Resistivity or electrical impedance bimodal tomography measuring device for soil seepage channel

Abstract

The invention relates to the technical field of geophysical exploration and geotechnical engineering monitoring, in particular to a soil seepage channel resistivity or electrical impedance bimodal tomography measuring device. Comprising an excitation signal adjusting module, a data acquisition module, a channel switching module, a sensing electrode module and a computer, the excitation signal adjusting module is composed of a signal generation module and an isolation switch QS. The data acquisition module consists of a power analysis module, a multi-channel synchronous acquisition module, a signal conditioning module and a phase-locked amplification module; the channel switching module consists of a relay switch module A and a relay switch module B; each relay is provided with a plurality of channels, and each channel comprises three general ports, namely a normally open end (NO), a common end (COM) and a normally closed end (NC). The invention provides a resistivity or electrical impedance bimodal tomography measurement device, which is used for realizing rapid high-resolution detection and description of a soil seepage channel with resistivity and electrical impedance combined.

Description

Technical Field

[0001] The invention relates to the technical field of geophysical detection and geotechnical engineering monitoring, in particular to a soil seepage channel resistivity or electrical impedance dual-mode tomography measuring device. Background Art

[0002] In the field of geophysical exploration and geotechnical engineering monitoring technology, accurate characterization and identification of soil seepage channels is the key to ensuring the safety and stability of earth-rock structure infrastructure, such as dams. Earth-rock dams are widely used around the world as an important barrier for optimizing water resources utilization and preventing floods and droughts. However, due to various factors, such as cracking of dam soil due to dry-wet cycles, nests of animals that damage the dam, and hydraulic erosion and penetration damage, seepage channels will be formed. These seepage channels are the main cause of endangering the safety of earth-rock dams and even causing dam failures.

[0003] Electrical tomography has been widely used in soil aquifer characterization and structural defect monitoring due to its advantages such as no radiation, fast response speed and low price. Among them, electrical resistivity tomography (ERT) and electrical impedance tomography (EIT) are two widely used methods in rock and soil structure detection. Resistivity tomography uses a direct current signal as the excitation signal, and the parameter obtained by inversion is resistivity; while electrical impedance tomography uses an alternating current signal as the excitation signal, and the parameter obtained by inversion is impedance. Although these two technologies have their own advantages, due to the difference in sensitivity of DC resistivity and impedance to parameters such as soil moisture content, the two have different sensitivities for identifying abnormal bodies in soil structures. In addition, affected by the observation mode and inversion model, resistivity tomography often has difficulty in characterizing abnormal bodies in boundary areas, while electrical impedance tomography has a higher resolution for abnormal bodies in boundary areas, but its ability to characterize the interior of the structure is relatively weak.

[0004] In order to improve the detection and identification accuracy of soil seepage channels, combining resistivity tomography technology with electrical impedance tomography technology is an effective way. However, traditional resistivity tomography and electrical impedance tomography measurements require two independent detection devices to collect detection data, and the sensor electrodes need to be connected to their respective acquisition devices, which greatly increases the complexity of the joint detection of the two methods, increases the equipment cost, and may cause signal interference and a greater probability of failure in field detection applications.

[0005] Therefore, in view of this, the existing technology is studied and improved, and a soil seepage channel resistivity or electrical impedance dual-mode tomography measurement device is proposed. Summary of the invention

[0006] The present invention provides a resistivity or electrical impedance dual-mode tomography measuring device to realize rapid high-resolution detection and characterization of soil seepage channels by combining ERT and EIT.

[0007] The technical solution adopted by the present invention is: a soil seepage channel resistivity or electrical impedance dual-mode tomography measurement device, characterized in that it includes an excitation signal adjustment module, a data acquisition module, a channel switching module, a sensor electrode module, and a computer;

[0008] The excitation signal adjustment module is composed of a signal generation module and an isolation switch QS;

[0009] The data acquisition module is composed of a power analysis module, a multi-channel synchronous acquisition module, a signal conditioning module, and a phase-locked amplification module;

[0010] The channel switching module is composed of a relay switch module A and a relay switch module B; each relay has multiple channels, and each channel includes three common ports: a normally open end (NO), a common end (COM), and a normally closed end (NC); wherein the normally closed end (NCA) of the relay switch module A is connected to the phase-locked amplifier module through a wire; all the normally open ends (NOA) of the relay switch module A are connected in series through a wire and connected to the positive pole of the power analysis module; the common end (COMA) of the relay switch module A is connected to the normally closed end (NCB) of the relay switch module B through a wire; all the normally open ends (NOB) of the relay switch module B are connected in series through a wire and connected to the negative pole of the power analysis module; the common end (COMB) of the relay switch module B is connected to the corresponding channel on the hub;

