KR102338724B1 - Method for monitoring soil with stabilizer using induced polarization survey - Google Patents

Abstract

By using the monitoring method of the land to which the stabilizer is applied using the induced polarization probe disclosed herein, it is possible to monitor whether the soil (stabilization layer) is maintained or not.

Description

Monitoring method of soil applied with stabilizer using induced polarization exploration {METHOD FOR MONITORING SOIL WITH STABILIZER USING INDUCED POLARIZATION SURVEY}

In the present specification, a method for monitoring soil to which a stabilizer is applied using induced polarization exploration is disclosed. Specifically, after stirring the stabilizer to lower the mobility and solubility of heavy metals in soil contaminated with heavy metals, it is a method of evaluating the state of the soil to which the stabilizer is applied for a long period of time.

The pollution of the underground environment is getting serious due to the reckless use of resources, and the need for the management of the underground environment is emerging due to the damage caused by the pollution. In particular, in the case of heavy metals, the natural purification time is long, and when they enter the human body through the route, it is difficult to discharge them, thereby causing various diseases.

Heavy metals behave in underground environments due to groundwater, rainfall, physical action, etc., and these behaviors can cause problems in soil remediation projects or soil use. Therefore, the treatment of heavy metals in the soil is receiving attention as a very important issue.

Currently, among the methods of treating heavy metals in soil, the method of stabilizing by lowering the mobility and solubility of heavy metals and blocking the elution of heavy metals in a solidified state is widely used. Overseas, the solidification/stabilization method has already been commercialized and generalized, but domestic stabilizing agent application is mainly used for soil improvement and restoration in farmland near abandoned mines.

At this time, as the stabilizer used, the stabilizer laid in powder form such as limestone and steelmaking slag causes a problem of scattering when the soil layer is weakened, and the stabilizer in liquid form easily flows out during rain. After applying stabilization/solidification, the evaluation of stabilizer-treated soil relies on analysis after collection of soil samples through excavation. This may cause secondary contamination due to destruction of the stabilization layer.

In addition, in the case of the existing soil contamination survey, it can be seen that the continuous input of manpower and the pre-treatment and analysis of soil samples when conducting the soil survey project through general survey and detailed survey result in serious waste of time and labor.

On the other hand, Induced Polarization (IP) exploration is a technology that induces polarization by supplying electric current to the underground medium and measures it to determine the induced polarization difference. is known

However, until now, only qualitative analysis through soil chemical analysis has been performed, and thus a geophysical evaluation method for a site to which a stabilizing agent is applied has not been performed.

Korean Registered Patent No. 10-1436260 Korean Registered Patent No. 10-1612027

In one aspect of the present invention, it is an object of the present invention to provide a method for identifying and monitoring the retention of solidified/stabilized soil for a site to which a stabilizer is applied due to heavy metal contamination.

In another aspect of the present invention, it is an object of the present invention to provide a method for non-destructively and effectively evaluating or monitoring whether a stabilizer is maintained for soil treated with a stabilization method.

In one aspect, in the present specification, the steps of installing a lateral line for induced polarization exploration on the land to which the stabilizer is applied; measuring an electrical resistivity value and an IP (Induced Polarization) value using the lateral line; and converting the measured electrical resistivity value and IP (Induced Polarization) value into an image. It provides a method of monitoring the land to which the stabilizer is applied using induced polarization exploration, including.

In one aspect, the monitoring method according to an embodiment of the present invention considers the conditions of the underground environment, and installs a lateral line in the shallow and/or deep part, so that electrical resistivity and fillability in polluted and non-polluting conditions (chargeability) can be secured.

In another aspect, the monitoring method according to an embodiment of the present invention shows different characteristics depending on the type of stabilizer used, so it is possible to verify whether the soil to which the stabilizer is applied (stabilization layer) is maintained, and the electrical resistivity of each soil layer It is possible to grasp the retention of the stabilization layer by identifying the characteristics of overfilling (IP effect). In addition, there is an advantage in that it is possible to acquire continuous ground information rather than a discontinuous analysis through conventional sampling for a wide area.

