A roadway global anchor rod cable anchoring force real-time monitoring system and method

Abstract

This invention provides a real-time monitoring system and method for the anchoring force of anchor bolts / cables throughout a roadway. Anchor bolts / cables are installed in boreholes in the roadway roof and sidewalls. The outer surface of the spherical crown portion of the tray, excluding the locking nut, serves as a ring-shaped monitoring area. A force gauge is positioned between the locking nut and the tray. A shotcrete-sensing composite layer includes a shotcrete layer and a micro-thin-film strain sensor array. An in-road processing terminal is connected to the micro-thin-film strain sensor array. A ground processing terminal is connected to the in-road processing terminal via a relay transmission device. The method involves simultaneously installing the force gauge and intelligent sensing unit during anchor bolt / cable installation; applying a design preload; receiving strain sequence signals and transmitting them to the ground processing terminal; obtaining strain force data through a strain-axial force calibration model and providing graded early warnings. This system and method enable unmanned, real-time, and intelligent monitoring of the anchoring force status of anchor bolts / cables throughout a roadway.

Description

Technical Field

[0001] This invention belongs to the field of coal mine roadway support safety monitoring technology, specifically a real-time monitoring system and method for the anchoring force of anchor cables throughout the roadway. Background Technology

[0002] Monitoring the stability of surrounding rock in coal mine roadways is a core aspect of ensuring safe mine production, with the anchoring force of bolt cables being a key indicator for evaluating support effectiveness. Current technologies suffer from significant limitations: First, insufficient spatial coverage and poor real-time performance. Mainstream methods rely on discretely deploying single-point bolt force gauges or surface displacement gauges at key locations, making it difficult to achieve continuous monitoring of the entire roadway roof and sidewall support system. Wired transmission methods are complex and prone to damage, resulting in severe data acquisition delays and failing to meet the need for rapid early warning of dynamic rock instability. Second, low automation and reliance on manual operation. Existing wireless monitoring technologies (such as wireless bolt force gauges) avoid wiring but are expensive and still require manual handheld data collection. While monitoring technologies based on mechanochromic materials reduce sensor costs, they still rely on manual handheld devices to scan the color signals of bolt trays point by point. These methods are inefficient for inspection, cannot achieve continuous real-time monitoring, are easily affected by the underground environment, and struggle to capture instantaneous deformation of the surrounding rock. Third, insufficient data reliability and analytical depth. Single-point sensors or manually collected data are susceptible to local interference and lack effective noise filtering mechanisms. Existing methods focus on judging the stress of a single anchor bolt, lacking intelligent identification methods for the coordinated stress state of anchor bolt groups across the entire roadway and potential instability areas, resulting in a high false alarm rate.

[0003] While technological improvements in recent years have increased coverage density to some extent, several technical bottlenecks remain: First, sensor network deployment is limited. The size and power supply methods of traditional sensors restrict high-density integration. The high cost of wireless anchor bolt force gauges and the manual dependence of force-sensitive films hinder full-area coverage. Second, reliable real-time transmission across the entire area is difficult to achieve. The complex underground environment makes it impossible for existing technologies (including handheld terminal point-to-point communication) to build a stable, low-latency automated transmission network. Finally, intelligent analysis and early warning capabilities are weak. The lack of real-time noise filtering, spatial collaborative analysis, and dynamic threshold algorithms makes it difficult to accurately predict instability risks.

[0004] To address the urgent need for comprehensive, real-time sensing, automatic monitoring, and precise early warning of roadway surrounding rock support systems, three major bottlenecks urgently need to be overcome: First, constructing a high-density, in-situ integrated, reliable sensor network to overcome the constraints of high cost and reliance on manual labor. Second, designing a comprehensive wireless real-time transmission architecture that requires no manual intervention. Third, developing intelligent early warning algorithms to achieve a leap from discrete manual interpretation to comprehensive collaborative intelligent early warning. Therefore, there is an urgent need to provide a real-time monitoring system and method for the anchoring force of roadway anchor bolts across the entire area. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a real-time monitoring system and method for the anchoring force of anchor bolts and cables throughout a roadway. The system has a simple structure and a high degree of intelligence, enabling accurate monitoring of the anchor bolt / cable support status throughout the roadway. The method is simple to implement, has low implementation cost, and a high degree of intelligence, enabling unmanned, real-time, and intelligent monitoring of the anchoring force status of anchor bolts and cables throughout the roadway.

