A method and apparatus for monitoring groundwater resources

Abstract

This invention provides a method and apparatus for monitoring groundwater resources, belonging to the field of groundwater flow measurement technology. The method includes: obtaining the comprehensive fluid interference intensity of groundwater based on the differences in signal amplitude and instantaneous phase between low-frequency and high-frequency ultrasonic signal sequences; obtaining the bubble intensity disturbance factor of groundwater based on the comprehensive fluid interference intensity and the changes in pipe environmental water pressure data in adjacent sampling periods; dynamically compensating a preset reference sound velocity based on the bubble intensity disturbance factor, and combining this with the ultrasonic propagation time difference to obtain corrected real groundwater flow velocity data. This invention improves the accuracy of groundwater resource monitoring.

Description

Technical Field

[0001] This invention belongs to the field of groundwater flow measurement technology, specifically relating to a groundwater resource monitoring method and device. Background Technology

[0002] With the increasing scarcity of groundwater resources and the continuous changes in the water environment, groundwater monitoring has become particularly important. As an important strategic resource, accurate monitoring of groundwater extraction is crucial for the scientific management of water resources. Currently, the ultrasonic time-of-flight method is commonly used for flow measurement in deep well pipelines; and traditional measurement algorithms are all based on the ideal premise that groundwater is a pure, single-phase, homogeneous liquid.

[0003] However, in actual deep well extraction environments, groundwater often forms a solid-liquid two-phase flow accompanied by sediment at the bottom. Simultaneously, the high-speed impeller suction of the pump or drastic changes in deep well pressure cause dissolved gases to be released from the water, generating numerous microbubbles and thus forming an extremely complex gas-liquid-solid multiphase flow. This multiphase fluid not only causes strong scattering and attenuation of ultrasonic signals, but also, primarily due to the presence of free bubbles, significantly alters the bulk modulus of the mixed fluid, leading to a drastic nonlinear change in the propagation velocity of ultrasonic waves. Existing monitoring technologies typically assume the medium is pure water and use fixed sound velocity parameters for calculations, directly resulting in significantly inflated groundwater flow rate data under sediment- or gas-bearing conditions. This leads to severe measurement errors in the final output groundwater flow rate data. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a method and apparatus for monitoring groundwater resources.

[0005] To achieve the above objectives, the present invention provides the following technical solution: Acquire the environmental water pressure data sequence inside the pipeline, as well as monitor the low-frequency and high-frequency ultrasonic signal sequences of groundwater inside the pipeline during the current sampling period; The overall fluid interference intensity of groundwater is obtained based on the differences in signal amplitude and instantaneous phase between low-frequency and high-frequency ultrasonic signal sequences. The bubble intensity disturbance factor of groundwater is obtained based on the comprehensive fluid disturbance intensity of groundwater and the changes in the water pressure data in the pipe environment during adjacent sampling periods. The preset reference sound velocity is dynamically compensated based on the bubble intensity disturbance factor, and the corrected real groundwater flow velocity data is obtained by combining the ultrasonic propagation time difference.

[0006] Preferably, obtaining the comprehensive fluid interference intensity of groundwater based on the difference in signal amplitude and instantaneous phase between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence includes: For the i-th sampling point within the current sampling period, obtain the signal amplitude difference value of the i-th sampling point based on the difference in signal amplitude between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence. The instantaneous phase difference at the i-th sampling point is determined by the difference in instantaneous phase between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence. The ratio between the signal amplitude difference value at the i-th sampling point and the instantaneous phase difference value at the i-th sampling point is denoted as the interference intensity factor at the i-th sampling point; the sum of the interference intensity factors at all sampling points is taken as the comprehensive fluid interference intensity of the groundwater.

[0007] Preferably, obtaining the signal amplitude difference value at the i-th sampling point based on the difference in signal amplitude between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence includes: The absolute value of the difference between the low-frequency ultrasonic signal amplitude at the i-th sampling point and the high-frequency ultrasonic signal amplitude at the i-th sampling point is denoted as the signal amplitude difference value at the i-th sampling point.

