KR100944096B1 - System for streamer electrical resistivity survey and method for analysis of underground structure below a riverbed - Google Patents

Abstract

In the present invention, a streamer electrical resistivity exploration apparatus capable of identifying the thickness and bedrock boundaries of a sedimentary layer of a river or a lake bottom in a short time, and a method for analyzing a bottom soil structure using the same are provided.

Streamer electrical resistivity exploration system of the present invention, the electrical resistivity exploration system for exploring the structure of the underwater ground using a probe; A streamer cable connected to the probe and attached with a plurality of electrodes; A multichannel electrical resistivity probe mounted on the probe and measuring electrical resistivity from a plurality of electrodes attached to the streamer cable; A first real time kinematic GPS (RTK GPS) mounted on the probe to measure the position of the probe in real time; And a second RTK GPS installed at the end of the streamer cable and measuring the position of the streamer cable end in real time.

Resistivity, Streamer Electrode

Description

SYSTEM FOR STREAMER ELECTRICAL RESISTIVITY SURVEY AND METHOD FOR ANALYSIS OF UNDERGROUND STRUCTURE BELOW A RIVERBED}

The present invention relates to an electrical resistivity exploration system and a method for analyzing the bottom soil structure using the same. The present invention relates to an electrical resistivity exploration system that analyzes underground structures by modeling measured electrical resistivity through inversion algorithms, and to a method of analyzing ground structure using the same.

Identifying the thickness and bedrock boundary of the river or lake bottom is essential for the calculation of the soil volume for dredging the bottom, securing the stability of the bridge design, and optimizing the excavation method for the canal design.

The most common way to identify bedrock boundaries is to drill, which is the most accurate way of knowing the boundaries of soil layers, weathered layers, and bedrocks, but it only provides depth information limited to the drilling point, which is very expensive and time-consuming. There is this.

Other methods may be applied to GPR (Ground Penetrating Radar) exploration or natural seismic exploration but have the following problems. First, the GPR exploration limits the detection depth according to the electric conductivity of the river or the lake, and the penetration of radar waves is very limited especially when the specific resistivity of the soil deposit is low. Next, natural seismic exploration needs to develop a suitable transmission source, and there is also a need for developing a receiver sensor accordingly.

Due to this problem, the present invention attempts to apply water electrical resistivity exploration. In general, electrical resistivity exploration is performed by calculating a resistance between two points by applying a constant current to a conductor and measuring a potential difference between two points. In other words, electrical resistivity exploration is an earth that detects geological structures or ideal zones by measuring the potential difference by artificially transmitting electric current in the basement to image the complicated geological structure formed by heterogeneous media. It is a physics method.

By the way, the electrical resistivity exploration is used to determine the geological structure of the lower surface by performing the exploration along the ground surface, as in the present invention, the electrical resistivity measurement problem according to the position change of the electrode in the water phase during the electrical resistivity survey as in the present invention In order to solve the problem more accurately, the electrical resistivity data for the river water according to the measurement location is additionally needed so that only the bottom soil structure can be analyzed except for the river water part that is not desired.

The present invention is to solve the problems of the prior art, by measuring the electrical conductivity of the steel as well as the electrical resistivity according to the position change of the electrode in the water phase in real time, has a very high accuracy in a quick time and river or lake The purpose of the present invention is to provide an electrical resistivity exploration system that can identify the thickness of sedimentary layers and the bedrock boundary, and the method of analyzing the ground structure using the same.

Streamer electrical resistivity exploration system of the present invention for achieving the above object, in the electrical resistivity exploration system for exploring the structure of the underwater ground using a probe; A streamer cable connected to the probe and attached with a plurality of electrodes; A multi-channel electrical resistivity probe mounted on the probe and measuring electrical resistivity from a plurality of electrodes attached to the streamer cable; A first real time kinematic GPS (RTK GPS) mounted on the probe to measure the position of the probe in real time; And a second RTK GPS installed at the end of the streamer cable and measuring the position of the streamer cable end in real time.

In addition, the probe has an electrical conductivity meter mounted to the lower portion of the probe to measure the electrical conductivity of the water temperature and water; And a side scan sonar mounted to the lower portion of the probe and measuring depth of water.