[0006] To achieve the above objectives, the present invention provides a real-time monitoring system for the anchoring force of anchor cables throughout a roadway, comprising an anchoring assembly, a force gauge, an intelligent monitoring unit, a processing terminal within the roadway, a relay transmission device, a ground processing terminal, and an alarm module.

[0007] The anchoring assembly includes an anchor bolt / anchor cable, a tray, and a locking nut. The anchor bolt / anchor cable is installed in boreholes in the roadway roof and roadway sidewalls. The locking nut locks the tray to the end of the anchor bolt / anchor cable. The outer surface of the spherical crown portion of the tray, excluding the locking nut, serves as an annular monitoring area.

[0008] The force gauge is positioned between the locking nut and the tray and is connected to a display.

[0009] The intelligent monitoring unit includes a spray-sensing composite layer; the spray-sensing composite layer includes a spray layer and a micro-thin-film strain sensor array. The spray layer covers the outer surface of the annular monitoring area on the tray. The micro-thin-film strain sensor array is disposed in the spray layer and includes multiple micro-thin-film strain sensors. The micro-thin-film strain sensor includes a MEMS resistance strain gauge, a micro battery, a microprocessor, and a wireless communication module. The microprocessor is connected to the MEMS resistance strain gauge, the micro battery, and the wireless communication module.

[0010] The in-tunnel processing terminal includes a controller, a second wireless communication module, and a display module. The controller is connected to the second wireless communication module and the display module, respectively. The in-tunnel processing terminal is set in the tunnel and is connected to the micro-thin film strain sensor array through a wireless communication link between the first wireless communication module and the second wireless communication module.

[0011] The relay transmission device is installed in the tunnel and is connected to the processing terminal in the tunnel via wireless communication.

[0012] The ground processing terminal is located in the ground monitoring center and is connected to the relay transmission equipment via wired communication.

[0013] The alarm module is located in the ground monitoring center and connected to the ground processing terminal.

[0014] As a preferred embodiment, both wireless communication module one and wireless communication module two are LoRa wireless communication modules.

[0015] As a preferred embodiment, the micro battery is a micro zinc-air battery.

[0016] As a preferred embodiment, the dimensions of the micro-thin film strain sensor are ≤8mm×8mm×0.5mm.

[0017] As a preferred embodiment, the thickness of the spray-sensor composite layer is 2 to 3 mm.

[0018] Furthermore, to ensure measurement accuracy, the number of micro-thin film strain sensors in the spray-sensing composite layer is 20 to 40.

[0019] In this invention, a force gauge with a display is installed between the locking nut and the tray, allowing for direct observation of the applied preload value during the application of preload to the anchor bolts / cables, ensuring the accuracy of preload application. A shotcrete-sensor composite layer is covered in the annular monitoring area on the tray, and a micro-thin-film strain sensor array is installed within this layer. This direct contact between the micro-thin-film strain sensor array and the tray facilitates real-time acquisition of strain force signals at various points on the tray during anchor component support, enabling the acquisition of strain force data at different points on the tray surface based on these signals. An in-tunnel processing terminal is installed within the tunnel, facilitating the centralized collection of strain force signals from several anchor bolts / cables within a defined monitoring range. This data is then centrally transmitted to a relay transmission device. The relay transmission device within the tunnel also facilitates the establishment of a communication connection between the in-tunnel processing terminal located underground and the ground processing terminal located at a remote monitoring center, ensuring real-time and reliable data transmission. By setting up a ground processing terminal, strain force data can be easily preprocessed. Simultaneously, it facilitates the extraction of axial pressure data for anchor bolts and cables based on the obtained strain force data. Furthermore, it can generate an axial force heat map based on the axial pressure data of all anchor bolts and cables within the monitoring range. This allows for a direct and comprehensive observation of the overall support situation, facilitating accurate assessment of the safety and stability of the tunnel support. Through the alarm module settings, different levels of early warning actions can be executed according to the control of the ground processing terminal, effectively alerting relevant management personnel.