[0011] The sensing electrode module is composed of a sensing electrode and a hub; wherein the sensing electrode is made of stainless steel or graphite inert electrode material and is connected to the corresponding channel of the hub through a wire; finally, the GND of the multi-channel synchronous acquisition module is connected to the negative electrode of the power analysis module;

[0012] The signal generation module, data acquisition module, and channel switching module are connected to a computer via a data transmission line, and channel switching control and data acquisition processing are implemented via host computer software on the computer side.

[0013] As a further solution of the present invention: the signal generating module is used to provide the periodic excitation electrical signal required in resistivity or electrical impedance tomography detection, and the isolating switch QS is adjusted to a closed state to provide a zero potential boundary around the area to be tested when conducting resistivity tomography detection.

[0014] As a further solution of the present invention: the power analysis module is connected to the signal generation module through a wire and a data transmission line, and is used to collect the excitation voltage signal and the main current signal; the multi-channel synchronous acquisition module is used to collect the voltage signals of each channel corresponding to the sensing electrode; the signal adjustment module is used to amplify and pre-process the original voltage signal of each channel; the phase-locked amplifier module is mainly used to enhance the target signal and suppress noise, and improve the quality of the voltage signal; the multi-channel synchronous acquisition module is connected to the signal adjustment module through the data transmission line, and the signal adjustment module is connected to the phase-locked amplifier module through the data transmission line.

[0015] As a further solution of the present invention: it also includes the measuring step:

[0016] S1. Measurement preparation: connect each module and the arranged sensing electrodes through data transmission lines and wires; test the communication status between the computer and each module, set the excitation signal parameters and data acquisition frequency through the computer, and import the running pole file of the control channel switching module;

[0017] S2, resistivity tomography test; close the isolation switch QS, connect the negative pole of the power analysis module to the conductive copper foil around the test area through a wire; set the output voltage of the signal generation module to a rectangular pulse signal; all switches of the relay switch module B are turned to the normally closed contact (NCB); after starting to execute the running pole file, control the switch on the Y1 channel of the relay switch module A to the normally open contact (NOA1) and maintain it for 5S, then control the switch on the Y1 channel of the relay switch module A to the normally closed contact (NCA1) and maintain it for 2S; then control the switch on the Y2 channel of the relay switch module A to the normally open contact (NOA2) and maintain it for 5S, then control the switch on the Y2 channel of the relay switch module A to the normally closed contact (NCA2) and maintain it for 2S; repeat the above operation until the above switch switching action traverses all channels of the relay switch module A; extract the peak voltage on the corresponding channel of the E1 to E25 sensing electrodes collected by the computer, and the peak current corresponding to each time the switch is turned to the normally open contact;

[0018] S3, electrical impedance tomography test; disconnect the isolation switch QS, set the output voltage of the signal generation module to a sinusoidal pulse signal, and reset the switches of the relay switch module A and the relay switch module B to the normally closed (NC) contact; after starting to execute the run-out file, control the switch on the X2 channel of the relay switch module B to the normally open contact (NOB2) and maintain it for 10S, then control the switch on the Y1 channel of the relay switch module A to the normally open contact (NOA1) and maintain it for 5S, then control the switch on the Y1 channel of the relay switch module A to the normally closed contact (NCA1) and maintain it for 5S, and then control the switch on the X2 channel of the relay switch module B to the normally closed contact (NCB2);

[0019] Then, the switch on the X3 channel of the relay switch module B is controlled to be turned to the normally open contact (NOB3) and maintained for 10S, then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally open contact (NOA2) and maintained for 5S, and then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally closed contact (NCA2) and maintained for 5S, and then the switch on the X3 channel of the relay switch module B is controlled to be turned to the normally closed contact (NCB3); repeat the above operation until the above switch switching action traverses all channels of the relay switch module A and the relay switch module B; extract the peak voltage on the corresponding channel of the E1 to E25 sensing electrodes collected by the computer, and the peak current corresponding to each time the switch is turned to the normally open contact.

[0020] Beneficial effects of the present invention:

[0021] 1. Improved data acquisition efficiency: The present invention integrates the composite channel switching module, the excitation signal adjustment module, the data acquisition module, and the sensor electrode module into the same measuring device, so that a set of equipment can simultaneously complete the resistivity / impedance dual-mode tomography measurement, which significantly improves the acquisition efficiency of the electrical tomography detection data of the soil seepage channel.

