Cross-hole electrodes for resistivity tomography and methods of making the same

Abstract

The application discloses a cross-hole electrode for resistivity tomography and a manufacturing method thereof, and belongs to the technical field of hydrogeophysical exploration. The cross-hole electrode comprises a plurality of sections of insulating tubes (1) with a fixed length, and the outer wall bottom of each section of the insulating tubes (1) is provided with a ring of stainless steel ring electrodes (2). The sections of the insulating tubes (1) are bonded into a cross-hole electrode rod body through 502 strong glue, and the cross-hole electrode rod body is filled with epoxy resin pouring sealant (5). The cross-hole electrode is manufactured in sections, the number of the insulating tubes can be increased or reduced according to the requirement of each test, and the cross-hole electrode is simple and efficient to assemble. The cross-hole electrode is filled with the epoxy resin pouring sealant in the tube body, water storage in the tube body is avoided to affect monitoring results, the structural stability of the cross-hole electrode is enhanced, and the cross-hole electrode is more reliable, so that the cross-hole electrode provides an efficient, economical and reliable detection device for high-density resistivity method, improves the depth resolution of survey data, and provides data support for internal structure identification of a 'key zone' and water migration process research in hydrology.

Description

Technical Field

[0001] This invention discloses a trans-hole electrode for resistivity tomography and its fabrication method, belonging to the field of hydrogeophysical exploration technology. Background Technology

[0002] In hydrogeophysical exploration, high-density electrical resistivity tomography (EDS) is mainly used to study the dynamics of water distribution and transport during hydrological processes. Typically, stainless steel electrodes are installed on the surface along measurement lines or planes, or trans-hole electrodes are arranged in the soil surrounding the target area. Power supply electrodes and measuring electrodes are installed, and power is supplied to the subsurface through the power supply electrodes to measure resistivity distribution. The soil's internal moisture state is then inferred from the resistivity distribution, and water transport is analyzed by measuring continuous temporal spatial variations in resistivity. However, surface electrodes have insufficient depth range, while trans-hole electrodes can obtain higher-resolution resistivity data at greater depths.

[0003] Utility model patent CN212060599U discloses a resistivity detection tube with annular electrodes. Supported by an insulated tube body, the required electrodes and measuring lines are integrated by cutting grooves in the tube body and installing them in a single unit. Utility model patent CN210835274U discloses an exploration electrode installation structure based on the high-density resistivity method, utilizing a spiral blade for easy installation by screwing it into the ground. Invention patent CN112362972B discloses a spiral electrode resistivity probe and its monitoring method, improving the probe's penetration device and converting the spiral electrode into evenly spaced annular electrodes through an electrode restoration device, reducing the time required for excavation, drilling, and backfilling. All of these patents involve integrated, one-piece fabrication of the detection devices. However, this integrated, cross-hole electrode fabrication is only suitable for current testing. Each test requires determining the required number of electrodes and the length of the measuring line based on the actual detection depth, making mass production impossible and resulting in low manufacturing efficiency. On the other hand, the tube structure of this type of trans-hole electrode is prone to internal water accumulation, which directly affects the in-situ monitoring results. Furthermore, its structural stability is poor, making it easily damaged during installation. Therefore, how to manufacture efficient, economical, and reliable trans-hole electrodes for hydrogeophysical exploration remains a challenge, requiring further research to promote modular fabrication and assembly of trans-hole electrodes, ensure structural stability and internal waterproofing and moisture resistance, and obtain more accurate and reliable measurement results. Summary of the Invention

[0004] The purpose of this invention is to propose a high-efficiency, economical, and reliable trans-hole electrode and its fabrication method to overcome the problems of existing integrated measurement devices, such as the inability to mass-produce them, low manufacturing efficiency, and the influence of water accumulation inside the detection device on in-situ monitoring results. This allows for obtaining higher resolution and more accurate information on water distribution and transport at depth. This trans-hole electrode is fabricated in segments, allowing for the addition or reduction of the number of insulating tubes according to the needs of each experiment, resulting in simple and efficient assembly. Furthermore, the epoxy resin potting compound inside the tubes prevents internal water accumulation from affecting the monitoring results, while simultaneously enhancing the structural stability and reliability of the trans-hole electrode. This provides a high-efficiency, economical, and reliable detection device for the high-density resistivity method, further improving the depth resolution of survey data and providing necessary technical and data support for the identification of the internal structure of the "critical zone" and the study of water transport processes in hydrology.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a trans-aperture electrode for resistivity tomography is provided, comprising several segments of fixed-length insulating tubes (1), each segment of insulating tube (1) having a stainless steel annular electrode (2) at the bottom of its outer wall, a wire (4) inserted into the diameter of the insulating tube (1), a fixed end (3) at the bottom of each segment of insulating tube (1), the fixed end (3) being used to fix the stainless steel annular electrode (2) at the bottom of each segment of insulating tube (1), one end of the wire (4) being connected to the fixed end (3) and the annular electrode (2), the other end of the wire (4) extending out from the insulating tube (1), each segment of insulating tube (1) being bonded together with 502 strong adhesive to form a trans-aperture electrode rod, and epoxy resin potting compound (5) being filled into the electrode rod.