[0020] The system has a simple structure and a high degree of intelligence, enabling precise monitoring of the support status of anchor bolts / anchor cables throughout the entire roadway.

[0021] This invention also provides a method for a real-time monitoring system of anchor cable anchoring force across the entire tunnel, comprising the following steps:

[0022] Step 1: Install anchor bolts / anchor cables on the roof and sides of the tunnel using lock nuts and trays. The outer surface of the spherical crown in the tray, excluding the lock nuts, serves as a ring-shaped monitoring area.

[0023] During the installation of anchor bolts / anchor cables, a force gauge and an intelligent monitoring unit are installed simultaneously. The force gauge is placed between the locking nut and the tray, and the intelligent monitoring unit includes a shotcrete-sensing composite layer that covers the outer surface of the annular monitoring area.

[0024] Step 2: Apply preload to each anchor bolt / cable and monitor the preload value in real time using a force gauge. The preload is released when it reaches the designed preload. Stop at this time;

[0025] Step 3: Use the processing terminal in the tunnel to collect the real-time strain sequence signal of each anchor bolt / anchor cable at a set sampling frequency A. And it is transmitted to the ground processing terminal via relay transmission equipment;

[0026] Step 4: The ground processing terminal receives the real-time strain sequence signal of each anchor bolt / anchor cable. Then, first, remove the data points that satisfy formula (1), and then convert the strain values ​​into the axial pressure values ​​of each anchor rod / cable according to the strain-axial force calibration model in formula (2). And based on the obtained axial pressure value, generate a full-area axial force thermogram of anchor bolts / anchor cables within the monitoring range;

[0027] (1);

[0028] In the formula, The average strain value of multiple micro-thin film strain sensors in the spray-sensing composite layer; This represents the standard deviation of axial pressure.

[0029] (2);

[0030] In the formula, The strain data is collected by a micro-thin film strain sensor; K is the strain correction coefficient, and n and C are constants.

[0031] Step 5: Ground treatment terminal based on axial pressure value Implement tiered early warning systems;

[0032] When a single anchor bolt / anchor cable meets the requirements When the alarm module triggers a yellow alert, the control module will activate the yellow alert. When five adjacent anchor bolts / cables meet the requirements... At that time, the control alarm module executes a red alert action; among which, It represents the yield strength.

[0033] As a preferred embodiment, in step one, the spray-sensor composite layer is made by the following method: multiple micro-thin film strain sensors are incorporated into quick-setting cement material to form a composite material, and then the composite material is adhered to the outer surface of the annular monitoring area, and after curing, the spray-sensor composite layer is formed.

[0034] As a preferred option, in step five, when the cumulative number of red alerts triggered in a single month... At that time, or when the measured displacement of the top plate At that time, the ground processing terminal issued a command to carry out reinforcement support, among which, The span of the tunnel.

[0035] As a preferred embodiment, in step five, when the axial pressure change rate... At that time, the ground processing terminal sends a dense sampling signal to the processing terminal in the roadway through the relay transmission equipment. After receiving the dense sampling signal, the processing terminal in the roadway collects the real-time strain sequence signal of each anchor bolt / anchor cable at a set sampling frequency B. Where the sampling frequency B is less than the sampling frequency A.

[0036] This invention addresses multiple technical bottlenecks in traditional roadway anchor bolt / cable stress monitoring, including insufficient full-area coverage, poor real-time performance, and low level of intelligence. It proposes a real-time monitoring method for the anchoring force of anchor bolts / cables across the entire roadway area. First, a large number of micro-thin-film strain sensors are incorporated into a quick-setting cement slurry and then uniformly coated onto the surface of a monitoring tray to form a uniformly covered composite monitoring layer. This allows the stress sensors to directly contact the tray surface, effectively sensing micro-deformations at various points on the tray. Second, a processing terminal within the roadway collects strain sequence signals from multiple anchor bolts / cables within the monitoring range at a set sampling frequency. These signals are then transmitted centrally to a ground processing terminal via a relay transmission device. The ground processing terminal, combined with the initial calibration of the anchor bolt force gauge, establishes a strain-axial force mapping model, enabling real-time inversion of the anchor bolt / cable stress state. Finally, a hierarchical intelligent prevention and control mechanism is formed by triggering a yellow alert through single-point axial force exceeding the limit, and triggering a red alert through coordinated exceeding of limits by adjacent anchor bolt groups or regional anomalies. This invention breaks through the limitations of traditional local single-point monitoring and achieves for the first time automated, visualized, and real-time monitoring of the stress on anchor cables throughout the entire roadway. Through three major technological innovations—integrated sensing in the shotcrete layer, wireless networking transmission, and collaborative early warning—it significantly improves the timeliness and reliability of surrounding rock stability control, providing proactive technical support for mine safety.

