KR20050010586A - Device for Measuring Electrical Resistivity of Soil with Hydraulic Characteristics - Google Patents

Abstract

PURPOSE: An apparatus for measuring electrical resistivity of soil using hydraulic characteristics thereof is provided to obtain a correlation among physical characteristics of the soil by measuring the electrical resistivity and a permeability constant simultaneously. CONSTITUTION: An apparatus for measuring electrical resistivity of soil includes a coil container(116), a first mass cylinder(100), a second mass cylinder(102), a current source(112), current electrodes(104,106), potential electrodes(108,110), and a voltage detector(114). The first mass cylinder is coupled with an upper portion of the soil container and contains water to detect hydraulic characteristics of the soil. The second mass cylinder is coupled with a lower portion of the soil container and contains water to detect hydraulic characteristics of the soil. The current electrodes are coupled with the soil container and the current source to provide the current from the current source to the soil container. The potential electrodes are coupled with the soil container between the current electrodes. The voltage detector detects the voltage difference between the potential electrodes.

Description

Device for Measuring Electrical Resistivity of Soil with Hydraulic Characteristics

The present invention relates to an electrical resistivity measuring device according to the hydraulic constant of the soil, and more particularly to a device that can measure the specific resistance of the soil by a relatively simple method, and can measure the electrical resistivity and permeability coefficient of the soil at the same time.

In general, soils and rocks that make up the ground are mainly composed of insulator minerals and groundwater, and the electrical conductivity of the ground depends on the ionic conduction of the groundwater and clay minerals in the pores. At this time, the electrical resistivity of rocks and layers not containing clay minerals is determined by the distribution state, porosity, specific resistance and saturation of the mineral particles constituting the rock or soil layer. This relationship can be expressed by Equation 1 below by Archie's empirical equation.

here Is the electrical resistivity of the ground, Is the porosity, Is the specific resistance of the pore water, a, m and n are integers depending on the properties of the rock and the strata, a is the net coefficient, m is the coefficient of freezing, and n is the saturation coefficient.

In general, sandstone is a = 0.5∼0.25, m = 1.3∼2.5, n = 2.

Equation 1 above shows that when rock or strata are almost close to the insulator, the electrical resistivity of the ground is proportional to the specific resistance of the porosity and inversely proportional to the m power of the porosity and the n power of the saturation. When the saturation is 100% (S = 1), the following equation (2) can be derived from equation (1).

Where F is called the layer resistivity coefficient. The stratum resistivity coefficient is related to the coefficient of circulation and the porosity, and is used for the determination of the type of rock and the low oil capacity because it is a natural coefficient of the rock reflecting the size, shape, and distribution of the voids. Arch's empirical formula, however, is empirically obtained for sandstones with a large effective porosity, and is less than the arch estimate for hydrous rocks containing clay minerals.

This is because in the hydrated clay mineral, an electric double layer having a high ion concentration is thickly developed, and the ion conductivity using the medium is high. The surface of the mineral particle in which the electric double layer is formed is related to the electrical conduction, and this phenomenon is called surface conduction.

Mineral particles with a large specific surface area, such as clay minerals, have a greater effect of surface conduction. Therefore, the following equation (3) is proposed because it is not possible to accurately determine the layer resistivity from the arch equation for rocks or strata containing clay minerals.

here Represents electrical conduction by the electric double layer of clay minerals.

On the other hand, it is common to reveal the physical properties of soils at different depths in soil layers by analyzing depth samples obtained through drilling under laboratory conditions. However, in case of using drilling, not only a lot of costs are generated, but also there are disadvantages in that it is vulnerable to disasters such as contamination due to drilling. In addition, when the results are obtained by drilling, since only one-dimensional data can be obtained, there are limitations in implementing physical properties of the spatial soil.

The electrical resistivity described above is closely related to the soil's physical properties such as porosity, porosity, electrical resistivity, saturation, permeability coefficient, and the electrical resistivity can be used as a useful data for spatially analyzing the physical properties of the soil.

However, in the related art, there is a difficulty in simply measuring the electrical resistivity, and since there is no device for measuring the electrical resistivity and the physical quantity of other soils together, it is difficult to analyze the correlation between the electrical resistivity and other physical quantities of the soil.

In the present invention, in order to solve the problems of the prior art as described above, it is proposed an electrical resistivity measuring device according to the soil repair constant that can measure the electrical resistivity of the soil simply and quickly in the laboratory.

