times of laboratory calibration, the algorithm error ≤ 0.2 mm; and both the coordinate calculation and the separated strata amount calculation are based on the X-Y plane rectangular coordinate system, ensuring the accuracy and consistency of the calculation; It should be noted that by using Kalman filtering to denoise the sensor data and combining with the moving window average, the positioning accuracy can be further improved to the 0.05 mm level; Specifically, for the noise reduction of the Kalman filtering algorithm, the state equation is: Among them, , are the coordinates of the light source in the X and Y directions at time k, and are respectively the position coordinates of the target in the X-axis and Y-axis directions at the discrete time point time, that is, at the previous moment of the current moment k, and are respectively the velocities of the target in the X-axis direction and Y-axis direction, reflecting the motion state of the target. T represents the sampling period, that is, the time interval between two adjacent discrete time points, and T = 0.01 s, and are process noises, respectively representing the deviations between the actual state and the ideal state in the X-axis direction and Y-axis direction due to various uncertain factors in the system, and the mean square error of the process noise is 0.01 mm, and the positioning accuracy is at the 0.05 mm level; ④ The data processing unit displays the separated strata amount curves of each layer in real time and stores the data in the SQL Server database; S4. Dynamic warning and maintenance: The data processing unit compares with the safety threshold. When the data processing unit judges whether the separated strata amount exceeds the limit, it is based on the separated strata amount data calculated in the X-Y plane rectangular coordinate system. If the separated strata amount exceeds the limit, it triggers an audible and visual alarm and pushes a remote warning message, and regularly checks the wear condition of the steel wire rope and the locking state of the anchor claws; Among them, the safety threshold is specifically a three-level safety threshold to achieve a gradient risk response: Yellow warning (5 mm ≤ <10 mm): The local audible and visual alarm is activated, the red warning light flashes, and at the same time, a text message warning is sent to the team leader through the 4G module. The text message content includes the measuring point position, the real-time separated strata amount, and the timestamp.

[0034] Orange warning (10 mm ≤ <15 mm): In addition to the yellow warning measures, the roadway voice broadcast system is linked to play the message "Roof separation warning, please immediately evacuate the working area and check for hidden dangers" in a loop, and at the same time, a warning frame in the ModbusTCP protocol is sent to the mine dispatching center. The monitoring software of the dispatching center automatically pops up a warning window and flashes for prompt.

[0035] Red Alert ( ≥15mm): trigger an emergency stop signal, cut off the power supply of non-intrinsically safe electrical equipment in the area through the PLC control relay, and push encrypted data to the group company's safety monitoring platform through industrial Ethernet, including the three-dimensional coordinates of the measuring point, the delamination change curve, the stress status of the anchor rod and other information. The platform automatically generates an emergency plan and notifies the emergency command center.

