A hydraulic engineering structure leakage monitoring system and method

Abstract

The application provides a water conservancy structure leakage monitoring system and method, and the system comprises: an active heating control module, which applies a controllable thermal excitation to a grating array temperature sensing module; the grating array temperature sensing module generates a temperature distribution of a region to be measured, and the temperature distribution comprises a reference temperature distribution before the controllable thermal excitation is applied, a heating temperature distribution during the controllable thermal excitation is applied, and a cooling temperature distribution after the controllable thermal excitation is stopped; a leakage identification module, which determines a temperature-time response curve based on the reference temperature distribution, the heating temperature distribution and the cooling temperature distribution, extracts a temperature rise rate, a maximum temperature rise amplitude, a peak time, a cooling rate and a thermal time constant in the temperature-time response curve, determines a comprehensive discrimination index based on the above parameters, and determines whether the water conservancy structure has leakage based on the comprehensive discrimination index. The application improves the sensitivity and accuracy of leakage monitoring.

Description

Technical Field

[0001] This invention relates to the field of hydraulic engineering structural health monitoring technology, specifically to a hydraulic engineering structural leakage monitoring system and method. Background Technology

[0002] During long-term service, leakage is one of the most common and harmful defects in hydraulic engineering structures. Leakage not only leads to water resource loss and reduced project efficiency, but can also trigger catastrophic accidents such as internal erosion, piping, and even dam failure. Therefore, leakage monitoring of hydraulic engineering structures such as dikes, canals, sluice chambers, and anti-seepage walls, especially the early identification and precise location of well-hidden internal leakage channels, is a core technical requirement for ensuring the safe operation of these projects.

[0003] Currently, leakage monitoring in water conservancy projects mainly employs methods such as piezometers, high-density electrical resistivity tomography (EDT), and manual inspection. Traditional piezometers are point sensors, and their placement relies on experience-based prediction, making it difficult to achieve continuous spatial sensing and precise location of leakage channels. While geophysical methods such as high-density EDT have a wide coverage area, they are periodic offline detection methods, unable to achieve continuous online monitoring. Furthermore, the equipment is complex and costly, making it unsuitable for long-term, routine monitoring of large-scale, long-distance water conservancy projects. Manual inspection has both low efficiency and accuracy.

[0004] In recent years, fiber optic leakage monitoring methods based on active heating have applied thermal excitation to the monitoring area using heating cables, and utilized distributed fiber optic temperature sensing technology to obtain temperature distribution, thereby identifying leaks by recognizing localized low-temperature anomalies. However, these methods still have the following inherent limitations: First, the identification mechanism is singular, mainly relying on steady-state temperature characteristics, lacking analysis of the dynamic response throughout the heating-cooling process, resulting in limited ability to identify minute seepage; second, they only focus on whether the temperature value exceeds a threshold, failing to extract fine dynamic temperature change characteristic parameters such as the rate of temperature rise and cooling rate, thus affecting the accuracy of leakage identification.

[0005] Therefore, there is an urgent need to provide a system and method for monitoring leakage in water conservancy engineering structures, so as to achieve high sensitivity and high accuracy in identifying leakage in water conservancy engineering structures. Summary of the Invention

[0006] In view of this, it is necessary to provide a leakage monitoring system and method for hydraulic engineering structures to solve the technical problems of existing technologies, such as the lack of analysis of the dynamic response of the entire heating-cooling process and the focus on whether the temperature value exceeds the threshold without extracting fine dynamic temperature change characteristic parameters such as the temperature rise rate and cooling rate, resulting in low sensitivity and accuracy of leakage identification.

[0007] To address the aforementioned technical problems, in a first aspect, the present invention provides a leakage monitoring system for hydraulic engineering structures, comprising: an active heating control module, a grating array temperature sensing module, and a leakage identification module; The active heating control module is used to apply controllable thermal excitation to the grating array temperature sensing module; The grating array temperature sensing module is set in the test area of ​​the hydraulic engineering structure to generate the temperature distribution of the test area. The temperature distribution includes the reference temperature distribution before the application of the controllable thermal excitation, the heating temperature distribution during the application of the controllable thermal excitation, and the cooling temperature distribution after the application of the controllable thermal excitation is stopped. The leakage identification module is used to determine the temperature-time response curve based on the reference temperature distribution, the heating temperature distribution, and the cooling temperature distribution, and to extract the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant from the temperature-time response curve. Based on the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, a comprehensive discrimination index is determined, and based on the comprehensive discrimination index, it is determined whether the hydraulic engineering structure has leaked.

[0008] In one possible implementation, the active heating control module includes: A heating power adjustment unit is used to adjust the heating power of the controllable thermal excitation; A heating time adjustment unit is used to adjust the heating duration of the controllable thermal excitation and the interval time between two adjacent heating cycles; The heating duration and the interval between two adjacent heating cycles can be adjusted to achieve either a periodic heating mode or an on-demand heating mode.