[0037] Compared with the prior art, the present invention has the following advantages:

[0038] 1) Seamless monitoring of anchor bolt / cable stress status across the entire roadway: Through deep integration of micro-sensors with the shotcrete layer, a high-density monitoring network can be constructed on the tray surface of all anchor bolts / cables in the roadway, completely eliminating monitoring blind spots that are prone to occur with traditional single-point deployment. Combined with a multi-level wireless transmission architecture, real-time data transmission and dynamic sensing are achieved, enabling visualized monitoring of the stress status of anchor bolts / cables across the entire roadway.

[0039] 2) Significantly improved early warning accuracy: By eliminating abnormal data, local interference data was effectively removed, and the true risk area was identified. An innovative two-level early warning system of "single point-group" was established. Through the coordinated over-limit early warning of adjacent anchor bolts, the limitations of traditional single-dimensional criteria were broken, and the false alarm rate was greatly reduced.

[0040] 3) An intelligent response closed loop has been established. Based on the real-time generated anchor bolt axial force heat map, risk location information can be automatically output, and graded early warning commands can be triggered simultaneously. Combined with a dynamic reinforcement linkage mechanism, the entire process of "monitoring-early warning-response" is automated, significantly improving emergency response efficiency.

[0041] This method is simple to implement, has low implementation costs, and is highly intelligent, enabling unmanned, real-time, and intelligent monitoring of the anchoring force status of anchor cables throughout the entire tunnel. Attached Figure Description

[0042] Figure 1 This is a block diagram of the monitoring system in this invention;

[0043] Figure 2 This is a schematic diagram of the support of the monitoring system in the tunnel cross section in this invention;

[0044] Figure 3 This is a schematic diagram of the anchor bolt / anchor cable structure in this invention;

[0045] Figure 4 This is a schematic diagram of the assembly of the intelligent monitoring unit on the anchor bolt / anchor cable in this invention;

[0046] Figure 5 This is a schematic diagram of the tray structure in this invention;

[0047] Figure 6 This is a schematic diagram of the assembly of the spray-sensor composite layer and the tray.

[0048] In the diagram: 1. Anchor bolt / anchor cable, 2. Tray, 2-1. Spherical crown section, 3. Force gauge, 4. Shotcrete-sensor composite layer, 5. Tunnel roof, 6. Tunnel sidewall, 7. Locking nut. Detailed Implementation

[0049] The invention will now be further described with reference to the accompanying drawings.

[0050] like Figures 1 to 6 As shown, the present invention provides a real-time monitoring system for the anchoring force of anchor cables throughout a roadway, including an anchoring component, a force gauge 3, an intelligent monitoring unit, a processing terminal in the roadway, a relay transmission device, a ground processing terminal, and an alarm module;

[0051] The anchoring assembly includes an anchor rod / anchor cable 1, a tray 2, and a locking nut 7. The anchor rod / anchor cable 1 is installed in a borehole in the roadway roof 5 and the roadway side 6. The locking nut 7 locks the tray 2 to the end of the anchor rod / anchor cable 1. The outer surface of the spherical crown portion 2-1 in the tray 2, outside the locking nut 7, serves as an annular monitoring area.

[0052] The force gauge 3 is positioned between the locking nut 7 and the tray 2, and is connected to a display.

[0053] The intelligent monitoring unit includes a spray-sensing composite layer 4; the spray-sensing composite layer 4 includes a spray layer and a micro-thin film strain sensor array. The spray layer covers the outer surface of the annular monitoring area on the tray 2. The micro-thin film strain sensor array is disposed in the spray layer and includes multiple micro-thin film strain sensors. The micro-thin film strain sensor includes a MEMS resistance strain gauge, a micro battery, a microprocessor, and a wireless communication module. The microprocessor is connected to the MEMS resistance strain gauge, the micro battery, and the wireless communication module.

