Self-adaptive frequency 4D electrical resistance tomography system for concrete conveying and measuring method

Abstract

The invention discloses a self-adaptive frequency 4D electrical resistance tomography imaging system for concrete conveying and a measuring method, the system comprises a measuring pipeline equipped with an electrode sensor, the measuring pipeline is connected with an electrical resistance tomography imaging instrument, and the electrical resistance tomography imaging instrument is connected with a data processing device through a wireless signal processing device. In the method, parameters such as a candidate frequency set and a sliding time window are set, and a prior model and a reference range are established based on first sampling; then, only a representative measurement subset is collected at each sampling moment, measurement consistency, time continuity and channel availability related to the prior model are calculated, a frequency point scoring function is constructed, the current working frequency is selected, and full data collection is completed; performing 4D joint inversion in a sliding time window to obtain conductivity three-dimensional time sequence distribution, calculating a section non-uniformity index, and performing quantitative judgment and risk prompt on the concrete segregation development trend. According to the invention, the imaging stability, real-time performance and engineering applicability of segregation monitoring in the concrete conveying process are improved.

Description

Technical Field

[0001] This invention belongs to the field of industrial process detection and resistance tomography technology, specifically relating to an adaptive frequency 4D resistance tomography system and measurement method for concrete conveying. Background Technology

[0002] Concrete pipeline transportation involves multiphase, non-Newtonian, complex flows. Affected by long-distance pumping, bends, pump start-up and shutdown, and pressure fluctuations, the slurry and aggregates are prone to migration and rearrangement, leading to aggregate enrichment, mortar flotation, and segregation such as bleeding. This results in uneven cross-sectional distribution, increased resistance, abnormal pressure, and even the risk of pipe blockage, affecting the stability of the output quality. Current monitoring methods rely heavily on a few point signals such as pressure and flow rate, or intermittent sampling, making it difficult to obtain the internal spatial distribution of the cross-section and its evolution over time. Early segregation identification and trend judgment criteria are insufficient.

[0003] "Segregation" refers to the separation or redistribution of components such as slurry, mortar, and coarse aggregate during concrete transportation through pipelines due to factors such as shearing, vibration, pump restart, and disturbance at bends or diameter changes. This manifests as uneven electrical properties along the cross section or along the pipeline (including but not limited to stratification segregation, coarse aggregate settling, slurry floating, and accompanying bleeding).

[0004] Electrical resistance tomography (ERT) injects excitation current through multiple electrodes and acquires voltage signals to invert the conductivity distribution of the medium. Combined with time-constrained 4D joint inversion, the temporal continuity can be improved. However, in actual pumping, the electrical properties of the medium and the electrode contact state change with the operating conditions. Fixed frequency measurement is prone to causing a decrease in signal-to-noise ratio, a reduction in available channels, and imaging flicker. Summary of the Invention

[0005] The purpose of this invention is to provide an adaptive frequency 4D resistivity tomography system and measurement method for concrete conveying, which can effectively solve the problems of existing segregation monitoring relying on a small number of point signals, difficulty in obtaining cross-sectional distribution, and the tendency of fixed frequency to cause imaging flicker, thereby improving the imaging stability, real-time performance, and engineering applicability of segregation monitoring during concrete conveying.

[0006] To achieve the above objectives, the present invention provides an adaptive frequency 4D resistivity tomography system for concrete conveying, comprising: The measuring pipe has flanges at both ends for connecting the pipe to be measured. An electrode sensor is connected and installed inside the measuring pipe to excite the current and collect the voltage of the concrete medium inside the measuring pipe. The resistivity tomography imager is connected to the measurement pipeline and electrically connected to the electrode sensor. It is used to output AC excitation within the candidate frequency set and to collect data according to the preset excitation and detection modes. The raw measurement data is then transmitted to the outside through the field wireless signal processing device. The data processing device receives the raw measurement data sent by the field wireless signal processing device through the processing terminal wireless signal processing device, processes it, and then sends the imaging results back to the resistivity tomography imager. An imaging display screen is connected to the resistivity tomography imager and is used to display the imaging results transmitted back by the data processing device in real time.

