Dam early warning system and method based on graphite electrode array resistivity sensing
Patent Information
- Application Number
- CN202611219703.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-12
- Publication Date
- 2026-10-30
AI Technical Summary
[0010]本发明所解决的技术问题：本发明提供一种基于石墨电极阵列电阻率感知的坝体预警系统及方法，解决现有技术中坝体预警存在的电极耐久性差、固定保护不足和防水密封不完善等引起预警稳定性和可靠性差的问题
[0029]1. 电极长期稳定性好。采用石墨电极棒替代传统金属电极，利用石墨优异的耐腐蚀性和化学稳定性，有效解决了电极在坝体内部长期埋设环境下的腐蚀、极化等问题，保证了监测数据的长期稳定性和可靠性。
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Figure CN123016648A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of dam safety monitoring and early warning technology, and in particular to a dam early warning system and method based on resistivity sensing of graphite electrode array. Background Technology
[0002] During long-term operation, dams (including earth-rock dams and concrete dams) are susceptible to internal safety hazards such as seepage, piping, and cracks due to factors such as reservoir water level changes, rainfall infiltration, and temperature fluctuations. Failure to detect and warn of these hazards in a timely manner could lead to major disasters such as dam failure. Therefore, real-time and accurate monitoring and early warning of the internal condition of dams are of paramount importance.
[0003] Resistivity method, as an important geophysical exploration method, has been attempted to be applied in the field of dam monitoring. Its basic principle is that the resistivity of dam filling materials is closely related to its physical properties such as water content, density, and porosity. When hidden dangers such as seepage and piping occur inside the dam, they will cause significant changes in local resistivity. By monitoring the spatiotemporal evolution of resistivity, the safety status of the dam can be indirectly reflected.
[0004] Currently, some technologies have been explored for applying resistivity methods to dam monitoring. For example, one approach proposes deploying an electrode array along the dam axis, using high-density resistivity methods to collect resistivity data at different depths, and then generating resistivity profiles to estimate the water content distribution within the dam body. Another approach proposes installing multiple metal electrodes within the dam body and calculating the resistivity changes across the dam cross-section by measuring electric field parameters. Furthermore, there are related schemes for monitoring the seepage field of earth-rock dams, using copper blocks as electrodes and acquiring data through an electrical resistivity data acquisition system.
[0005] However, existing technologies still have the following shortcomings:
[0006] First, the electrodes are buried inside the dam body for extended periods, facing a complex underground environment (humidity, high pressure, chemical corrosion, etc.). Conventional metal electrodes are prone to corrosion and polarization, leading to electrode performance degradation and increased contact resistance, which severely affects the long-term stability and reliability of monitoring data. Although existing solutions mention the use of metal electrodes such as copper blocks, they do not address the durability issue of electrodes under long-term buried conditions.
[0007] Second, the measures for fixing and protecting the electrodes are insufficient. During the construction and operation of the dam fill material, settlement and deformation will occur, and the electrodes are prone to displacement or loss of contact with the surrounding fill material, resulting in electrical contact failure. Although existing solutions include simple treatment methods such as wrapping the electrodes with clay clumps, they lack a systematic electrode fixing and protection structure.
[0008] Third, the waterproof sealing at the conductor connections is inadequate. The dam body is in a state of high humidity or even saturation for a long time. If the connection between the conductor and the electrode is not properly sealed, moisture will seep in, causing short circuits or poor contact, affecting the signal transmission quality.
[0009] Fourth, existing dam resistivity monitoring largely remains at the data acquisition and imaging stage, lacking a scientific and systematic early warning and judgment mechanism. Although some schemes mention issuing alarms based on preset thresholds, the classification of early warning levels is relatively simplistic and fails to comprehensively consider multi-dimensional factors such as resistivity change characteristics, spatial distribution characteristics, and environmental auxiliary information. Summary of the Invention
[0010] The technical problem solved by this invention: This invention provides a dam early warning system and method based on resistivity sensing of graphite electrode array, which solves the problems of poor electrode durability, insufficient fixed protection and imperfect waterproof sealing in the existing dam early warning technology, which cause poor early warning stability and reliability.