Another object of the present invention is to propose an electrical resistivity measuring device of soil which can more easily recognize the relationship between the electrical resistivity and other physical properties of the soil by simultaneously measuring the electrical resistivity and permeability coefficient of the soil.

1 is a conceptual diagram showing the overall configuration of the electrical resistivity measuring apparatus according to the soil repair constant according to an embodiment of the present invention.

Figure 2 is a perspective view of the electrical resistivity measuring apparatus according to an embodiment of the present invention.

3 is a cross-sectional view of the electrical resistivity measuring apparatus according to a preferred embodiment of the present invention.

4 is a plan view of a second top plate and a first bottom plate according to an exemplary embodiment of the present invention.

5 is a graph derived through experiments the relationship between the electrical resistivity of the saturated sample according to the porosity and the electrical resistivity of the pore water.

FIG. 6 is a graph showing the electrical resistivity of a saturated sample versus porosity as the pore number changes.

In order to achieve the object as described above, according to an embodiment of the present invention, the soil receiving portion accommodates the soil to measure the electrical resistivity; A first measuring cylinder coupled to an upper portion of the soil receiving part and accommodating water for measuring the variable position; A second measuring cylinder coupled to a lower portion of the soil receiving part and accommodating water for measuring a variable; A current source for supplying current; A current electrode coupled to the soil receiving portion and the current source and providing a current output from the current source to the soil accommodated in the soil receiving portion; A potential electrode coupled to the soil receiving portion in a section between the current electrodes; And an electrical resistivity measuring device according to a hydraulic constant of the soil, including a voltage meter for measuring a potential difference generated between the potential electrodes.

The electrical resistivity measuring device, the first top plate coupled to the upper portion of the soil receiving portion; A second top plate spaced apart from and parallel to the first top plate; A first nozzle formed on the second upper plate, coupled to the first measuring cylinder, and penetrating water accommodated in the first measuring cylinder; A support member for supporting the first and second top plates; A first lower plate coupled to the support member and the lower portion of the soil receiving portion; A second lower plate spaced apart from and parallel to the first lower plate; And a second nozzle formed on the second lower plate, coupled to the second measuring cylinder, and penetrating water accommodated in the soil receiving unit.

The current electrode may be coupled to the soil receiver in the form of a metal plate, and the potential electrode may be coupled to the soil receiver in the form of a metal strip.

On the other hand, the electrical resistivity measuring apparatus according to the repair constant of the soil according to the present invention is provided in the space between the first top plate and the second top plate to accommodate water, the first having a diameter equal to the soil receiving portion It may further include a receiver.

In addition, the electrical resistivity measuring apparatus according to the repair constant of the soil according to the present invention is provided in the space between the first lower plate and the second lower plate to accommodate water, the second receiving portion having the same diameter as the soil receiving portion It may further include.

A plurality of permeation holes may be formed in the first upper plate such that water accommodated in the first accommodating part is uniformly provided to the soil receiving part.

A plurality of permeation holes may be formed in the first lower plate such that water existing in the soil accommodating part is uniformly discharged to the second accommodating part.

Preferably, the plurality of permeation holes formed in the first upper plate and the first lower plate are formed in a radial shape.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the electrical resistivity measuring apparatus according to the soil repair constant according to the present invention.

1 is a conceptual diagram showing the overall configuration of the electrical resistivity measuring device according to the soil repair constant according to an embodiment of the present invention.

As shown in FIG. 1, the electrical resistivity measuring apparatus according to an embodiment of the present invention includes a first measuring cylinder 100, a second measuring cylinder 102, two current electrodes 104 and 106, and two potentials. It may include electrodes 108 and 110, current source 112, voltage meter 114, and soil receptacle 116.

In Figure 1, the soil receiving portion 116 is accommodated in the soil to measure the electrical resistivity. For soil-specific experiments, samples separated by USDA and uniform classification mood may be used.

According to a preferred embodiment of the present invention, the soil receiving portion 116 is preferably manufactured in a cylindrical shape so that water flows uniformly between the contained soil. However, the shape of the soil receiving portion 116 in the present invention is not limited to a cylindrical shape, it will be apparent to those skilled in the art that it can be implemented in various other forms.

Two current electrodes 104 and 106 are coupled to the top and bottom of the soil receiver 116. According to one embodiment of the invention, the current electrodes 104, 106 may be coupled to the soil receiving portion 116 in the form of a metal plate. The metal plate is preferably a metal plate having the same diameter as the soil container so that current flows uniformly in the soil container 116.