According to the present invention, according to the changing position, the electrical resistivity of the bottom and the restriction data of the river (depth, water temperature, electrical conductivity of the water) by using the position information through RTK GPS in real time to measure the bottom ground structure It can provide a new exploration system that can interpret.

In addition, in the present invention described above, it is preferable that the streamer cable connects a tail buoy at its end so that the streamer cable maintains a straight line, and a buoy is provided between the plurality of electrodes. It is preferred that the plurality of electrodes be floated while maintaining contact with water.

In addition, the second RTK GPS is preferably provided with a radio modem, so that the location information of the streamer cable end can be delivered to the probe, the location information of the streamer cable end is delivered in the first RTK GPS It is calculated along with the measured position information of the probe to provide a precise measuring position.

In addition, the streamer electrical resistivity exploration system of the present invention further comprises a computing device for inputting the measurement data to image the bottom ground structure through the electrical resistivity inversion;

The computing device generates the geographic information system (GIS) data using the electrical conductivity data of the water measured by the electrical conductivity meter and the depth data measured by the side scan sonar using the position data measured by the first RTK GPS. To; Calculating GPS data of a precise measurement position based on the position data measured by the first RTK GPS and the position data measured by the second RTK GPS; A two-dimensional inversion is performed on the electrical resistivity data measured by the multi-channel electrical resistivity probe based on the GPS data of the measurement position, and an operation of imaging the bottom soil structure is performed using the inversion result.

At this time, in performing the two-dimensional inversion of the measured electrical resistivity data, the depth data and the electrical conductivity data of the water is characterized in that the input as a constraint condition.

By using such a computing device, it is possible to image the bottom and bottom structures, and through this, it is possible to easily check the thickness and bedrock boundary of the bottom layer.

In addition, the bottom ground structure analysis method using the streamer electrical resistivity exploration system of the present invention for achieving the above object,

A method for analyzing a bottom ground structure using data measured in a computing device including a memory, a data calculating section, an underground structure analyzing section, and a control unit; (c) generating precision measurement position data by receiving the probe position data and streamer cable end position data from the memory at the data operation unit; (d) performing two-dimensional inversion on the electrical resistivity measurement data according to the precise position data in the underground structure analyzing unit; And (e) imaging the bottom ground structure by using the inversion result in the underground structure analyzing unit. In the step (d), the electrical conductivity of the water depth and the water is input as a limiting condition. .

In addition, the bottom ground structure analysis method using another streamer electrical resistivity exploration system of the present invention for achieving the above object,

A method for analyzing a bottom ground structure using data measured in a computing device including a memory, a data calculating section, an underground structure analyzing section, and a control unit; (a) receiving the electrical conductivity data of the water and the position data of the probe from the memory in the data calculating unit and generating an electrical conductivity map of the water according to the position; (b) receiving depth data from the memory and position data of the probe from the memory to generate a depth map according to a position; (c) generating precision measurement position data by receiving the probe position data and streamer cable end position data from the memory at the data operation unit; (d) performing two-dimensional inversion on the electrical resistivity measurement data according to the precise position data in the underground structure analyzing unit; And (e) imaging the bottom soil structure by using the inversion result in the underground structure analyzing unit.

In the step (d), the electrical conductivity data of the water according to the position obtained in the step (a) and the water depth data according to the position obtained in the step (b) is input as a restriction condition.

In this way, by inserting data on the water depth and water electrical conductivity according to the location as the constraint condition for inversion, the inversion can be performed only for the underground structure of the lower part of the river. Will be.

According to the present invention described above, in analyzing the bottom structure based on the electrical resistivity measurement result, first, the data on the electrical resistivity and the river at the same time are measured quickly and rapidly using real-time position information through RTK GPS. It is possible to reduce the error by inputting the depth and electrical conductivity of each location as a limiting condition in the inversion, and has an advantage of obtaining accurate analysis results.

That is, according to the present invention, it is possible to accurately identify the thickness and bedrock boundary of the sedimentary layer at the bottom of the river or lake in a short time.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the invention to those skilled in the art.

1 is a block diagram of a streamer electrical resistivity exploration system according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating a device configuration of the system of the present invention.