[0006] Preferably, each section of insulating tube (1) is of equal length and is 5 to 100 centimeters long. Multiple insulating tubes (1) are connected through each other by 502 glue. The cross-sectional edges of the insulating tubes (1) that come into contact with each other are provided with glue for bonding and fixing, so as to form a number of observation electrodes connected in series at equal intervals.

[0007] Preferably, the outer diameter of the stainless steel annular electrode (2) is larger than the outer diameter of each section of the insulating tube (1), and the height of the stainless steel annular electrode (2) is 0.5 to 5 cm.

[0008] Preferably, the fixed end (3) is provided with bolts and nuts inside and outside the insulating tube (1), and the fixed end (3) is connected to the wire (4).

[0009] Preferably, epoxy resin potting compound (5) fills the interior of the insulating tube (1) until it is solidified, which is moisture-proof and waterproof, and plays a supporting role for the cross-hole electrode rod. During installation and removal in the soil, the electrode body can be prevented from tilting or misaligning.

[0010] Preferably, the insulating tube (1) is made of PVC or acrylic material, and the outer wall of the insulating tube (1) is smooth or has threads.

[0011] A second aspect of the present invention provides a method for fabricating a transap electrode for resistivity tomography, comprising the following steps:

[0012] Step 1: Determine that the length of the stainless steel ring electrode (2) is greater than the outer cross-sectional perimeter of the insulating tube (1), and use a cutting machine to cut a stainless steel sheet with a width of 0.5-5cm as the ring electrode (2);

[0013] Step 2: Take a section of insulating tube and wrap the stainless steel ring electrode (2) around the bottom end of the insulating tube (1). The stainless steel ring electrode (2) should be aligned with the bottom edge of the insulating tube (1). When wrapping, it should be tightly wrapped and not loosened to ensure that the stainless steel ring electrode (2) is fully attached to the surface of the insulating tube (1) and the starting point and the ending point overlap. Use insulating tape to bind and fix it along the wrapping direction.

[0014] Step 3: Use a hand drill to drill a hole at the overlapping part of the stainless steel ring electrode (2), penetrating the stainless steel ring electrode (2) and the wall of the insulating tube (1) on one side. First, connect a certain length of wire (4) to the bolt, ensuring that the length of the wire (4) is greater than the length of the insulating tube (1). Then, the bolt with the wire (4) is inserted into the inside of the insulating tube (1) from the top of the insulating tube (1) and passed into the drilled hole. The nut is installed and tightened on the outside of the insulating tube (1). Finally, remove the insulating tape wrapped around the insulating tube (1).

[0015] Step 4: Repeat steps 2 and 3 to obtain several segments of insulating tube (1) with stainless steel ring electrode (2) and connecting wire (4). When making the second segment of insulating tube (1), the length of the wire (4) needs to be greater than twice the length of the insulating tube (1). When making the third segment of insulating tube (1), the length of the wire (4) needs to be greater than three times the length of the insulating tube (1), and so on.

[0016] Step 5: Apply 502 super glue to the cross-sectional edge of the bottom of each insulating tube (1). Following the manufacturing sequence, make the glued ends of each insulating tube (1) contact each other to connect the insulating tubes (1). Seal the bottom of the entire insulating tube (1) with a circular sheet of the same PVC or acrylic material. The diameter of the circular sheet is equal to the outer diameter of the insulating tube (1).

[0017] Step 6: Based on the internal volume of the entire insulating tube (1) and the density of the epoxy resin potting compound, estimate the required amount of epoxy resin potting compound, pour the required amount of epoxy resin potting compound (5) into the prepared clean container, and stir thoroughly.