[0011] The technical solution adopted by this invention to solve the above-mentioned technical problems is as follows: a dam early warning system based on resistivity sensing of a graphite electrode array, comprising a graphite electrode array, an electrode fixing and protection unit, a wire and waterproof connector assembly unit, a resistivity acquisition unit, an environmental auxiliary monitoring unit, a data processing unit, and an early warning unit; the graphite electrode array consists of multiple graphite electrode rods arranged in a preset space and buried in the dam monitoring area, each graphite electrode rod having a conductive connection part; the electrode fixing and protection unit is disposed on the outer periphery of each graphite electrode rod to maintain the positioning and electrical contact stability of the graphite electrode rod; the wire and waterproof connector assembly unit includes waterproof wires and corresponding waterproof wires disposed at each conductive connection part. The system includes: a sealing structure at the connection point; one end of a waterproof wire connected to a corresponding graphite electrode rod via the sealing structure, and the other end connected to a resistivity acquisition unit; the resistivity acquisition unit for acquiring the apparent resistivity between the graphite electrode rods; an environmental auxiliary monitoring unit for collecting environmental auxiliary information, including reservoir water level, rainfall, ambient temperature, seepage pressure, water content, seepage flow, turbidity, and water conductivity; a data processing unit for calculating the rate of change of apparent resistivity and the low-resistivity anomaly coefficient based on the apparent resistivity; and an early warning unit for determining the early warning level and issuing a corresponding early warning based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and the environmental auxiliary information.
[0012] Furthermore, the preset spatial arrangement includes layout along the dam axis, layout along the dam height direction, cross-sectional grid layout, and dense layout at seepage-sensitive locations.
[0013] Furthermore, the electrode fixing and protection unit includes an open protective sleeve, a permeable protective layer, a geotextile covering layer, and a flexible buffer layer; the open protective sleeve is disposed on the outer periphery of the graphite electrode rod, the permeable protective layer fills the outer side of the open protective sleeve, the geotextile covering layer wraps around the outer side of the permeable protective layer, and the flexible buffer layer is disposed between the geotextile covering layer and the dam body fill material.
[0014] Furthermore, the graphite electrode rod is a cylindrical graphite rod with a diameter of 10mm to 80mm and a length of 50mm to 600mm.
[0015] Furthermore, the sealing structure includes epoxy resin, waterproof adhesive, heat shrink tubing, or sealing end cap.
[0016] Furthermore, the apparent resistivity between the graphite electrode rods is obtained, including using the four-electrode method to obtain the input current of the two graphite electrode rods and the corresponding potential difference between the two graphite electrode rods, and calculating the apparent resistivity according to the apparent resistivity formula, which is: ,in, Indicates apparent resistivity. Represents the coefficient. Indicates potential difference. It represents electric current.
[0017] Furthermore, the formula for calculating the rate of change of apparent resistivity is: The formula for calculating the low-resistance anomaly coefficient is: ,in, Indicates the first Each test area is in The rate of change of apparent resistivity at time t. Indicates the first Each test area is in Apparent resistivity at time t. Indicates the first The baseline apparent resistivity of each test area Indicates the first Each test area is in The low resistance anomaly coefficient at any given time.
[0018] Furthermore, the warning level is determined based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and environmental auxiliary information, including: if the rate of change of apparent resistivity exceeds the first threshold, and the environmental auxiliary information shows signs of abnormal seepage pressure, sudden increase in seepage flow, turbid water, or piping, the warning level is Level 4; if the rate of change of apparent resistivity does not exceed the first threshold, the low-resistivity anomaly coefficient is lower than the second threshold, and the area corresponding to the low-resistivity anomaly coefficient lower than the second threshold is a connected strip or the corresponding area is related to the reservoir water level, the warning level is Level 3; if the rate of change of apparent resistivity does not exceed the first threshold, the low-resistivity anomaly coefficient is between the second and third thresholds, and the area corresponding to the low-resistivity anomaly coefficient lower than the second threshold extends along the dam slope, dam foundation, or seepage prevention structure, the warning level is Level 2; if the rate of change of apparent resistivity does not exceed the first threshold, and the low-resistivity anomaly coefficient is between the third and fourth thresholds, the warning level is Level 1.