[0054] The in-tunnel processing terminal includes a controller, a second wireless communication module, and a display module. The controller is connected to the second wireless communication module and the display module, respectively. The in-tunnel processing terminal is set in the tunnel and is connected to the micro-thin film strain sensor array through a wireless communication link between the first wireless communication module and the second wireless communication module.

[0055] The relay transmission device is installed in the tunnel and connected to the processing terminal in the tunnel via wireless communication; preferably, there are multiple relay transmission devices, and the spacing between adjacent relay transmission devices is... The relay transmission equipment uses the LoRa protocol to communicate with the ground processing terminal;

[0056] The ground processing terminal is located in the ground monitoring center and is connected to the relay transmission equipment via wired communication.

[0057] The alarm module is located in the ground monitoring center and connected to the ground processing terminal.

[0058] As a preferred embodiment, both wireless communication module one and wireless communication module two are LoRa wireless communication modules. Preferably, the transmission distance of the LoRa wireless communication module is ≥100m.

[0059] As a preferred embodiment, the micro battery is a micro zinc-air battery; more preferably, a micro zinc-air battery with a lifespan of ≥3 years is used.

[0060] Preferably, the dimensions of the micro-thin-film strain sensor are ≤8mm×8mm×0.5mm. More preferably, the sleep power of the micro-thin-film strain sensor is ≤10μW.

[0061] As a preferred option, the miniature thin-film strain sensor is vacuum-encapsulated with polyimide, has an IP68 protection rating, an operating temperature range of -20℃ to 85℃, a compressive strength of ≥5MPa, and a surface pre-coated with a quick-setting cement adhesive layer (thickness of 0.1~0.2mm).

[0062] As a preferred embodiment, the thickness of the spray-sensing composite layer 4 is 2 to 3 mm.

[0063] To ensure measurement accuracy, the number of micro-thin film strain sensors in the spray-sensing composite layer 4 is 20 to 40, that is, the distribution density of micro-thin film strain sensors on each tray 2 is 20 to 40.

[0064] In this invention, a force gauge with a display is installed between the locking nut and the tray, allowing for direct observation of the applied preload value during the application of preload to the anchor bolts / cables, ensuring the accuracy of preload application. A shotcrete-sensor composite layer is covered in the annular monitoring area on the tray, and a micro-thin-film strain sensor array is installed within this layer. This direct contact between the micro-thin-film strain sensor array and the tray facilitates real-time acquisition of strain force signals at various points on the tray during anchor component support, enabling the acquisition of strain force data at different points on the tray surface based on these signals. An in-tunnel processing terminal is installed within the tunnel, facilitating the centralized collection of strain force signals from several anchor bolts / cables within a defined monitoring range. This data is then centrally transmitted to a relay transmission device. The relay transmission device within the tunnel also facilitates the establishment of a communication connection between the in-tunnel processing terminal located underground and the ground processing terminal located at a remote monitoring center, ensuring real-time and reliable data transmission. By setting up a ground processing terminal, strain force data can be easily preprocessed. Simultaneously, it facilitates the extraction of axial pressure data for anchor bolts and cables based on the obtained strain force data. Furthermore, it can generate an axial force heat map based on the axial pressure data of all anchor bolts and cables within the monitoring range. This allows for a direct and comprehensive observation of the overall support situation, facilitating accurate assessment of the safety and stability of the tunnel support. Through the alarm module settings, different levels of early warning actions can be executed according to the control of the ground processing terminal, effectively alerting relevant management personnel.

[0065] The system has a simple structure and a high degree of intelligence, enabling precise monitoring of the support status of anchor bolts / anchor cables throughout the entire roadway.

[0066] This invention also provides a method for a real-time monitoring system of anchor cable anchoring force across the entire tunnel, comprising the following steps:

[0067] Step 1: Install anchor bolts / anchor cables 1 on the roof 5 and sidewalls 6 of the tunnel using locking nuts 7 and trays 2. The outer surface of the spherical crown portion 2-1 in the tray 2, excluding the locking nuts 7, serves as a ring-shaped monitoring area.