[0007] As a further aspect of the present invention: several groups of electrode sensors are evenly spaced along the circumference of the measuring pipe.

[0008] As a further aspect of the present invention: the electrode sensors are arranged at uniform intervals along the axial direction of the measuring pipe.

[0009] To achieve the above objectives, the present invention also provides a measurement method based on the above-mentioned adaptive frequency 4D resistivity tomography system for concrete conveying, comprising the following steps: Step 1: Set the candidate frequency set Initial operating frequency Safety rollback frequency Sampling period, sliding time window length Number of test frequency points Representative measurement subset, threshold for cross-sectional non-uniformity index Continuous increase in frame rate threshold and the threshold for continuous over-threshold time ; Step 2: Establish a reference range and initial prior model during the first sampling; for subsequent samplings, use the 4D inversion results from the previous time step or within the sliding time window. Based on this, the first [unit / item] is obtained through extrapolation, weighted averaging, or time smoothing. Prior model at sampling time And update the reference range and prior model simultaneously. This will serve as the initial model for subsequent frequency point evaluation and 4D joint inversion, in order to obtain the... Inversion results of three-dimensional conductivity distribution at sampling time ; Step 3, in the Sampling time from candidate frequency set Select test frequency point set Data was collected from a representative subset of measurement combinations to obtain subset measurement data. ,in, ; Step 4: Frequency evaluation and selection based on 4D imaging quality feedback: Calculate measurement consistency for each test frequency. Imaging time continuity Cost of channel availability Construct a frequency scoring function and determine the operating frequency at this sampling time. ; Step 5: Operating frequency at this sampling time The system then performs full data acquisition using the preset excitation and detection modes to obtain the full measurement data. ; Step Six: In a length of Perform 4D joint inversion within a sliding time window to obtain the three-dimensional conductivity time-series distribution at each sampling time. Select a preset typical cross-section to calculate the cross-sectional non-uniformity index. To characterize the uneven evolution trend of the relative distribution of slurry and aggregate during pumping; when continuous The number of sampling times shows an upward trend, or Exceeding the threshold within a certain period of time At that time, it will output a risk warning of segregation or a risk warning of pipe blockage.

[0010] As a further aspect of the present invention: in step one and The target response time is determined through offline testing or on-site trial operation.

[0011] As a further aspect of the present invention: measurement consistency in step four The forward consistency residual based on the prior model is expressed as: ; in, For the first The frequency of time is A subset of measurement data, As a priori model, For the subset forward operator corresponding to the representative measurement combination subset, To prevent positive numbers with a denominator of zero; Imaging time continuity Used to measure candidate frequency points The deviation of the updated model from the prior model, to characterize the risk of temporal discontinuity caused by candidate frequencies, is expressed as: ; in, In candidate frequency points Based on prior models A fast model obtained through lightweight updates; temporal continuity is demonstrated by the amount of change in the fast model relative to the prior model. Characterization, An operator for smoothing or constraining the change. To prevent positive numbers with a denominator of zero; Channel availability cost Determined based on the proportion of abnormal or saturated channels: ; in, The proportion of abnormal (unsaturated) channels. This represents the saturation channel ratio; The total number of channels in a representative subset of measurement combinations; In frequency point The number of channels that meet the anomaly criteria and are not saturated channels. In frequency point The number of channels that satisfy the saturation criterion; These are the weighting coefficients.

[0012] As a further aspect of the present invention: measurement consistency Imaging time continuity With channel availability Perform weighted fusion to construct a frequency point scoring function: ; in, , , These are the weighting coefficients; Frequency point scoring function The frequency with the lowest score is selected as the working frequency at this moment.

[0013] As a further aspect of the present invention: the 4D joint inversion in step six employs an objective function that includes data fitting terms, spatial constraint terms, and time constraint terms. ; in, For the first Three-dimensional conductivity distribution at any given time; For the first Full measurement data at all times; To operate at frequency The forward operator below; This is the data weight matrix; For space regularization operators; , These are the spatial and temporal regularization parameters, respectively; This represents the length of the sliding time window.