[0019] This invention also provides a dam early warning method based on resistivity sensing of a graphite electrode array, applied to the dam early warning system based on resistivity sensing of a graphite electrode array as described above. The method includes the following steps:
[0020] S1. Determine the placement of graphite electrode rods on the dam body and the environmental auxiliary monitoring unit based on the characteristics of the dam body;
[0021] S2. Arrange graphite electrode rods at the deployment location to form a graphite electrode array, and install electrode fixing and protection units for each graphite electrode rod.
[0022] S3. Connect each graphite electrode rod to the resistivity acquisition unit via wires and waterproof connector assembly unit;
[0023] S4. Before water storage or during stable operation, obtain the apparent resistivity of multiple periods through the resistivity acquisition unit to establish a reference resistivity field.
[0024] S5. According to the set cycle, the apparent resistivity is obtained through the resistivity acquisition unit and the environmental auxiliary information is collected through the environmental auxiliary monitoring unit.
[0025] S6. The data processing unit calculates the rate of change of apparent resistivity and the low-resistivity anomaly coefficient based on apparent resistivity.
[0026] S7. The early warning unit determines the early warning level based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and environmental auxiliary information, and issues a corresponding early warning.
[0027] Furthermore, the method also includes: S8, periodically checking whether the connection between the data processing unit and the graphite electrode rod is insulated from the dam body, and correcting the reference resistivity according to seasonal temperature and water level.
[0028] Beneficial effects of the present invention: Compared with the prior art, the present invention has the following significant advantages:
[0029] 1. Excellent long-term electrode stability. By using graphite electrode rods instead of traditional metal electrodes, the excellent corrosion resistance and chemical stability of graphite effectively solve the problems of corrosion and polarization of electrodes in the long-term buried environment inside the dam body, ensuring the long-term stability and reliability of monitoring data.
[0030] 2. Reliable electrode fixation and protection. Through a multi-layered composite structure consisting of a perforated protective sleeve, a permeable protective layer, a geotextile covering layer, and a flexible buffer layer, precise electrode positioning, stable electrical contact, and deformation-resistant protection are achieved, overcoming the adverse effects of dam fill material settlement and deformation on the electrodes.
[0031] 3. Excellent waterproof and sealing performance. Sealing structures such as epoxy resin, waterproof adhesive, heat shrink tubing, or sealing caps are installed at the connection points between the wires and the graphite electrode rods to effectively prevent moisture infiltration and ensure long-term reliability of signal transmission.
[0032] 4. Multi-dimensional three-dimensional monitoring. By arranging data in various spatial ways, such as along the dam axis, along the dam height, along the cross-sectional grid, and at seepage-sensitive locations, a three-dimensional and refined perception of the resistivity field inside the dam body is achieved, making up for the shortcomings of traditional monitoring methods, such as limited measuring points and incomplete coverage.
[0033] 5. A scientific multi-level early warning mechanism. For the first time, this invention combines the rate of change of apparent resistivity with the low-resistivity anomaly coefficient, and integrates environmental auxiliary information to establish a four-level early warning judgment system. This system enables graded early warning from minor anomalies to serious hazards, providing a scientific and quantitative basis for dam safety management. Compared to the single threshold alarm method in existing technologies, the early warning mechanism of this invention is more comprehensive and accurate.
[0034] 6. Comprehensive consideration of environmental factors. By simultaneously collecting multi-dimensional environmental information such as reservoir water level, rainfall, temperature, seepage pressure, water content, seepage flow, turbidity, and water conductivity, the impact of environmental factors is fully considered in the early warning judgment, thereby improving the accuracy and reliability of the early warning.
[0035] 7. A complete monitoring and early warning closed loop has been formed, from electrode layout, benchmark establishment, periodic monitoring to early warning judgment. Quality control links such as periodic insulation testing and benchmark correction have been set up to ensure the long-term effective operation of the system. Attached Figure Description
[0036] Figure 1 This is a schematic diagram of a dam early warning system based on resistivity sensing of a graphite electrode array, provided by the present invention.