[0068] During the installation of anchor bolts / anchor cables 1, force gauges 3 and intelligent monitoring units are installed simultaneously; the force gauge 3 is set between the locking nut 7 and the tray 2, and the intelligent monitoring unit includes a shotcrete-sensing composite layer 4, which covers the outer surface of the annular monitoring area.

[0069] Step 2: Apply preload to each anchor rod / anchor cable 1, and monitor the preload value in real time using a force gauge 3. When the preload value reaches the design preload... Stop at this time;

[0070] Step 3: Use the processing terminal in the tunnel to collect the real-time strain sequence signal of each anchor bolt / anchor cable 1 at a set sampling frequency A. And it is transmitted to the ground processing terminal via relay transmission equipment;

[0071] Step 4: The ground processing terminal receives the real-time strain sequence signal of each anchor bolt / anchor cable 1. First, data points satisfying formula (1) are removed. Then, the data after removal is processed according to the spatial clustering algorithm. Finally, the strain value is converted into the axial pressure value of each anchor rod / cable according to the strain-axial force calibration model in formula (2). The unit is kN, and an axial force thermogram of the entire anchor bolt / anchor cable 1 within the monitoring range is generated based on the obtained axial pressure value;

[0072] (1);

[0073] In the formula, The average strain value of multiple micro-thin film strain sensors in the spray-sensing composite layer 4; This represents the standard deviation of axial pressure.

[0074] (2);

[0075] In the formula, The strain data acquired by the miniature thin-film strain sensor is in units of... K is the strain correction factor, and n and C are constants.

[0076] As a preferred option, when constructing the strain-axial force calibration model in formula (2), ensure that the fitting error R² ≥ 0.95;

[0077] Step 5: Ground treatment terminal based on axial pressure value Implement tiered early warning systems;

[0078] When a single anchor bolt / anchor cable 1 satisfies When the alarm module triggers a yellow warning, the control module will activate the warning. When five adjacent anchor bolts / cables meet the following conditions... At that time, the control alarm module executes a red alert action; among which, It represents the yield strength.

[0079] As a preferred embodiment, in step one, the spray-sensor composite layer 4 is made by the following method: multiple micro-thin film strain sensors are incorporated into quick-setting cement material to form a composite material, and then the composite material is adhered to the outer surface of the annular monitoring area, and after curing, the spray-sensor composite layer 4 is formed.

[0080] As a preferred option, in step five, when the cumulative number of red alerts triggered in a single month... At that time, or when the measured displacement of the top plate At that time, the ground processing terminal issued a command to carry out reinforcement support, among which, The span of the tunnel.

[0081] As a preferred embodiment, in step five, when the axial pressure change rate... At that time, the ground processing terminal sends a dense sampling signal to the processing terminal in the roadway through the relay transmission equipment. After receiving the dense sampling signal, the processing terminal in the roadway collects the real-time strain sequence signal of each anchor bolt / anchor cable 1 at a set sampling frequency B. Where the sampling frequency B is less than the sampling frequency A. This allows for dynamic power consumption adjustment.

[0082] As a preferred option, sampling frequency A is 1Hz and sampling frequency B is 0.2Hz.

[0083] This invention addresses multiple technical bottlenecks in traditional roadway anchor bolt / cable stress monitoring, including insufficient full-area coverage, poor real-time performance, and low level of intelligence. It proposes a real-time monitoring method for the anchoring force of anchor bolts / cables across the entire roadway area. First, a large number of micro-thin-film strain sensors are incorporated into a quick-setting cement slurry and then uniformly coated onto the surface of a monitoring tray to form a uniformly covered composite monitoring layer. This allows the stress sensors to directly contact the tray surface, effectively sensing micro-deformations at various points on the tray. Second, a processing terminal within the roadway collects strain sequence signals from multiple anchor bolts / cables within the monitoring range at a set sampling frequency. These signals are then transmitted centrally to a ground processing terminal via a relay transmission device. The ground processing terminal, combined with the initial calibration of the anchor bolt force gauge, establishes a strain-axial force mapping model, enabling real-time inversion of the anchor bolt / cable stress state. Finally, a hierarchical intelligent prevention and control mechanism is formed by triggering a yellow alert through single-point axial force exceeding the limit, and triggering a red alert through coordinated exceeding of limits by adjacent anchor bolt groups or regional anomalies. This invention breaks through the limitations of traditional local single-point monitoring and achieves for the first time automated, visualized, and real-time monitoring of the stress on anchor cables throughout the entire roadway. Through three major technological innovations—integrated sensing in the shotcrete layer, wireless networking transmission, and collaborative early warning—it significantly improves the timeliness and reliability of surrounding rock stability control, providing proactive technical support for mine safety.