[0036] Working principle: After the device uses the anchor drill to drill a hole in the roof, the X-shaped four-claw anchor claw 12 is inserted into the hole. The hinged joint at the end of the single claw of the anchor claw 12 can be adjusted to an angle of ±15°. The locking bolt fits the hole wall and injects a fast-hardening resin anchoring agent to form a mechanical bite structure. When different rock layers on the roof are relatively displaced, the anchor claw 12 moves with the target rock layer, directly driving the connected wire rope 15 to produce axial stretching or contraction movement. When the roof is separated from the layer, the anchor claw 12 moves with the rock layer, driving the connected wire rope 15 to move, and the wire rope 15 pulls or releases the light strip 10. The spring spring on the light strip disk 9 provides constant tension for the light strip 10 to ensure that the movement of the light strip 10 is consistent with the position of the roof. The four groups of ambient light sensors 14 arranged with the center as the origin in the bottom shell 1 detect the light intensity emitted by the light strip 10. The position of the light strip 10 changes due to the delamination of the top plate, and the light intensity detected by each sensor also changes accordingly. Subsequently, a group of equations is established based on the Lambert-Beer law and the sensor light intensity data, and the least squares method is used to solve the position coordinates of the light strip 10, the delamination amount is calculated, and the extended Kalman filter algorithm is used to process the data to reduce underground noise interference. Finally, the data processing unit compares the calculated delamination amount with the preset three-level safety threshold. When different thresholds are reached, corresponding sound and light alarms, SMS notifications, voice broadcasts, power cuts and other early warning and control measures are triggered respectively.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A tunnel roof separation monitoring device based on optical sensing technology, characterized in that: It comprises a bottom shell (1), an upper cover (2), and an anchor rod tube (3) fixedly mounted on the outer wall of the upper cover (2); The top of the bottom shell (1) is detachably mounted with an upper cover (2) via a fixing seat (16) and anti-loosening bolts (17); a mounting seat (18) with a hexagonal slot is integrally formed in the center of the bottom shell (1); a hollow connecting strip (7) made of aluminum alloy is sleeved on the mounting seat (18) via an interference fit; a flange (13) is welded to the end of the connecting strip (7); positioning holes are evenly distributed on the surface of the flange (13) for fixing four sets of light strips (9) at equal distances around the outer wall of the connecting strip (7); A light strip (10) is wound inside the light strip reel (9), and four groups of ambient light sensors (14) are distributed in a ring shape at 90° intervals with the mounting seat (18) as the center on the inner wall of the bottom shell (1), and the center of the probe of each group of ambient light sensors (14) is at the same height as the axis of the light strip reel (9) and faces the light-emitting surface of the light strip (10); An anchor rod tube (3) is fixedly installed in the center of the outer side of the upper cover (2); an anchor plate (6) for dispersing radial load is sleeved on the outer wall of the anchor rod tube (3); an inverted cone anchor head (5) is fixedly installed at the other end of the anchor rod tube (3); one end of the four groups of light strips (10) away from the light strip plate (9) is fixedly connected to a steel wire rope (15) through a copper crimping terminal; the steel wire rope (15) passes through the anchor rod tube (3) and the anchor head (5); an angle-adjustable anchor claw (12) is fixedly installed at the end; The outer wall of the light strip disk (9) is provided with a spring seat (8), and the spring seat (8) has a built-in spring for providing a constant tension of 6±0.3N for the light strip (10), so as to ensure the position detection accuracy of the light strip (10) when it moves with the steel wire rope (15).

2. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: An aviation plug (11) is embedded on the top of the bottom shell (1), and the aviation plug (11) integrates a two-core 24V power line and a four-core shielded signal line, which are used to realize power supply and data transmission between the light strip (10) and the ambient light sensor (14) and the external power supply and signal processing module; The front end of the ambient light sensor (14) is integrated with a 525nm bandpass filter and a 20dB gain amplifier circuit, the half bandwidth of the bandpass filter is ≤10nm, and the amplifier noise density is ≤1nV / √Hz, so that the sensor's detection resolution of the light source position reaches 0.03mm.

3. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: The bottom shell (1) and the upper cover (2) are integrally formed with an annular fixing seat (16) at the butt edge thereof and are connected via four sets of anti-loosening bolts (17). The anti-loosening bolts (17) are double-nut insert structures and coated with thread locking agent, and are matched with a silicone rubber sealing ring with a cross-sectional diameter of 3 mm to form an IP66-level dustproof and waterproof sealing structure. The sealing structure has been tested with a positive pressure of 1.5 kPa, and the pressure decay within two hours is ≤5%.

4. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: The anchor claw (12) adopts an X-shaped four-claw structure, and a locking mechanism consisting of an articulated joint and a locking bolt is provided at the end of a single claw, and the adjustable angle range is ±15°, which is suitable for anchoring requirements with a rock formation inclination angle of 0° to 30°; The surface of the anchor claw (12) is welded with tungsten carbide alloy teeth, and the pull-out resistance in sandstone formations is ≥55kN. The hardness of the tungsten carbide alloy teeth is ≥HV1500, and the teeth are evenly distributed with a spacing of 2mm to enhance the rock formation bite ability.

5. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: The surface of the steel wire rope (15) is coated with a polytetrafluoroethylene wear-resistant coating with a thickness of 0.3 mm, the diameter is 0.5-1.5 mm, the tensile strength is not less than 2000 MPa, and the steel wire rope (15) adopts a stainless steel wire twisted structure.

6. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: The connecting strip (7) is a hollow aluminum alloy rod with a length of 80 mm and an inner wall that is anodized. The flange (13) and the connecting strip (7) are welded by a friction stir welding process, and the tensile strength of the weld is ≥300 MPa, ensuring that the installation coaxiality error of the four sets of light strips (9) is ≤0.1 mm.

7. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: The light strip (10) is 8 mm wide, the surface is covered with a temperature-resistant silicone layer, the minimum bending radius is 15 mm, the light-emitting surface of the light strip (10) is treated with diffuse reflection, and the light-emitting angle is ≥120°, ensuring that the ambient light sensor (14) can detect the position of the light source at all angles.

8. The tunnel roof separation monitoring device based on optical sensing technology according to claim 1 is characterized in that: The hexagonal slot of the mounting seat (18) is interference-fitted with the connecting strip (7), and the fitting tolerance is H7 / g6, so as to prevent the connecting strip (7) from rotating in the circumferential direction. The inner wall of the bottom shell (1) is provided with four groups of ambient light sensors (14) distributed in a ring at 90° intervals with the mounting seat (18) as the center, and the center of the bottom shell is taken as the origin O(0,0), wherein the direction of one group of sensors is the positive direction of the X axis, and the direction of another group of sensors perpendicular thereto is the positive direction of the Y axis, thereby forming an XY plane rectangular coordinate system.

9. A monitoring method for a tunnel roof separation monitoring device based on optical sensing technology according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Installation of the device: Drill a hole in the top plate using an anchor drill, insert the anchor claw (12) into the hole and adjust the locking mechanism so that the claw body fits the hole wall. After the quick-hardening resin anchoring agent is injected and cured, the connecting strip (7) connected to the light belt disk (9) is embedded in the mounting seat (18) of the bottom shell (1), the upper cover (2) is buckled and the anti-loosening bolts (17) are tightened in diagonal order to ensure that the sealing ring is evenly compressed to achieve IP66 level sealing; S2, connect a 24V DC power supply through the aviation plug (11), light the light strip (10) and stabilize it for 5 minutes, the ambient light sensor (14) collects initial light intensity data at a frequency of 100 Hz, fits the center position of the light source based on the least squares method, and establishes polar coordinate reference data; The polar coordinate reference data is established by taking the center of the bottom shell as the origin O(0,0), and using the formula Calculate the initial center coordinates of the light source to eliminate the initial installation deviation, where: is the initial center coordinate of the light source, is the real-time detection coordinate of the sensor, n is the number of sampling points and n≥2000, and the initial installation deviation is eliminated by the least squares method; S3, real-time monitoring of delamination: when the top rock layer is displaced, the anchor claw (12) drives the wire rope (15) to move, the light strip (10) is pulled out from the light strip disc (9) or reeled in under the action of the spring, and the ambient light sensor (14) captures the light source displacement signal at a frequency of 100 Hz and converts it into an electrical signal, which is transmitted to the external PLC via the RS485 bus; S4, dynamic warning and maintenance: the data processing unit presets three levels of safety thresholds. Reach yellow warning 5mm≤ <10mm, trigger local sound and light alarm and team SMS notification, orange warning 10mm≤ When the diameter is less than 15 mm, voice broadcast and dispatch center data interaction will be triggered, and red warning will be issued. When the diameter is ≥15 mm, the non-safety power supply in the area is cut off and the encrypted data is uploaded to the group monitoring platform. At the same time, the wear of the wire rope (15) and the locking status of the anchor claw (12) are regularly checked.

10. The monitoring method of the tunnel roof separation monitoring device based on optical sensing technology according to claim 9 is characterized in that: The PLC calculates the separation amount by using a triangulated positioning algorithm combined with a Kalman filter, specifically: Establish a mathematical model of the distance from the light source to the sensor and the light intensity based on the Lambert-Beer law ,in, is the light intensity value detected by the i-th group of sensors, k is the light source intensity constant, is the distance from the light source to the sensor, and the real-time coordinates of the light source are solved by the least squares method , the amount of separation And the positioning accuracy is improved to 0.05mm level through Kalman filtering.

Images