[0014] As a further aspect of the present invention: the cross-sectional non-uniformity index in step six The coefficient of variation is obtained based on the statistical analysis of the conductivity of cross-sectional pixels or units, and is expressed as a function: ; in, For the first Within the cross section at time 1 The conductivity of a single pixel or unit. The average conductivity of the cross section, The number of pixels or units in the cross section.

[0015] As a further aspect of the present invention: the length of the sliding time window Selected based on the sampling period and target response time, it is used to ensure real-time performance while utilizing the nearest... Frame data enhances the continuity and noise resistance of temporal imaging.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention utilizes a flange to quickly connect the pre-positioned electrode sensor measuring pipe to the concrete delivery pipe to be tested, forming a detection pipe section. This avoids drilling holes in the existing pipe body for electrode placement on-site, reducing damage to the pumping pipeline and downtime, simplifying the construction process, and lowering the difficulty of modification. It is suitable for typical working conditions such as vertical pumping of ready-mixed concrete in multi-story buildings, long-distance horizontal transportation, and pipelines with multiple bends and diameter changes. In terms of data link, a separate wireless transmission architecture is adopted for on-site data acquisition and processing, enabling bidirectional wireless transmission of measurement data and imaging results. This reduces the workload of long-distance wiring and cable fixing, and minimizes cable coupling interference and signal attenuation. Simultaneously, the data processing device can be placed in a safe area away from the concrete transportation environment, facilitating maintenance and upgrades in the batching plant control room or pump truck operating area, improving the system's reliability in complex construction environments. The on-site display terminal can present real-time imaging of the concrete cross-section and changes in segregation indicators, providing operators with intuitive reference. To address the issues of varying dielectric properties and electrode contact states, as well as noise level fluctuations caused by slump loss, aggregate settlement, and insufficient slurry during concrete pipeline transportation, this invention employs an adaptive frequency selection mechanism based on 4D imaging quality feedback. At each sampling moment, candidate frequency points are rapidly evaluated, and a more stable operating frequency is selected. This reduces the degrading effects of invalid channels, saturated channels, and low signal-to-noise ratio frequencies on imaging from the source, avoiding imaging flicker and discontinuous results caused by fixed-frequency measurements during pump start-up and shutdown, pressure fluctuations, and the early stages of pipe blockage. By using a sliding time window for 4D joint inversion and introducing a time constraint term, the results from adjacent moments maintain reasonable continuity throughout the pumping process, reducing the impact of random noise and artifacts on temporal imaging. This invention evaluates only a representative subset of test frequencies using representative measurement combinations, and then performs full acquisition at the selected frequencies, balancing real-time performance and imaging quality during pumping. The cross-sectional non-uniformity index is calculated from the inversion results, transforming the complex three-dimensional temporal conductivity distribution into a quantifiable concrete segregation trend quantity for threshold discrimination, pipe blockage risk warning, and construction parameter optimization. Attached Figure Description

[0017] Figure 1 This is a block diagram of the overall system structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the electrode sensor distribution of the present invention.

[0019] Figure 3 This is a schematic diagram illustrating the operation of the present invention.

[0020] In the diagram: 1. Flange, 2. Electrical resistance tomography, 3. Field wireless signal processing device, 4. Imaging display screen, 5. Measuring pipe, 6. Electrode sensor, 7. Processing wireless signal processing device, 8. Data processing device. Detailed Implementation

[0021] The invention will now be further described with reference to the accompanying drawings.