[0009] In one possible implementation, the grating array temperature sensing module includes a grating array sensing composite cable and a demodulation unit. The grating array sensing composite cable includes a temperature optical fiber, a thermally conductive material layer, and a pair of heating wires. The thermally conductive material layer covers the temperature optical fiber, the pair of heating wires is embedded in the thermally conductive material layer, and the pair of heating wires is connected to the active heating control module. The heating wires are used to transfer electrical energy to the thermally conductive material layer in response to the controllable thermal excitation; The thermally conductive material layer is used to generate heat after being energized, and to apply active thermal excitation to the area under test; The temperature fiber is used to sense temperature signals in the area under test before, during and after the application of active thermal excitation. The demodulation unit is connected to the temperature optical fiber and is used to demodulate the temperature sensing signal to generate the reference temperature distribution, the heating temperature distribution, and the cooling temperature distribution.

[0010] In one possible implementation, the grating array sensing composite cable further includes an isolation rubber sheath disposed between the temperature optical fiber and the thermally conductive material layer, and a water-blocking grease layer disposed between the temperature optical fiber and the isolation rubber sheath. The insulating rubber sleeve is used to physically isolate the temperature optical fiber from the external structure. The water-blocking grease layer is used to prevent moisture from penetrating along the axial direction of the temperature-sensitive optical fiber.

[0011] In one possible implementation, the grating array sensing composite cable further includes a double-sided coated steel strip covering the thermally conductive material layer, a rubber outer sheath covering the double-sided coated steel strip, and reinforcing ribs embedded in the rubber outer sheath; the double-sided coated steel strip provides longitudinal tensile strength for the grating array sensing composite cable, the reinforcing ribs provide tensile protection for the grating array sensing composite cable, and the rubber outer sheath provides waterproof and corrosion-resistant protection for the grating array sensing composite cable.

[0012] In one possible implementation, the leakage identification module includes a weight determination unit and a comprehensive discrimination index determination unit; The weighting unit is used to determine the weights of the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant based on the sensitivity to the convective heat transfer effect caused by seepage. The comprehensive discrimination index determination unit is used to standardize the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant to obtain multi-dimensional standardized parameters, and to perform weighted fusion of the multi-dimensional standardized parameters based on the weights to obtain the comprehensive discrimination index.

[0013] In one possible implementation, the comprehensive discrimination index corresponds one-to-one with the measurement points in the area to be tested, and the leakage identification module further includes a leakage identification unit; The leakage identification unit is used to determine whether the comprehensive discrimination index of the current measuring point is greater than the leakage threshold, and whether the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of at least one adjacent measuring point is greater than a preset difference. When the comprehensive discrimination index of the current measuring point is greater than the leakage threshold and the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of at least one adjacent measuring point is greater than the preset difference, it is determined that leakage has occurred at the current measuring point.

[0014] In one possible implementation, the leakage identification module further includes a leakage location unit, which is used to determine the location of the leakage based on the mapping relationship between the measuring point and the spatial location.

[0015] In one possible implementation, the system further includes a visualization module for displaying the temperature distribution of the hydraulic engineering structure and identifying the location of the leakage in the hydraulic engineering structure.

[0016] Secondly, the present invention also provides a method for monitoring leakage in hydraulic engineering structures, employing the hydraulic engineering structure leakage monitoring system described in any of the above possible implementations, the method comprising: The active heating control module applies controllable thermal excitation to the grating array temperature sensing module; The temperature distribution of the test area is generated by a grating array temperature sensing module set in the test area of ​​the hydraulic engineering structure. The temperature distribution includes a reference temperature distribution before the application of the controllable thermal excitation, a heating temperature distribution during the application of the controllable thermal excitation, and a cooling temperature distribution after the application of the controllable thermal excitation is stopped. Based on the reference temperature distribution, the heating temperature distribution, and the cooling temperature distribution, a temperature-time response curve is determined, and the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant are extracted from the temperature-time response curve. Based on the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, a comprehensive discrimination index is determined, and based on the comprehensive discrimination index, it is determined whether the hydraulic engineering structure has leaked.

[0017] The beneficial effects of this invention are as follows: The hydraulic engineering structure leakage monitoring system provided by this invention applies controllable thermal excitation to the area under test through an active heating control module, amplifying the convective heat transfer effect caused by seepage. Simultaneously, the leakage identification module extracts dynamic characteristic parameters such as temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant based on the temperature distribution throughout the entire process before heating, during heating, and after cooling, and constructs a comprehensive discrimination index for leakage identification. Compared to existing technologies that rely solely on static temperature distribution or steady-state temperature difference, this invention introduces time-dimensional information, enabling more sensitive capture of thermal response anomalies caused by minute seepage, effectively improving the ability to identify early-stage leakage, thus enhancing the sensitivity of leakage identification.