[0018] Step 7: Place the entire insulating tube (1) vertically to the ground and fix it to the support frame with insulating tape. Slowly inject the prepared and well-stirred epoxy resin potting compound (5) into the entire insulating tube (1) until it is full. Let it stand for 24 hours to allow the epoxy resin potting compound (5) to fully fill the tube. If the epoxy resin potting compound (5) sinks slightly in the insulating tube (1), prepare epoxy resin potting compound (5) again to fill it until it is solidified.

[0019] Step 8: Use a multimeter to test the circuit continuity of the through-hole electrode. One end of the multimeter is in contact with the wire (4) extending out of the insulating tube (1), and the other end is in contact with the stainless steel ring electrode (2) connected to it. If you hear a "beep" sound, it means that the wire is connected.

[0020] Step 9: Determine the length and number of transaperettes used for resistivity tomography based on the on-site detection environment. Repeat steps 1-8 to obtain multiple transaperettes, forming a transaperette array perpendicular to the ground and equidistantly surrounding the target.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] I. Compared to the current method of installing electrodes and measuring lines by cutting grooves on a single insulating tube, this invention mounts the annular electrode at the bottom of each segment of the insulating tube via a fixed end. The segments are then bonded together with 502 super glue, ensuring equal distances between the measuring electrodes. This segmented manufacturing method allows for adjustments to the number of insulating tubes used for bonding based on the needs of each test, making it more environmentally adaptable and significantly improving manufacturing efficiency.

[0023] Second, existing trans-hole electrodes are extremely prone to water accumulation inside, directly affecting monitoring results. Furthermore, due to their poor structural stability, they are easily damaged during installation. This invention uses epoxy resin potting compound to fill the interior of the insulating tube, preventing moisture accumulation inside the tube from affecting signal quality and measurement results. It also prevents the trans-hole electrode from tilting, ensuring the stability of the trans-hole electrode structure.

[0024] Third, this trans-hole electrode is manufactured using a segmented method, allowing for the addition or reduction of the number of insulating tubes according to the needs of each experiment, resulting in simple and efficient assembly. Furthermore, the internal filling of the tubes with epoxy resin potting compound prevents internal water accumulation from affecting monitoring results, while simultaneously enhancing the structural stability and reliability of the trans-hole electrode. This provides an efficient, economical, and reliable detection device for the high-density resistivity method, further improving the depth resolution of survey data and providing necessary technical and data support for the identification of the internal structure of the "critical zone" and the study of water transport processes in hydrology. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the transhole electrode structure of the present invention.

[0026] Figure 2 This is a schematic diagram of the transhole electrode usage device in Example 1.

[0027] Figure 3 This is the resistivity tomography result of the trans-hole electrode in Example 1.

[0028] Wherein: 1-insulating tube; 2-ring electrode; 3-fixed end; 4-wire; 5-epoxy resin potting compound. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0030] Example 1:

[0031] Please see Figure 1 A trans-hole electrode for resistivity tomography mainly includes several fixed-length insulating tubes (1). Each insulating tube (1) has a stainless steel annular electrode (2) at the bottom of its outer wall. A wire (4) is inserted into the diameter of the insulating tube (1). Each insulating tube (1) has a fixed end (3) at its bottom. The fixed end (3) is used to fix the stainless steel annular electrode (2) at the bottom of each insulating tube (1). One end of the wire (4) is connected to the fixed end (3) and the annular electrode (2). The other end of the wire (4) extends out from the insulating tube (1). Each insulating tube (1) is bonded together with 502 strong glue to form a trans-hole electrode rod, and epoxy resin potting compound (5) is filled into the electrode rod.

[0032] Each section of the insulating tube (1) is 10cm long, with an outer diameter of 3.2cm and an inner diameter of 2.8cm. The edges of the cross sections of each insulating tube (1) that come into contact with each other and the bottom edge of the cross section are provided with 502 strong adhesive for bonding and fixing, forming several observation electrodes connected in series at equal intervals of 10cm.

[0033] The outer diameter of the stainless steel annular electrode (2) is larger than the outer diameter of each section of the insulating tube (1), and it is attached to the outside of the insulating tube (1). The height of the stainless steel annular electrode (2) is 1 cm, which is 1 / 10 of the length of each section of the insulating tube (1).

[0034] The fixed end (3) is provided with bolts and nuts inside and outside the insulating tube (1), and the fixed end (3) is connected to the wire (4).

[0035] The epoxy resin potting compound (5) fills the interior of the insulating tube (1) until it is solidified, providing moisture and water protection and a supporting function. It can prevent the electrode body from tilting or misaligning during installation and removal in the soil.