On the other hand, by monitoring the maintenance of the stabilization layer through periodic measurements, information on the site can be grasped and physical changes applied to the stabilization layer can be observed.

1 is a schematic diagram showing a comparison between the evaluation method (right) and the existing evaluation method (left) of the stabilization treatment site according to an embodiment of the present invention.
2A is a diagram illustrating a monitoring (or measurement) system according to an embodiment of the present invention.
2B is a diagram illustrating a state in which a current electrode and a potential electrode are installed to be spaced apart according to an embodiment of the present invention.
3 is a view showing the chargeability (Chargeability) decay over time in the method for measuring induced polarization according to an embodiment of the present invention.
4 is a two-dimensional electrical resistivity and time-domain induced polarization imaging results of a site using lime as a stabilizer in an embodiment of the present invention.
5 is a two-dimensional electrical resistivity and time-domain induced polarization imaging results of a site using limestone and steelmaking slag as stabilizers in an embodiment of the present invention.

Term Definition

In the present specification, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

exemplary of embodiments Explanation

Hereinafter, the present invention will be described in detail.

With reference to the accompanying drawings of the present specification, a method of monitoring (or measuring) the stabilizer applied land using induced polarization exploration according to an embodiment of the present invention will be described.

The present invention is to determine the maintenance of the stabilization layer using induced polarization exploration after stabilization treatment on a site contaminated with heavy metals. Specifically, referring to FIG. 1 , after first identifying the stabilization layer of the stabilizing soil, the IP response is higher or lower than that of the adjacent soil according to the characteristics of the stabilizer used in the stabilizing soil and compared with the electrical resistivity. It can be checked whether the soil applied for stabilization is maintained in its original state.

In exemplary embodiments of the present specification, the steps of installing a lateral line for induced polarization exploration on the land to which the stabilizer is applied; measuring an electrical resistivity value and an IP (Induced Polarization) value using the lateral line; and converting the measured electrical resistivity value and IP (Induced Polarization) value into an image. It provides a monitoring method of the stabilizer applied land using induced polarization exploration, including.

As shown in Figure 1, in order to evaluate the soil of the existing site, the soil is excavated over several points, samples are collected (sampling), dried and pre-treated, all heavy metals in the soil are extracted and the concentration is analyzed. (left side of Fig. 1). However, this method has disadvantages in that it is labor-intensive, expensive analysis cost is incurred, and it is difficult to obtain continuous stratum information because it is limited to the sampling point.

In order to improve these points, in the present specification, a method of measuring the induced polarization for a site treated with a stabilizer, editing the data, and then passing through an imaging step to determine the maintainability of the soil to which the stabilizer is applied (right side of FIG. 1) ).

First, as shown in Figure 2a, a lateral line for induced polarization exploration is installed on the land to which the stabilizer is applied. Since the polarization effect generated by the electrode in the induced polarization survey acts as noise on the measurement data, it is preferable to install the current electrode (transmitting) and the potential electrode (receiving) separately as shown in FIG. 2A.

The current electrode supplies current to the ground, and the potential electrode measures the electric resistivity value of the ground by measuring the potential difference, and as shown in FIG.

In one embodiment, the IP (Induced Polarization) value is measured from one or more channels, and converting the IP (Induced Polarization) value measured from the one or more channels to a single IP (Induced Polarization) effect by integrating after editing; may further include. Specifically, a portion indicated by a time slot in FIG. 3 is a fillability value measured for each channel, and may be calculated by removing an abnormal value from these values and integrating the remaining values.