The streamer electrical resistivity exploration system according to the present invention includes a probe 100 on which various measuring devices are mounted and a streamer cable 110 to which a plurality of electrodes are attached.

The probe 100 is equipped with a multi-channel electrical resistivity probe 160, a first RTK GPS (Real Time Kinematic GPS, 150), and an electric conductivity meter 130 and a side scan sonar 140 at a lower portion thereof. Can be installed.

The multi-channel electrical resistivity probe 160 simultaneously measures the electrical resistivity in multiple channels from a plurality of electrodes attached to the streamer cable 110, and the first RTK GPS 150 measures the position of the probe in real time at the cm level. Done.

The electrical conductivity meter 130 mounted in the probe lower water measures the electrical conductivity of the water, and the side scan sonar 140 measures the depth of the river or the lake by using ultrasonic waves, where the measured depth and the electrical conductivity are inverted. Used as a time constraint.

In general, when the underground structure is identified through the inversion after the electrical resistivity exploration, the entire measurement electrode is covered. When the exploration is performed through the electrode floating on the river as in the present invention, the entire inversion of the river and the lower strata of the river is inverted. Will be targeted. By the way, when the river and the entire lower strata of the river are subjected to inversion, errors are greatly generated in the analysis of the lower strata structure of the target steel. Therefore, in the inversion model, if the depth and electrical resistivity (inverse of the electrical conductivity) of the river are set to a fixed value and the inversion is performed with the electrical resistivity measurement result only for the strata under the river, the inversion is performed including the river water. The accuracy is very high.

Therefore, this requires data on the depth and electrical conductivity (inverse of the electrical resistivity) of the river to be used as a limiting condition in the inversion process, in the present invention, the conductivity meter 130 and the side scan sonar under the probe 100 By mounting the 140, it is possible to quickly and accurately analyze the bottom ground structure by simultaneously measuring the water depth and the electrical conductivity of the water to be used as the constraint of inversion.

The electrical conductivity and depth data of such rivers may use data measured separately from the exploration system of the present invention, in which case the conductivity meter and side scan sonar may not be mounted in the exploration system of the present invention.

The streamer cable 110 connected to the probe 100 is attached with a plurality of metal electrodes 112 for measuring electrical resistivity, and a small buoy is installed between the electrodes so that the electrode 112 is connected to water. Keep contact and float. A tail buoy (116) is connected to the end of the streamer cable (110) to keep the streamer cable straight, and a second RTK GPS (120) is installed at the end buoy (116) to the streamer cable The exact position of the tip is measured in real time. In addition, the second RTK GPS 120 has a radio modem and transmits the location information to the probe 110 through the radio modem, and is recorded together with the position of the probe 110 measured by the first RTK GPS 150.

In addition, the streamer electrical resistivity exploration system of the present invention, the measurement data is input is made further comprises an operation device 200 for imaging the bottom ground structure through the electrical resistivity inversion. The arithmetic unit 200 may be mounted directly on the probe 100 to show an image of the underfloor ground structure in real time according to the exploration data. You can also image the structure.

The computing device 200 may include a memory 210, a data calculator 220, an underground structure analyzer 230, and a controller 240. The memory 210 stores various measurement data, and the data operation unit 220 reconstructs the measured data into location-specific data applicable to the underground structure analysis, and the underground structure analysis unit 230 is based on the electrical resistivity data. 2D inversion is performed and the underground structure is imaged based on the analysis result of the final underground electrical resistivity model, and the controller 240 controls the calculation process.

The computing device 200 images the bottom ground structure by performing the following steps using the algorithm shown in FIG. 3.

First, in the data calculator 220, the electrical conductivity data of the water measured by the electrical conductivity meter 130 and the depth data measured by the side scan sonar 140 are generated as Geographic Information System (GIS) data using the GPS data. do. That is, (a) receiving the electrical conductivity data and the probe position data of the water from the memory 210 in the data calculating unit 220 to generate the electrical conductivity map of the water according to the position (S312), and (b) the data calculating unit 220 In operation 314, a depth map according to a location is generated using the depth data and the probe position data from the memory 210.