[0008] Preferably, the instantaneous phase difference value at the i-th sampling point, based on the instantaneous phase difference between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence, includes: The Hilbert transform algorithm is used to analyze the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence respectively to obtain the phase angle of each sampling point in the low-frequency ultrasonic signal sequence and the phase angle of each sampling point in the high-frequency ultrasonic signal sequence. The difference between the phase angle of the i-th sampling point in the high-frequency ultrasonic signal sequence and the amplitude of the high-frequency ultrasonic signal at the i-th sampling point in the low-frequency ultrasonic signal sequence is denoted as the instantaneous phase difference value of the i-th sampling point.

[0009] Preferably, the step of obtaining the groundwater bubble intensity disturbance factor based on the overall fluid disturbance intensity of groundwater and the changes in the pipe environment water pressure data in adjacent sampling periods includes: Based on the changes in the water pressure data inside the pipe during adjacent sampling periods, the current water pressure difference inside the pipe is obtained. Based on the current water pressure difference within the pipe, obtain the rate of change of the current water pressure within the pipe. The ratio between the overall fluid disturbance intensity of groundwater and the rate of change of the current water pressure in the pipe environment is used as the groundwater bubble intensity disturbance factor.

[0010] Preferably, obtaining the current intra-pipe environmental water pressure difference based on the changes in intra-pipe environmental water pressure data in adjacent sampling periods includes: The absolute value of the difference between the pipe environmental water pressure data in the current sampling period and the pipe environmental water pressure data in the previous sampling period is recorded as the current pipe environmental water pressure difference.

[0011] Preferably, obtaining the rate of change of the current water pressure in the pipe based on the current water pressure difference includes: The time interval between the current sampling period and the previous sampling period is denoted as the adjacent sampling period time interval; the ratio between the current difference in the ambient water pressure in the pipe and the adjacent sampling period time interval is denoted as the rate of change of the ambient water pressure in the pipe.

[0012] Preferably, the step of dynamically compensating for the preset reference sound velocity based on the bubble intensity disturbance factor and combining it with the ultrasonic wave propagation time difference to obtain the corrected real groundwater flow velocity data includes: Obtain the time difference between upstream and downstream propagation of groundwater; The distance between adjacent ultrasonic transducer probes in the ultrasonic transducer array is denoted as the physical sound path distance; the specific formula for obtaining the corrected true groundwater flow velocity data is as follows:

[0013] In the formula, This represents the corrected actual groundwater flow velocity data; This represents the preset standard sound velocity constant for pure water; The bubble intensity disturbance factor of groundwater; This indicates the time difference between upstream and downstream propagation of groundwater. This indicates the distance between adjacent ultrasonic transducer probes in an ultrasonic transducer array. This represents an exponential function with the natural constant as its base.

[0014] Preferably, obtaining the propagation time difference of groundwater upstream and downstream includes: The downstream propagation time of ultrasonic waves when they propagate along the flow direction of groundwater in the monitoring pipeline and the upstream propagation time when they propagate in the opposite direction of groundwater flow in the monitoring pipeline are measured using an ultrasonic transducer. The absolute value of the difference between the downstream propagation time and the upstream propagation time is recorded as the downstream and upstream propagation time difference of groundwater.

[0015] This invention also proposes an information collection device for monitoring plant carbon sequestration, the device comprising: Processor, memory, display screen, and touch interface; the processor includes: The system comprises a data acquisition module, a real groundwater flow velocity acquisition module, and a groundwater resource monitoring module. The remote sensing image acquisition module is used to acquire environmental water pressure data sequences within the pipeline, as well as to monitor low-frequency and high-frequency ultrasonic signal sequences of groundwater within the pipeline during the current sampling period. The real groundwater flow velocity acquisition module obtains corrected real groundwater flow velocity data by calling a computer program to perform the steps described above. The groundwater resource monitoring module is used for water resource sampling alarm control based on the corrected real groundwater flow velocity data.

