Monitoring system and evaluation method for supporting quality of concrete spraying layer of coal mine tunnel

Abstract

The invention provides a coal mine tunnel concrete spraying layer support quality monitoring system and evaluation method, monitoring units are installed in a coal mine tunnel in groups, each monitoring unit comprises an exciter and a receiver, the exciter is installed at the end of an anchor rod in the center of a coal mine tunnel top plate, and the receiver is installed at the end of the anchor rod. Carrying out instantaneous impact on the end part of the anchor rod at a fixed frequency; by taking the exciter as a center, receivers are mounted at the top plate on the periphery of the exciter and the end parts of the anchor rods on the two sides and are used for receiving vibration waves excited by the exciter. And carrying out statistical analysis on the vibration speed change rate of the test waveform compared with the initial waveform when the monitoring system is installed during the concrete spraying layer support test in any area, and the vibration frequency change rate of the test spectrogram compared with the initial spectrogram, so as to determine an evaluation coefficient, thereby carrying out accurate quantitative evaluation on the quality of the concrete spraying layer support of the coal mine tunnel. And long-term and continuous monitoring is realized, and treatment measures are taken in time, so that the safety of the coal mine tunnel is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of concrete spraying support for coal mine tunnels, and in particular to a monitoring system and an evaluation method for the quality of concrete spraying support for coal mine tunnels. Background Art

[0002] Coal mine tunnel concrete spraying support is a support technology widely used in coal mine tunnel engineering. It uses special spraying equipment to spray the concrete mixture prepared according to a certain mix ratio directly onto the surface of the tunnel surrounding rock at high speed, forming a layer of continuous and dense concrete support layer with a certain thickness on the surface of the surrounding rock. This layer of concrete spraying can fit closely with the surrounding rock, play a role in reinforcing the surrounding rock, preventing the surrounding rock from weathering, and preventing the surrounding rock from further deformation and collapse, thereby improving the stability and safety of coal mine tunnels and providing a reliable and safe tunnel environment for coal mining operations.

[0003] In the related technologies, the stability and support effect of the tunnel after concrete spraying support mostly rely on experience and some simple monitoring methods, which makes it difficult to achieve accurate quantitative evaluation. In addition, there is often a lack of long-term and continuous monitoring of coal mine tunnels after concrete spraying support, and potential support failure risks cannot be discovered in time, making it difficult to take adjustment measures in time, which may lead to roof accidents, resulting in varying degrees of casualties and property losses. Summary of the invention

[0004] The first purpose of this application is to propose a monitoring system for the quality of concrete spraying support in coal mine tunnels. The system conducts accurate quantitative evaluation of the quality of concrete spraying support in coal mine tunnels, as well as long-term and continuous monitoring, and takes timely disposal measures to ensure the safety of coal mine tunnels.

[0005] The second purpose of this application is to propose a method for evaluating the quality of concrete spraying support in coal mine tunnels.

[0006] To achieve the above first purpose, the first aspect of the present application proposes a monitoring system for the quality of concrete spraying support in coal mine tunnels, the monitoring system comprising an analysis computer, a centralized controller, a collector, and a monitoring unit, the monitoring unit comprising an exciter and a receiver, wherein:

[0007] The exciter is installed at the end of the anchor rod at the center of the roof of the coal mine tunnel, and performs instantaneous impact on the end of the anchor rod at a fixed frequency;

[0008] With the exciter as the center, receivers are installed on the top plate around the exciter and the ends of the anchor rods on both sides to receive the vibration waves excited by the exciter during instantaneous impact. Each monitoring unit contains 4 sets of receiver strings, and the arrangement directions of the 4 sets of receiver strings are 0°, 45°, 90°, and 135° to the coal mine tunnel excavation direction respectively.

[0009] The collector is used to collect the vibration waves received by the receiver, the centralized controller is used to control the exciter and the receiver, and ensure the clock synchronization between the exciter and the receiver, and the analysis computer is used to analyze the vibration waves and remotely monitor the quality of the concrete spraying support of the coal mine tunnel and display faults.

