An integrated sandwich type optical fiber sensing grouting pipeline mud state monitoring method

Abstract

This invention discloses an integrated sandwich-type fiber optic sensing method for monitoring the state of grouting pipelines, relating to the field of goaf filling monitoring technology. The method includes: S1: embedding an integrated sandwich-type fiber optic sensing component within the pipeline sandwich space between the inner liner and outer protective pipe; S2: real-time acquisition of vibration, acoustic, and strain response signals distributed along the pipeline by the sandwich-type fiber optic sensing component; S3: extraction of time-domain, frequency-domain, and spatial distribution characteristic parameters; and S4: outputting early warning information and locating the location of abnormal sections. This invention completely avoids the wear and debonding problems caused by direct contact between the sensor and the grout, while also solving the signal attenuation defects caused by external wall adhesion. It can accurately locate sections with abnormal conditions such as grout flow interruption, local deposition, enhanced pulsating impact, and blockage trends, significantly improving the safety and controllability of grouting construction in coal mine goafs.

Description

Technical Field

[0001] This invention relates to the field of monitoring technology for goaf filling, and in particular to an integrated sandwich-type fiber optic sensing method for monitoring the state of grouting pipe mud. Background Technology

[0002] Grouting and filling of coal mine goaf areas is an important means of controlling surface subsidence and mitigating mining-related disasters. During the grouting process, the flow state of the slurry within the grouting pipeline directly affects the filling efficiency and project quality. The underground grouting environment is complex, with long pipeline distances, numerous bends, frequent fluctuations in slurry concentration, and easy deposition of solid particles. Grouting pipelines are highly susceptible to abnormal conditions such as slowed flow, localized deposition, intermittent pulsating impacts, and even blockages. Once a blockage occurs, it often requires work stoppage, dismantling, or replacement of the pipeline, significantly increasing construction costs and safety risks. In coal mine goaf grouting construction, point sensors such as pressure gauges and flow meters are commonly used to monitor grouting conditions, or manual judgment is relied upon based on the experience of on-site operators. These methods can only obtain local or overall information about the pipeline, making it difficult to achieve distributed and continuous sensing of the slurry flow state along the pipeline. Abnormal conditions are detected late, and early signs of blockage are difficult to capture in a timely manner. To achieve early warning and proactive intervention, fiber optic sensing technology has been gradually introduced into the pipeline monitoring field in recent years due to its advantages such as resistance to electromagnetic interference, corrosion resistance, and the ability to achieve long-distance distributed measurement. In existing solutions for applying fiber optic sensing technology to grouting pipeline monitoring, the fiber optic sensors are mostly arranged by "attaching to the inner or outer surface of the pipeline." This method has the following shortcomings: First, when the fiber is attached to the inner wall, it is easily subjected to continuous scouring and abrasion from high-concentration solid particles in the slurry, leading to sensor wear, detachment, or failure. Second, when attached to the outer wall, due to the vibration isolation and filtering effect of the pipeline wall, it is difficult to effectively acquire the weak vibrations and acoustic signals generated by the slurry flow inside the pipe, limiting monitoring sensitivity. Third, whether attached to the inner or outer wall, secondary construction is required on the formed pipeline, which not only increases the workload on site but also makes it difficult to guarantee construction quality and ensures insufficient encapsulation reliability, making it difficult to meet the stringent requirements of long-term service in coal mines.

[0003] However, current common solutions have many drawbacks, including: existing fiber optic sensors in grouting pipeline monitoring technologies are generally attached to the inner or outer surface of the pipeline. Attachment to the inner wall is susceptible to erosion and debonding by mud particles, and can also damage the smoothness of the flow channel. Attachment to the outer wall results in severe signal attenuation and insufficient sensitivity due to vibration isolation. Traditional point-based monitoring methods such as pressure gauges and flow meters have blind spots, making it difficult to achieve distributed and continuous sensing along the pipeline. Anomaly detection is delayed, and the monitoring parameters are limited, lacking comprehensive acquisition of multiple physical quantities such as vibration, acoustics, and strain. This makes it impossible to effectively identify early abnormalities such as localized deposition, increased pulsating impact, and blockage trends. Sensors require secondary on-site installation after pipeline formation, which is labor-intensive and makes it difficult to guarantee packaging reliability. The monitoring system also lacks a linkage mechanism with grouting pumps and valve controllers, making proactive intervention impossible. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] To address the aforementioned problems in existing technologies, this invention provides an integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines.