[0016] The groundwater resource monitoring method provided by this invention has the following beneficial effects: This invention obtains the comprehensive fluid interference intensity of groundwater based on the differences in signal amplitude and instantaneous phase between low-frequency and high-frequency ultrasonic signal sequences; it obtains the bubble intensity disturbance factor of groundwater based on the comprehensive fluid interference intensity of groundwater and the changes in the water pressure data in the pipe environment during adjacent sampling periods; it dynamically compensates for the preset reference sound velocity based on the bubble intensity disturbance factor and combines it with the ultrasonic propagation time difference to obtain the corrected real groundwater flow velocity data. The combined interference of sediment and air bubbles is quantified by measuring the overall fluid interference intensity of groundwater. By utilizing the rate of change of environmental water pressure data within the pipe, a bubble intensity disturbance factor that purely reflects the bubble concentration is extracted from the overall fluid interference intensity. Finally, this bubble intensity disturbance factor is converted into a dynamic sound velocity compensation coefficient, and the real groundwater flow velocity is obtained by real-time correction of the reference sound velocity. This solves the problem of inflated flow measurement caused by gas-liquid-solid multiphase flow in deep well extraction environments, and significantly improves the accuracy of water resource monitoring. Attached Figure Description

[0017] To more clearly illustrate the embodiments and design schemes of the present invention, the accompanying drawings required for this embodiment will be briefly described below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart illustrating the steps of a groundwater resource monitoring method and apparatus according to an exemplary embodiment of the present invention. Figure 2 This is a bar chart comparing the accuracy of groundwater resource monitoring under different operating conditions of a groundwater resource monitoring method and device according to an exemplary embodiment of the present invention. Figure 3 This is a comparison curve of measurement errors of a groundwater resource monitoring method and device provided by the present invention according to an exemplary embodiment. Detailed Implementation

[0019] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0020] The technical solutions provided by the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] First, this invention provides a method and apparatus for monitoring groundwater resources, specifically as follows: Figure 1 As shown, it includes the following steps: Step S001: Obtain the environmental water pressure data sequence inside the pipeline, as well as the low-frequency ultrasonic signal sequence and high-frequency ultrasonic signal sequence of groundwater inside the pipeline during the current sampling period.

[0022] It should be noted that the fluid environment inside the pipe during deep well pumping is extremely complex. In order to obtain accurate basic signals, in-situ detection must be carried out without damaging the original pipeline structure. When groundwater flows at high speed, it carries fine sediment from the bottom layer. Under the action of pumping, dissolved gases (such as oxygen and nitrogen) in the water will precipitate due to the sudden drop in pressure, forming tiny bubbles. These substances have drastically different physical responses to acoustic detection waves of different frequencies. Therefore, it is necessary to extract the most original monitoring data simultaneously from multi-frequency physical fields and environmental pressure fields.

[0023] Preferably, in one embodiment of the present invention, the specific method for obtaining the low-frequency ultrasonic signal sequence, high-frequency ultrasonic signal sequence, and environmental water pressure data sequence of groundwater in the monitoring pipeline during the current sampling period is as follows: An asymmetric multi-frequency ultrasonic transducer array installed outside the pipeline is used to alternately emit low-frequency (e.g., 200kHz) and high-frequency (e.g., 1MHz) ultrasonic pulses with a sampling period of 100 milliseconds and a sampling frequency of 10MHz. The echo signals are converted from analog to digital by a high-speed acquisition card to obtain the low-frequency signal amplitude and high-frequency and low-frequency signal amplitude of groundwater in the pipeline at several sampling points within the period. At the same time, the embedded static pressure sensor acquires the environmental water pressure data in the pipeline in real time. The sequences formed by the low-frequency signal amplitude and high-frequency signal amplitude of all sampling points in the monitoring pipeline within the current sampling period are respectively denoted as the low-frequency ultrasonic signal sequence and high-frequency ultrasonic signal sequence of the monitoring pipeline within the period; the sequence formed by the environmental water pressure data in the pipeline for all sampling periods is denoted as the environmental water pressure data sequence in the pipeline.

[0024] Thus, the low-frequency ultrasonic signal sequence, high-frequency ultrasonic signal sequence, and environmental water pressure data sequence of the groundwater in the monitoring pipeline during the current sampling period were obtained.