[0037] Figure 2This is a schematic diagram of a dam early warning method based on resistivity sensing of a graphite electrode array provided by the present invention. Detailed Implementation
[0038] This invention addresses the problems of poor electrode durability, insufficient fixing and protection, and inadequate waterproof sealing in existing dam early warning technologies, which lead to poor stability and reliability. It provides a dam early warning system and method based on resistivity sensing using a graphite electrode array. By replacing traditional metal electrodes with graphite electrode rods that exhibit excellent corrosion resistance and chemical stability, and combining this with a multi-layered composite electrode fixing and protection unit, a waterproof joint assembly unit with waterproof sealing, and a four-level hierarchical early warning mechanism integrating multi-dimensional parameters, this invention effectively solves the problems of poor early warning stability and reliability caused by poor electrode durability, insufficient fixing and protection, and inadequate waterproof sealing in existing technologies. It enables long-term, stable, accurate, and reliable monitoring and early warning of internal safety hazards within the dam body.
[0039] like Figure 1 As shown, this invention provides a dam early warning system based on resistivity sensing using a graphite electrode array, comprising a graphite electrode array, an electrode fixing and protection unit, a wire and waterproof connector assembly unit, a resistivity acquisition unit, an environmental auxiliary monitoring unit, a data processing unit, and an early warning unit. The graphite electrode array consists of multiple graphite electrode rods arranged in a preset spatial arrangement and buried within the dam monitoring area; each graphite electrode rod has a conductive connection portion. The electrode fixing and protection unit is located on the outer periphery of each graphite electrode rod to maintain its positioning and electrical contact stability. The wire and waterproof connector assembly unit includes a waterproof wire and a sealing wire located at the connection point between each conductive connection portion and the corresponding waterproof wire. The system includes a sealed structure; one end of a waterproof wire is connected to a corresponding graphite electrode rod through the sealed structure, and the other end is connected to a resistivity acquisition unit; the resistivity acquisition unit is used to acquire the apparent resistivity between the graphite electrode rods; the environmental auxiliary monitoring unit is used to collect environmental auxiliary information, including reservoir water level, rainfall, ambient temperature, seepage pressure, water content, seepage flow, turbidity, and water conductivity; the data processing unit is used to calculate the rate of change of apparent resistivity and the low-resistivity anomaly coefficient based on the apparent resistivity; and the early warning unit is used to determine the early warning level based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and the environmental auxiliary information, and issue a corresponding early warning.
[0040] Using graphite electrode rods as monitoring electrodes offers superior resistance to chemical corrosion and polarization compared to traditional metal electrodes. In the high-humidity and highly corrosive long-term buried environment inside the dam, graphite rods can maintain stable conductivity, effectively preventing data drift and inaccuracy caused by electrode corrosion and polarization, and significantly improving the overall long-term operational stability of the system.
[0041] In some optional implementations, the preset spatial arrangement includes layout along the dam axis, layout along the dam height, cross-sectional grid layout, and dense layout at seepage-sensitive locations.
[0042] Graphite electrode rods are deployed at intervals along the dam axis on the dam crest, slope, or inside the dam body to identify low-resistivity anomaly zones developing along the dam axis. Graphite electrode rods are also deployed along the dam height to form a vertical profile monitoring array within the dam cross-section at different elevations to determine the rise of the phreatic line and changes in the elevation of seepage channels. A two-dimensional grid is formed on the upstream dam slope, the middle of the dam body, the downstream dam slope, or the dam foundation to invert the resistivity distribution of the dam cross-section. A denser deployment is also implemented near seepage-sensitive areas, such as the cutoff wall, core wall, abutment contact zone, around culverts, drainage prisms, dam foundation overburden, or historical seepage areas, to improve the sensitivity of anomaly identification.
[0043] The spacing between graphite electrode rods can be determined based on the dam size, target resolution, and number of acquisition device channels. The horizontal spacing between adjacent electrode rods inside the dam can be 2m to 20m, and the vertical spacing can be 1m to 10m; the spacing can be appropriately increased for seepage-sensitive areas or small dams, and appropriately relaxed for large earth-rock dams.