[0006] Therefore, the purpose of this invention is to provide an integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines. This method addresses the common practice in existing grouting pipeline monitoring technologies of attaching fiber optic sensors to the inner or outer wall of the pipeline. Attaching to the inner wall is susceptible to erosion and debonding by slurry particles, and can also disrupt the smoothness of the flow channel. Attaching to the outer wall results in severe signal attenuation and insufficient sensitivity due to vibration isolation. Traditional point-based monitoring methods such as pressure gauges and flow meters have blind spots, making it difficult to achieve distributed and continuous sensing along the pipeline. Anomaly detection is delayed, and the monitoring parameters are limited, lacking comprehensive acquisition of multiple physical quantities such as vibration, acoustics, and strain. This makes it difficult to effectively identify early abnormalities such as localized deposition, increased pulsating impact, and blockage trends. Furthermore, the sensors require secondary on-site installation after pipeline formation, which is labor-intensive and makes it difficult to guarantee packaging reliability. The monitoring system also lacks a linkage mechanism with the grouting pump and valve controller, hindering proactive intervention.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: In a first aspect, embodiments of the present invention provide an integrated sandwich-type fiber optic sensing method for monitoring the state of grouting pipeline slurry, comprising: S1: During the manufacturing or forming process of a double-layer sleeve-type grouting pipeline assembly, an integrated sandwich-type fiber optic sensing component is pre-embedded within the pipeline interlayer space between its inner liner and outer protective pipe, and positioned and encapsulated by an interlayer fixing and sealing protection component to keep the inner surface of the pipeline flat; S2: During the grouting operation, the vibration, acoustic, and strain response signals of the sandwich-type fiber optic sensing component distributed along the pipeline are acquired in real time by a fiber optic demodulation acquisition module; S3: The acquired distributed sensing signals are pre-processed by an analysis and early warning module to extract time-domain, frequency-domain, and spatial distribution characteristic parameters, and the flow state of slurry in the pipeline is identified based on the characteristic parameters; S4: When abnormal conditions including slurry flow interruption, abnormal flow velocity, enhanced pulsation impact, and local deposition or blockage trend are identified, an early warning information is output and the location of the abnormality is located.

[0008] As a preferred embodiment of the integrated sandwich-type fiber optic sensing method for monitoring the mud condition of grouting pipelines according to the present invention, in step S1, during the manufacturing or forming process of the sandwich-type mudguard, the sandwich-type fiber optic sensing component of the mudguard is integrated and pre-embedded within the sandwich space of the mudguard body; during the manufacturing or forming process of the sandwich-type slurry tank, the sandwich-type fiber optic sensing component of the slurry tank is integrated and pre-embedded within the sandwich space of the tank wall; the sandwich-type fiber optic sensing component of the mudguard, the sandwich-type fiber optic sensing component of the grouting pipeline, and the sandwich-type fiber optic sensing component of the slurry tank are respectively connected to the fiber optic demodulation and acquisition module through independent fiber optic channels to realize independent acquisition and differentiation of signals from each monitoring zone.

[0009] As a preferred embodiment of the integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines according to the present invention, the fiber optic demodulation acquisition module in step S2 includes a distributed acoustic sensing (DAS) demodulation module, a distributed strain sensing (DSS) demodulation module, and a distributed temperature sensing (DTS) demodulation module; wherein the spatial resolution of DAS and DSS is set in the range of 0.1m to 5m, the DAS sampling frequency is set in the range of 1kHz to 100kHz, and the DSS measurement resolution is not less than 1με.