[0025] Step S002: Based on the differences in signal amplitude and instantaneous phase between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence, obtain the comprehensive fluid interference intensity of groundwater.

[0026] It should be noted that in actual deep well pumping operations, the groundwater often contains a complex multiphase flow environment, mainly consisting of bottom sediment and tiny free bubbles formed by dissolved gases released due to the high-speed suction of the pump impeller and the drastic pressure fluctuations inside the pipeline. This solid-liquid-gas three-phase mixture of sediment, bubbles, and water will produce extremely complex interference effects on the propagation of ultrasonic signals.

[0027] Existing methods only correct signal attenuation through amplitude compensation. This method ignores the differentiated effects of different phase media on sound waves of different frequencies and cannot accurately reflect the actual signal changes in complex multiphase fluid environments. Sediment particles mainly cause volume scattering of sound waves across the entire frequency band, leading to overall signal energy attenuation. This effect manifests as an overall weakening of amplitude, but has a relatively small impact on wave phase. Microbubbles not only produce strong nonlinear absorption of high-frequency sound waves, but also cause significant phase dragging and hysteresis of ultrasonic wave packets due to bubble pulsation effects. This makes it impossible for existing methods based on amplitude attenuation compensation to quantify phase changes, thus undermining the physical basis for subsequent sound velocity correction. Therefore, existing methods cannot distinguish the mixed interference of sediment scattering and bubble absorption, and cannot quantify the severe phase shift caused by the presence of the gas phase, resulting in objective biases in signal correction.

[0028] To address the aforementioned issues, the amplitude attenuation caused by sediment and the phase hysteresis caused by air bubbles were analyzed to obtain the comprehensive interference intensity of groundwater fluids that can distinguish the effects of different phase media. Specifically, by analyzing the amplitude differences of high- and low-frequency ultrasonic waves after penetrating multiphase fluids and coupling them with the phase change difference of high-frequency sound waves, the comprehensive interference degree of multiphase media in groundwater fluids can be amplified.

[0029] Preferably, in one embodiment of the present invention, the specific method for obtaining the comprehensive fluid interference intensity of groundwater based on the difference in signal amplitude and instantaneous phase between low-frequency ultrasonic signal sequences and high-frequency ultrasonic signal sequences is as follows: For the i-th sampling point in the current sampling period, the absolute value of the difference between the low-frequency ultrasonic signal amplitude and the high-frequency ultrasonic signal amplitude at the i-th sampling point is denoted as the signal amplitude difference value at the i-th sampling point. The Hilbert transform algorithm is used to analyze the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence respectively to obtain the phase angle of each sampling point in the low-frequency ultrasonic signal sequence and the phase angle of each sampling point in the high-frequency ultrasonic signal sequence. The difference between the phase angle of the i-th sampling point in the high-frequency ultrasonic signal sequence and the amplitude of the high-frequency ultrasonic signal at the i-th sampling point in the low-frequency ultrasonic signal sequence is denoted as the instantaneous phase difference value of the i-th sampling point. The ratio between the signal amplitude difference value at the i-th sampling point and the instantaneous phase difference value at the i-th sampling point is denoted as the interference intensity factor at the i-th sampling point; the sum of the interference intensity factors at all sampling points is taken as the comprehensive fluid interference intensity of the groundwater. The specific formula is as follows:

[0030] In the formula, This indicates the overall intensity of fluid disturbance to groundwater. This indicates the number of all sampling points within the current sampling period; This represents the low-frequency ultrasonic signal amplitude at the i-th sampling point of the groundwater within the current sampling period; This represents the amplitude of the high-frequency ultrasonic signal at the i-th sampling point of groundwater within the current sampling period; This represents the instantaneous phase difference of groundwater at the i-th sampling point within the current sampling period; This represents the preset hyperparameters; this implementation uses the preset hyperparameters. This is used to prevent the denominator from being 0; This indicates taking the absolute value.