[0022] like Figure 1 As shown, an adaptive frequency 4D resistivity tomography system for concrete conveying includes: Measuring pipe 5, with flanges 1 at both ends for connecting to the pipe to be tested, the measuring pipe 5 is connected to the pipe to be tested through the flanges 1 to form a test pipe section; Electrode sensor 6 is connected and installed inside the measuring pipe 5, and is used to excite the current and collect the voltage of the concrete medium in the measuring pipe 5. The resistivity tomography imager 2 is connected to the measurement pipe 5 and electrically connected to the electrode sensor 6. It is used to output AC excitation within the candidate frequency set and to collect data according to the preset excitation and detection mode, forming raw measurement data that is transmitted to the outside through the field wireless signal processing device 3. The data processing device 8 receives the raw measurement data sent by the field wireless signal processing device 3 through the processing terminal wireless signal processing device 7, processes it, and then sends the imaging results back to the resistivity tomography imager 2. Specifically, the field-end wireless signal processing device 3 is connected to the resistivity tomography imager 2 to receive the raw measurement data and wirelessly transmit it to the processing-end wireless signal processing device 7; the processing-end wireless signal processing device 7 receives the raw measurement data and transmits it to the data processing device 8; the data processing device 8 performs data preprocessing, performs frequency point evaluation and operating frequency selection based on 4D imaging quality feedback, performs 4D joint inversion update within a sliding time window, and outputs three-dimensional conductivity time series distribution and cross-sectional non-uniformity index for segregation trend characterization and risk warning; and the imaging results and index information output by the data processing device 8 are transmitted back to the field-end wireless signal processing device 3 via the processing-end wireless signal processing device 7.

[0023] The imaging display screen 4 is connected to the resistivity tomography imager 2 and is used to display the imaging results returned by the data processing device 8 in real time. It can also indicate the level of segregation risk or tube blockage risk on the interface.

[0024] Furthermore, such as Figure 2 As shown, several groups of electrode sensors 6 are evenly distributed along the circumference of the measuring pipe 5, preferably 16 electrode sensors 6 per circle.

[0025] To enhance three-dimensional sensitivity and for reconstruction of three-dimensional conductivity distribution, the electrode sensors 6 are further arranged at uniform intervals along the axial direction of the measuring pipe 5, preferably in three rings.

[0026] To facilitate the explanation of the installation method and working process of this invention in the context of concrete pipeline transportation, as follows: Figure 3 As shown, the present invention uses a measuring pipe with pre-arranged electrode sensors as a detection pipe section, which is quickly connected to the concrete conveying pipe to be tested through flanges at both ends, so as to achieve rapid assembly under conditions of no work stoppage or short-term work stoppage; the resistivity tomography imager completes data acquisition at the field end, and the data is transmitted to the data processing device for 4D inversion and the imaging and index results are returned for on-site display.

[0027] Preferably, the detection pipe section can be arranged near the pump truck outlet, at key locations in long-distance conveying pipelines, before and after bends or diameter changes, and at the entrance of uphill or vertical sections, etc., to more sensitively capture the uneven changes in cross-section and signs of segregation or pipe blockage caused by the shearing and pressure pulsation of concrete. When it is necessary to lubricate the pipe, stop and restart the pump, or change the pumping speed on site, the detection pipe section can also be used to track the temporal evolution of the concrete state.

[0028] The measurement method based on the above-mentioned adaptive frequency 4D resistivity tomography system for concrete conveying includes the following steps: Step 1: Set the candidate frequency set Initial operating frequency Safety rollback frequency Sampling period, sliding time window length Number of test frequency points Representative measurement subset, threshold for cross-sectional non-uniformity index Continuous increase in frame count threshold and the threshold time for continuous over-threshold ; Preferably, and The target response time is determined through offline testing or on-site trial operation. The candidate frequency set is used to cover the effective frequency domain corresponding to the changes in water content, component ratio, temperature and electrode contact state of concrete slurry during transportation. The representative measurement combination subset is used to quickly evaluate the candidate frequency points to reduce the time overhead caused by full-frequency full-quantity scanning at each sampling moment. As an implementation method for physical testing, the measurement pipeline 5 can be installed in the experimental loop or the field testing section.

[0029] Step 2: During the initial sampling, baseline data is acquired under conditions of uniform mixing and relatively stable conveying conditions to establish a reference range and an initial prior model. The reference range should include at least one or more of the following: reference voltage level, noise level, and available channel ratio. For subsequent sampling, the 4D inversion results from the previous moment or within the sliding time window are used. Based on this, the first [unit / item] is obtained through extrapolation, weighted averaging, or time smoothing. Prior model at sampling time And update the reference range and prior model simultaneously. This will serve as the initial model for subsequent frequency point evaluation and 4D joint inversion, in order to obtain the... Inversion results of three-dimensional conductivity distribution at sampling time This ensures that the frequency selection decision is consistent with the imaging target, avoiding imaging flicker or instability caused by relying solely on signal amplitude or a single channel index for frequency selection.