[0010] As a preferred embodiment of the integrated sandwich fiber optic sensing method for monitoring the slurry condition of grouting pipelines according to the present invention, the characteristic parameters in step S3 include at least one of the following: time domain amplitude, root mean square, peak factor, kurtosis, pulsation intensity, energy spectral density, characteristic frequency band energy ratio, correlation index, or spatial continuity index; the working condition identification is achieved based on threshold rules, baseline models, statistical discrimination, or machine learning models.

[0011] As a preferred embodiment of the integrated sandwich fiber optic sensing grouting pipeline mud condition monitoring method of the present invention, wherein: the early warning information in step S4 includes the abnormality type, abnormality location and risk level, and is visualized and output through a display terminal; when the abnormal working condition is identified, the method links the grouting pump controller or valve controller according to the early warning information to perform at least one of the following actions: speed reduction, pump stoppage, backflushing or pipeline switching.

[0012] As a preferred embodiment of the integrated sandwich-type fiber optic sensing method for monitoring the slurry status of grouting pipelines according to the present invention, the specific manner in which the linkage grouting pump controller or valve controller performs the handling action is as follows: the analysis and early warning module converts the early warning information into control commands and transmits them to the grouting pump controller or valve controller through a preset communication protocol; the grouting pump controller reduces the speed of the grouting pump or stops operation according to the command; the valve controller switches the status of the pipeline valves according to the command, starts the backflushing process, or switches the grouting channel to the backup pipeline.

[0013] As a preferred embodiment of the integrated sandwich fiber optic sensing grouting pipeline mud condition monitoring method of the present invention, wherein: when the analysis and early warning module detects a blockage trend, it first performs a speed reduction or backflushing action; if the abnormal characteristics are not eliminated or continue to deteriorate within a specified time, it performs a pump stop action and issues a high-level alarm.

[0014] Secondly, to further solve the above-mentioned technical problems, the present invention provides an integrated sandwich-type fiber optic sensing grouting pipeline mud condition monitoring system, comprising: a double-layer grouting module, used to integrate and pre-embed the sandwich-type fiber optic sensing component of the grouting pipeline into the pipe sandwich space between its inner liner and outer protective pipe during the manufacturing or forming process of the double-layer sleeve-type grouting pipeline assembly, and to position and encapsulate it through the sandwich fixing and sealing protection component to keep the inner surface of the pipeline flat; a signal acquisition module, used to acquire in real time the vibration, acoustic and strain response signals of the sandwich-type fiber optic sensing component of the grouting pipeline distributed along the pipeline through the fiber optic demodulation acquisition module during the grouting operation; an analysis and early warning module, used to preprocess the acquired distributed sensing signals, extract time domain, frequency domain and spatial distribution characteristic parameters, and identify the flow state of mud in the pipeline based on the characteristic parameters; and an information output module, used to output early warning information and locate the location segment where the abnormality occurs when abnormal conditions including mud flow interruption, abnormal flow velocity, enhanced pulsation impact, local deposition or blockage trend are identified.

[0015] Thirdly, embodiments of the present invention provide a computer device, including a memory and a processor, wherein the memory stores a computer program, and the computer program, when executed by the processor, implements any of the steps of the integrated sandwich fiber optic sensing grouting pipeline mud condition monitoring method as described in the first aspect of the present invention.

[0016] Fourthly, embodiments of the present invention provide a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program is executed by a processor, it implements any step of the integrated sandwich fiber optic sensing grouting pipeline mud condition monitoring method as described in the first aspect of the present invention.