[0018] Furthermore, by extracting the dynamic response characteristics of the entire heating-cooling process for discrimination, the leakage identification results are made relatively independent of external interference factors such as ambient temperature fluctuations and solar radiation. Compared with existing technologies that rely on absolute temperature values ​​or simple threshold judgments, this method has stronger anti-interference capabilities and a lower false alarm rate, thus improving the accuracy of leakage identification. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0020] Figure 1 A schematic diagram of an embodiment of the hydraulic engineering structure leakage monitoring system provided by the present invention; Figure 2 A schematic diagram of an embodiment of the grating array sensing composite cable provided by the present invention; Figure 3 This is a schematic diagram of an embodiment of the leakage identification module provided by the present invention; Figure 4 This is a schematic flowchart of an embodiment of the water conservancy engineering structure leakage monitoring method provided by the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] It should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the invention. It should be understood that the operations in the flowcharts may be implemented out of order, and steps without logical contextual relationships may be reversed or performed simultaneously. Furthermore, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0023] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0024] This invention provides a system and method for monitoring leakage in hydraulic engineering structures, which will be described below.

[0025] Figure 1 This is a schematic diagram of an embodiment of the water conservancy engineering structure leakage monitoring system provided by the present invention, as shown below. Figure 1 As shown, the hydraulic engineering structure leakage monitoring system 10 includes: an active heating control module 100, a grating array temperature sensing module 200, and a leakage identification module 300; The active heating control module 100 is used to apply controllable thermal excitation to the grating array temperature sensing module.

[0026] Among them, by setting controllable thermal excitation, controllable heating can be achieved, avoiding the adverse effects on the hydraulic engineering structure caused by unstoppable heating, and improving the safety and reliability of system operation.

[0027] The grating array temperature sensing module 200 is set in the test area of ​​the hydraulic engineering structure to generate the temperature distribution of the test area. The temperature distribution includes the reference temperature distribution before the application of controllable thermal excitation, the heating temperature distribution during the application of controllable thermal excitation, and the cooling temperature distribution after the application of controllable thermal excitation is stopped.

[0028] Among them, the results of water conservancy projects include, but are not limited to, dams, canals, sluice chambers, culverts, and seepage barriers.

[0029] The leakage identification module 300 is used to determine the temperature-time response curve based on the reference temperature distribution, heating temperature distribution, and cooling temperature distribution, and to extract the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant from the temperature-time response curve. Based on the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, a comprehensive discrimination index is determined, and based on the comprehensive discrimination index, it is determined whether leakage has occurred in the hydraulic engineering structure.

[0030] The grating array temperature sensing module 200 includes multiple measuring points, each of which is used to monitor the temperature of a portion of the area to be measured.

[0031] Specifically, the temperature rise rate refers to the slope of the temperature increase at a measuring point over time during controlled thermal excitation, reflecting how quickly the medium's temperature rises after absorbing heat per unit time. In leakage identification, the temperature rise rate is a crucial dynamic characteristic distinguishing seepage areas from non-seepage areas: in non-seepage areas (such as dry soil or concrete), heat is primarily conducted, accumulating locally, resulting in a faster temperature rise rate; while in seepage areas, the presence of water allows for rapid heat removal through convection, inhibiting temperature rise and manifesting as a significantly reduced temperature rise rate. Therefore, by extracting the temperature rise rate and comparing it with neighboring measuring points or historical benchmarks, abnormal thermal responses caused by leakage can be effectively identified.

[0032] The maximum temperature rise refers to the difference between the temperature at the measuring point and the peak temperature during controlled thermal excitation, reflecting the highest temperature rise the medium can achieve under thermal excitation. This parameter directly characterizes the local heat accumulation capacity of the medium: in leak-free areas, heat accumulates in the medium, resulting in a higher maximum temperature rise; while in leaking areas, due to the continuous convective heat transfer of the seeping water, heat is rapidly carried away, significantly suppressing the temperature rise, and the maximum temperature rise is significantly lower than in the surrounding areas. Analyzing the spatial distribution differences of the maximum temperature rise can help identify the location of leaks and preliminarily assess the intensity of leaks.

[0033] Peak time refers to the time elapsed from the application of controlled thermal excitation to the temperature at the measuring point reaching its peak value, reflecting the length of time required for the medium to reach its maximum temperature rise. This parameter comprehensively reflects the coupled effect of the medium's thermal diffusion capacity and convective heat transfer intensity: in non-permeable regions, heat mainly relies on thermal conduction for diffusion, the heating process is relatively slow but continuous, and the peak time is relatively long; in permeable regions, the permeable water rapidly removes heat, the temperature rise is suppressed, and it may reach thermal equilibrium earlier, resulting in a shorter peak time. As a dynamic characteristic parameter of the heating stage, peak time, when analyzed in conjunction with the temperature rise rate, can more comprehensively characterize the impact of permeation on the thermal response process.