[0030] Step 3, in the Sampling time from candidate frequency set Select test frequency point set Data was collected from a representative subset of measurement combinations to obtain subset measurement data. ,in, Preferably, the representative measurement subset covers typical channels within the same loop and across loops, so as to reflect the cross-sectional non-uniformity changes and the response of key sensitive paths with low acquisition overhead; in concrete pumping, when local enrichment of aggregate, insufficient paste or increased bleeding leads to changes in electrical properties and contact state, this subset of data can quickly reflect the channel effectiveness and noise change trend. Step 4: Frequency evaluation and selection based on 4D imaging quality feedback: Calculate measurement consistency for each test frequency. Imaging time continuity Cost of channel availability Construct a frequency scoring function and determine the operating frequency at this sampling time. ; Specifically, measurement consistency The forward consistency residual based on the prior model is expressed as: ; in, For the first The frequency of time is A subset of measurement data, As a priori model, For the subset forward operator corresponding to the representative measurement combination subset, To prevent positive numbers with a denominator of zero; Imaging time continuity Used to measure candidate frequency points The deviation of the updated model from the prior model, to characterize the risk of temporal discontinuity caused by candidate frequencies, is expressed as: ; in, In candidate frequency points Based on prior models A fast model obtained through lightweight updates; temporal continuity is demonstrated by the amount of change in the fast model relative to the prior model. Characterization, An operator (which can be a unit operator or a smoothing operator) is used to smooth or constrain the change. To prevent positive numbers with a denominator of zero; Channel availability cost Determined based on the proportion of abnormal or saturated channels: ; in, The proportion of abnormal (unsaturated) channels. This represents the saturation channel ratio; The total number of channels in a representative subset of measurement combinations; In frequency point The number of channels that meet the anomaly criteria and are not saturated channels. In frequency point The number of channels that satisfy the saturation criterion; These are the weighting coefficients.

[0031] Measurement consistency Imaging time continuity With channel availability Perform weighted fusion to construct a frequency point scoring function: ; in, , , These are the weighting coefficients; Frequency point scoring function The frequency with the lowest score is selected as the working frequency at this moment.

[0032] The scoring mechanism is used to adaptively select a more stable frequency point when fluctuations in pumping conditions lead to increased noise, changes in electrode contact impedance, or a reduction in effective channels. It also uses hysteresis parameters to suppress frequent frequency jumps between adjacent sampling times and can back down to a safe backoff frequency if necessary. In practical testing, the data processing device 8 can record the operating frequency at each sampling time. Channel availability statistics and score changes are used for result tracing and comparative analysis.

[0033] Step 5: Operating frequency at this sampling time The system then performs full data acquisition using the preset excitation and detection modes to obtain the full measurement data. The full measurement data is then transmitted to the data processing device 8. Step 6: Length of the sliding time window Selected based on the sampling period and target response time, it is used to ensure real-time performance while utilizing the nearest... Frame data enhances the continuity and noise resistance of temporal imaging, in lengths of [missing information]. A 4D joint inversion was performed within a sliding time window to obtain the three-dimensional conductivity time series distribution and to calculate the cross-sectional non-uniformity index. To characterize the trend of segregation development, when If the risk of segregation increases continuously over time or exceeds a threshold, a segregation risk warning will be output.

[0034] Preferably, when The trend increases over T consecutive sampling times, or the threshold is exceeded over a duration of Δt. At that time, it outputs segregation risk warnings or pipe blockage risk alerts, and can be combined with operating condition signals such as pumping pressure, flow rate, pump speed, and start / stop status for joint judgment to improve the reliability of the warnings and prompt measures to be taken to adjust pumping process parameters such as pump speed, start / stop strategy, and cleaning measures, or material parameters such as admixture dosage, water consumption, sand ratio, or mix proportion; then it will invert the results at this moment. As a priori update for the next moment, it is used for frequency point evaluation, frequency selection and 4D joint inversion at subsequent sampling moments.

