A soil sample resistivity measuring device and a measuring method thereof

Abstract

This invention discloses a soil sample resistivity measuring device and method, comprising a soil sample box and a cover plate covering the soil sample box. Emitting electrode plates are placed inside both ends of the soil sample box, and two receiving electrode rods are inserted in the middle. The bottom of the transmitting electrode plates contacts the bottom of the soil sample box, and their sides extend to the side walls of the soil sample box. The cover plate has transmitting electrode slots for the transmitting electrode plates to pass through and receiving electrode holes for the receiving electrode rods to pass through. The transmitting electrode plates and receiving electrode rods are respectively connected to a full-waveform impedance analyzer after exiting through the transmitting electrode slots and receiving electrode holes, forming a four-electrode connection structure. This device, by adding a cover plate to the soil sample box and leading the long, strip-shaped transmitting electrode plates out from the top holes of the cover plate, can greatly reduce the contact between external air and the soil sample, avoid moisture evaporation, reduce the influence of the external environment on the soil sample, and ensure the accuracy of the test results.

Description

Technical Field

[0001] This invention belongs to the field of geotechnical engineering technology, and in particular relates to a soil sample resistivity measuring device and its measuring method. Background Technology

[0002] Soil resistivity is a fundamental physical property of soil, representing the conductivity of a unit volume of soil between two opposite faces under a given electric field. Soil resistivity provides important reference for analyzing the propagation of electromagnetic waves in soil. Therefore, soil resistivity measurement is widely used in geotechnical engineering. However, current indoor methods and devices for soil sample resistivity measurement suffer from disturbances to the measurement results caused by environmental factors such as moisture evaporation during the measurement process. Summary of the Invention

[0003] The main objective of this invention is to provide a soil sample resistivity measuring device and its measuring method. This device, by adding a cover plate to the soil sample box and extending the long strip-shaped emitting electrode plates at both ends from the top hole of the cover plate, can greatly reduce the contact between external air and soil sample, avoid moisture evaporation, reduce the influence of the external environment on soil sample, and ensure the accuracy of test results.

[0004] To address this, the present invention provides a soil sample resistivity measuring device, comprising a soil sample box and a cover plate covering the soil sample box. Emitting electrode plates are placed inside both ends of the soil sample box, and two receiving electrode rods are inserted in the middle. The bottom of the emitting electrode plates contacts the bottom of the soil sample box, and both sides extend to the side walls of the soil sample box. The cover plate has an emitting electrode slot for the emitting electrode plates to pass through and a receiving electrode hole for the receiving electrode rods to pass through. The emitting electrode plates and receiving electrode rods are respectively connected to a full-waveform impedance analyzer after passing through the emitting electrode slot and the receiving electrode hole, forming a four-electrode connection structure.

[0005] Specifically, the material of the transmitting electrode sheet and the receiving electrode rod is silver.

[0006] Specifically, the soil sample box is a transparent box.

[0007] Specifically, the soil sample box is a rigid acrylic box.

[0008] Specifically, the top of the transmitting electrode is provided with a connecting tab for connection to a full waveform impedance analyzer.

[0009] A method for measuring the resistivity of a soil sample using the above-mentioned soil sample resistivity measuring device includes the following steps:

[0010] Step 1: Prepare soil samples according to measurement requirements;

[0011] Step 2: Place the prepared soil sample into the soil sample box, add an appropriate amount of soil sample according to the designed compaction value, and ensure that the soil sample at both ends of the soil sample box is in close contact with the emitting electrode plate.

[0012] Step 3: Cover the cover plate and lead out the emission electrode plates at both ends of the soil sample box from the emission electrode seams on both sides of the cover plate;

[0013] Step 4: Insert the receiving electrode rod into the soil sample through the receiving electrode hole in the middle of the cover plate;

[0014] Step 5: Connect the transmitting electrode and receiving electrode rod to the full waveform impedance analyzer in a four-electrode configuration;

[0015] Step 6: Based on the approximate resistivity range of the soil sample, select the power supply mode. Finally, turn on the full waveform impedance analyzer, set the parameters in the startup software, and use the full waveform impedance analyzer to automatically collect and record voltage, current, and resistivity values.

[0016] Compared with the prior art, at least one embodiment of the present invention has the following beneficial effects:

[0017] 1. By adding a cover plate to the soil sample box and extending the long strip-shaped transmitting electrode plates at both ends from the transmitting electrode slot at the top of the cover plate, and inserting the receiving electrode rod into the soil sample through the receiving electrode hole, the contact between external air and soil sample can be greatly reduced, moisture evaporation can be avoided, the influence of the external environment on the soil sample can be reduced, and the accuracy of test results can be guaranteed.