[0034] Cooling rate refers to the rate of temperature decrease at a measuring point over time after the controlled thermal excitation is stopped. It reflects how quickly the medium dissipates heat to the environment after losing an external heat source. In leak detection, cooling rate is a key indicator characterizing the intensity of convective heat transfer: in non-seepage areas, heat dissipation is mainly through conduction, resulting in a relatively slow cooling rate; in seepage areas, the cooling rate is significantly faster due to the continuous removal of heat by the flowing water. Compared to the heating phase, the cooling phase is less affected by fluctuations in active heating power and can more accurately reflect the local heat dissipation characteristics of the medium. Therefore, cooling rate is often used as a highly sensitive characteristic parameter for leak detection.

[0035] The thermal time constant refers to the characteristic parameter in the decay exponent when fitting the temperature-time curve using an exponential decay model during the cooling phase after the controllable thermal excitation has ceased. Its physical meaning is the time required for the temperature to drop from its peak value to the initial temperature difference. The thermal time constant comprehensively reflects the local heat capacity and thermal resistance characteristics of the medium: in dry or non-permeable regions, the medium has a large heat capacity and high thermal resistance, resulting in slow heat dissipation and a large thermal time constant; in permeable regions, the convective heat transfer of water significantly enhances heat loss, resulting in a smaller thermal time constant. As an integral characteristic parameter of the cooling phase, the thermal time constant has strong noise immunity and can stably characterize the overall heat dissipation characteristics of the medium.

[0036] The above five parameters together form the basis for leakage detection, which characterize the impact of seepage on the thermal response process from the heating stage (temperature rise rate, maximum temperature rise amplitude, peak time) and the cooling stage (cooling rate, thermal time constant). Through the fusion of multi-dimensional dynamic features, the sensitivity and reliability of leakage identification are significantly improved.

[0037] Compared with existing technologies, the hydraulic engineering structure leakage monitoring system 10 provided in this embodiment of the invention applies controllable thermal excitation to the area under test through the active heating control module 100, amplifying the convective heat transfer effect caused by seepage. Simultaneously, the leakage identification module 300 extracts dynamic characteristic parameters such as temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant based on the temperature distribution throughout the entire process before heating, during heating, and after cooling, and constructs a comprehensive discrimination index for leakage identification. Compared with existing technologies that rely solely on static temperature distribution or steady-state temperature difference, this system introduces time dimension information, enabling more sensitive capture of thermal response anomalies caused by minute seepage, effectively improving the ability to identify early leakage, thus enhancing the sensitivity of leakage identification.

[0038] Furthermore, by extracting the dynamic response characteristics of the entire heating-cooling process for discrimination, the leakage identification results are made relatively independent of external interference factors such as ambient temperature fluctuations and solar radiation. Compared with existing technologies that rely on absolute temperature values ​​or simple threshold judgments, this method has stronger anti-interference capabilities and a lower false alarm rate, thus improving the accuracy of leakage identification.

[0039] In specific embodiments of the present invention, such as Figure 1 As shown, the active heating control module 100 includes: The heating power adjustment unit 110 is used to adjust the heating power of the controllable thermal excitation; The heating time adjustment unit 120 is used to adjust the heating duration of the controllable thermal excitation and the interval time between two adjacent heating cycles; By adjusting the heating duration and the interval between two adjacent heating cycles, a periodic heating mode or an on-demand heating mode can be achieved.

[0040] This invention improves the applicability of the hydraulic engineering structure leakage monitoring system 10 by adjusting the heating duration and the interval between adjacent heating cycles to achieve either a periodic heating mode or an on-demand triggered heating mode. Specifically, when the monitoring requirement is an unattended field scenario, it can be set to a periodic heating mode to achieve a periodic automated monitoring mode.

[0041] In some embodiments of the present invention, such as Figure 1 and Figure 2As shown, the grating array temperature sensing module 200 includes a grating array sensing composite cable 210 and a demodulation unit 220. The grating array sensing composite cable 210 includes a temperature optical fiber 211, a thermally conductive material layer 212, and a heating wire pair 213. The thermally conductive material layer 212 covers the temperature optical fiber 211, the heating wire pair 213 is embedded in the thermally conductive material layer 212, and the heating wire pair 213 is connected to the active heating control module 100. Heating wires 213 are used to transfer electrical energy to the thermally conductive material layer 212 in response to controllable thermal excitation; The thermally conductive material layer 212 is used to generate heat after energization and apply active thermal excitation to the area to be measured; Temperature fiber optic cable 211 is used to sense temperature sensing signals in the area to be measured before, during and after the application of active thermal excitation. The demodulation unit 220 is connected to the temperature fiber optic cable 211 and is used to demodulate the temperature sensing signal to generate a reference temperature distribution, a heating temperature distribution, and a cooling temperature distribution.

[0042] Among them, the temperature fiber 211 is composed of multiple fiber Bragg gratings arranged uniformly or non-uniformly along the fiber axis. Each fiber Bragg grating serves as a measurement point. Through wavelength division / time division hybrid multiplexing technology, a large-scale quasi-distributed integration of tens of thousands of measurement points in a single channel is achieved, which is used to realize distributed temperature measurement along the length direction of the grating array sensing composite cable 210.