The current source 112 supplies current to the current electrodes 104 and 106, and current flows using the soil contained in the soil receiving unit 104 as a medium. According to an embodiment of the present invention, a variable constant current generator may be used as the current source 112.

Two potential electrodes 108 and 110 are coupled to the soil receiving portion 116. The two potential electrodes 108 and 110 need to be coupled to the soil receiving portion 116 at appropriate intervals, and the distance difference between the two potential electrodes is not important. The potential electrodes 108 and 110 may be coupled to the soil receiving portion 116 in the form of a metal strip.

When a current is supplied from a current source, a current flows using the soil as a medium, so that a potential difference is formed between two potential electrodes. A voltage meter 114 is coupled to the two potential electrodes 108 and 110, and measures the voltage formed on the two potential electrodes 108 and 110.

The specific resistance of the soil can be measured using the voltage measured by the voltage meter.

According to Ohm's law, the following equation 1 holds.

In Equation 4, V is the potential difference between the two potential electrodes 106 and 108, and I is the intensity of the current supplied from the current source 112. Also, Is the resistivity, L is the distance between two potential electrodes, A is the cross-sectional area of the soil receptacle.

Using the above Equation 4, the electrical resistivity can be obtained as Equation 2 below.

Therefore, according to the present invention, the electrical resistivity of the soil can be obtained simply by measuring the potential difference between the potential electrodes coupled to the soil receiving portion 116.

Referring to FIG. 1, two scalpel cylinders 100 and 102 are coupled to the soil receiving portion 116. As shown in FIG. 1, the first scalpel cylinder 100 is coupled to the upper portion of the soil receiving portion 116, and the second scalpel cylinder is coupled to the lower portion of the soil receiving portion 116. The first measuring cylinder 100 and the second measuring cylinder 102 may be coupled to the soil receiving unit 116 through a general nozzle.

In addition to the measuring cylinder, it will be apparent to those skilled in the art that any device capable of measuring the amount of water can be applied to the present invention.

As shown in FIG. 1, the first measuring cylinder 100 and the second measuring cylinder 102 are placed at different heights with a distance difference d. As shown in FIG. 2, the second scalpel cylinder 102 is preferably positioned higher than the first scalpel cylinder 100. Before the permeation experiment, the first measuring cylinder 100 and the second measuring cylinder 102 are in a locked state, but when the permeation experiment is started, the locked state of the first measuring cylinder 100 and the second measuring cylinder 102 is released. The water contained in the first measuring cylinder 100 is transferred to the soil contained in the soil receiving unit 116, thereby increasing the water contained in the second measuring cylinder 102. The above process is continued until the height of the water accommodated in the first measuring cylinder 100 and the second measuring cylinder 102 is the same.

Permeability coefficient of the soil can be obtained by measuring the time until the height of the first measuring cylinder 100 and the second measuring cylinder 102 are equal, that is, until reaching an equilibrium state.

Therefore, according to the present invention, the measurement of the electrical resistivity and the measurement of the permeability coefficient can be performed at the same time, and it is possible to provide an experimental apparatus for revealing the correlation of the electrical resistivity for each permeability coefficient.

2 is a view showing a perspective view of the electrical resistivity measuring apparatus according to an embodiment of the present invention.

As shown in FIG. 2, the electrical resistivity measuring apparatus according to the preferred embodiment of the present invention includes a first top plate 200, a second top plate 202, a first nozzle 204, a support member 206, The soil receiving part 208, the first lower plate 210 and the second lower plate 212 may be included.

The first top plate 200 and the second top plate 202 are disposed above the soil receiving portion 208 through the support member 206. The first top plate 200 and the second top plate 202 are spaced apart from each other at predetermined intervals, and although not shown in FIG. 2, a receiving portion for receiving water between the first top plate and the second top plate is provided. It is provided. The first top plate 200, the second top plate 202, the first bottom plate 210, and the second bottom plate 212 may be made of an acrylic material that is electrically insulator. It will be apparent to those skilled in the art that other insulator materials may be used in addition to acrylic.

The first nozzle 204 is formed at the center of the second upper plate 202, and the first measuring cylinder 100 is coupled to the formed first nozzle 204. The first measuring cylinder 100 may be coupled to the first nozzle 204 through a common tube through which water may pass.

As shown in FIG. 2, the soil receiving portion 208 may be implemented in a cylindrical beaker form and is coupled to the first upper plate 200 and the first lower plate 210. At the upper and lower ends of the soil receiving portion, a current electrode is coupled in a band form, and a potential electrode is coupled in a band form in the middle portion.