[0084] Compared with the prior art, the present invention has the following advantages:

[0085] 1) Seamless monitoring of anchor bolt / cable stress status across the entire roadway: Through deep integration of micro-sensors with the shotcrete layer, a high-density monitoring network can be constructed on the tray surface of all anchor bolts / cables in the roadway, completely eliminating monitoring blind spots that are prone to occur with traditional single-point deployment. Combined with a multi-level wireless transmission architecture, real-time data transmission and dynamic sensing are achieved, enabling visualized monitoring of the stress status of anchor bolts / cables across the entire roadway.

[0086] 2) Significantly improved early warning accuracy: By eliminating abnormal data, local interference data was effectively removed, and the true risk area was identified. An innovative two-level early warning system of "single point-group" was established. Through the coordinated over-limit early warning of adjacent anchor bolts, the limitations of traditional single-dimensional criteria were broken, and the false alarm rate was greatly reduced.

[0087] 3) An intelligent response closed loop has been established. Based on the real-time generated anchor bolt axial force heat map, risk location information can be automatically output, and graded early warning commands can be triggered simultaneously. Combined with a dynamic reinforcement linkage mechanism, the entire process of "monitoring-early warning-response" is automated, significantly improving emergency response efficiency.

[0088] This method is simple to implement, has low implementation costs, and is highly intelligent, enabling unmanned, real-time, and intelligent monitoring of the anchoring force status of anchor cables throughout the entire tunnel.

Claims

1. A real-time monitoring system for the anchoring force of anchor bolts and cables throughout a roadway, comprising an anchoring assembly, the anchoring assembly comprising an anchor bolt / anchor cable (1), a tray (2), and a locking nut (7), wherein the anchor bolt / anchor cable (1) is installed in boreholes in the roadway roof (5) and roadway sidewalls (6), and the locking nut (7) locks the tray (2) to the end of the anchor bolt / anchor cable (1), and the outer surface of the spherical crown portion (2-1) of the tray (2), excluding the locking nut (7), serves as an annular monitoring area; characterized in that, It also includes a force gauge (3), an intelligent monitoring unit, a roadway processing terminal, a relay transmission device, a ground processing terminal, and an alarm module; The force gauge (3) is positioned between the locking nut (7) and the tray (2) and is connected to a display. The intelligent monitoring unit includes a spray-sensing composite layer (4); the spray-sensing composite layer (4) includes a spray layer and a micro-thin film strain sensor array. The spray layer covers the outer surface of the annular monitoring area on the tray (2). The micro-thin film strain sensor array is disposed in the spray layer and includes multiple micro-thin film strain sensors. The micro-thin film strain sensor includes a MEMS resistance strain gauge, a micro battery, a microprocessor, and a wireless communication module. The microprocessor is connected to the MEMS resistance strain gauge, the micro battery, and the wireless communication module. The in-tunnel processing terminal includes a controller, a second wireless communication module, and a display module. The controller is connected to the second wireless communication module and the display module, respectively. The in-tunnel processing terminal is set in the tunnel and is connected to the micro-thin film strain sensor array through a wireless communication link between the first wireless communication module and the second wireless communication module. The relay transmission device is installed in the tunnel and is connected to the processing terminal in the tunnel via wireless communication. The ground processing terminal is located in the ground monitoring center and is connected to the relay transmission equipment via wired communication. The alarm module is located in the ground monitoring center and connected to the ground processing terminal.