In one embodiment, the IP (Induced Polarization) value is measured from one or more time channels, and after editing data including noise measured from the one or more time channels, the edited data is integrated into a single IP value and converted It may further include; Since the IP value automatically provided by the equipment may contain noise, it is converted into a single IP data by integrating the channel data after editing the data for each time channel. Specifically, a portion indicated by a time slot in FIG. 3 is a fillability value measured for each channel, and may be calculated by removing an abnormal value from these values and integrating the remaining values.

In other words, IP values are measured in multiple time channels, and after editing the exploration data for each time channel, the exploration data for all channels are integrated and converted into single-channel IP data. After that, a two-dimensional electrical resistivity/induced polarization inverse calculation is performed and an image is obtained using the inverse calculation result. If the measurement area is expanded or added, a 3D distribution image may be obtained.

In one embodiment, the lateral line may include two or more current electrodes and two or more potential electrodes.

In one embodiment, the two or more current electrodes may be installed at regular intervals of 0.1 m to 5 m, respectively, and may be installed at regular intervals of, for example, 0.1 to 3 m, 0.1 to 2 m, or 0.1 to 1 m, Two or more potential electrodes may be installed at regular intervals of 0.1 m to 5 m, respectively, and may be installed at regular intervals of, for example, 0.1 to 3 m, 0.1 to 2 m, or 0.1 to 1 m, and the total horizontal length of the lateral line is 10 to 30 m (see FIG. 2B).

In addition, in one embodiment, the distance between the two or more current electrodes and the two or more potential electrodes may be 0.5 m to 2 m, preferably 1 to 2 m. In addition, it is preferable that the burial depth of each electrode is uniformly installed to maintain contact with the soil.

For example, referring to FIG. 2B , the two or more current electrodes 1-24 and the two or more potential electrodes 25-48 may be installed with a constant distance (about 1 m) from each other.

In an embodiment, the image may be a 2D image or a 3D image.

In one embodiment, the converting into the image may be performed by inversely calculating the measured electrical resistivity value and the IP (Induced Polarization) value.

In one embodiment, the land to which the stabilizer is applied includes topsoil, a stabilization layer, and subsoil from the land surface, and the lateral line may be installed in topsoil (or cover soil). Even if the lateral line is installed only in the topsoil, it can be confirmed by imaging whether the polarization is induced to the subsoil.

Hereinafter, the present invention will be described in more detail through the following examples. However, the following examples are provided only for the purpose of illustration to help the understanding of the present invention, and the scope and scope of the present invention are not limited thereto.

Example

By applying the method of determining the maintenance of the stabilizer at the site where the stabilizer is applied according to the present invention, the results measured in the actual field will be described in detail.

Example One

Experimental area 1 is an agricultural land near the mine where manganese was mined in the past, and is mainly contaminated with arsenic, cadmium, lead, and zinc. The mine area is included in the mountainous valley topography, and most of the agricultural land in the work area is low-slope land (2-7%). The level of contamination before restoration near Experimental Area 1 is an area exceeding the Cd, Pb, and Zn concern standards (Cd: 4 mg/kg, Pb: 200 mg/kg, Zn: 300 mg/kg).

Stabilization was applied by mixing granular limestone at a rate of 5% as a stabilizer for contaminated soil. The site to which the stabilizer was applied was used as a field for growing crops, so data were obtained by installing a lateral line in the furrow where no crops were planted. This test area 1 is a site where the stabilization layer is 20cm thick on the top of the contaminated raw ground (subsoil), and the 40cm thick cover layer is applied. To this end, a total of 16.5 m of lateral wire was installed with an electrode spacing of 0.3 m. The electrode array used for the measurement used a dipole-dipole array with excellent resolution, and in order to exclude the polarization phenomenon occurring in the electrode, the transmitting electrode and the receiving electrode were installed apart from each other.