[0010] In addition, the monitoring system for the quality of concrete spraying support in coal mine tunnels proposed in the present application may also have the following additional technical features:

[0011] In some embodiments, when the exciter is a pneumatic exciter, the monitoring system further comprises an air duct, wherein:

[0012] The air duct is connected to the pneumatic exciter and is used to provide power for the pneumatic exciter.

[0013] In some embodiments, a plurality of groups of monitoring units are arranged in the coal mine tunnel, the spacing between adjacent monitoring units is a preset first threshold, and the spacing between adjacent receivers in each string of receivers is also the first threshold.

[0014] In some embodiments, the receiver string corresponding to the coal mine tunnel excavation direction of 0° is only arranged on the top plate around the exciter, and the receiver string corresponding to the coal mine tunnel excavation directions of 45°, 90°, and 135° is in a gate shape, and the receivers are arranged on the top plate and side parts around the exciter.

[0015] In some embodiments, the receiver string at the side of the exciter is arranged in a vertical direction perpendicular to the roof of the coal mine tunnel.

[0016] In some embodiments, the exciter in the coal mine tunnel can perform instantaneous impact on the end of the anchor rod only during non-production periods. The exciters in the same coal mine tunnel take turns to perform instantaneous impacts, and the instantaneous impact time interval is 1s.

[0017] In order to achieve the above second purpose, the second aspect of the present application proposes a method for evaluating the quality of concrete spraying support in coal mine tunnels, the method comprising:

[0018] When the concrete spraying support construction of the coal mine tunnel is completed and the monitoring system is installed, the acquisition instrument of the monitoring system is used to obtain j first shock waves received by the receiver when the exciter in the monitoring unit at j initial sampling points performs instantaneous impact, and transmit them to the analysis computer through the centralized controller to perform arithmetic averaging on the j first shock waves to obtain a first average shock wave, use the first average shock wave as the initial shock wave, and construct an initial frequency spectrum of the initial shock wave;

[0019] When testing the target concrete spraying support in any area of ​​the coal mine tunnel, the acquisition instrument of the monitoring system is used to obtain j second shock waves received by the receiver when the exciter in the monitoring unit at j test sampling points is subjected to instantaneous impact, and the second shock waves are transmitted to the analysis computer through the centralized controller to perform arithmetic averaging on the j second shock waves to obtain a second average shock wave, and the second average shock wave is used as a test shock wave, and a test spectrum diagram of the test shock wave is constructed;

[0020] Accumulate the vibration velocity value of each initial sampling point in the initial vibration wave to obtain a first total vibration velocity value, accumulate the vibration velocity value of each test sampling point in the test waveform to obtain a second total vibration velocity value, and calculate the vibration velocity change rate corresponding to the target concrete spraying support according to the first total vibration velocity value and the second total vibration velocity value;

[0021] Accumulate the vibration frequency value of each initial sampling point in the initial spectrum diagram to obtain a first vibration frequency total value, accumulate the vibration frequency value of each test sampling point in the test spectrum diagram to obtain a second vibration frequency total value, and calculate the vibration frequency change rate corresponding to the target concrete spraying support according to the first vibration frequency total value and the second vibration frequency total value;

[0022] According to the vibration velocity change rate and the vibration frequency change rate, an evaluation coefficient of the target concrete spraying layer support quality is calculated, wherein the evaluation coefficient has multiple value ranges, and each value range corresponds to a different danger level and disposal measure of the concrete spraying layer support;

[0023] According to the evaluation coefficient of each test sampling point in any area, the danger level of the concrete spraying support is determined, and the disposal measures corresponding to the danger level are implemented.