[0044] The multi-spaced graphite electrode array can achieve three-dimensional and refined coverage of the dam monitoring area. Combined with the apparent resistivity change rate, low resistivity anomaly coefficient and multi-dimensional environmental auxiliary information to construct a four-level early warning mechanism, it can accurately identify the development degree of seepage anomalies inside the dam, greatly improve the accuracy and reliability of dam safety early warning, and provide timely and accurate risk decision-making basis for dam operation and maintenance management.
[0045] In some optional embodiments, the electrode fixing and protection unit includes an open protective sleeve, a permeable protective layer, a geotextile covering layer, and a flexible buffer layer; the open protective sleeve is disposed on the outer periphery of the graphite electrode rod, the permeable protective layer fills the outer side of the open protective sleeve, the geotextile covering layer wraps around the outer side of the permeable protective layer, and the flexible buffer layer is disposed between the geotextile covering layer and the dam body fill material; the positioning bracket is used to control the electrode installation position and embedment direction; the open protective sleeve is used to withstand local construction loads and allow pore water exchange; the permeable protective layer is used to form a stable electrical contact environment; the geotextile covering layer is used to prevent fine particles from entering the protective layer and reduce the risk of clogging; the flexible buffer layer is used to adapt to dam body settlement and deformation. This multi-layered composite structure can firmly fix the position of the graphite electrode rods during dam construction and long-term operation, ensuring the accuracy of the spatial distribution of the graphite electrode array. At the same time, it will not block the seepage path of pore water inside the dam body, nor change the original seepage field distribution of the dam body, thus avoiding systematic deviations in monitoring data. The flexible buffer structure can effectively absorb the stress generated by the settlement deformation of the dam body, preventing the graphite electrode rods from bending, shifting, or failing in contact due to uneven settlement of the dam body. This further ensures the continuous stability of long-term monitoring data and greatly improves the adaptability of the entire system to dam deformation.
[0046] In some alternative embodiments, the graphite electrode rod is a cylindrical graphite rod with a diameter of 10 mm to 80 mm and a length of 50 mm to 600 mm.
[0047] In some optional embodiments, the sealing structure includes epoxy resin, waterproof adhesive, heat shrink tubing, or sealing caps. The dedicated sealing structure at the connection between the waterproof wire and the electrode effectively prevents moisture from seeping into the connection point, avoiding short circuits and poor contact caused by moisture intrusion, and ensuring long-term stable transmission of monitoring signals.
[0048] In some optional implementations, the apparent resistivity between the graphite electrode rods is obtained by using a four-electrode method to obtain the input current to the two graphite electrode rods and the corresponding potential difference between the two graphite electrode rods, and by calculating the apparent resistivity according to the apparent resistivity formula, which is: ,in, Indicates apparent resistivity. Represents the coefficient. Indicates potential difference. This represents current. For example, two graphite electrode rods are selected as power supply electrodes A and B, supplying current I; another two graphite electrode rods are selected as measuring electrodes M and N to measure the potential difference. The apparent resistivity is calculated using the apparent resistivity formula based on the device coefficient K. Through multi-channel switching, apparent resistivity data for different electrode combinations can be quickly obtained.
[0049] In some alternative implementations, the formula for calculating the rate of change of apparent resistivity is: The formula for calculating the low-resistance anomaly coefficient is: ,in, Indicates the first Each test area is in The rate of change of apparent resistivity at time t. Indicates the first Each test area is in Apparent resistivity at time t. Indicates the first The baseline apparent resistivity of each test area Indicates the first Each test area is in The low resistance anomaly coefficient at any given time.