[0022] 2. Reduced hardware and labor costs: The traditional method requires two independent sets of ERT and EIT equipment and corresponding sensing electrodes and cables, while the present invention only requires one set of equipment to complete dual-mode detection, greatly reducing hardware costs. At the same time, due to the reduction in the number and complexity of equipment, the human resource cost during the observation process is also reduced.

[0023] 3. Improved detection accuracy: By combining the advantages of resistivity tomography and electrical impedance tomography, the present invention can more comprehensively characterize the characteristics of soil seepage channels and improve detection accuracy. Resistivity tomography has a good ability to characterize the interior of the structure, while electrical impedance tomography has a high resolution for abnormal bodies in the boundary area. The combination of the two can achieve fine characterization and identification of soil seepage channels.

[0024] 4. Enhanced technical practicality: The measuring device of the present invention has a compact structure and is easy to operate. It is suitable for soil seepage channel detection tasks in various complex environments. It provides strong technical support for the resistivity / impedance dual-mode fusion and fine characterization and identification of soil seepage channels, which is of great significance for ensuring the safety and stability of earth-rock structure infrastructure such as dams. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an overall schematic diagram of the soil seepage channel resistivity or electrical impedance dual-mode tomography measurement device of the present invention.

[0026] Figure 2 It is a potential cloud diagram of resistivity tomography measurement of the soil seepage channel resistivity or electrical impedance dual-mode tomography measurement device of the present invention.

[0027] Figure 3 It is a potential cloud diagram of the electrical impedance tomography measurement of the soil seepage channel resistivity or electrical impedance dual-mode tomography measurement device of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below.

[0029] like Figure 1 As shown, a soil seepage channel resistivity or electrical impedance dual-mode tomography measuring device includes an excitation signal adjustment module, a data acquisition module, a channel switching module, a sensor electrode module, and a computer;

[0030] The excitation signal adjustment module is mainly composed of a signal generation module and an isolating switch QS. The signal generation module is used to provide the periodic excitation electrical signal required for resistivity or electrical impedance tomography detection, and the isolating switch QS is used to adjust to a closed state to provide a zero potential boundary around the area to be tested when conducting resistivity tomography detection.

[0031] The data acquisition module is mainly composed of a power analysis module, a multi-channel synchronous acquisition module, a signal conditioning module, and a phase-locked amplifier module. Among them, the power analysis module is connected to the signal generation module through wires and data transmission lines to collect excitation voltage signals and main current signals. The multi-channel synchronous acquisition module is used to collect voltage signals of each channel corresponding to the sensing electrode. The signal conditioning module is used to amplify the original voltage signals of each channel and perform other pre-processing to ensure that these signals can be correctly interpreted and used by the subsequent multi-channel synchronous acquisition module. The phase-locked amplifier module is mainly used to enhance the target signal and suppress noise to improve the quality of the voltage signal. The multi-channel synchronous acquisition module is connected to the signal conditioning module through a data transmission line, and the signal conditioning module is connected to the phase-locked amplifier module through a data transmission line.

[0032] The channel switching module is mainly composed of relay switch module A and relay switch module B. Each relay has multiple channels, and each channel contains three common ports: normally open (NO), common (COM), and normally closed (NC). The normally closed end (NCA) of relay switch module A is connected to the phase-locked amplifier module through wires. All normally open ends (NOA) of relay switch module A are connected in series through wires and connected to the positive pole of the power analysis module. The common end (COMA) of relay switch module A is connected to the normally closed end (NCB) of relay switch module B through wires. All normally open ends (NOB) of relay switch module B are connected in series through wires and connected to the negative pole of the power analysis module. The common end (COMB) of relay switch module B is connected to the corresponding channel on the hub.

[0033] The sensor electrode module is mainly composed of sensor electrodes and a hub. The sensor electrodes are made of inert electrode materials such as stainless steel or graphite, and are connected to the corresponding channels of the hub through wires. Finally, the GND of the multi-channel synchronous acquisition module is connected to the negative electrode of the power analysis module.

[0034] The signal generation module, the data acquisition module, and the channel switching module are connected to the computer through a data transmission line, and the channel switching control and data acquisition processing are realized through the host computer software on the computer side.

[0035] Measurement steps:

[0036] S1. Measurement preparation. Connect each module and the arranged sensing electrodes through data transmission lines and wires. Test the communication status between the computer and each module, set the excitation signal parameters and data acquisition frequency through the computer, and import the running electrode file of the control channel switching module.