[0018] 2. The bottom of the emitting electrode plate contacts the bottom of the soil sample box, and extends to the side walls of the soil sample box on both sides, covering the entire end of the soil sample box. This can effectively prevent electrons from escaping and improve the accuracy of the test. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying 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.

[0020] Figure 1 This is a schematic diagram of the soil sample resistivity measuring device provided in an embodiment of the present invention;

[0021] Figure 2 This is a top view schematic diagram of the soil sample resistivity measuring device provided in an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the emitting electrode sheet structure provided in an embodiment of the present invention;

[0023] The components include: 1. Soil sample; 2. Soil sample box; 3. Transmitting electrode plate; 4. Receiving electrode rod; 5. Full waveform impedance analyzer; 6. Receiving electrode hole; 7. Transmitting electrode slot; 8. Cover plate; 9. Connecting tab. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0027] See Figure 1 and Figure 2 A soil sample resistivity measuring device includes a soil sample box 2 and a cover plate 8 covering the soil sample box 2. The cover plate 8 is detachably connected to the soil sample box 2 and can be connected by snap-fit ​​or the like. Emitting electrode plates 3 are placed inside both ends of the soil sample box 2, and two receiving electrode rods 4 are inserted in the middle. The bottom of the emitting electrode plates 3 contacts the bottom of the soil sample box 2, and the two sides extend to the side wall of the soil sample box 2 (i.e., equal width). The cover plate 8 is provided with an emitting electrode slot 7 for the emitting electrode plates 3 to pass through and a receiving electrode hole 6 for the receiving electrode rods 4 to pass through. The emitting electrode plates 3 and the receiving electrode rods 4 are respectively connected to a full waveform impedance analyzer 5 after passing through the emitting electrode slot 7 and the receiving electrode hole 6, forming a four-electrode connection structure.

[0028] See Figures 1-3During the test, soil samples 1 with different moisture contents are first prepared. The soil samples are divided into five equal parts according to the total mass required for one test soil sample 1. They are then placed into the soil sample box 2 step by step. One part of soil sample 1 is taken first and placed in the soil sample box 2. After the emitting electrode sheet 3 is in close contact with the soil sample, the soil sample box 2 is filled in layers in turn, and the compaction degree of each layer is kept the same.

[0029] Cover the cover plate 8, and lead the long strip connecting tabs on the upper part of the emission electrode plates 3 at both ends of the soil sample box 2 out from the emission electrode slot 7 on the cover plate 8, and connect them to the A and B interfaces of the full waveform impedance analyzer 5 respectively using electric clamps.

[0030] Insert the receiving electrode rod 4 into the soil sample 1 through the receiving electrode hole 6 in the middle of the cover plate 8, keeping the soil sample 1 in close contact with the receiving electrode rod 4, and connect the receiving electrode rod 4 to the M and N interfaces of the full waveform impedance analyzer 5 with electric clamps.

[0031] When selecting the power supply mode, you can use an ohmmeter to roughly measure the resistance of the soil sample in advance. If the resistance is less than 1Ω, you can choose the constant current mode to protect the instrument and avoid burning it out due to excessive current. If the resistance is greater than 1Ω, you can choose the constant voltage mode. Here we choose the constant voltage mode with a constant voltage of 1V.

[0032] Finally, turn on the full-waveform impedance analyzer 5 and set the parameters in the startup software. L1 is the length of the soil sample box 2, L2 and L3 are the side lengths of the soil sample box 2, and the distance d between the receiving electrode rod 4 and the transmitting electrode plate 3 is d = L1 / 3. After setting the parameters, click "Start Measurement." The instrument will automatically collect and record the voltage, current, and resistivity values ​​ρ. Once the readings stabilize, the values ​​can be directly read as the resistance value of the tested soil sample.

[0033] In this embodiment, by adding a cover plate 8 to the soil sample box 2 and extending the elongated emission electrode plates 3 at both ends from the emission electrode slots 7 at the top of the cover plate 8, the contact between external air and the soil sample can be greatly reduced, preventing moisture evaporation, reducing the influence of the external environment on the soil sample, and ensuring the accuracy of the test results. Furthermore, the bottom of the emission electrode plates 3 contacts the bottom of the soil sample box 2, and extends to the side walls of the soil sample box 2 on both sides, covering the entire end of the soil sample box 2, which can effectively prevent electron escape and improve the accuracy of the test.