[0043] Specifically, the distance between adjacent measuring points can be set according to the actual monitoring, such as 1.0m or 0.1m.

[0044] It should be noted that, under the condition of meeting the requirements of temperature resolution and spatial positioning accuracy, fiber Bragg grating arrays can be replaced by distributed fiber optic sensing technology based on optical frequency domain reflection to achieve continuous measurement with higher spatial resolution.

[0045] To improve thermal conductivity, in a specific embodiment of the present invention, the heating wire pair 213 is a galvanized copper heating wire pair.

[0046] In a preferred embodiment of the present invention, the thermally conductive material layer 212 is a PTC (Positive Temperature Coefficient) thermally conductive rubber material layer. The rubber's flexibility allows the thermally conductive material layer 212 to fit tightly against the temperature optical fiber 211 and adapt to the bending and laying requirements of the grating array sensing composite cable 210, achieving integrated heating and sensing elements. The positive temperature coefficient has self-limiting temperature characteristics, which enable the grating array sensing composite cable 210 to automatically reduce its heating power when the temperature is too high, preventing localized overheating damage to the grating array sensing composite cable 210. This ensures both uniform and safe thermal excitation, while achieving long-term, stable, and controllable thermal excitation for hydraulic engineering structures.

[0047] In the actual service environment of hydraulic engineering structures, the grating array sensing composite cable 210 is buried underwater, in high-humidity soil or concrete structures for a long time. The temperature fiber 211 is easily affected by the axial penetration of water, which leads to optical signal attenuation and unstable wavelength drift, thus affecting the long-term reliability of temperature measurement. At the same time, if external mechanical strain (such as structural deformation, soil displacement, and laying tension) is directly transmitted to the fiber Bragg grating, due to its cross-sensitivity to strain and temperature, strain components will be mixed into the wavelength drift, causing temperature measurement distortion.

[0048] To solve the above-mentioned technical problems, in some embodiments of the present invention, such as Figure 2 As shown, the grating array sensing composite cable 210 also includes an isolation rubber sleeve 214 disposed between the temperature optical fiber 211 and the thermally conductive material layer 212, and a water-blocking grease layer 215 disposed between the temperature optical fiber 211 and the isolation rubber sleeve 214. The isolation rubber sleeve 214 is used to physically isolate the temperature optical fiber from the external structure; Water-blocking grease layer 215 is used to prevent moisture from penetrating along the axial direction of the temperature fiber.

[0049] This invention, through the placement of an insulating rubber sleeve 214 between the temperature fiber 211 and the thermally conductive material layer 212, physically isolates the temperature fiber 211 from the external structure. This ensures that the wavelength drift of the fiber Bragg grating responds only to changes in the temperature field, satisfying a pure temperature measurement relationship and improving the accuracy of leakage monitoring. Furthermore, a water-blocking grease layer 215 is filled between the temperature fiber 211 and the insulating rubber sleeve 214, providing a continuous waterproof barrier along the axial direction to prevent moisture penetration along the temperature fiber axially. The synergistic effect of these two elements effectively suppresses strain interference and water-induced damage, significantly improving the reliability, stability, and long-term service capability of temperature measurement.

[0050] Furthermore, leakage monitoring in water conservancy projects typically requires the laying of grating array sensing composite cables 210 in long-distance linear projects such as dams and canals. During the laying process, the grating array sensing composite cables 210 need to withstand large tensile tensions, and during long-term service, they also need to resist complex mechanical loads such as soil compression, water level changes, and water flow impacts. At the same time, underwater or deeply buried soil environments place stringent requirements on the waterproof and corrosion-resistant performance of the grating array sensing composite cables 210.

[0051] To ensure the long-term, stable monitoring of the grating array sensing composite cable 210 even in the face of the aforementioned complex and harsh environments, in some embodiments of the present invention, such as... Figure 2As shown, the grating array sensing composite cable 210 also includes a double-sided coated steel strip 216 covered with a thermally conductive material layer 212, a rubber outer sheath 217 covered with the double-sided coated steel strip 216, and a reinforcing rib 218 embedded in the rubber outer sheath 217; the double-sided coated steel strip 216 is used to provide longitudinal tensile strength for the grating array sensing composite cable 210, the reinforcing rib 218 is used to provide tensile protection for the grating array sensing composite cable 210, and the rubber outer sheath 217 is used to provide waterproof and corrosion-resistant protection for the grating array sensing composite cable 210.