[0024] The present application discloses a monitoring system and evaluation method for the quality of concrete spraying support in coal mine tunnels. Monitoring units are installed in groups in coal mine tunnels. Each group of monitoring units includes an exciter and a receiver. The exciter is installed at the end of the anchor rod in the center of the roof of the coal mine tunnel, and the anchor rod end is instantaneously impacted at a fixed frequency. With the exciter as the center, receivers are installed at the top plate around the exciter and the ends of the anchor rods on both sides to receive the vibration waves excited by the exciter. The vibration velocity change rate of the test waveform compared to the initial waveform when the monitoring system is installed during the concrete spraying support test in any area, as well as the vibration frequency change rate of the test spectrum diagram compared to the initial spectrum diagram, are statistically analyzed to determine the evaluation coefficient. Thus, the quality of concrete spraying support in coal mine tunnels can be accurately and quantitatively evaluated, and long-term and continuous monitoring can be carried out, and disposal measures can be taken in a timely manner to ensure the safety of coal mine tunnels.

[0025] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0027] Figure 1 A schematic diagram of the structure of a monitoring system for the quality of concrete spraying support in a coal mine tunnel provided in an embodiment of the present application;

[0028] Figure 2 A top view of a monitoring unit arrangement provided in an embodiment of the present application;

[0029] Figure 3 A side view of a monitoring unit arrangement provided in an embodiment of the present application;

[0030] Figure 4 A three-dimensional diagram of the arrangement of a monitoring unit provided in an embodiment of the present application;

[0031] Figure 5 A schematic diagram of the installation of an exciter and a receiver provided in an embodiment of the present application;

[0032] Figure 6 A schematic diagram of a flow chart of a method for evaluating the quality of concrete spraying support in a coal mine tunnel provided in an embodiment of the present application;

[0033] Figure 7 A vibration wave and vibration wave spectrum diagram provided in an embodiment of the present application. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, but cannot be understood as limiting the present application.

[0035] The following describes a system for monitoring the quality of concrete spraying support in coal mine tunnels according to an embodiment of the present application with reference to the accompanying drawings.

[0036] Figure 1 It is a structural diagram of a monitoring system for the quality of concrete spraying support in coal mine tunnels according to an embodiment of the present application.

[0037] like Figure 1 As shown, the monitoring system of the coal mine tunnel concrete spraying support quality of the embodiment of the present application includes an analysis computer 1, a centralized controller 2, a collector 3, and a monitoring unit (not shown in the figure), and the monitoring unit includes an exciter 4 and a receiver 5, wherein:

[0038] The exciter 4 is installed at the end of the anchor rod at the center of the roof of the coal mine tunnel, and performs instantaneous impact on the end of the anchor rod at a fixed frequency.

[0039] With the exciter 4 as the center, receivers 5 are installed on the top plate around the exciter 4 and the ends of the anchor rods on both sides, which are used to receive the vibration waves excited by the exciter 4 when it performs instantaneous impact. Each monitoring unit contains 4 groups of receiver strings, and the arrangement directions of the 4 groups of receiver strings are 0°, 45°, 90°, and 135° to the coal mine tunnel excavation direction respectively.

[0040] The collector 3 is used to collect the vibration waves received by the receiver 5, the centralized controller 2 is used to control the exciter 4 and the receiver 5, and ensure the clock synchronization between the exciter 4 and the receiver 5, the analysis computer 1 is used to analyze the vibration waves, and remotely monitor the quality of the concrete spraying support in the coal mine tunnel and display faults.

[0041] In some embodiments, Figure 1 As shown, in the case where the exciter 4 is a pneumatic exciter 4 , the monitoring system further includes an air duct 6 , wherein the air duct 6 is connected to the pneumatic exciter 4 to provide power for the pneumatic exciter 4 to achieve stable excitation of the pneumatic exciter 4 .

[0042] In some embodiments, multiple groups of monitoring units are arranged in the coal mine tunnel, the spacing between adjacent monitoring units is a preset first threshold, and the spacing between adjacent receivers 5 in each string of receivers is also the first threshold.

[0043] The first threshold may be 1 m, that is, the distance between adjacent monitoring units is 1 m, and the distance between adjacent receivers 5 is 1 m, but it is not limited thereto.

[0044] In some embodiments, the receiver string corresponding to the coal mine tunnel excavation direction of 0° is only arranged on the top plate around the exciter 4, and the receiver string corresponding to the coal mine tunnel excavation directions of 45°, 90°, and 135° is in a gate shape, and the receiver 5 is arranged on the top plate and the side around the exciter 4.