[0037] S2. Resistivity tomography test. Close the isolation switch QS and connect the negative pole of the power analysis module to the conductive copper foil around the test area through a wire. Set the output voltage of the signal generation module to a rectangular pulse signal. All switches of the relay switch module B are turned to the normally closed contact (NCB). After the execution of the running pole file begins, the switch on the Y1 channel of the relay switch module A is controlled to be turned to the normally open contact (NOA1) and maintained for 5S, and then the switch on the Y1 channel of the relay switch module A is controlled to be turned to the normally closed contact (NCA1) and maintained for 2S. Then, the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally open contact (NOA2) and maintained for 5S, and then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally closed contact (NCA2) and maintained for 2S. Repeat the above operation until the above switch switching action traverses all channels of the relay switch module A. Extract the peak voltage on the corresponding channel of the E1 to E25 sensing electrodes collected by the computer, and the peak current corresponding to each time the switch is turned to the normally open contact. Taking the data collected when the switch on the Y21 channel of relay switch module A is turned to the normally open contact (NOA21) as an example, the potential response cloud diagram in the detection area is as follows: Figure 2 shown.

[0038] S3, electrical impedance tomography test. Disconnect the isolation switch QS, set the output voltage of the signal generation module to a sinusoidal pulse signal, and reset the switches of the relay switch module A and the relay switch module B to the normally closed (NC) contact. Taking the adjacent excitation mode as an example, after the execution of the running pole file starts, the switch on the X2 channel of the relay switch module B is controlled to be turned to the normally open contact (NOB2) and maintained for 10S, and then the switch on the Y1 channel of the relay switch module A is controlled to be turned to the normally open contact (NOA1) and maintained for 5S, and then the switch on the Y1 channel of the relay switch module A is controlled to be turned to the normally closed contact (NCA1) and maintained for 5S, and then the switch on the X2 channel of the relay switch module B is controlled to be turned to the normally closed contact (NCB2).

[0039] Then, the switch on the X3 channel of the relay switch module B is controlled to be turned to the normally open contact (NOB3) and maintained for 10S, and then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally open contact (NOA2) and maintained for 5S, and then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally closed contact (NCA2) and maintained for 5S, and then the switch on the X3 channel of the relay switch module B is controlled to be turned to the normally closed contact (NCB3). Repeat the above operation until the above switch switching action traverses all channels of the relay switch module A and the relay switch module B. Extract the peak voltage on the corresponding channel of the E1 to E25 sensing electrodes collected by the computer, and the corresponding peak current each time the switch is turned to the normally open contact. Taking the data collected when the switch on the X2 channel of the relay switch module B is turned to the normally open contact (NOB2) and the switch on the Y1 channel of the relay switch module A is turned to the normally open contact (NOA1) as an example, the potential response cloud diagram in the detection area is obtained as follows: Figure 3 shown.

[0040] The present invention proposes a soil seepage channel resistivity or electrical impedance dual-mode tomography measurement device. By integrating the composite channel switching module, the excitation signal adjustment module, the data acquisition module, and the sensor electrode module into the same measurement device, a set of equipment can simultaneously realize resistivity / electrical impedance dual-mode tomography measurement, improve the collection efficiency of soil seepage channel electrical tomography detection data, and reduce the hardware and human resource costs in the observation process. This technology provides technical support for the resistivity / electrical impedance dual-mode fusion fine characterization and identification of soil seepage channels, which is of great significance to ensuring the safety and stability of the foundation setting of earth-rock structures such as dams.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A soil seepage channel resistivity or electrical impedance dual-mode tomography measuring device, characterized in that: It includes an excitation signal adjustment module, a data acquisition module, a channel switching module, a sensor electrode module, and a computer; the excitation signal adjustment module is composed of a signal generation module and an isolation switch QS; The data acquisition module is composed of a power analysis module, a multi-channel synchronous acquisition module, a signal conditioning module, and a phase-locked amplification module; The channel switching module is composed of a relay switch module A and a relay switch module B; each relay has multiple channels, and each channel includes three common ports: a normally open terminal NO, a common terminal COM, and a normally closed terminal NC; wherein the normally closed terminal NCA of the relay switch module A is connected to the phase-locked amplifier module through a wire; all the normally open terminals NOA of the relay switch module A are connected in series through a wire and connected to the positive electrode of the power analysis module; the common terminal COMA of the relay switch module A is connected to the normally closed terminal NCB of the relay switch module B through a wire; all the normally open terminals NOB of the relay switch module B are connected in series through a wire and connected to the negative electrode of the power analysis module; the common terminal COMB of the relay switch module B is connected to the corresponding channel on the hub; The sensing electrode module is composed of a sensing electrode and a hub; wherein the sensing electrode is made of stainless steel or graphite inert electrode material and is connected to the corresponding channel of the hub through a wire; finally, the GND of the multi-channel synchronous acquisition module is connected to the negative electrode of the power analysis module; The signal generation module, data acquisition module, and channel switching module are connected to a computer via a data transmission line, and channel switching control and data acquisition processing are implemented via host computer software on the computer side.