[0052] This invention constructs a multi-layered mechanical protection and sealing structure by sequentially arranging a double-sided adhesive steel strip 216, reinforcing ribs 218, and a rubber outer sheath 217 on the outside of the thermally conductive material layer 212. The double-sided adhesive steel strip 216 serves as a longitudinal reinforcing layer, providing high tensile strength to prevent excessive stretching of the grating array sensing composite cable 210 during laying. The reinforcing ribs 218 embedded in the rubber outer sheath 217 further enhance tensile and impact resistance, ensuring the structural integrity of the grating array sensing composite cable 210 under complex working conditions. The rubber outer sheath 217, as the outermost layer, provides overall waterproof, corrosion-resistant, and wear-resistant protection, meeting IP68 protection requirements. The synergistic effect of these structures enables the grating array sensing composite cable 210 to possess both excellent mechanical strength and environmental adaptability, making it suitable for harsh working conditions such as underwater and deep-buried soil environments, thus meeting the engineering deployment requirements for long-distance hydraulic engineering structure leakage monitoring.

[0053] In a specific embodiment of the present invention, the reinforcing rib 218 is a KFRP reinforcing rib.

[0054] It should be noted that, depending on the different engineering conditions, the grating array sensing composite cable 210 can be laid out by drilling, surface grooving, traction through pipe or pre-embedding in the structure, so as to meet the differentiated needs of new and existing projects.

[0055] In actual identification, different dynamic characteristic parameters, namely temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, exhibit significant differences in their sensitivity to the convective heat transfer effect caused by seepage. If multiple features are processed using simple averaging or empirical thresholds, the importance of each feature in leakage identification cannot be distinguished. This leads to the dilution of strongly correlated features sensitive to seepage by weakly correlated features, reducing the sensitivity of the comprehensive discrimination index to identifying minor leaks.

[0056] To solve this technical problem, in some embodiments of the present invention, such as Figure 3 As shown, the leakage identification module 300 includes a weight determination unit 310 and a comprehensive discrimination index determination unit 320; The weighting determination unit 310 is used to determine the weights of the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant based on the sensitivity to the convective heat transfer effect caused by seepage.

[0057] In specific embodiments of the present invention, the cooling rate and thermal time constant have the highest weight, followed by the temperature rise rate and maximum temperature rise amplitude, while the peak time has the lowest weight. This weighting is based on the different sensitivities of each feature to the convective heat transfer effect caused by seepage: the cooling stage (cooling rate, thermal time constant) directly reflects the ability of the seeping water to remove heat through convective heat transfer, providing direct evidence of seepage, and is unaffected by fluctuations in active heating power, making it the purest feature with the highest sensitivity; while the temperature rise rate and maximum temperature rise amplitude of the heating stage can reflect the inhibitory effect of seepage on heat accumulation, they are significantly affected by factors such as heating power uniformity and initial temperature differences, resulting in lower sensitivity; the peak time, as a temporal characteristic of the heating stage, is influenced by the combined effects of the medium's heat capacity and heating conditions, exhibiting a lag and non-uniqueness in its response to seepage, thus having relatively low sensitivity.

[0058] The comprehensive discrimination index determination unit 320 is used to standardize the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate and thermal time constant to obtain multi-dimensional standardized parameters, and to perform weighted fusion of the multi-dimensional standardized parameters based on weights to obtain the comprehensive discrimination index.

[0059] This invention assigns weights to each feature based on its sensitivity to the convective heat transfer effect caused by seepage, ensuring that the feature most sensitive to leakage response dominates the fusion process. This effectively enhances the response amplitude of the comprehensive discrimination index to leakage signals, improving the sensitivity and accuracy of leakage identification. Simultaneously, before weighted fusion, each feature is standardized to eliminate differences in dimensions and numerical ranges, allowing different features to be weighted and fused on the same scale. This avoids interference from magnitude deviations in the discrimination results, further improving the sensitivity and anti-interference capability of leakage identification, and achieving reliable identification of even minor leaks.

[0060] Factors such as ambient temperature fluctuations, seasonal changes, or system baseline drift can cause a systematic shift in the overall discriminant index at different measuring points, making it easy to miss or false alarms if relying solely on fixed thresholds. Furthermore, thermal response anomalies caused by leakage typically exhibit localized concentration characteristics, meaning that the overall discriminant index at the leakage point differs significantly from that of the surrounding non-leaking areas.

[0061] Based on the above characteristics, in some embodiments of the present invention, such as Figure 3 As shown, the leakage detection module 300 also includes a leakage detection unit 330; The leakage identification unit 330 is used to determine whether the comprehensive discrimination index of the current measuring point is greater than the leakage threshold, and whether the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of at least one adjacent measuring point is greater than a preset difference. When the comprehensive discrimination index of the current measuring point is greater than the leakage threshold and the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of at least one adjacent measuring point is greater than the preset difference, it is determined that leakage has occurred at the current measuring point.

[0062] This invention, through its leakage identification unit 330, not only determines whether the comprehensive discrimination index of the current measuring point exceeds the leakage threshold, but also introduces a comparison condition with adjacent measuring points: whether the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of adjacent measuring points exceeds a preset difference. This dual judgment mechanism fully utilizes the spatial locality of leakage anomalies, effectively eliminating false judgments caused by global interference factors and significantly reducing the false alarm rate. Simultaneously, cross-validation using spatial neighborhood information makes the leakage identification results more robust and reliable, suitable for on-site monitoring scenarios in water conservancy projects with complex environments and numerous interference sources.