[0045] In some embodiments, the receiver strings at the side of the exciter 4 are arranged in a vertical direction perpendicular to the roof of the coal mine tunnel.

[0046] In some embodiments, the exciter 4 can perform instantaneous impact on the end of the anchor rod only during non-production periods (such as maintenance shifts) in the coal mine tunnel. The exciters 4 in the same coal mine tunnel take turns to perform instantaneous impacts, and the instantaneous impact time interval is 1s.

[0047] In summary, if Figure 2 , Figure 3 , Figure 4 As shown, Figure 2 Layout of the monitoring unit. Figure 3 Side view of the monitoring unit layout. Figure 4 The following is a stereogram of the monitoring unit arrangement. Taking each monitoring unit including one exciter 4 and 58 receivers 5 as an example, the receivers 5 are arranged in a star shape around the exciter 4, and the monitoring range covers the roof and two sides around the exciter 4. The arrangement directions of the receiver strings are 0°, 45°, 90°, and 135° (string No. 1, string No. 2, string No. 3, and string No. 4) with the coal mine tunneling direction, respectively. Among them, the receiver string corresponding to 0° is arranged on the roof, containing 6 receivers 5; the other 3 receiver strings are in a gate shape, and the receivers 5 are arranged on the roof and two sides. Receiver strings No. 2 and No. 4 each contain 18 receivers 5, and receiver string No. 3 contains 16 receivers 5. The receiver strings of the two sides are arranged in a vertical direction perpendicular to the roof, and each string contains 5 receivers 5.

[0048] Furthermore, the present application also provides a schematic diagram of the installation of an exciter 4 and a receiver 5, as shown in FIG. Figure 5 As shown, a receiver 5 and an exciter 4 installed on the end of an anchor rod 52 on a coal mine tunnel roof 51 are taken as an example, wherein the anchor rod 52 is fixed to the coal mine tunnel roof 51 by an anchoring agent 53 and a tray 54, an exciter 4 (55) is installed on the end of an anchor rod 52 selected on the coal mine tunnel roof 51, and a receiver 5 (56) is installed on the adjacent anchor rod 52.

[0049] In addition, the monitoring system also includes an explosion-proof power supply (not shown in the figure), a data transmission cable (not shown in the figure) and an optical cable (not shown in the figure), wherein the exciters 4 in the same coal mine tunnel are arranged in series and connected to the centralized controller 2 at the entrance of the coal mine tunnel through the data transmission cable. Each pneumatic exciter 4 is connected to the air duct 6, using wind as a power source. The receiver 5 is arranged in a series and finally connected to the collector 3 through an optical cable, and the collector 3 is connected to the centralized controller 2. The centralized controller 2 can control the exciter 4 and the receiver 5 at the same time, and ensure the clock synchronization of the exciter 4 and the receiver 5.

[0050] Among them, the A / D conversion accuracy used by the analysis computer 1 in the monitoring system can be 32 bits; the sampling frequency of the collector 3 can be 100kHz, and the sampling time can be 2ms; the excitation time interval of the exciter 4 can be 1s; the receiving interval of the receiver 5 can be 1m; the excitation mode of each group of 4 exciters can be alternate excitation.

[0051] The present application discloses a monitoring system for the quality of concrete spraying support in coal mine tunnels. The monitoring system comprises an analysis computer, a centralized controller, a collector and a monitoring unit. The monitoring unit comprises an exciter and a receiver, wherein: the exciter is installed at the end of an anchor rod at the central position of the roof of the coal mine tunnel, and performs instantaneous impact on the end of the anchor rod at a fixed frequency; with the exciter as the center, receivers are installed on the roof and the ends of the anchor rods on both sides around the exciter, and are used to receive vibration waves excited by the instantaneous impact of the exciter, wherein each monitoring unit contains 4 groups of receiver strings, and the arrangement directions of the 4 groups of receiver strings are 0°, 45°, 90° and 135° to the coal mine tunnel excavation direction respectively; the collector is used to collect the vibration waves received by the receiver, the centralized controller is used to control the exciter and the receiver, and at the same time ensure the clock synchronization between the exciter and the receiver, the analysis computer is used to analyze the vibration waves, and remotely monitor and display the quality of concrete spraying support in coal mine tunnels, so as to achieve the purpose of real-time evaluation.