The first lower plate 210 and the second lower plate 212 are also spaced apart from each other at a predetermined interval, and are not shown in FIG. 2 between the first lower plate 210 and the second lower plate 212 to receive water. A receiving unit is provided.

Although not shown in FIG. 2, a second nozzle is formed at the center of the second lower plate 212, and the second nozzle is coupled to the second measuring cylinder 102. As in the case of the first nozzle 204, the second measuring cylinder may be coupled to the second nozzle 214 through a tube through which water may flow.

3 is a cross-sectional view of an electrical resistivity measuring apparatus according to a preferred embodiment of the present invention.

As shown in FIG. 3, a first accommodating part 300 is provided between spaced spaces of the first upper plate 200 and the second upper plate 202, and the first lower plate 210 and the second lower plate. The second receiving portion is provided between the spaced spaces 212.

Water is accommodated in the first accommodating part 300 and the second accommodating part 302. According to a preferred embodiment of the present invention, the first accommodating part 300 and the second accommodating part 302 are preferably made of a rubber material. In addition, it is preferable that the diameter of a 1st accommodating part and a 2nd accommodating part is the same as a soil accommodating part.

The permeation experiment is carried out in a state in which water is filled in the first accommodating part 300 and the second accommodating part 302 as well as between the soil accommodated in the soil accommodating part.

The first accommodating part 300 and the second accommodating part 302 serve to uniformly absorb water into the soil during the permeation experiment.

As shown in FIG. 3, the diameters of the first nozzle through which the water of the measuring cylinder enters and the second nozzle through which the water comes out of the soil container are smaller than those of the soil container. Therefore, when the locking state of the measuring cylinder is released without the first accommodating part 300 and the second accommodating part 302, water is introduced into the soil accommodating part through the nozzle having a small diameter. Water cannot flow evenly through the nozzle, and also water cannot flow out evenly through the nozzle having a small diameter.

Therefore, in the present invention, the first receiving part 300 and the second receiving part 302 are provided so that water does not flow directly from the nozzle, but the water is supplied to the soil receiving part through the first receiving part 300 and the second receiving part 302. Allow inflow.

Since the diameter of the first accommodating part 300 and the second accommodating part 302 is the same as that of the soil accommodating part, water may be uniformly introduced into the soil accommodating part.

Meanwhile, in the first upper plate 200 and the first lower plate 210, water contained in the first accommodating part 300 and the second accommodating part 302 uniformly flows into the soil accommodating part or the water of the soil accommodating part is uniform. Permeable holes 304 and 306 are formed to flow out easily.

It is preferable that a plurality of permeation holes are formed in the second upper plate and the first lower plate in a radial form, and the water permeable holes may be formed in other forms as long as the water can flow out or flow evenly even if it is not a radial form. It will be apparent to those skilled in the art.

4 is a plan view illustrating a first top plate and a first bottom plate according to an exemplary embodiment of the present invention.

As shown in FIG. 4, it can be seen that a plurality of holes are formed in a radial shape in the first upper plate and the first lower plate.

The water contained in the first receiving part is introduced into the soil receiving part through the formed hole, and the water present in the soil receiving part is introduced into the second receiving part through the formed hole.

Hereinafter, an experimental example in which the electrical resistivity according to the porosity is analyzed according to the change in the pore number using the above-described electrical resistivity measuring apparatus will be described.

5 is a graph derived through experiments the relationship between the electrical resistivity of the saturated sample according to the porosity and the electrical resistivity of the pore water.

FIG. 5 shows the relationship between the electrical resistivity of the sample and the electrical resistivity of the pore number when the porosity is 38.5%, 36,7%, 33.38% and 31.36%. Referring to FIG. 5, a relatively linear result is shown in the pore number section of 30 to 200 Ohm-m, but a relatively non-linear result is shown when the electrical conductivity of the pore number is very high or low. This shows that the specific resistance of the saturated sample is high when the electrical resistivity of the pore water is very low, and the electrical resistivity of the saturated sample is fine but low when the electrical resistivity of the pore water is very high. In the case of general groundwater, the electrical resistivity is mostly around 100 Ohm-m, so the experimental result can be interpreted as a linear result.

Table 1 below shows functions and correlation coefficients representing the relationship between the electrical resistivity of the saturated sample and the electrical resistivity of the pore number.