[0017] The beneficial effects of this invention are as follows: By integrating the distributed optical fiber sensing components into the interlayer space during the manufacturing process of the double-layer sleeve, mudguard, and slurry storage tank, the invention keeps the inner surface of the flow channel flat, completely avoiding the wear and de-adhesion problems caused by direct contact between the sensor and the mud, and solving the signal attenuation defects caused by the outer wall attachment; through the integration of distributed acoustic, strain, and temperature sensing modules, continuous acquisition of multiple physical quantities such as vibration, acoustic, strain, and temperature along the entire pipeline is achieved. Combined with the intelligent extraction of time-domain, frequency-domain, and spatial distribution characteristic parameters and the identification of thresholds, baselines, or machine learning models, it can accurately locate sections with abnormal conditions such as mud flow interruption, local deposition, enhanced pulsation impact, and blockage trend. Based on the graded linkage strategy, it automatically executes actions such as deceleration, backwashing, pump shutdown, or pipeline switching, forming a closed-loop monitoring of the entire process from slurry supply and transportation to the filling terminal, which significantly improves the safety and controllability of grouting construction in coal mine goaf areas. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 This is a schematic diagram of the system composition and signal control path of the device of the present invention; Figure 2 Schematic diagram of a grouting device for goaf areas; Figure 3 A schematic diagram of the sandwich-type fiber optic sensing component for grouting pipelines laid in a sandwich layer along the pipeline axis. Figure 4 This is a schematic diagram of the cross-section of sandwich optical fibers symmetrically distributed in four and eight directions around the circumference of the pipe. Figure 5 This is a schematic diagram of the signal acquisition, analysis, and early warning process.

[0019] In the figure: 1— Sandwiched mudguard; 2—Double-layer sleeve grouting pipe assembly; 3—Support; 4—Sandwiched grout storage tank; 5—Mudguard sandwiched fiber optic sensing assembly; 6—Grouting pipe sandwiched fiber optic sensing assembly; 7—Grouting tank sandwiched fiber optic sensing assembly; 8—Display terminal. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0023] Example 1 Reference Figures 1-5 This is the first embodiment of the present invention, which provides an integrated sandwich-type fiber optic sensing method for monitoring the mud condition of grouting pipelines, comprising the following steps: S1: During the manufacturing or forming process of the double-layer sleeve grouting pipe assembly (2), the grouting pipe sandwich fiber optic sensing assembly (6) is embedded in the pipe sandwich space between its inner liner and outer protective pipe, and is positioned and encapsulated by the sandwich fixing and sealing protection assembly to keep the inner surface of the pipe flat.

[0024] Preferably, in step S1, during the manufacturing or forming process of the sandwich mudguard (1), the sandwich fiber optic sensing component (5) of the mudguard is integrated and pre-embedded in the sandwich space of the mudguard body, and during the manufacturing or forming process of the sandwich slurry tank (4), the sandwich fiber optic sensing component (7) of the slurry tank is integrated and pre-embedded in the sandwich space of the tank wall. The mudguard sandwich fiber optic sensing component (5), the grouting pipe sandwich fiber optic sensing component (6) and the grout storage tank sandwich fiber optic sensing component (7) are respectively connected to the fiber optic demodulation acquisition module through independent fiber optic channels to realize independent acquisition and differentiation of signals in each monitoring zone.

[0025] Furthermore, the interlayer fixing and sealing protection component includes an interlayer receiving groove or interlayer cavity prefabricated during the manufacturing process of the double-layer sleeve grouting pipe component (2). The interlayer receiving groove is set continuously or intermittently along the pipe axis to accommodate and limit the interlayer fiber optic sensing component (6) of the grouting pipe. An elastic buffer layer is set on the inner wall of the interlayer receiving groove to absorb the thermal stress and mechanical vibration generated during manufacturing and service. After the fiber optic sensing component is installed, a wear-resistant sealing cover layer is used to fill and seal the interlayer receiving groove. The wear-resistant sealing cover layer is formed by epoxy resin, polyurethane or ceramic matrix composite material, which forms an integral solidified structure with the outer wall of the inner liner and the inner wall of the outer protective pipe, so that the fiber optic sensing component is completely encapsulated in the interlayer space, while ensuring that the inner surface of the inner liner remains absolutely flat without protrusions.