[0052] Figure 6 It is a flowchart diagram of a method for evaluating the quality of concrete spraying support in coal mine tunnels according to one embodiment of the present application.

[0053] Step 601, when the concrete spraying support construction of the coal mine tunnel is completed and the monitoring system is installed, the data collector of the monitoring system is used to obtain j first shock waves received by the receiver when the exciter in the monitoring unit at j initial sampling points performs instantaneous impact, and transmit them to the analysis computer through the centralized controller to perform arithmetic averaging on the j first shock waves to obtain a first average shock wave, use the first average shock wave as the initial shock wave, and construct an initial spectrum diagram of the initial shock wave.

[0054] In some embodiments, after the monitoring system is installed and debugged, the initial parameter collection begins, and the initial parameters are used as standard parameters. Specifically, the exciter performs 10 impacts at an interval of 1 second, and the receiver records the first shock waves of the 10 impacts. The absolute values ​​of the amplitudes of the 10 shock waves are first taken, and then the arithmetic average of the 10 shock waves is taken to obtain a new first average shock wave, which is called the initial shock wave. The initial shock wave (initial waveform diagram) is subjected to Fourier transform to obtain the initial spectrum diagram of the initial shock wave, as shown in FIG. Figure 7 (a) shown.

[0055] Step 602, when testing the target concrete spraying support in any area of ​​the coal mine tunnel, the data collector of the monitoring system is used to obtain j second shock waves received by the receiver when the exciter in the monitoring unit at j test sampling points is subjected to instantaneous impact, and the second shock waves are transmitted to the analysis computer through the centralized controller to perform arithmetic averaging on the j second shock waves to obtain a second average shock wave, and the second average shock wave is used as a test shock wave, and a test spectrum diagram of the test shock wave is constructed.

[0056] In some embodiments, during the use of coal mine tunnels, the target concrete spraying support quality of any area can be tested at any time. During the test, the exciter performs 10 impacts at a frequency of 1s, and the receiver records the second shock waves of the 10 impacts. The absolute value of the amplitude of the 10 second shock waves is first taken, and then the arithmetic average of the 10 second shock waves is taken to obtain a new second average shock wave, which is called a test shock wave. Performing Fourier transform on this test shock wave (test waveform diagram) can obtain a test spectrum diagram of the test shock wave, such as Figure 7 (b) as shown.

[0057] Step 603, the vibration velocity value of each initial sampling point in the initial vibration wave is accumulated to obtain a first total vibration velocity value, the vibration velocity value of each test sampling point in the test waveform is accumulated to obtain a second total vibration velocity value, and the vibration velocity change rate corresponding to the target concrete sprayed layer support is calculated based on the first total vibration velocity value and the second total vibration velocity value.

[0058] In some embodiments, when the number of j initial sampling points is 10, the vibration velocity value W of the i-th initial sampling point in the initial vibration wave is pi , and the vibration velocity value W of the i-th test sampling point in the test waveform ti The calculation formula is as follows:

[0059]

[0060] And through W pi and W tiCalculate the vibration velocity change rate A w , A w The calculation formula is as follows:

[0061]

[0062] Step 604, the vibration frequency value of each initial sampling point in the initial spectrum diagram is accumulated to obtain the first total vibration frequency value, the vibration frequency value of each test sampling point in the test spectrum diagram is accumulated to obtain the second total vibration frequency value, and the vibration frequency change rate corresponding to the target concrete sprayed layer support is calculated based on the first total vibration frequency value and the second total vibration frequency value.