2. The soil seepage channel resistivity or electrical impedance dual-mode tomography measuring device according to claim 1, characterized in that: The signal generating module is used to provide the periodic excitation electrical signal required in resistivity or electrical impedance tomography detection, and the isolating switch QS is used to be adjusted to a closed state to provide a zero potential boundary around the area to be detected when conducting resistivity tomography detection.

3. The soil seepage channel resistivity or electrical impedance dual-mode tomography measuring device according to claim 2, characterized in that: The power analysis module is connected to the signal generation module through a conductor and a data transmission line, and is used to collect the excitation voltage signal and the main circuit current signal; The multi-channel synchronous acquisition module is used to collect the voltage signals of each channel corresponding to the sensing electrode; the signal conditioning module is used to amplify and pre-process the original voltage signals of each channel; the phase-locked amplifier module is mainly used to enhance the target signal and suppress noise, thereby improving the quality of the voltage signal; the multi-channel synchronous acquisition module is connected to the signal conditioning module through a data transmission line, and the signal conditioning module is connected to the phase-locked amplifier module through a data transmission line.

4. The soil seepage channel resistivity or electrical impedance dual-mode tomography measuring device according to claim 3, characterized in that: Also includes the measurement steps: S1. Measurement preparation: connect each module and the arranged sensing electrodes through data transmission lines and wires; test the communication status between the computer and each module, set the excitation signal parameters and data acquisition frequency through the computer, and import the running pole file of the control channel switching module; S2, resistivity tomography test: close the isolation switch QS, and connect the negative pole of the power analysis module to the conductive copper foil around the test area through a wire; Set the output voltage of the signal generating module to a rectangular pulse signal; all switches of the relay switch module B are turned to the normally closed contact NCB; after starting to execute the running pole file, control the switch on the Y1 channel of the relay switch module A to turn to the normally open contact NOA1 and maintain it for 5S, and then control the switch on the Y1 channel of the relay switch module A to turn to the normally closed contact NCA1 and maintain it for 2S; then control the switch on the Y2 channel of the relay switch module A to turn to the normally open contact NOA2 and maintain it for 5S, and then control the switch on the Y2 channel of the relay switch module A to turn to the normally closed contact NCA2 and maintain it for 2S; repeat the above operation until the above switch switching action traverses all channels of the relay switch module A; extract the peak voltage on the corresponding channel of the E1 to E25 sensing electrodes acquired by the computer, and the corresponding peak current each time the switch is turned to the normally open contact; S3, electrical impedance tomography test; disconnect the isolation switch QS, set the output voltage of the signal generating module to a sinusoidal pulse signal, reset the switches of the relay switch module A and the relay switch module B to the normally closed NC contacts; after starting to execute the run-out file, control the switch on the X2 channel of the relay switch module B to the normally open contact NOB2 and maintain it for 10S, then control the switch on the Y1 channel of the relay switch module A to the normally open contact NOA1 and maintain it for 5S, then control the switch on the Y1 channel of the relay switch module A to the normally closed contact NCA1 and maintain it for 5S, and then control the switch on the X2 channel of the relay switch module B to the normally closed contact NCB2; Then, the switch on the X3 channel of the relay switch module B is controlled to be turned to the normally open contact NOB3 and maintained for 10S, then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally open contact NOA2 and maintained for 5S, and then the switch on the Y2 channel of the relay switch module A is controlled to be turned to the normally closed contact NCA2 and maintained for 5S, and then the switch on the X3 channel of the relay switch module B is controlled to be turned to the normally closed contact NCB3; repeat the above operation until the above switch switching action traverses all channels of the relay switch module A and the relay switch module B; extract the peak voltage on the corresponding channel of the E1 to E25 sensing electrodes collected by the computer, and the peak current corresponding to each time the switch is turned to the normally open contact.

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