[0026] Specifically, the sandwich mudguard (1) has a grid-like guide groove in the sandwich space of the plate body, and the sandwich fiber optic sensing component (5) of the mudguard is arranged in a grid pattern in the guide groove to cover the main area of ​​the mudguard that is impacted; the sandwich slurry tank (4) has a spiral or vertically arranged annular guide groove in the sandwich space of the tank wall, and the sandwich fiber optic sensing component (7) of the slurry tank is arranged along the guide groove to sense the structural response of the tank in the circumferential and height directions.

[0027] S2: During the grouting operation, the vibration, acoustic and strain response signals of the sandwich fiber optic sensing component (6) distributed along the grouting pipe are collected in real time by the fiber optic demodulation acquisition module.

[0028] Preferably, the fiber optic demodulation acquisition module in step S2 includes a distributed acoustic sensing DAS demodulation module, a distributed strain sensing DSS demodulation module, and a distributed temperature sensing DTS demodulation module. The spatial resolution of DAS and DSS is set in the range of 0.1m to 5m, the DAS sampling frequency is set in the range of 1kHz to 100kHz, and the DSS measurement resolution is not less than 1με.

[0029] Specifically, the distributed acoustic sensing DAS demodulation module uses phase-sensitive optical time-domain reflectometry (Φ-OTDR) technology to demodulate vibration and acoustic signals distributed along the optical fiber by injecting coherent optical pulses into the fiber and detecting the phase change of the backscattered Rayleigh light; the distributed strain sensing DSS demodulation module uses Brillouin optical time-domain analysis (BOTDA) or Brillouin optical time-domain reflectometry (BOTDR) technology to demodulate strain values ​​distributed along the optical fiber by detecting changes in Brillouin frequency shift; and the distributed temperature sensing DTS demodulation module uses Raman optical time-domain reflectometry (ROTDR) technology to demodulate temperature values ​​distributed along the optical fiber by detecting the intensity ratio of the anti-Stokes light to the Stokes light.

[0030] Furthermore, the sampling frequency of the DAS demodulation module is adaptively adjusted according to the pulse frequency of the grouting pump and the characteristic frequency of mud particle scouring. When enhanced pulsating impact is detected, the sampling frequency is automatically increased to a maximum of 100kHz to fully capture the details of high-frequency impact. The DSS demodulation module automatically densifies the strain acquisition points in stress concentration areas such as pipe bends, diameter changes, and valves to achieve refined monitoring of local strain fields.

[0031] S3: The analysis and early warning module preprocesses the collected distributed sensor signals, extracts time-domain, frequency-domain, and spatial distribution characteristic parameters, and identifies the flow state of the mud in the pipeline based on the characteristic parameters.

[0032] Preferably, the characteristic parameters in step S3 include at least one of the following: time-domain amplitude, root mean square, peak factor, kurtosis, pulsation intensity, energy spectral density, characteristic band energy ratio, correlation index, or spatial continuity index. Operating condition identification is achieved based on threshold rules, baseline models, statistical discrimination, or machine learning models.

[0033] Further, the preprocessing includes: using wavelet threshold denoising to suppress high-frequency random noise, using sliding median filtering to remove abnormal pulse interference, and using adaptive filtering to eliminate background noise generated by the periodic vibration of the grouting pump; the denoised signal is segmented into fixed time windows with a window length of 1s to 60s and a 50% overlap rate between adjacent windows to ensure the continuity of signal processing.

[0034] Specifically, in the time domain characteristic parameters, the root mean square value reflects the average energy level of the signal, the peak factor reflects the strength of the impact component, and the kurtosis reflects whether there are sudden pulses in the signal; the frequency domain characteristic parameters are obtained through fast Fourier transform, the energy spectral density reflects the energy distribution of each frequency component, and the characteristic frequency band energy ratio is used to extract the energy proportion of characteristic frequency bands (such as the 100Hz-500Hz frequency band) related to mud particle collisions and pulsating impacts; the spatial distribution characteristic parameters include the correlation coefficient of signals from adjacent measuring points and the spatial continuity index of the signal along the pipeline, which are used to determine whether the anomaly is local or global.