[0034] Understandably, the emitting electrode 3 is a thin silver sheet with a convex shape, a square bottom, and a long strip-shaped connecting lug 9 at the top, about 2 cm long. The electrode sheet is placed close to both ends of the soil sample box 2. The long strip-shaped connecting lug 9 passes through the emitting electrode seam 7 at both ends of the cover plate 8. The receiving electrode rod 4 is a silver rod that passes through the receiving electrode hole 6 on the cover plate 8 and is inserted into the soil sample 1. The electrode material of this device is silver. As the metal with the best conductivity, silver can greatly reduce the influence of the electrode sheet on the soil resistivity measurement results and improve the accuracy of the measurement results.

[0035] Additionally, it should be noted that the silver electrodes used must be peroxidized with an oxidizing agent before use to avoid polarization reactions during the measurement process and further improve the accuracy of the measurement results. For easy observation, the soil sample box 2 can be designed to be transparent, made of hard acrylic material, with a thickness of 0.5cm and dimensions of 5cm*5cm*30cm.

[0036] Unless otherwise stated, if any of the technical solutions disclosed in this invention specify a numerical range, then the disclosed numerical range is a preferred numerical range. Anyone skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this invention discloses only some numerical values ​​to illustrate the technical solutions of this invention. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this invention.

[0037] Furthermore, if the present invention discloses or relates to mutually fixedly connected components or structural parts, then unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured using a casting process) (except where it is obviously impossible to use an integral molding process).

[0038] Furthermore, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this invention include states or shapes that are similar to, analogous to, or close to those states or shapes. Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured using a one-piece molding process.

[0039] The above embodiments are merely illustrative examples to clearly illustrate the present invention and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A soil sample resistivity measuring device, characterized in that: The sample includes a soil sample box (2) and a cover plate (8) covering the soil sample box (2). Emitting electrode plates (3) are placed inside both ends of the soil sample box (2), and two receiving electrode rods (4) are inserted in the middle. The bottom of the emitting electrode plates (3) contacts the bottom of the soil sample box (2), and the two sides extend to the side wall of the soil sample box (2). The cover plate (8) is provided with an emitting electrode slot (7) for the emitting electrode plates (3) to pass through and a receiving electrode hole (6) for the receiving electrode rods (4) to pass through. The emitting electrode plates (3) and the receiving electrode rods (4) are respectively connected to the full waveform impedance analyzer (5) after passing through the emitting electrode slot (7) and the receiving electrode hole (6), forming a four-electrode connection structure. The two output current terminals of the full waveform impedance analyzer are respectively connected to the two transmitting electrode plates to inject alternating current signals into the soil sample, and the two input voltage terminals are respectively connected to the two receiving electrode rods to measure the potential difference generated by the soil sample. The complex resistivity spectrum of the soil sample is calculated from the data measured by the full waveform impedance analyzer.

2. The soil sample resistivity measuring device according to claim 1, characterized in that: The transmitting electrode sheet (3) and the receiving electrode rod (4) are made of silver.

3. The soil sample resistivity measuring device according to claim 1 or 2, characterized in that: The soil sample box (2) is a transparent box.

4. The soil sample resistivity measuring device according to claim 3, characterized in that: The soil sample box (2) is a rigid acrylic box.

5. The soil sample resistivity measuring device according to claim 1 or 2, characterized in that: The top of the transmitting electrode (3) is provided with a connecting tab that connects to the full waveform impedance analyzer (5).

6. A method for measuring the resistivity of a soil sample using the soil resistivity measuring device according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Prepare soil samples according to measurement requirements; Step 2: Place the prepared soil sample into the soil sample box, add an appropriate amount of soil sample according to the designed compaction value, and ensure that the soil sample at both ends of the soil sample box is in close contact with the emitting electrode plate. Step 3: Cover the cover plate and lead out the emission electrode plates at both ends of the soil sample box from the emission electrode seams on both sides of the cover plate; Step 4: Insert the receiving electrode rod into the soil sample through the receiving electrode hole in the middle of the cover plate; Step 5: Connect the transmitting electrode and receiving electrode rod to the full waveform impedance analyzer in a four-electrode configuration; Step 6: Select the power supply mode based on the approximate resistivity range of the soil sample. Beforehand, use an ohmmeter to roughly measure the resistance of the soil sample. When the resistance is less than 1Ω, select the constant current mode; when the resistance is greater than 1Ω, select the constant voltage mode. Finally, turn on the full waveform impedance analyzer and set the parameters in the startup software. Use the full waveform impedance analyzer to automatically collect and record the voltage, current, and resistivity values.

Images