[0035] Specifically, the 4D joint inversion uses an objective function that includes data fitting terms, spatial constraint terms, and time constraint terms: ; By minimizing the above objective function, the three-dimensional conductivity distribution at each moment within the sliding time window is obtained. and take As the inversion result at this sampling time; among which, For the first Three-dimensional conductivity distribution at any given time; For the first Full measurement data at all times; To operate at frequency The forward operator below; This is the data weight matrix; For space regularization operators; , These are the spatial and temporal regularization parameters, respectively; This represents the length of the sliding time window.

[0036] Cross-sectional non-uniformity index The coefficient of variation or normalized variance is obtained based on the statistical analysis of cross-sectional pixel or unit resistivity, preferably the coefficient of variation, and is expressed as a function: ; in, For the first Within the cross section at time 1 The conductivity of a single pixel or unit. The average conductivity of the cross section, The number of pixels or units in the cross section.

[0037] Will With preset threshold By comparing and combining the triggering conditions, it can be used to indicate an increased risk of concrete segregation. Preferably, the triggering condition includes at least: And the duration reached ; continuous Each sampling time point exhibits an upward trend, preferably a monotonically increasing trend or a cumulative increment exceeding a preset threshold within the continuous interval; more preferably, while satisfying the trend criterion, it also requires... To reduce false alarms, the imaging display screen 4 is used to display the 4D reconstruction results in real time. Time series and threshold lines It can also simultaneously display the continuously rising count value (e.g.) ) or overthreshold duration (e.g. );when or The system outputs segregation risk warnings in real time and, if necessary, pipe blockage risk alerts. Simultaneously, it stores imaging results, operating frequency, and channel availability statistics for each corresponding moment, facilitating traceability and comparative analysis. Preferably, the trend results can be compared with laboratory testing or on-site sampling results to verify the effectiveness of segregation trend identification and provide a reference for adjusting pumping parameters and optimizing material mix proportions.

Claims

1. An adaptive frequency 4D electrical resistance tomography system for concrete delivery, characterized in that, It comprises: a measuring pipe (5) provided with flanges (1) at both ends for connecting to the pipe to be measured; an electrode sensor (6) connected to the measuring pipe (5) for exciting the concrete medium in the measuring pipe (5) with current and collecting voltage; an electrical resistance tomography instrument (2) connected to the measuring pipe (5) and electrically connected to the electrode sensor (6), for outputting alternating excitation in a candidate frequency set and collecting data according to a preset excitation and detection mode to form raw measurement data which is transmitted to the outside through a field end wireless signal processing device (3); a data processing device (8) receiving the raw measurement data transmitted by the field end wireless signal processing device (3) through a processing end wireless signal processing device (7) and returning the imaging result to the electrical resistance tomography instrument (2) after processing; an imaging display screen (4) connected to the electrical resistance tomography instrument (2) for displaying the imaging result returned by the data processing device (8) in real time.

2. The self-adapting frequency 4D electrical resistivity tomography system for concrete delivery according to claim 1, characterized in that, The electrode sensor (6) is uniformly and evenly spaced along the circumferential direction of the measuring pipe (5).

3. An adaptive frequency 4D electrical resistivity tomography system for concrete delivery according to claim 1 or 2, characterized in that, The electrode sensor (6) is uniformly and evenly spaced along the axial direction of the measuring pipe (5).