[0035] Furthermore, the baseline model is established using stable operating condition signals within the first 5 to 10 minutes after grouting begins, including the mean, standard deviation, and normal fluctuation range of each feature parameter; the threshold rule sets a dynamic threshold based on the statistical results of the baseline model, and anomalies are judged when the feature parameter exceeds the mean ± 3 times the standard deviation; the machine learning model uses support vector machines, random forests, or convolutional neural networks, with historically labeled grouting condition data as training samples, to achieve automatic classification and identification of abnormal operating conditions.

[0036] Specifically, when the mud flows normally in the pipeline, the vibration signal is stably and randomly distributed, the strain signal remains relatively stable, and the temperature changes slowly along the pipeline. When the mud flow velocity increases abnormally, the root mean square value of the vibration signal increases, and the energy ratio of the characteristic frequency band shifts to higher frequencies. When local deposition occurs, the vibration signal energy in the deposition section attenuates, the strain signal shows a local increase in positive strain, and the temperature rises locally due to frictional heating. When the pulsating impact intensifies, the peak factor and kurtosis increase significantly, and periodic impact pulses appear in the signal. When a blockage trend forms, the vibration signal upstream of the blockage point intensifies, the strain signal continues to rise, the signal downstream of the blockage point attenuates severely, and the spatial continuity index decreases significantly.

[0037] S4: When abnormal operating conditions are detected, including mud flow interruption, abnormal flow velocity, enhanced pulsation impact, local deposition or blockage trend, an early warning message is output and the location of the abnormality is located.

[0038] Preferably, the warning information in step S4 includes the anomaly type, anomaly location and risk level, and is visualized and output through the display terminal (8); When an abnormal operating condition is detected, the method will trigger the grouting pump controller or valve controller to perform at least one of the following actions: speed reduction, pump shutdown, backflushing, or pipeline switching, based on the early warning information.

[0039] Specifically, the method by which the linkage grouting pump controller or valve controller executes the handling action is as follows: the analysis and early warning module converts the early warning information into control commands and transmits them to the grouting pump controller or valve controller through a preset communication protocol; the grouting pump controller reduces the speed of the grouting pump or stops operation according to the command; the valve controller switches the status of the pipeline valves according to the command, starts the backwashing process or switches the grouting channel to the backup pipeline.

[0040] Furthermore, when the analysis and early warning module detects a blockage trend, it first performs a speed reduction or backflushing action; if the abnormal characteristics are not eliminated or continue to worsen within a specified time, it performs a pump shutdown action and issues a high-level alarm.

[0041] Furthermore, the location of the anomaly is achieved through the principle of optical time-domain reflection: the propagation time of the optical signal from the optical fiber input end to the anomaly feature point is calculated, and the distance to the anomaly point is calculated according to the formula L=(c×t) / (2n) in combination with the optical fiber refractive index and the speed of light, where L is the length of the distance from the anomaly point to the input end, c is the speed of light in vacuum, t is the time delay from the emission of the optical pulse to the receipt of the anomaly feature echo signal, and n is the refractive index of the optical fiber core; the display terminal (8) displays the anomaly location in the form of a pipeline schematic diagram and uses different colors to indicate the risk level: yellow represents mild anomaly (such as local deposition, enhanced pulsation), orange represents moderate anomaly (such as abnormal flow velocity, blockage trend), and red represents high anomaly (such as flow interruption, impending blockage).

[0042] Specifically, when local deposition is detected, the display terminal (8) displays a deposition icon and the percentage of deposition at the corresponding position on the pipeline diagram; when a blockage trend is detected, the display terminal (8) automatically pops up a treatment suggestion window, providing options such as "reduce speed", "backwash", and "stop pump" for the operator to confirm. At the same time, if the system has already started the automatic linkage mode, the preset treatment strategy will be executed automatically.