[0050] In some optional implementations, the environmental auxiliary monitoring unit includes: a reservoir water level monitor (for collecting reservoir water level data), a rain gauge (for collecting rainfall data), a temperature sensor (for collecting ambient temperature data), a piezometer (for collecting seepage pressure data), a moisture content sensor (for collecting moisture content data), a measuring weir (for collecting seepage flow data), a turbidity meter (for collecting turbidity data), and a water conductivity meter (for collecting water conductivity data). Each sensor is deployed at appropriate locations within the dam body and reservoir area using conventional methods. The environmental auxiliary information collected by the environmental auxiliary monitoring unit can quickly determine whether there are signs of abnormal seepage pressure, sudden increases in seepage flow, turbid water, or piping. By collecting temperature, reservoir water level, and rainfall data, the data processing unit can eliminate "false anomalies" in resistivity caused by non-hazardous factors such as seasonal temperature differences and periodic fluctuations in reservoir water level. This prevents the early warning system from frequently issuing false alarms due to normal seasonal changes, significantly improving the accuracy and reliability of the early warning system. After introducing piezometers (measuring head pressure) and seepage flow monitoring, if resistivity decreases but seepage pressure remains stable and flow rate is constant, it indicates only normal water saturation. If resistivity decreases simultaneously with a sudden increase in seepage pressure and a surge in seepage flow, it confirms the formation of a seepage channel. This "electricity-power-water" multi-parameter cross-verification mechanism provides necessary data support for early warning. By comparing the time series of reservoir water level and rainfall (external input) with water content and seepage pressure (internal response), the system can accurately determine whether low-resistivity anomaly areas are related to external water supply and can accurately infer that the area is a reservoir seepage path, rather than surface rainfall infiltration, providing clear targeted guidance for emergency reinforcement. Turbidity meters and water conductivity meters are "direct evidence" for identifying piping. If the resistivity is abnormal, but the seepage water is clear and the conductivity is stable, it is mostly due to pore water pressure adjustment. If the resistivity is abnormal, and at the same time the seepage flow increases, the turbidity soars (containing sediment), and the water conductivity increases (dissolved ions), it directly verifies that particle loss (piping) is occurring inside the dam body, greatly enhancing the irrefutability of the hazard assessment. Upgrading dam resistivity monitoring from "single electrical measurement" to "multi-field coupled comprehensive sensing of the dam body" not only technically solves the problem of "multiple solutions to resistivity," but also provides data support for the subsequent four-level early warning and judgment system.
[0051] In some optional implementations, the warning level is determined based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and environmental auxiliary information, including: if the rate of change of apparent resistivity exceeds a first threshold, and the environmental auxiliary information shows signs of abnormal seepage pressure, sudden increase in seepage flow, turbid water, or piping, the warning level is level four; if the rate of change of apparent resistivity does not exceed the first threshold, the low-resistivity anomaly coefficient is lower than the second threshold, and the area corresponding to the low-resistivity anomaly coefficient lower than the second threshold is a connected strip or the corresponding area is related to the reservoir water level, the warning level is level three; if the rate of change of apparent resistivity does not exceed the first threshold, the low-resistivity anomaly coefficient is between the second and third thresholds, and the area corresponding to the low-resistivity anomaly coefficient lower than the second threshold extends along the dam slope, dam foundation, or seepage prevention structure, the warning level is level two; if the rate of change of apparent resistivity does not exceed the first threshold, and the low-resistivity anomaly coefficient is between the third and fourth thresholds, the warning level is level one; if none of these conditions are met, the situation is considered normal.
[0052] The first threshold is set in the range of 15% to 25%, the second threshold is set in the range of 0.5 to 0.65, the third threshold is set in the range of 0.65 to 0.8, and the fourth threshold is set in the range of 0.8 to 0.9. Abnormal seepage pressure refers to seepage pressure exceeding the normal value by more than 20%, and a sudden increase in seepage flow refers to seepage flow increasing by more than 50% compared to the previous period. The corresponding area is related to the reservoir water level, meaning that the low resistance anomaly intensifies when the reservoir water level rises.
[0053] Different warning levels correspond to different response mechanisms: Level 1 warnings correspond to minor anomalies, indicating a possible increase in water content or localized low-resistivity disturbances, reminding maintenance personnel to focus on tracking abnormal changes in the area during the next monitoring cycle; Level 2 warnings correspond to more serious anomalies, indicating the possibility of abnormal seepage development, requiring maintenance personnel to conduct a full-coverage on-site inspection of the dam section corresponding to the anomaly to verify whether there are any visible signs of seepage or deformation; Level 3 warnings correspond to severe anomalies, indicating the possible formation of concentrated seepage channels, requiring the organization of a professional safety assessment team to conduct hazard verification and develop targeted prevention and control plans; Level 4 warnings correspond to emergency situations, indicating a high safety risk to the dam body, triggering the emergency plan, initiating emergency response procedures, and organizing risk evacuation in the relevant areas.