[0036] The insulating tube (1) is made of PVC or acrylic material, and the outer wall of the insulating tube (1) is smooth or has threads.

[0037] The method for fabricating the trans-hole electrode in this embodiment includes the following steps:

[0038] Step 1: Determine that the length of the stainless steel ring electrode (2) is greater than the perimeter of the outer cross section of the insulating tube (1). Use a cutting machine to cut several stainless steel sheets with a width of 1cm from the whole stainless steel strip with a thickness of 0.1cm as the ring electrode (2).

[0039] Step 2: Take a section of insulating tube and wrap the stainless steel ring electrode (2) around the bottom end of the insulating tube (1). The stainless steel ring electrode (2) should be aligned with the bottom edge of the insulating tube (1). When wrapping, it should be tightly wrapped and not loosened to ensure that the stainless steel ring electrode (2) is fully attached to the surface of the insulating tube (1) and the starting point and the ending point overlap. Use insulating tape to bind and fix it along the wrapping direction.

[0040] Step 3: Use a hand drill to drill a hole at the overlapping part of the stainless steel ring electrode (2), penetrating the stainless steel ring electrode (2) and the wall of the insulating tube (1) on one side. First, connect the 20cm long wire (4) to the bolt, ensuring that the length of the wire (4) is greater than the length of the insulating tube (1). Then, the bolt with the wire (4) is inserted into the inside of the insulating tube (1) from the top of the insulating tube (1) and passed into the drilled hole. The nut is installed and tightened on the outside of the insulating tube (1). Finally, remove the insulating tape wrapped around the insulating tube (1).

[0041] Step 4: Repeat steps 2 and 3 a total of 6 times to obtain 6 insulating tubes (1) with stainless steel ring electrodes (2) and connecting wires (4). When making the second insulating tube (1), the wire length is 30cm. When making the third insulating tube (1), the wire length is 40cm. When making the fourth insulating tube (1), the wire length is 50cm. When making the fifth insulating tube (1), the wire length is 60cm. When making the sixth insulating tube (1), the wire length is 70cm.

[0042] Step 5: Apply 502 super glue to the cross-sectional edge of the bottom of each insulating tube (1). Following the manufacturing sequence, make the glued ends of each insulating tube (1) contact each other to connect the insulating tubes (1). Seal the bottom of the entire insulating tube (1) with a circular sheet of the same PVC or acrylic material. The diameter of the circular sheet is equal to the outer diameter of the insulating tube (1).

[0043] Step 6: Based on the internal volume of the entire insulating tube (1) and the density of the epoxy resin potting compound, estimate the required mass of epoxy resin potting compound to be approximately 370g. Pour the epoxy resin potting compound (5) into a prepared clean container and stir thoroughly.

[0044] Step 7: Place the entire insulating tube (1) vertically to the ground and fix it to the support frame with insulating tape. Slowly inject the prepared and well-stirred epoxy resin potting compound (5) into the entire insulating tube (1) until it is full. Let it stand for 24 hours to allow the epoxy resin potting compound (5) to fully fill the tube. If the epoxy resin potting compound (5) sinks slightly in the insulating tube (1), prepare epoxy resin potting compound (5) again to fill it until it is solidified.

[0045] Step 8: Use a multimeter to test the circuit continuity of the through-hole electrode. One end of the multimeter is in contact with the wire (4) extending out of the insulating tube (1), and the other end is in contact with the stainless steel ring electrode (2) connected to it. If you hear a "beep" sound, it means that the wire is connected.

[0046] Step 9: Determine the length and number of transaperettes used for resistivity tomography based on the on-site detection environment. Repeat steps 1-8 to obtain multiple transaperettes, forming a transaperette array perpendicular to the ground and equidistantly surrounding the target.

[0047] Example 2:

[0048] Please see Figure 2 According to Example 1, the trans-hole electrode for resistivity tomography and its fabrication method mainly include the following steps in its implementation:

[0049] Step 1: Based on the selected field detection environment, use four trans-hole electrodes B1, B2, B3, and B4 to form a trans-hole electrode group that is perpendicular to the ground and equidistantly surrounds the detection target.

[0050] Step 2: Determine the number of insulating tube (1) segments used for the cross-hole electrode fabrication based on the monitoring depth. Due to the influence of the underground bedrock, the monitoring depth is limited at one location, thus forming a set of cross-hole electrodes of varying lengths: 130cm, 130cm, 60cm, and 130cm. The first stainless steel annular electrode (2) at the top of the cross-hole electrode is buried just below the topsoil layer. Therefore, the cross-hole electrode set is used to monitor the resistivity distribution at the surface and at depths of 120cm, 120cm, 50cm, and 120cm underground.