[0043] In summary, this invention integrates distributed optical fiber sensing components into the interlayer space during the manufacturing process of the double-layer sleeve, mudguard, and slurry storage tank, keeping the inner surface of the flow channel flat and completely avoiding wear and debonding problems caused by direct contact between the sensor and the slurry. It also solves the signal attenuation defects caused by external wall attachment. Through the integration of distributed acoustic, strain, and temperature sensing modules, continuous acquisition of multiple physical quantities such as vibration, acoustics, strain, and temperature along the entire pipeline is achieved. Combined with intelligent extraction of time-domain, frequency-domain, and spatial distribution characteristic parameters and threshold, baseline, or machine learning model identification, it can accurately locate sections with abnormal conditions such as slurry flow interruption, local deposition, enhanced pulsation impact, and blockage trends. Based on a graded linkage strategy, it automatically executes actions such as speed reduction, backwashing, pump shutdown, or pipeline switching, forming a closed-loop monitoring system from slurry supply and transportation to the filling terminal. This significantly improves the safety and controllability of grouting construction in coal mine goaf areas.

[0044] Example 2, an embodiment of the present invention, provides an integrated sandwich-type fiber optic sensing grouting pipeline mud condition monitoring system, comprising: a double-layer grouting module, used to integrate and pre-embed the sandwich-type fiber optic sensing component of the grouting pipeline into the pipe sandwich space between its inner liner and outer protective pipe during the manufacturing or forming process of the double-layer sleeve-type grouting pipeline assembly, and to position and encapsulate it through a sandwich fixing and sealing protection component to keep the inner surface of the pipeline flat; a signal acquisition module, used to acquire in real time the vibration, acoustic and strain response signals of the sandwich-type fiber optic sensing component distributed along the pipeline during the grouting operation through a fiber optic demodulation acquisition module; an analysis and early warning module, used to preprocess the acquired distributed sensing signals, extract time-domain, frequency-domain and spatial distribution characteristic parameters, and identify the flow state of mud in the pipeline based on the characteristic parameters; and an information output module, used to output early warning information and locate the location segment where the abnormality occurs when abnormal conditions including mud flow interruption, abnormal flow velocity, enhanced pulsation impact, and local deposition or blockage trend are identified.

[0045] Example 3 is an embodiment of the present invention, which differs from the previous embodiment in that: If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0046] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-including system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0047] More specific examples of computer-readable media (a non-exhaustive list) include: electrical connections (electronic devices) having one or more wires, portable computer disk drives (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, computer-readable media can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in computer memory.

[0048] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0049] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An integrated sandwich-type fiber optic sensing method for monitoring the state of grouting pipeline mud, characterized in that: include: S1: During the manufacturing or forming process of the double-layer sleeve grouting pipe assembly (2), the grouting pipe sandwich fiber optic sensing assembly (6) is embedded in the pipe sandwich space between its inner liner and outer protective pipe, and is positioned and encapsulated by the sandwich fixing and sealing protection assembly to keep the inner surface of the pipe flat. S2: During the grouting operation, the vibration, acoustic and strain response signals of the sandwich fiber optic sensing component (6) distributed along the grouting pipe are collected in real time by the fiber optic demodulation acquisition module. S3: The analysis and early warning module preprocesses the collected distributed sensor signals, extracts time-domain, frequency-domain, and spatial distribution characteristic parameters, and identifies the flow state of the mud in the pipeline based on the characteristic parameters. S4: When abnormal operating conditions are detected, including mud flow interruption, abnormal flow velocity, enhanced pulsation impact, local deposition or blockage trend, output early warning information and locate the location of the abnormality.