[0031] It should be noted that when sediment and air bubbles in a multiphase fluid act on ultrasound, as the concentration of sediment particles and air bubbles increases, the high-frequency signal experiences more severe nonlinear attenuation compared to the low-frequency signal. The unique pulsation hysteresis effect of air bubbles, as the gas content increases, causes the transmission time of the high-frequency sound wave packet to be lengthened, resulting in a smaller instantaneous phase difference. This amplifies the overall interference intensity of the groundwater fluid, thus quantifying the overall distortion state of the adverse medium.

[0032] The Hilbert transform algorithm is an existing technology, and will not be described in detail here.

[0033] Thus, the overall fluid disturbance intensity of groundwater is obtained.

[0034] Step S003: Based on the comprehensive fluid disturbance intensity of groundwater and the changes in the environmental water pressure data in the pipe during adjacent sampling periods, obtain the bubble intensity disturbance factor of groundwater.

[0035] It should be noted that the overall interference intensity of groundwater fluids quantifies the interference of fluids on ultrasonic signals; however, the volume scattering effect of sediment particles and the phase drag effect of free air bubbles are still inevitably mixed within it. In groundwater hydrodynamics, the root cause of the severe nonlinear change in ultrasonic propagation speed is simply the presence of air bubbles in the fluid, because free gas will greatly change the bulk elastic modulus of the mixed fluid, while the influence of sediment particles on the equivalent stiffness of the fluid is relatively weak.

[0036] Existing signal separation techniques typically rely on complex frequency domain filtering analysis. However, in high-noise, enclosed environments like underground water pipes, these methods struggle to accurately distinguish the independent contributions of the solid and gas phases and are prone to introducing additional computational errors. Therefore, relying solely on the overall fluid interference intensity cannot completely solve the core problem of how to quantify bubble interference separately.

[0037] To solve this problem, we need to find an independent physical parameter that is unaffected by the solid phase but reflects the gas phase state. According to the principles of fluid mechanics, the shape and volume of sediment particles hardly change with the water pressure in the pipe, while microbubbles are compressible and their volume changes strictly inversely with the water pressure. When the water pump operates and causes a sudden drop in the transient water pressure in the pipe, the microbubbles will expand rapidly, which will aggravate the distortion of the ultrasonic signal. Therefore, by combining the comprehensive fluid interference intensity and the water pressure change rate, we can effectively separate the pressure-dominated gas phase interference from the solid-liquid mixture, while filtering out the fixed sediment background noise.

[0038] Preferably, in one embodiment of the present invention, the specific method for obtaining the bubble intensity disturbance factor of groundwater based on the comprehensive fluid disturbance intensity of groundwater and the changes in the pipe environmental water pressure data of adjacent sampling periods is as follows: The absolute value of the difference between the pipe environmental water pressure data in the current sampling period and the pipe environmental water pressure data in the previous sampling period is recorded as the current pipe environmental water pressure difference. The time interval between the current sampling period and the previous sampling period is denoted as the adjacent sampling period time interval; the ratio between the current difference in the ambient water pressure in the pipe and the adjacent sampling period time interval is denoted as the rate of change of the ambient water pressure in the pipe. The ratio between the overall disturbance intensity of groundwater fluids and the rate of change of the current water pressure in the pipe environment is used as the groundwater bubble intensity disturbance factor. The specific formula is as follows:

[0039] In the formula, The bubble intensity disturbance factor of groundwater; This indicates the overall intensity of fluid disturbance to groundwater. This represents the water pressure data within the pipe during the current sampling period; This represents the water pressure data within the pipe during the previous sampling period; Indicates the time interval between adjacent sampling periods; This represents the preset hyperparameters; this implementation uses the preset hyperparameters. This is used to prevent the denominator from being 0; This indicates taking the absolute value.

[0040] It should be noted that the sudden pressure drop caused by groundwater extraction is the core cause of the intensified gas phase interference. As the pumping intensifies, the ambient water pressure drops sharply, increasing the rate of change of the ambient water pressure inside the pipe. The rate of change of the ambient water pressure inside the pipe mainly reflects the intensity of transient bubble expansion. As the rate of change of the ambient water pressure inside the pipe increases, the intensity of the overall fluid interference, which was originally abnormally amplified due to the violent expansion of bubbles, is suppressed, making the overall situation more gradual. The bubble intensity disturbance factor of the groundwater decreases and returns to stability, thereby eliminating the transient false distortion caused by the sudden pressure change and restoring the true gas phase interference that continuously exists in the fluid.