Porosity (%) Y = aX + b Correlation Coefficient (R ² ) a b 31.36 0.2062 -16.637 0.9861 33.38 0.2171 -7.4003 0.9964 36.7 0.2018 5.137 0.9948 38.5 0.2065 11.765 0.9928

In Table 1, X is the electrical resistivity of the saturated sample and Y is the electrical resistivity of the pore water. According to the correlation coefficient, the case of the porosity of 31.36% shows more error than the case of other cases. However, since most of the correlation coefficient is 0.98 or more, it can be said that the correlation coefficient is usually very large.

FIG. 6 is a graph showing the electrical resistivity of a saturated sample with respect to porosity as the pore number changes.

As shown in FIG. 6, it can be seen that the electrical resistivity of the sample and the porosity are inversely related, and the slope increases as the electrical resistivity of the pore number decreases. Therefore, it can be confirmed that the porosity has a greater effect on the electrical resistivity of the sample containing the pore water.

In the above, the experimental results of the relationship between the porosity and the electrical resistivity using the apparatus according to the present invention were examined. In the case of using the measuring device according to the present invention, the above-described repeated measurement of the electrical resistivity can be made simply, so that the relationship between the electrical resistivity and the porosity can be identified more quickly and simply.

In addition to the relationship between the porosity, the specific resistance of the pore water and the electrical resistivity of the soil, the device according to the present invention can be usefully used to determine the correlation with other physical properties (saturation, clay content, etc.) of the soil. Could be.

As described above, according to the electrical resistivity measuring device according to the soil repair constant according to the present invention, there is an advantage that the physical properties of the soil can be determined at a low cost through a relatively simple device. Further, according to the device according to the present invention, the electrical resistivity of the soil can be easily measured, and the electrical resistivity and permeability coefficient can be measured simultaneously, so that the apparatus according to the present invention has a relationship between the electrical resistivity and other physical properties of the soil. This can be useful for revealing correlations.

Claims (9)

A soil receiving portion accommodating soil for measuring electrical resistivity; A first measuring cylinder coupled to an upper portion of the soil receiving part and accommodating water for measuring the variable position; A second measuring cylinder coupled to a lower portion of the soil receiving part and accommodating water for measuring a variable; A current source for supplying current; A current electrode coupled to the soil receiving portion and the current source and providing a current output from the current source to the soil accommodated in the soil receiving portion; A potential electrode coupled to the soil receiving portion in a section between the current electrodes; And Electrical resistance measurement apparatus according to the hydraulic constant of the soil, characterized in that it comprises a voltage meter for measuring the potential difference generated between the potential electrode. The method of claim 1, A first top plate coupled to an upper portion of the soil receiving portion; A second top plate spaced apart from and parallel to the first top plate; A first nozzle formed on the second upper plate, coupled to the first measuring cylinder, and penetrating water accommodated in the first measuring cylinder; A support member for supporting the first and second top plates; A first lower plate coupled to the support member and the lower portion of the soil receiving portion; A second lower plate spaced apart from and parallel to the first lower plate; And And a second nozzle formed on the second lower plate, coupled to the second measuring cylinder, and penetrating water accommodated in the soil accommodating part. The method of claim 1, The electric current resistance device according to the repair constant of the soil, characterized in that the current electrode is coupled to the soil receiving portion in the form of a metal plate. The method of claim 1, And the potential electrode is coupled to the soil receiving portion in the form of a metal strip. The method of claim 2, The electrical resistivity according to the hydraulic constant of the soil, characterized in that it further comprises a first receiving portion provided in the space between the first upper plate and the second upper plate and having the same diameter as the soil receiving portion Measuring device. The method of claim 2, Electrical resistivity measuring device according to the repair constant of the soil, characterized in that it further comprises a second receiving portion provided in the space between the first lower plate and the second lower plate, the water receiving portion having the same diameter as the soil receiving portion . The method of claim 5, The electrical resistivity measuring device according to the hydraulic constant of the soil, characterized in that the first upper plate is formed with a plurality of permeable holes so that the water accommodated in the first receiving portion is uniformly provided to the soil receiving portion. The method of claim 6, And a plurality of permeable holes are formed in the first lower plate such that water existing in the soil accommodating part is uniformly discharged to the second accommodating part. The method according to claim 7 or 8, Electrical resistivity measuring device according to the repair constant of the soil, characterized in that the plurality of permeable holes formed in the first upper plate and the second lower plate is formed in a radial shape.