[0051] Step 3: Drill holes with a diameter of 5cm and depths of 120cm, 120cm, 50cm and 120cm at the selected location boundary of the detection area. Install the cross-hole electrode into the hole, backfill the gaps in the hole in layers to ensure good contact between the cross-hole electrode and the surrounding soil, and connect it to the electrical resistivity meter using a multi-core cable.

[0052] Step 4: Debug the resistivity meter. Use the dipole-dipole four-electrode detection method for in-situ resistivity monitoring. Select two stainless steel ring electrodes as power supply electrodes A and B within one trans-hole electrode B1, and select two stainless steel ring electrodes as measuring electrodes M and N within another trans-hole electrode B2. The distance between two adjacent electrodes is 10cm (electrode spacing). First, observe all dipole devices with possible electrode spacing of 10cm: For the first measurement, power supply electrodes A and B in trans-hole electrode B1 are powered on starting at electrodes 1# and 2#, respectively. Measuring electrodes M and N in trans-hole electrode B2 sequentially measure the potential of any electrode with an electrode spacing of 10cm and record the potential values. For the second measurement, power supply electrodes A and B in trans-hole electrode B1 are powered on starting at electrodes 2# and 3#, respectively. Measuring electrodes M and N in trans-hole electrode B2 sequentially measure the potential of any electrode with an electrode spacing of 10cm and record the potential values. Following this pattern, electrodes #1 to #13 in cross-hole electrode B1 with a distance of 10cm are powered sequentially, and electrodes #1 to #13 in cross-hole electrode B2 with a distance of 10cm are measured sequentially. After completing the observation series with an electrode distance of 10cm, the next step is to measure the electrode distance with a distance of n×10cm (n is the electrode distance factor, usually taken as the maximum value of 6). When n is 2, electrodes #1 to #13 in cross-hole electrode B1 with a distance of 20cm are powered sequentially, and electrodes #1 to #13 in cross-hole electrode B2 with a distance of 20cm are measured sequentially, and the potential values ​​are recorded. The same repeated observation process is followed for electrode distances of 30cm, 40cm, 50cm, and 60cm.

[0053] Step 5: Select two stainless steel ring electrodes in one of the trans-hole electrodes B1, B2, B3, and B4 as power supply electrodes, and select two stainless steel ring electrodes in another trans-hole electrode as measurement electrodes. Repeat the measurement process of Step 4.

[0054] Step 6: Convert the measured potential to apparent resistivity. Apparent resistivity ρ a It can be calculated using the injected current I at the power supply electrode and the potential difference ΔU measured at the measuring electrode:

[0055] ρ a =KΔUI

[0056] In the formula, K is a geometric factor that depends only on the spatial position of the electrodes. In practice, there can be various electrode configurations, but once the arrangement and distance between the electrodes are determined, the value of K can be calculated.

[0057] Step 7: Perform resistivity tomography. The acquired apparent resistivity data is used for forward and inverse numerical simulations to obtain the resistivity tomography results. Please refer to [link to relevant documentation]. Figure 3The results of resistivity tomography, combined with geological conditions, can be used to interpret underground structures and the distribution of underground water content.

[0058] Step 8: Repeat steps 4-7 at different times to acquire apparent resistivity data and perform resistivity tomography. Ratio the resistivity at different times with the background resistivity (generally, the resistivity at the initial time is selected as the background resistivity) to obtain the relative change of resistivity tomography over time. This can be combined with geological conditions to interpret the movement of water beneath the ground.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A transaperture electrode for resistivity tomography, characterized in that: The device includes several fixed-length insulating tubes (1). Each insulating tube (1) has a stainless steel ring electrode (2) at the bottom of its outer wall. A wire (4) is inserted into the diameter of the insulating tube (1). Each insulating tube (1) has a fixed end (3) at its bottom. The fixed end (3) is used to fix the stainless steel ring electrode (2) at the bottom of each insulating tube (1). One end of the wire (4) is connected to the fixed end (3) and the ring electrode (2). The other end of the wire (4) extends out of the insulating tube (1). Each insulating tube (1) is bonded together with 502 strong glue to form a cross-hole electrode rod. Epoxy resin potting compound (5) is filled into the electrode rod. The fixed end (3) is provided with bolts and nuts inside and outside the insulating tube (1). The fixed end (3) is connected to the wire (4). The epoxy resin potting compound (5) fills the interior of the insulating tube (1) until it is solidified. It is moisture-proof and waterproof, and plays a supporting role for the cross-hole electrode rod. It can prevent the electrode from tilting or misaligning during installation and removal in the soil.