[0041] Thus, the bubble intensity perturbation factor of groundwater was obtained.

[0042] Step S004: Dynamically compensate the preset reference sound velocity according to the bubble intensity disturbance factor, and combine it with the ultrasonic propagation time difference to obtain the corrected real groundwater flow velocity data.

[0043] It should be noted that traditional ultrasonic time-of-flight flowmeters typically assume a fixed sound velocity for pure water when calculating flow velocity. This assumption holds true in a pure water environment. However, in groundwater, if a large number of air bubbles are mixed in to form a gas-liquid mixture, the density and bulk elasticity of the fluid will decrease significantly with increasing gas content, resulting in the actual propagation speed of ultrasound being much lower than the standard sound velocity. If the groundwater bubble intensity disturbance factor does not directly affect the basic algorithm for flow calculation, a fixed sound velocity will still be used to analyze the time difference data for both upstream and downstream flows, leading to a significantly higher calculated groundwater flow velocity. Applying only an empirical discount factor to the final flow result lacks both physical basis and the ability to handle real-time changes in groundwater gas content.

[0044] To address this issue, the bubble intensity disturbance factor of groundwater is transformed into a dynamic sound velocity correction coefficient and directly applied to the core formula for ultrasonic flow velocity calculation. By mapping the bubble concentration to the attenuation of the reference sound velocity, the sound velocity can be adjusted in real time according to the change in bubble concentration in the pipe, thereby ensuring the accuracy of the groundwater flow velocity calculation results.

[0045] Preferably, in one embodiment of the present invention, the specific method for dynamically compensating the preset reference sound velocity based on the bubble intensity disturbance factor and combining it with the ultrasonic wave propagation time difference to obtain the corrected real groundwater flow velocity data is as follows: The downstream propagation time of ultrasonic waves when they propagate along the flow direction of groundwater in the monitoring pipeline and the upstream propagation time when they propagate in the opposite direction of groundwater flow in the monitoring pipeline are measured using an ultrasonic transducer. The absolute value of the difference between the downstream propagation time and the upstream propagation time is recorded as the downstream and upstream propagation time difference of groundwater. The distance between adjacent ultrasonic transducer probes in an ultrasonic transducer array is denoted as the physical sound path distance. The product of the preset pure water standard sound velocity constant, the inverse proportional value of the bubble intensity disturbance factor of groundwater, and the time difference between upstream and downstream propagation of groundwater, and the ratio of the physical sound path distance, is used as the corrected real groundwater flow velocity data. The specific formula is as follows:

[0046] In the formula, This represents the corrected actual groundwater flow velocity data; This represents the preset standard sound velocity constant for pure water (usually taken as 1480 m / s). The bubble intensity disturbance factor of groundwater; This indicates the time difference between upstream and downstream propagation of groundwater. This indicates the distance between adjacent ultrasonic transducer probes in an ultrasonic transducer array. This represents an exponential function with the natural constant as its base.

[0047] It should be noted that, since the bulk elastic modulus of the gas-liquid mixture decreases nonlinearly with the gas content, as the concentration of free bubbles in the pipe increases, the bubble intensity disturbance factor increases. This factor acts directly on the reference sound velocity as a correction factor. As the correction factor decreases, the reference value of the actual sound velocity used in the calculation decreases, making the actual groundwater flow velocity smaller and closer to the actual groundwater flow velocity data. This triggers the monitoring terminal to perform water resource sampling alarm control according to the actual groundwater flow velocity data, thus eliminating the errors caused by complex operating conditions.