2. The real-time monitoring system for the anchoring force of anchor cables throughout a roadway according to claim 1, characterized in that, Both wireless communication module one and wireless communication module two are LoRa wireless communication modules.

3. The real-time monitoring system for the anchoring force of anchor cables throughout a roadway according to claim 2, characterized in that, The micro battery is a micro zinc-air battery.

4. The real-time monitoring system for the anchoring force of anchor cables throughout a roadway according to claim 2, characterized in that, The dimensions of the micro-thin film strain sensor are ≤8mm×8mm×0.5mm.

5. A real-time monitoring system for the anchoring force of anchor cables throughout a roadway according to claim 4, characterized in that, The thickness of the spray-sensor composite layer (4) is 2-3 mm.

6. The real-time monitoring system for the anchoring force of anchor cables throughout a roadway according to claim 5, characterized in that, The number of micro-thin film strain sensors in the spray-sensing composite layer (4) is 20 to 40.

7. A method for real-time monitoring of the anchoring force of anchor cables throughout a roadway, comprising a real-time monitoring system for the anchoring force of anchor cables throughout a roadway as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Install anchor bolts / anchor cables (1) on the roof (5) and sidewalls (6) of the roadway using locking nuts (7) and trays (2). The outer surface of the spherical crown part (2-1) in the tray (2), outside the locking nuts (7), serves as a ring-shaped monitoring area. During the installation of anchor bolts / anchor cables (1), a force gauge (3) and an intelligent monitoring unit are installed simultaneously; wherein, the force gauge (3) is set between the locking nut (7) and the tray (2), and the intelligent monitoring unit includes a shotcrete-sensing composite layer (4), which covers the outer surface of the annular monitoring area; Step 2: Apply preload to each anchor rod / anchor cable (1) and monitor the preload value in real time using a force gauge (3). When the preload value reaches the design preload... Stop at this time; Step 3: Use the processing terminal in the tunnel to collect the real-time strain sequence signal of each anchor bolt / anchor cable (1) at a set sampling frequency A. And it is transmitted to the ground processing terminal via relay transmission equipment; Step 4: After receiving the real-time strain sequence signal of each anchor rod / anchor cable (1), the ground processing terminal first removes the data points that satisfy formula (1), and then converts the strain value into the axial pressure value of each anchor rod / anchor cable (1) according to the strain-axial force calibration model in formula (2). And based on the obtained axial pressure value, generate a full-range axial force thermogram of anchor bolts / anchor cables (1) within the monitoring range; （1）； In the formula, The average strain of multiple micro-thin film strain sensors in the spray-sensing composite layer (4); This represents the standard deviation of axial pressure. （2）； In the formula, The strain data is collected by a micro-thin film strain sensor; K is the strain correction coefficient, and n and C are constants. Step 5: Ground treatment terminal based on axial pressure value Implement tiered early warning systems; When a single anchor bolt / anchor cable (1) satisfies When the alarm module executes a yellow warning action; when five adjacent anchor bolts / anchor cables (1) meet the condition... At that time, the control alarm module executes a red alert action; among which, It represents the yield strength.

8. The method for real-time monitoring of anchoring force of anchor cables throughout a roadway according to claim 7, characterized in that, In step one, the spray-sensing composite layer (4) is made by the following method: multiple micro-thin film strain sensors are incorporated into quick-setting cement material to form a composite material, and then the composite material is adhered to the outer surface of the annular monitoring area and cured to form the spray-sensing composite layer (4).

9. The method for real-time monitoring of anchoring force of anchor cables throughout a roadway according to claim 7, characterized in that, In step five, the cumulative number of red alerts triggered in a single month is counted. At that time, or when the measured displacement of the top plate At that time, the ground processing terminal issued a command to carry out reinforcement support, among which, The span of the tunnel.

10. A method for real-time monitoring of anchoring force of anchor cables throughout a roadway according to claim 7, characterized in that, In step five, when the axial pressure change rate At that time, the ground processing terminal sends a dense sampling signal to the processing terminal in the roadway through the relay transmission equipment. After receiving the dense sampling signal, the processing terminal in the roadway collects the real-time strain sequence signal of each anchor bolt / anchor cable (1) at a set sampling frequency B. Where the sampling frequency B is less than the sampling frequency A.

Images