[0063] In some embodiments, when the number of j test sampling points is 10, the vibration frequency value F of the i-th initial sampling point in the initial spectrum graph is pi , and the vibration frequency value F of the i-th test sampling point in the test spectrum ti The calculation formula is as follows:

[0064]

[0065] And through F pi and F ti Calculate the vibration frequency change rate A f , A f The calculation formula is as follows:

[0066]

[0067] Step 605, calculate the evaluation coefficient of the target concrete spraying layer support quality according to the vibration velocity change rate and the vibration frequency change rate, wherein the evaluation coefficient has multiple value ranges, and each value range corresponds to a different danger level and disposal measure of the concrete spraying layer support.

[0068] In some embodiments, the vibration velocity change rate A may be w and vibration frequency change A f The maximum value of the target concrete spraying layer support quality evaluation coefficient K, that is, K = max (A w ,A f ).

[0069] Furthermore, the value range includes a first value range, a second value range, and a third value range which increase in sequence. The danger levels of concrete spraying support corresponding to the first value range, the second value range, and the third value range are no or weak danger, medium danger, and strong danger, respectively. The corresponding disposal measures for no or weak danger, medium danger, and strong danger are no need to take measures, on-site inspection of concrete spraying support and enhanced monitoring, pedestrians are strictly prohibited, and concrete should be sprayed again immediately.

[0070] Specifically, when the first value range a is K ≤ 0.25, the second value range b is 0.25 < K ≤ 0.5, and the third value range c is 0.5 < K ≤ 1, the quality assessment criteria (assessment level, K value range, danger level) and treatment measures of the shotcrete support are shown in Table 1. The K value range of assessment level a is K ≤ 0.25, with no or weak danger and no measures required. The K value range of assessment level b is 0.25 < K ≤ 0.5, with medium danger. Conduct on-site verification of the shotcrete support and strengthen monitoring. The K value range of assessment level c is 0.5 < K ≤ 1, with strong danger. Pedestrians are prohibited and shotcrete should be immediately replenished.

[0071] Table 1 Quality Assessment Criteria and Treatment Measures of Shotcrete Support

[0072] Assessment Level K value range Hazard Level Disposal measures a K≤0.25 No or weak danger No action required b 0.25<K≤0.5 Moderate risk On-site inspection and enhanced monitoring c 0.5<K≤1 High Danger It is strictly forbidden to pass through, spray again immediately

[0073] In addition, based on the above Figure 7 (a), when the calculated A w is 32%, and based on the above Figure 7 (b), when the calculated vibration frequency change ΔA f is 45%, 45% is the evaluation coefficient of the target shotcrete support quality obtained from this test. By querying Table 1, it can be concluded that the evaluation level is level b and the danger level is medium, indicating that the target shotcrete has been damaged. It is necessary to go down the well for on-site inspection and verification, handle problems in a timely manner, and at the same time strengthen monitoring of the surrounding area, closely pay attention to the change trend of the K value of this test and the change trend of the number of dangerous measuring points.

[0074] Step 606: Determine the danger level of the shotcrete support according to the evaluation coefficients of each test sampling point in any area, and implement the treatment measures corresponding to the danger level.

[0075] In some embodiments, when multiple test sampling points in the same area are simultaneously in a medium danger and strong danger state, it indicates that large-area damage has occurred to the shotcrete support, and it is regarded as a high-danger state. Pedestrians are prohibited and shotcrete should be immediately replenished.