[0048] Please see Figure 2The paper presents a bar chart comparing the accuracy of groundwater resource monitoring under different operating conditions. The horizontal axis is divided into three scenarios: pure water environment, sediment-laden environment, and gas-liquid-solid multiphase flow. The vertical axis represents the accuracy of water resource monitoring. In an ideal pure water environment, the values ​​of the two methods are close. However, under the complex operating conditions of sediment-laden environment and gas-liquid-solid multiphase flow, the accuracy of the existing method is significantly reduced, while the value of the method of the present invention is relatively superior. The comparison shows that the dynamic compensation mechanism of the present invention has outstanding accuracy under harsh operating conditions.

[0049] Please see Figure 3 The figure shows a comparison curve of measurement error of a groundwater resource monitoring method. The figure shows the comparison trend of groundwater flow velocity measurement error with sampling period. The horizontal axis is the sampling period and the vertical axis is the measurement error. The curve of the existing method shows a significant increase with the progress of the process and is accompanied by violent fluctuations, reflecting the measurement false high caused by untreated multiphase flow interference. The curve of the present invention remains at a lower and relatively stable level, and the final value of the curve of the present invention is even lower, indicating that the present invention has better measurement accuracy.

[0050] This concludes the embodiment.

[0051] Another embodiment of the present invention provides a groundwater resource monitoring device, the device comprising: Processor, memory, display screen, and touch interface; the processor includes: The system comprises a data acquisition module, a real groundwater flow velocity acquisition module, and a groundwater resource monitoring module. The remote sensing image acquisition module is used to acquire environmental water pressure data sequences within the pipeline, as well as to monitor low-frequency and high-frequency ultrasonic signal sequences of groundwater within the pipeline during the current sampling period. The real groundwater flow velocity acquisition module executes steps S001 to S004 of the above method by calling a computer program to obtain corrected real groundwater flow velocity data. The groundwater resource monitoring module is used to perform water resource sampling alarm control based on the corrected real groundwater flow velocity data.

[0052] It should be noted that the specific embodiments described above enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way. Therefore, although the present invention has been described in detail in this specification, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention; and all technical solutions and improvements that do not depart from the spirit and scope of the present invention are covered within the protection scope of the patent of the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for monitoring groundwater resources, characterized in that, The method includes: Acquire the environmental water pressure data sequence inside the pipeline, as well as monitor the low-frequency and high-frequency ultrasonic signal sequences of groundwater inside the pipeline during the current sampling period; The overall fluid interference intensity of groundwater is obtained based on the differences in signal amplitude and instantaneous phase between low-frequency and high-frequency ultrasonic signal sequences. The bubble intensity disturbance factor of groundwater is obtained based on the comprehensive fluid disturbance intensity of groundwater and the changes in the water pressure data in the pipe environment during adjacent sampling periods. The preset reference sound velocity is dynamically compensated based on the bubble intensity disturbance factor, and the corrected real groundwater flow velocity data is obtained by combining the ultrasonic propagation time difference.

2. The groundwater resource monitoring method according to claim 1, characterized in that, The method of obtaining the comprehensive fluid interference intensity of groundwater based on the differences in signal amplitude and instantaneous phase between low-frequency and high-frequency ultrasonic signal sequences includes: For the i-th sampling point within the current sampling period, obtain the signal amplitude difference value of the i-th sampling point based on the difference in signal amplitude between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence. The instantaneous phase difference at the i-th sampling point is determined by the difference in instantaneous phase between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence. The ratio between the signal amplitude difference value at the i-th sampling point and the instantaneous phase difference value at the i-th sampling point is denoted as the interference intensity factor at the i-th sampling point; the sum of the interference intensity factors at all sampling points is taken as the comprehensive fluid interference intensity of the groundwater.

3. The groundwater resource monitoring method according to claim 2, characterized in that, The step of obtaining the signal amplitude difference value at the i-th sampling point based on the difference in signal amplitude between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence includes: The absolute value of the difference between the low-frequency ultrasonic signal amplitude at the i-th sampling point and the high-frequency ultrasonic signal amplitude at the i-th sampling point is denoted as the signal amplitude difference value at the i-th sampling point.