2. The integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines as described in claim 1, characterized in that: In step S1, during the manufacturing or forming process of the sandwich mudguard (1), the sandwich fiber optic sensing component (5) of the mudguard is embedded in the sandwich space of the plate body, and during the manufacturing or forming process of the sandwich slurry tank (4), the sandwich fiber optic sensing component (7) of the slurry tank is embedded in the sandwich space of the tank wall. The mudguard sandwich fiber optic sensing component (5), the grouting pipe sandwich fiber optic sensing component (6) and the slurry tank sandwich fiber optic sensing component (7) are respectively connected to the fiber optic demodulation acquisition module through independent fiber optic channels to realize independent acquisition and differentiation of signals in each monitoring zone.

3. The integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines as described in claim 1, characterized in that: The fiber optic demodulation acquisition module in step S2 includes a distributed acoustic sensing DAS demodulation module, a distributed strain sensing DSS demodulation module, and a distributed temperature sensing DTS demodulation module. The spatial resolution of DAS and DSS is set in the range of 0.1m to 5m, the DAS sampling frequency is set in the range of 1kHz to 100kHz, and the DSS measurement resolution is not less than 1με.

4. The integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines as described in claim 1, characterized in that: The characteristic parameters in step S3 include at least one of the following: time-domain amplitude, root mean square, peak factor, kurtosis, pulsation intensity, energy spectral density, characteristic band energy ratio, correlation index, or spatial continuity index. The operating condition identification is achieved based on threshold rules, baseline models, statistical discrimination, or machine learning models.

5. The integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines as described in claim 1, characterized in that: The warning information in step S4 includes the anomaly type, anomaly location and risk level, and is visualized and output through the display terminal (8); When an abnormal operating condition is detected, the method will trigger the grouting pump controller or valve controller based on the early warning information to perform at least one of the following actions: speed reduction, pump shutdown, backflushing, or pipeline switching.

6. The integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines as described in claim 5, characterized in that: The specific manner in which the linkage grouting pump controller or valve controller performs the handling action is as follows: the analysis and early warning module converts the early warning information into control commands and transmits them to the grouting pump controller or valve controller through a preset communication protocol; the grouting pump controller reduces the speed of the grouting pump or stops operation according to the command; the valve controller switches the status of the pipeline valves according to the command, starts the backwashing process or switches the grouting channel to the backup pipeline.

7. The integrated sandwich-type fiber optic sensing method for monitoring the slurry condition of grouting pipelines as described in claim 6, characterized in that: When the analysis and early warning module detects a blockage trend, it first performs a speed reduction or backflushing action; if the abnormal characteristics are not eliminated or continue to worsen within a specified time, it performs a pump shutdown action and issues a high-level alarm.

8. An integrated sandwich-type fiber optic sensing grouting pipeline slurry condition monitoring system, based on the integrated sandwich-type fiber optic sensing grouting pipeline slurry condition monitoring method according to any one of claims 1 to 7, characterized in that: include, The double-layer grouting module is used in the manufacturing or forming process of double-layer sleeve grouting pipe assembly to integrate the grouting pipe sandwich fiber optic sensing component into the pipe sandwich space between its inner liner and outer protective pipe, and to position and encapsulate it through sandwich fixing and sealing protection components to keep the inner surface of the pipe flat. The signal acquisition module is used to acquire, in real time, the vibration, acoustic and strain response signals of the sandwich fiber optic sensing component distributed along the grouting pipe during the grouting operation through the fiber optic demodulation acquisition module. The analysis and early warning module is used to preprocess the collected distributed sensor signals, extract time-domain, frequency-domain and spatial distribution feature parameters, and identify the flow state of mud in the pipeline based on the feature parameters. The information output module is used to output early warning information and locate the location of the abnormality when abnormal working conditions are detected, including mud flow interruption, abnormal flow velocity, enhanced pulsation impact, local deposition or blockage trend.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, it implements the steps of the integrated sandwich fiber optic sensing grouting pipeline mud condition monitoring method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the integrated sandwich fiber optic sensing grouting pipeline mud condition monitoring method according to any one of claims 1 to 7.

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