[0054] This invention also provides a dam early warning method based on resistivity sensing of a graphite electrode array, applied to the dam early warning system based on resistivity sensing of a graphite electrode array as described above. The method, as follows... Figure 2 As shown, it includes the following steps:
[0055] S1. Determine the placement of graphite electrode rods on the dam body and the environmental auxiliary monitoring unit based on the characteristics of the dam body;
[0056] S2. Arrange graphite electrode rods at the deployment location to form a graphite electrode array, and install electrode fixing and protection units for each graphite electrode rod.
[0057] S3. Connect each graphite electrode rod to the resistivity acquisition unit via wires and waterproof connector assembly unit;
[0058] S4. Before water storage or during stable operation, obtain the apparent resistivity of multiple periods through the resistivity acquisition unit to establish a reference resistivity field.
[0059] S5. According to the set cycle, the apparent resistivity is obtained through the resistivity acquisition unit and the environmental auxiliary information is collected through the environmental auxiliary monitoring unit.
[0060] S6. The data processing unit calculates the rate of change of apparent resistivity and the low-resistivity anomaly coefficient based on apparent resistivity.
[0061] S7. The early warning unit determines the early warning level based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and environmental auxiliary information, and issues a corresponding early warning.
[0062] In some optional implementations, the method further includes: S8, periodically checking the insulation of the connection between the data processing unit and the graphite electrode rod and the dam body, and correcting the reference resistivity according to seasonal temperature and water level. For example, a system insulation test is performed quarterly or semi-annually to ensure good insulation between each measurement circuit and the dam body. Simultaneously, the reference resistivity is dynamically corrected according to seasonal temperature and reservoir water level changes: when the temperature change exceeds ±5℃ or the reservoir water level change exceeds ±5m, the reference resistivity is remeasured or historical reference values are corrected for temperature and water level to eliminate the influence of environmental factors on resistivity measurement and ensure the accuracy of early warning judgments.
Claims
1. A dam early warning system based on resistivity sensing of a graphite electrode array, characterized in that, The system includes a graphite electrode array, an electrode fixing and protection unit, a wire and waterproof connector assembly unit, a resistivity acquisition unit, an environmental auxiliary monitoring unit, a data processing unit, and an early warning unit. The graphite electrode array consists of multiple graphite electrode rods arranged in a preset spatial arrangement and buried within the dam monitoring area; each graphite electrode rod has a conductive connection portion. The electrode fixing and protection unit is located on the outer periphery of each graphite electrode rod to maintain its positioning and electrical contact stability. The wire and waterproof connector assembly unit includes waterproof wires and sealing structures located at the connection points between each conductive connection portion and the corresponding waterproof wire. One end of the waterproof wire is connected to the corresponding graphite electrode rod through the sealing structure, and the other end is connected to the resistivity acquisition unit; the resistivity acquisition unit is used to acquire the apparent resistivity between the graphite electrode rods; the environmental auxiliary monitoring unit is used to collect environmental auxiliary information, including reservoir water level, rainfall, ambient temperature, seepage pressure, water content, seepage flow, turbidity, and water conductivity; the data processing unit is used to calculate the rate of change of apparent resistivity and the low-resistivity anomaly coefficient based on the apparent resistivity; the early warning unit is used to determine the early warning level based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and the environmental auxiliary information, and issue a corresponding early warning.
2. The dam early warning system based on resistivity sensing of graphite electrode array according to claim 1, characterized in that, The preset spatial arrangement includes layout along the dam axis, layout along the dam height, cross-sectional grid layout, and dense layout in seepage-sensitive areas.
3. The dam early warning system based on resistivity sensing of graphite electrode array according to claim 1, characterized in that, The electrode fixing and protection unit includes an open protective sleeve, a permeable protective layer, a geotextile covering layer, and a flexible buffer layer; the open protective sleeve is disposed on the outer periphery of the graphite electrode rod, the permeable protective layer fills the outside of the open protective sleeve, the geotextile covering layer wraps around the outside of the permeable protective layer, and the flexible buffer layer is disposed between the geotextile covering layer and the dam body fill material.