4. The groundwater resource monitoring method according to claim 2, characterized in that, The instantaneous phase difference value at the i-th sampling point, based on the instantaneous phase difference between the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence, includes: The Hilbert transform algorithm is used to analyze the low-frequency ultrasonic signal sequence and the high-frequency ultrasonic signal sequence respectively to obtain the phase angle of each sampling point in the low-frequency ultrasonic signal sequence and the phase angle of each sampling point in the high-frequency ultrasonic signal sequence. The difference between the phase angle of the i-th sampling point in the high-frequency ultrasonic signal sequence and the amplitude of the high-frequency ultrasonic signal at the i-th sampling point in the low-frequency ultrasonic signal sequence is denoted as the instantaneous phase difference value of the i-th sampling point.

5. A groundwater resource monitoring method according to claim 1, characterized in that, The method for obtaining the groundwater bubble intensity disturbance factor based on the overall fluid disturbance intensity of groundwater and the changes in the pipe environment water pressure data in adjacent sampling periods includes: Based on the changes in the water pressure data inside the pipe during adjacent sampling periods, the current water pressure difference inside the pipe is obtained. Based on the current water pressure difference within the pipe, obtain the rate of change of the current water pressure within the pipe. The ratio between the overall fluid disturbance intensity of groundwater and the rate of change of the current water pressure in the pipe environment is used as the groundwater bubble intensity disturbance factor.

6. A groundwater resource monitoring method according to claim 5, characterized in that, The step of obtaining the current water pressure difference in the pipe based on the changes in the water pressure data in adjacent sampling periods includes: The absolute value of the difference between the pipe environmental water pressure data in the current sampling period and the pipe environmental water pressure data in the previous sampling period is recorded as the current pipe environmental water pressure difference.

7. A groundwater resource monitoring method according to claim 5, characterized in that, The step of obtaining the rate of change of the current environmental water pressure within the pipe based on the current water pressure difference includes: The time interval between the current sampling period and the previous sampling period is denoted as the adjacent sampling period time interval; the ratio between the current difference in the ambient water pressure in the pipe and the adjacent sampling period time interval is denoted as the rate of change of the ambient water pressure in the pipe.

8. A groundwater resource monitoring method according to claim 1, characterized in that, The process of dynamically compensating for a preset reference sound velocity based on a bubble intensity disturbance factor, and combining this with the ultrasonic wave propagation time difference to obtain corrected real groundwater flow velocity data, includes: Obtain the time difference between upstream and downstream propagation of groundwater; The distance between adjacent ultrasonic transducer probes in the ultrasonic transducer array is denoted as the physical sound path distance; the specific formula for obtaining the corrected true groundwater flow velocity data is as follows: In the formula, This represents the corrected actual groundwater flow velocity data; This represents the preset standard sound velocity constant for pure water; The bubble intensity disturbance factor of groundwater; This indicates the time difference between upstream and downstream propagation of groundwater. This indicates the distance between adjacent ultrasonic transducer probes in an ultrasonic transducer array. This represents an exponential function with the natural constant as its base.

9. A groundwater resource monitoring method according to claim 8, characterized in that, The acquisition of the propagation time difference of groundwater upstream and downstream includes: The downstream propagation time of ultrasonic waves when they propagate along the flow direction of groundwater in the monitoring pipeline and the upstream propagation time when they propagate in the opposite direction of groundwater flow in the monitoring pipeline are measured using an ultrasonic transducer. The absolute value of the difference between the downstream propagation time and the upstream propagation time is recorded as the downstream and upstream propagation time difference of groundwater.

10. A groundwater resource monitoring device, the device comprising: Processor, memory, display, and touch interface; The processor includes The data acquisition module is used to acquire the environmental water pressure data sequence inside the pipeline, as well as to monitor the low-frequency ultrasonic signal sequence and high-frequency ultrasonic signal sequence of groundwater inside the pipeline during the current sampling period. The real groundwater flow velocity acquisition module is used to implement the steps of the groundwater resource monitoring method as described in any one of claims 1-9 by calling a computer program, and to obtain corrected real groundwater flow velocity data. The groundwater resource monitoring module is used for water resource sampling alarm control based on corrected real groundwater flow velocity data.

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