[0063] It should be noted that, since there are significant differences between the comprehensive discrimination index for leakage and non-leakage, in some other embodiments of the present invention, the comprehensive discrimination index of the current measuring point can be compared with the historical comprehensive discrimination index when no leakage occurred at the current measuring point. If the difference between the two is greater than a set difference, then leakage is determined to have occurred.

[0064] It should also be noted that the leakage threshold and preset difference can be adaptively set or adjusted according to the actual application scenario, and no specific limitation is made here.

[0065] To provide maintenance personnel with precise location information, in some embodiments of the present invention, such as Figure 3 As shown, the leakage identification module 300 also includes a leakage location unit 340, which is used to determine the location of leakage based on the mapping relationship between the measuring point and the spatial location.

[0066] That is, the location of leakage is determined based on the mapping relationship between the measurement point number and the spatial location.

[0067] The mapping relationship was established before the actual leakage monitoring was carried out.

[0068] In some embodiments of the present invention, to intuitively demonstrate the leakage monitoring results, such as... Figure 1 As shown, the hydraulic engineering structure leakage monitoring system 10 also includes a visualization module 400, which is used to display the temperature distribution of the hydraulic engineering structure and mark the location of leakage in the hydraulic engineering structure.

[0069] In summary, the hydraulic engineering structure leakage monitoring system proposed in this embodiment of the invention: 1. By actively applying thermal excitation to amplify the convective heat transfer effect caused by seepage and analyzing it based on the dynamic response characteristics of the entire temperature process, the system significantly enhances the ability to identify minute leaks compared to traditional static temperature discrimination methods, while effectively suppressing interference caused by environmental temperature fluctuations. 2. Relying on the spatial discrete distribution characteristics and high-precision temperature measurement capabilities of fiber Bragg grating arrays (FBGs), continuous sensing along the structural direction is achieved; combined with a multi-feature fusion discrimination method, precise location of the leakage point can be achieved, with the positioning accuracy determined by the spacing between measuring points. 3. The grating array sensing composite cable has excellent waterproof, corrosion-resistant, and mechanical protection performance, adaptable to underwater and buried environments, and supports various deployment methods to meet the requirements of different engineering structures and construction conditions. 4. The system integrates heating control, data acquisition, and analysis functions, enabling periodic or on-demand triggered automatic operation modes, reducing the need for manual inspections and improving the continuity and efficiency of monitoring work.

[0070] On the other hand, embodiments of the present invention also provide a method for monitoring leakage in hydraulic engineering structures, applicable to the hydraulic engineering structure leakage monitoring system in any of the above embodiments, such as... Figure 4 As shown, the methods for monitoring leakage in hydraulic engineering structures include: S401. The active heating control module applies controllable thermal excitation to the grating array temperature sensing module. S402. Based on the temperature sensing module of the grating array set in the test area of ​​the hydraulic engineering structure, the temperature distribution of the test area is generated. The temperature distribution includes the reference temperature distribution before the application of controllable thermal excitation, the heating temperature distribution during the application of controllable thermal excitation, and the cooling temperature distribution after the application of controllable thermal excitation is stopped. S403. Based on the reference temperature distribution, heating temperature distribution, and cooling temperature distribution, determine the temperature-time response curve, and extract the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant from the temperature-time response curve. Based on the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, determine the comprehensive discrimination index, and based on the comprehensive discrimination index, determine whether leakage has occurred in the hydraulic engineering structure.

[0071] It should be noted that the water conservancy engineering structure leakage monitoring method provided in the above embodiments can realize the technical solutions described in the above water conservancy engineering structure leakage monitoring system embodiments. The principles or specific implementation details of the above steps can be found in the corresponding content of the above water conservancy engineering structure leakage monitoring system embodiments, which will not be elaborated here.

[0072] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware (such as a processor, controller, etc.), and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0073] The above provides a detailed description of the leakage monitoring system and method for hydraulic engineering structures provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A leakage monitoring system for hydraulic engineering structures, characterized in that, include: Active heating control module, grating array temperature sensing module, and leakage detection module; The active heating control module is used to apply controllable thermal excitation to the grating array temperature sensing module; The grating array temperature sensing module is set in the test area of ​​the hydraulic engineering structure to generate the temperature distribution of the test area. The temperature distribution includes the reference temperature distribution before the application of the controllable thermal excitation, the heating temperature distribution during the application of the controllable thermal excitation, and the cooling temperature distribution after the application of the controllable thermal excitation is stopped. The leakage identification module is used to determine the temperature-time response curve based on the reference temperature distribution, the heating temperature distribution, and the cooling temperature distribution, and to extract the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant from the temperature-time response curve. Based on the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, a comprehensive discrimination index is determined, and based on the comprehensive discrimination index, it is determined whether the hydraulic engineering structure has leaked.