4. A method of measurement for a self-adapting frequency 4D electrical resistivity tomography system for concrete delivery according to any one of claims 1 to 3, characterized in that, It comprises the following steps: Step one, set candidate frequency set , initial operating frequency , security fallback frequency , sampling period, sliding time window length , test frequency points , representative measurement combination subset, cross-section non-uniformity index threshold , continuous rising frame number threshold And the threshold value of the duration of the threshold value ; Step two, establish reference range and initial prior model at the first sampling; at the non-first sampling, use the 4D inversion results of the previous time or within the sliding time window For reference, obtain the prior model at the sampling time through extrapolation, weighted average or time smoothing And update the reference range and the prior model synchronously Use it as the initial model for subsequent frequency point evaluation and 4D joint inversion to obtain the three-dimensional conductivity distribution inversion result at the sampling time ;​​ Step three, in the first sampling time from the candidate frequency set select test frequency set , according to the representative measurement combination subset data acquisition, get subset measurement data , wherein ; Step four, frequency point evaluation and selection based on 4D imaging quality feedback: calculate the measurement consistency for each test frequency point , imaging time continuity and channel availability cost , construct a frequency point score function and determine the working frequency at this sampling time ; Step five, the working frequency at the present sampling moment Collecting full-quantity data according to preset excitation and detection mode to obtain full-quantity measurement data ; Step Six: In a length of Perform 4D joint inversion within a sliding time window to obtain the three-dimensional conductivity time-series distribution at each sampling time. Select a preset typical cross-section to calculate the cross-sectional non-uniformity index. To characterize the uneven evolution trend of the relative distribution of slurry and aggregate during pumping; when continuous The number of sampling times shows an upward trend, or Exceeding the threshold within a certain period of time At that time, it will output a risk warning of segregation or a risk warning of pipe blockage.

5. The method of measuring a concrete delivery self-adapting frequency 4D electrical resistivity tomography system according to claim 4, characterized in that, The step one and Determined by offline testing or field commissioning depending on target response time.

6. The method of measuring a concrete delivery self-adapting frequency 4D electrical resistive tomography system according to claim 4, characterized in that, Measurement consistency in step four The forward consistency residual based on the prior model is represented as: ; wherein, is the first is the time instant frequency, is the subset measurement data, is the prior model, is the subset forward operator corresponding to the representative measurement combination subset, is a positive number to prevent the denominator from being zero; Imaging time continuity For measuring candidate frequency points The deviation of the lower model update from the prior model is used to represent the timing discontinuity risk caused by the candidate frequency point, expressed as: ; wherein, is a prior model, is a prior model, is a fast model obtained by light-weight updating; time continuity is through the change amount of the fast model relative to the prior model characterizes, is an operator for smoothing or constraining the change amount, is a positive number to prevent the denominator from being zero; Channel availability cost Determination of abnormal channel or saturation channel proportion: ; wherein, is the proportion of abnormal (non-saturated) channels, is the proportion of saturated channels; is the total number of channels in the representative measurement combination subset; is the number of channels that satisfy the abnormal criterion and do not belong to the saturated channels at the frequency point is the number of channels that satisfy the abnormal criterion and do not belong to the saturated channels at the frequency point is the number of channels that satisfy the saturated criterion at the frequency point is the number of channels that satisfy the saturated criterion at the frequency point is the weight coefficient.

7. The measurement method of the self-adaptive frequency 4D electrical resistance tomography system for concrete conveying according to claim 5, characterized in that, measure consistency , imaging time continuity with channel availability weighted fusion, construct frequency point score function: ; wherein , , are weight coefficients; Through the frequency point scoring function Select the frequency point with the minimum score as the working frequency at this moment.

8. The method of measuring a concrete delivery self-adapting frequency 4D electrical resistive tomography system according to claim 4, characterized in that, The 4D joint inversion in step six adopts a target function containing a data fitting term, a spatial constraint term and a time constraint term: ; wherein, is the first is the three-dimensional conductivity distribution at time t; is the first is the full measurement data at time t; is the forward operator at the working frequency is the data weight matrix; is the spatial regularization operator; , , are the spatial and temporal regularization parameters, respectively; is the length of the sliding time window.

9. The method of measuring a concrete delivery self-adapting frequency 4D electrical resistive tomography system according to claim 4, characterized in that, The cross-sectional non-uniformity index in step six The coefficient of variation is based on the statistical variation of the cross-sectional pixel or cell conductivities, and is represented by the function: ; wherein, is the first is the first is the first is the first is the first 10. The method of measuring a concrete delivery self-adapting frequency 4D electrical resistive tomography system according to claim 4, characterized in that, Sliding time window length According to the sampling period and the target response time selection, the most recent Frame data enhances the continuity and noise resistance of time sequence imaging.

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