2. The transaperometer electrode for resistivity tomography according to claim 1, characterized in that: Each section of insulating tube (1) is of equal length and is between 5 and 100 centimeters. Multiple insulating tubes (1) are connected by 502 glue. The cross-sectional edges of the insulating tubes (1) that come into contact with each other are provided with glue for bonding and fixing, so as to form several observation electrodes connected in series at equal intervals.

3. The transaperometer electrode for resistivity tomography according to claim 1, characterized in that: The outer diameter of the stainless steel ring electrode (2) is larger than the outer diameter of each section of the insulating tube (1), and the height of the stainless steel ring electrode (2) is 0.5 to 5 cm.

4. The transaperometer electrode for resistivity tomography according to claim 1, characterized in that: The insulating tube (1) is made of PVC or acrylic material, and the outer wall of the insulating tube (1) is smooth or has threads.

5. The method for fabricating a trans-aperture electrode for resistivity tomography according to any one of claims 1-4, characterized in that, Includes the following steps: Step 1: Determine that the length of the stainless steel ring electrode (2) is greater than the perimeter of the outer cross-section of the insulating tube (1), and use a cutting machine to cut a stainless steel sheet with a width of 0.5-5cm as the ring electrode (2). Step 2: Take a section of insulating tube and wrap the stainless steel ring electrode (2) around the bottom end of the insulating tube (1). The stainless steel ring electrode (2) should be aligned with the bottom edge of the insulating tube (1). When wrapping, it should be tightly wrapped and not loosened to ensure that the stainless steel ring electrode (2) is fully attached to the surface of the insulating tube (1) and the starting point and the ending point overlap. Use insulating tape to bind and fix it along the wrapping direction. Step 3: Use a pistol drill to drill a hole at the overlapping part of the stainless steel ring electrode (2), penetrating the stainless steel ring electrode (2) and the wall of the insulating tube (1) on one side. First, connect a certain length of wire (4) to the bolt, ensuring that the length of the wire (4) is greater than the length of the insulating tube (1). Then, the bolt with the wire (4) enters the insulating tube (1) from the top and passes through the drilled hole. Install and tighten the nut on the outside of the insulating tube (1). Finally, remove the insulating tape wrapped around the insulating tube (1). Step 4: Repeat steps 2 and 3 to obtain several segments of insulating tube (1) with stainless steel ring electrode (2) and connecting wire (4). When making the second segment of insulating tube (1), the length of the wire (4) needs to be greater than twice the length of the insulating tube (1). When making the third segment of insulating tube (1), the length of the wire (4) needs to be greater than three times the length of the insulating tube (1), and so on. Step 5: Apply 502 strong glue to the cross-sectional edge of the bottom of each insulating tube (1). According to the manufacturing sequence, make the glued ends of each insulating tube (1) contact each other and connect the insulating tubes (1) together. Use a circular sheet of the same PVC or acrylic material to seal the bottom of the entire insulating tube (1). The diameter of the circular sheet is equal to the outer diameter of the insulating tube (1). Step 6: Based on the internal volume of the entire insulating tube (1) and the density of the epoxy resin potting compound, estimate the required amount of epoxy resin potting compound, pour the required amount of epoxy resin potting compound (5) into a clean container, and stir thoroughly. Step 7: Place the entire insulating tube (1) vertically to the ground and fix it to the support frame with insulating tape. Slowly inject the prepared and well-stirred epoxy resin potting compound (5) into the entire insulating tube (1) until it is full. Let it stand for 24 hours to allow the epoxy resin potting compound (5) to fully fill the tube. If the epoxy resin potting compound (5) sinks slightly in the insulating tube (1), prepare epoxy resin potting compound (5) again to fill it until it is solidified. Step 8: Use a multimeter to test the circuit continuity of the through-hole electrode. One end of the multimeter is in contact with the wire (4) extending out of the insulating tube (1), and the other end is in contact with the stainless steel ring electrode (2) connected to it. If you hear a "beep" sound, it means that the wire is connected. Step 9: Determine the length and number of transaperence electrodes for resistivity tomography based on the on-site detection environment; repeat steps 1-8 to obtain multiple transaperence electrodes, forming a transaperence electrode group that is perpendicular to the ground and equidistantly surrounds the detection target.

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