[0076] The present application discloses a method for evaluating the quality of concrete spraying support in a coal mine tunnel. When the construction of concrete spraying support in a coal mine tunnel is completed and a monitoring system is installed, a data acquisition instrument of the monitoring system is used to obtain j first vibration waves received by a receiver when an exciter in a monitoring unit performs an instantaneous impact at j initial sampling points, and the waves are transmitted to an analysis computer through a centralized controller, so as to perform arithmetic averaging on the j first vibration waves to obtain a first average vibration wave, use the first average vibration wave as an initial vibration wave, and construct an initial spectrum diagram of the initial vibration wave; when testing the target concrete spraying support in any area of ​​a coal mine tunnel, j second vibration waves received by the receiver when an exciter in a monitoring unit performs an instantaneous impact at j test sampling points are obtained through a data acquisition instrument of the monitoring system, and the waves are transmitted to an analysis computer through a centralized controller, so as to perform arithmetic averaging on the j second vibration waves to obtain a second average vibration wave, use the second average vibration wave as a test vibration wave, and construct a test spectrum diagram of the test vibration wave; each initial sampling point in the initial spectrum diagram is used as the first average vibration wave, so as to obtain a second average vibration wave, use the second average vibration wave as a test vibration wave, and construct a test spectrum diagram of the test vibration wave. The vibration frequency values ​​of the target concrete spraying layer support are accumulated to obtain a first vibration frequency total value, the vibration frequency value of each test sampling point in the test spectrum diagram is accumulated to obtain a second vibration frequency total value, and the vibration frequency change rate corresponding to the target concrete spraying layer support is calculated according to the first vibration frequency total value and the second vibration frequency total value; the vibration frequency value of each initial sampling point in the initial spectrum diagram is accumulated to obtain a first vibration frequency total value, the vibration frequency value of each test sampling point in the test spectrum diagram is accumulated to obtain a second vibration frequency total value, and the vibration frequency change rate corresponding to the target concrete spraying layer support is calculated according to the first vibration frequency total value and the second vibration frequency total value; according to the vibration velocity change rate and the vibration frequency change rate, an evaluation coefficient of the quality of the target concrete spraying layer support is constructed, wherein the evaluation coefficient has multiple value ranges, and each value range corresponds to a different danger level and disposal measures of the concrete spraying layer support; according to the evaluation coefficient of each test sampling point in any area, the danger level of the concrete spraying layer support is determined, and the disposal measures corresponding to the danger level are executed. Therefore, relying on the vibration velocity change rate and vibration frequency change rate, an accurate quantitative assessment of the concrete shotcrete support in coal mine tunnels can be made, thereby improving the stability and safety of coal mine tunnels and providing a reliable and safe tunnel environment for coal mining operations.

[0077] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory. In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0078] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the embodiments of the present application includes additional implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0079] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0080] A person skilled in the art may understand that all or part of the steps of the system implementing the above-mentioned embodiment may be completed by instructing related hardware through a computer program, and the computer program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the system embodiment.

[0081] In addition, each functional unit in each embodiment of the present application may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0082] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A monitoring system for the quality of concrete spraying support in coal mine tunnels, the monitoring system comprising an analysis computer, a centralized controller, a collection instrument, and a monitoring unit, characterized in that: The monitoring unit comprises an exciter and a receiver, wherein: The exciter is installed at the end of the anchor rod at the center of the roof of the coal mine tunnel, and performs instantaneous impact on the end of the anchor rod at a fixed frequency; With the exciter as the center, receivers are installed on the top plate around the exciter and the ends of the anchor rods on both sides to receive the vibration waves excited by the exciter during instantaneous impact. Each monitoring unit contains 4 sets of receiver strings, and the arrangement directions of the 4 sets of receiver strings are 0°, 45°, 90°, and 135° to the coal mine tunnel excavation direction respectively. The collector is used to collect the vibration waves received by the receiver, the centralized controller is used to control the exciter and the receiver, and ensure the clock synchronization between the exciter and the receiver, and the analysis computer is used to analyze the vibration waves and remotely monitor the quality of the concrete spraying support of the coal mine tunnel and display faults.

2. The monitoring system for the quality of concrete spraying support in coal mine tunnels according to claim 1 is characterized in that: In the case where the exciter is a pneumatic exciter, the monitoring system further comprises an air duct, wherein: The air duct is connected to the pneumatic exciter and is used to provide power for the pneumatic exciter.

3. The monitoring system for the quality of concrete spraying support in coal mine tunnels according to claim 1 is characterized in that: A plurality of groups of monitoring units are arranged in the coal mine tunnel, the spacing between adjacent monitoring units is a preset first threshold, and the spacing between adjacent receivers in each string of receivers is also the first threshold.