4. The dam early warning system based on resistivity sensing of graphite electrode array according to claim 1, characterized in that, The graphite electrode rod is a cylindrical graphite rod with a diameter of 10mm to 80mm and a length of 50mm to 600mm.
5. The dam early warning system based on resistivity sensing of a graphite electrode array according to claim 1, characterized in that, The sealing structure includes epoxy resin, waterproof adhesive, heat shrink tubing, or sealing end cap.
6. The dam early warning system based on resistivity sensing of a graphite electrode array according to claim 1, characterized in that, Obtaining the apparent resistivity between graphite electrode rods involves using the four-electrode method to obtain the input current to the two graphite electrode rods and the corresponding potential difference between them, and then calculating the apparent resistivity using the apparent resistivity formula: ,in, Indicates apparent resistivity. Represents the coefficient. Indicates potential difference. It represents electric current.
7. The dam early warning system based on resistivity sensing of graphite electrode array according to claim 1, characterized in that, The formula for calculating the rate of change of apparent resistivity is: The formula for calculating the low-resistance anomaly coefficient is: ,in, Indicates the first Each test area is in The rate of change of apparent resistivity at time t. Indicates the first Each test area is in Apparent resistivity at time t. Indicates the first The baseline apparent resistivity of each test area Indicates the first Each test area is in The low resistance anomaly coefficient at any given time.
8. The dam early warning system based on resistivity sensing of graphite electrode array according to claim 1, characterized in that, The warning level is determined based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and environmental auxiliary information, including: if the rate of change of apparent resistivity exceeds the first threshold, and the environmental auxiliary information shows signs of abnormal seepage pressure, sudden increase in seepage flow, turbid water, or piping, the warning level is Level 4; if the rate of change of apparent resistivity does not exceed the first threshold, the low-resistivity anomaly coefficient is lower than the second threshold, and the area corresponding to the low-resistivity anomaly coefficient lower than the second threshold is a connected strip or the corresponding area is related to the reservoir water level, the warning level is Level 3; if the rate of change of apparent resistivity does not exceed the first threshold, the low-resistivity anomaly coefficient is between the second and third thresholds, and the area corresponding to the low-resistivity anomaly coefficient lower than the second threshold extends along the dam slope, dam foundation, or seepage prevention structure, the warning level is Level 2; if the rate of change of apparent resistivity does not exceed the first threshold, and the low-resistivity anomaly coefficient is between the third and fourth thresholds, the warning level is Level 1.
9. A dam early warning method based on resistivity sensing of graphite electrode array, characterized in that, The method, applied to the dam early warning system based on resistivity sensing of graphite electrode array as described in claim 1, includes the following steps: S1. Determine the placement of graphite electrode rods on the dam body and the environmental auxiliary monitoring unit based on the characteristics of the dam body; S2. Arrange graphite electrode rods at the deployment location to form a graphite electrode array, and install electrode fixing and protection units for each graphite electrode rod. S3. Connect each graphite electrode rod to the resistivity acquisition unit via wires and waterproof connector assembly unit; S4. Before water storage or during stable operation, obtain the apparent resistivity of multiple periods through the resistivity acquisition unit to establish a reference resistivity field. S5. According to the set cycle, the apparent resistivity is obtained through the resistivity acquisition unit and the environmental auxiliary information is collected through the environmental auxiliary monitoring unit. S6. The data processing unit calculates the rate of change of apparent resistivity and the low-resistivity anomaly coefficient based on apparent resistivity. S7. The early warning unit determines the early warning level based on the rate of change of apparent resistivity, the low-resistivity anomaly coefficient, and environmental auxiliary information, and issues a corresponding early warning.
10. The dam early warning method based on resistivity sensing of graphite electrode array according to claim 9, characterized in that, The method further includes: S8, periodically checking whether the connection between the data processing unit and the graphite electrode rod is insulated from the dam body, and correcting the reference resistivity according to seasonal temperature and water level.