2. The water conservancy engineering structure leakage monitoring system according to claim 1, characterized in that, The active heating control module includes: A heating power adjustment unit is used to adjust the heating power of the controllable thermal excitation; A heating time adjustment unit is used to adjust the heating duration of the controllable thermal excitation and the interval time between two adjacent heating cycles; The heating duration and the interval between two adjacent heating cycles can be adjusted to achieve either a periodic heating mode or an on-demand heating mode.

3. The water conservancy engineering structure leakage monitoring system according to claim 1, characterized in that, The grating array temperature sensing module includes a grating array sensing composite cable and a demodulation unit. The grating array sensing composite cable includes a temperature optical fiber, a thermally conductive material layer, and a pair of heating wires. The thermally conductive material layer covers the temperature optical fiber, the pair of heating wires is embedded in the thermally conductive material layer, and the pair of heating wires is connected to the active heating control module. The heating wires are used to transfer electrical energy to the thermally conductive material layer in response to the controllable thermal excitation; The thermally conductive material layer is used to generate heat after being energized, and to apply active thermal excitation to the area under test; The temperature fiber is used to sense temperature signals in the area under test before, during and after the application of active thermal excitation. The demodulation unit is connected to the temperature optical fiber and is used to demodulate the temperature sensing signal to generate the reference temperature distribution, the heating temperature distribution, and the cooling temperature distribution.

4. The water conservancy engineering structure leakage monitoring system according to claim 3, characterized in that, The grating array sensing composite cable also includes an isolation rubber sheath disposed between the temperature optical fiber and the thermally conductive material layer, and a water-blocking grease layer disposed between the temperature optical fiber and the isolation rubber sheath. The insulating rubber sleeve is used to physically isolate the temperature optical fiber from the external structure. The water-blocking grease layer is used to prevent moisture from penetrating along the axial direction of the temperature-sensitive optical fiber.

5. The water conservancy engineering structure leakage monitoring system according to claim 4, characterized in that, The grating array sensing composite cable also includes a double-sided coated steel strip covering the thermally conductive material layer, a rubber outer sheath covering the double-sided coated steel strip, and reinforcing ribs embedded in the rubber outer sheath. The double-sided coated steel strip provides longitudinal tensile strength for the grating array sensing composite cable, the reinforcing rib provides tensile protection for the grating array sensing composite cable, and the rubber outer sheath provides waterproof and corrosion-resistant protection for the grating array sensing composite cable.

6. The water conservancy engineering structure leakage monitoring system according to claim 1, characterized in that, The leakage identification module includes a weight determination unit and a comprehensive discrimination index determination unit; The weighting unit is used to determine the weights of the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant based on the sensitivity to the convective heat transfer effect caused by seepage. The comprehensive discrimination index determination unit is used to standardize the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant to obtain multi-dimensional standardized parameters, and to perform weighted fusion of the multi-dimensional standardized parameters based on the weights to obtain the comprehensive discrimination index.

7. The water conservancy engineering structure leakage monitoring system according to claim 1, characterized in that, The comprehensive discrimination index corresponds one-to-one with the measurement points in the area to be tested, and the leakage identification module also includes a leakage identification unit. The leakage identification unit is used to determine whether the comprehensive discrimination index of the current measuring point is greater than the leakage threshold, and whether the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of at least one adjacent measuring point is greater than a preset difference. When the comprehensive discrimination index of the current measuring point is greater than the leakage threshold and the difference between the comprehensive discrimination index of the current measuring point and the comprehensive discrimination index of at least one adjacent measuring point is greater than the preset difference, it is determined that leakage has occurred at the current measuring point.

8. The water conservancy engineering structure leakage monitoring system according to claim 7, characterized in that, The leakage identification module also includes a leakage location unit, which is used to determine the location of leakage based on the mapping relationship between measuring points and spatial locations.

9. The water conservancy engineering structure leakage monitoring system according to claim 8, characterized in that, The system also includes a visualization module, which is used to display the temperature distribution of the hydraulic engineering structure and to identify the location of the leakage in the hydraulic engineering structure.

10. A method for monitoring leakage in hydraulic engineering structures, characterized in that, The method of using the water conservancy engineering structure leakage monitoring system according to any one of claims 1-9 includes: The active heating control module applies controllable thermal excitation to the grating array temperature sensing module; The temperature distribution of the test area is generated by a grating array temperature sensing module set in the test area of ​​the hydraulic engineering structure. The temperature distribution includes a reference temperature distribution before the application of the controllable thermal excitation, a heating temperature distribution during the application of the controllable thermal excitation, and a cooling temperature distribution after the application of the controllable thermal excitation is stopped. Based on the reference temperature distribution, the heating temperature distribution, and the cooling temperature distribution, a temperature-time response curve is determined, and the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant are extracted from the temperature-time response curve. Based on the temperature rise rate, maximum temperature rise amplitude, peak time, cooling rate, and thermal time constant, a comprehensive discrimination index is determined, and based on the comprehensive discrimination index, it is determined whether the hydraulic engineering structure has leaked.

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