4. The monitoring system for the quality of concrete spraying support in coal mine tunnels according to claim 1 is characterized in that: The receiver string corresponding to the coal mine tunnel excavation direction of 0° is only arranged on the top plate around the exciter, and the receiver string corresponding to the coal mine tunnel excavation directions of 45°, 90°, and 135° is in a gate shape, and the receivers are arranged on the top plate and side parts around the exciter.

5. The monitoring system for the quality of concrete spraying support in coal mine tunnels according to claim 1 is characterized in that: The receiver string at the side of the exciter is arranged in a vertical direction perpendicular to the roof of the coal mine tunnel.

6. The monitoring system for the quality of concrete spraying support in coal mine tunnels according to claim 1 is characterized in that: In coal mine tunnels, the exciters can only perform instantaneous impact on the ends of anchor rods during non-production periods. The exciters in the same coal mine tunnel take turns to perform instantaneous impacts, and the instantaneous impact time interval is 1s.

7. A method for evaluating the quality of concrete spraying support in coal mine tunnels, characterized in that: The method comprises: When the concrete spraying support construction of the coal mine tunnel is completed and the monitoring system is installed, the acquisition instrument of the monitoring system is used to obtain j first shock waves received by the receiver when the exciter in the monitoring unit at j initial sampling points performs instantaneous impact, and transmit them to the analysis computer through the centralized controller to perform arithmetic averaging on the j first shock waves to obtain a first average shock wave, use the first average shock wave as the initial shock wave, and construct an initial frequency spectrum of the initial shock wave; When testing the target concrete spraying support in any area of ​​the coal mine tunnel, the acquisition instrument of the monitoring system is used to obtain j second shock waves received by the receiver when the exciter in the monitoring unit at j test sampling points is subjected to instantaneous impact, and the second shock waves are transmitted to the analysis computer through the centralized controller to perform arithmetic averaging on the j second shock waves to obtain a second average shock wave, and the second average shock wave is used as a test shock wave, and a test spectrum diagram of the test shock wave is constructed; Accumulate the vibration velocity value of each initial sampling point in the initial vibration wave to obtain a first total vibration velocity value, accumulate the vibration velocity value of each test sampling point in the test waveform to obtain a second total vibration velocity value, and calculate the vibration velocity change rate corresponding to the target concrete spraying support according to the first total vibration velocity value and the second total vibration velocity value; Accumulate the vibration frequency value of each initial sampling point in the initial spectrum diagram to obtain a first vibration frequency total value, accumulate the vibration frequency value of each test sampling point in the test spectrum diagram to obtain a second vibration frequency total value, and calculate the vibration frequency change rate corresponding to the target concrete spraying support according to the first vibration frequency total value and the second vibration frequency total value; According to the vibration velocity change rate and the vibration frequency change rate, an evaluation coefficient of the target concrete spraying layer support quality is calculated, wherein the evaluation coefficient has multiple value ranges, and each value range corresponds to a different danger level and disposal measure of the concrete spraying layer support; According to the evaluation coefficient of each test sampling point in any area, the danger level of the concrete spraying support is determined, and the disposal measures corresponding to the danger level are implemented.

8. A method for evaluating the quality of concrete spraying support in coal mine tunnels, characterized in that: The value range includes a first value range, a second value range, and a third value range which increase in sequence. The danger levels of concrete spraying support corresponding to the first value range, the second value range, and the third value range are no or weak danger, medium danger, and strong danger, respectively. The corresponding disposal measures for no or weak danger, medium danger, and strong danger are no need to take measures, on-site inspection of concrete spraying support and enhanced monitoring, pedestrians are strictly prohibited, and concrete should be sprayed again immediately.

9. A method for evaluating the quality of concrete spraying support in coal mine tunnels, characterized in that: The method also includes: when multiple test sampling points are simultaneously in medium and strong danger in the same area, it indicates that a large area of ​​concrete spraying support has been damaged, and it is treated as a high-risk state, pedestrians are strictly prohibited and concrete must be sprayed again immediately.

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