4 is a result of conducting electrical resistivity/induced polarization exploration for a site using granular limestone as a stabilizer. In the above electrical resistivity survey result, it can be seen that the low electrical resistivity appears at about 0.4 ~ 0.6 m. This point is the area where the stabilizer is mixed, and it is possible to check the presence or absence of stabilized soil by confirming that it is clearly distinguished from the adjacent topsoil (0 ~ 0.4 m) and subsoil (over 0.6 m). The IP exploration result at the bottom shows the characteristic of showing a low IP response in the area where the stabilizer is mixed. Through electrical resistivity/IP exploration, the location and maintenance of the stabilizer layer can be grasped for sites treated with lime as a stabilizer, so it is judged to be usefully applied.

Example 2

Experimental Zone 2 is a site adjacent to a mine where gold, silver, copper, lead, and zinc were mined as the main mineral types in the past. distributed The level of pollution before restoration in neighboring areas is equivalent to an area where Cd, As, Pb, Zn exceeds the countermeasure standards (Cd: 12 mg/kg, As: 75 mg/kg, Pb: 300 mg/kg, Zn: 900 mg/kg) More than 10 times the standard of this measure was detected as As.

In Experimental Area 2, 2% of granular limestone + 3% of steelmaking slag was mixed and used as a stabilizer. As in Experimental Area 1, it is before crops are grown, so data were obtained by installing a lateral line in the furrow. Data was acquired under the same conditions as in Experimental Area 1, and the results are shown in FIG. 5 .

5 is a result of conducting an electrical resistivity/induced polarization survey on a site where limestone and steelmaking slag were mixed and used as a stabilizer. It can be seen that it is difficult to confirm the clear difference between the surface and the stabilized soil, unlike the experimental area 1 in the above electric resistivity exploration result. Although it is difficult to clearly distinguish the area mixed with the stabilizer from the adjacent topsoil (0 ~ 0.4 m) only with the results of the electrical resistivity survey, the presence or absence of the stabilized soil can be confirmed from the IP survey results at the bottom. Unlike Experimental Area 1, it exhibits high IP response in the area where iron-containing steelmaking slag is mixed as a stabilizer.

From these results, it is judged that it will be usefully used to identify the location and maintainability of the stabilizer treatment area by applying the electrical resistivity/IP exploration to the site where the stabilizer is applied.

Claims (9)

Installing a lateral line for induced polarization exploration on the land to which the stabilizer is applied;
measuring an electrical resistivity value and an IP (Induced Polarization) value using the lateral line; and
Including; converting the measured electrical resistivity value and IP (Induced Polarization) value into an image;
The IP (Induced Polarization) value is measured from one or more channels,
The step of converting the IP (Induced Polarization) values measured from the one or more channels to a single IP (Induced Polarization) effect after editing and integrating; According to claim 1,
The IP (Induced Polarization) value is measured from one or more time channels,
After editing the data including the noise measured from the one or more time channels, integrating the edited data into a single IP value and converting the data; further comprising, a method for monitoring a land to which a stabilizer is applied using induced polarization exploration. According to claim 1,
Wherein the lateral line includes two or more current electrodes and two or more potential electrodes. 4. The method of claim 3,
The two or more current electrodes are installed at regular intervals of 0.1 m to 5 m, respectively,
Wherein the two or more potential electrodes are installed at regular intervals of 0.1 m to 5 m, respectively, a method for monitoring the land using a stabilizer application using induced polarization exploration. 4. The method of claim 3,
The distance between the two or more current electrodes and the two or more potential electrodes is 0.5 m to 2 m, a method for monitoring a land with a stabilizer applied using induced polarization exploration. According to claim 1,
The image is a two-dimensional image or a three-dimensional image, a method of monitoring a land to which a stabilizer is applied using induced polarization exploration. According to claim 1,
The step of converting to the image is made by inversely calculating the measured electrical resistivity value and IP (Induced Polarization) value. According to claim 1,
The stabilizing agent applied land includes topsoil, a stabilizing layer, and subsoil from the land surface, and the lateral line is installed in the topsoil. delete

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