Next, the GPS data of the precise measurement position is calculated based on the position data measured by the first RTK GPS 150 and the position data measured by the second RTK GPS 120. That is, (c) step S316 of generating the precision measurement position data by receiving the probe position data and the streamer cable end position data from the memory 210 in the data operation unit 220 is performed. Thus, precise position data for the measurement position of each electrode may be calculated based on the position data of the first RTK GPS and the position data of the second RTK GPS.

Next, two-dimensional inversion is performed on the electrical resistivity data measured by the multi-channel electrical resistivity probe 160 based on the GPS data of the measurement position, and an operation of imaging the bottom ground structure using the inversion result is performed. That is, (d) performing a two-dimensional inversion on the electrical resistivity measurement data according to the precise position data in the underground structure analyzing unit 230 (S320) and (e) the result of the inversion in the underground structure analyzing unit 230. Imaging the bottom ground structure using the step (S322) is performed.

At this time, in the step (d), the electrical conductivity data of the water according to the position obtained in the step (a) and the water depth data according to the position obtained in the step (b) are inserted as a restriction condition.

The result of the analysis of the final underground resistivity model is derived through the inversion step (S320), and the bottom ground structure is imaged using this, and the thickness and the bedrock boundary of the bottom layer are easily identified by analyzing the images. . In particular, in the inversion step (S320), by inserting data on the water depth and water electrical conductivity according to the position as a constraint condition, it is possible to perform the inversion only for the underground structure of the lower part of the river, which is very high accuracy compared to the inversion including the river You can get it.

In the analysis of electrical resistivity exploration data, the inversion calculates the theoretical potential or apparent resistivity at each point with respect to the assumed underground electrical resistivity model, and modifies the underground electrical resistivity model so that the theoretical value is close to the field survey data. Done. When the difference between the theoretical value and the measured value is small enough, the inversion is converged and the underground structure is imaged based on the analysis result of the final underground electrical resistivity model. This inversion and imaging process is performed by analysis software based on the algorithm.

As described above, the electrical conductivity and the water temperature of the water inserted in the inversion step S320 may be measured separately from the exploration system of the present invention, and data stored in the form of GIS may be used. In this case, step (a) of step S312 may be used. ) And (b) step S314 may be omitted.

Hereinafter will be described the operation of the streamer electrical resistivity exploration system according to the present invention configured as described above.

The probe 100 moves to an exploration destination, floats the streamer cable 110 on the water, and applies current to the probe electrodes 112 attached to the streamer cable 110 and in contact with the water. This current is applied underwater through the probe electrodes 112 and this current flows through the current path to other probes 112.

At this time, an equipotential line having a potential of a value obtained perpendicular to the current path is formed, and the equipotential line continues to the surface of the water, and the difference of the equipotential lines between the probe electrodes 112, that is, the potential difference is measured, and the data is inversely multi-channel. It is input to the electrical resistivity probe 160. Therefore, by using the amount of current passed to the probe electrodes 112 and the measured potential difference, it is possible to know the exact actual resistivity of the homogeneous underground medium.

In addition, when materials with different electrical resistivities exist underground, current flows more toward materials with lower electrical resistivity, resulting in deformation of equipotential lines perpendicular to the path and also affecting the potential difference measured at the surface. By using the potential difference measured at the surface of the water, an apparent electrical resistivity having information about the electrical ideal zone of the underground medium can be obtained, and the electrical resistivity structure of the underground can be obtained from this data.

In addition, as described above, in order to accurately analyze the bottom ground structure, it is necessary to insert the electrical resistivity data of the river water in the inversion condition as a limit condition. For this purpose, the conductivity meter 130 and the side scan mounted under the probe The sonar 140 measures the electrical conductivity and the water depth of the water.

The electrical conductivity measuring device 130 is attached to a water temperature sensor to measure the water temperature together with the electrical conductivity of the water, since the activity of the water ions is changed according to the water temperature of the water, the electrical conductivity is changed.

The side scan sonar 140 transmits the ultrasonic waves into the water and receives the ultrasonic waves reflected from the bottom to measure the depth.

The electrical conductivity and depth data of the measured water are combined with the GPS data of the probe and stored as GIS data to be input as a limiting condition when inverting the electrical resistivity according to the measurement position.

As described above, in the present invention, the water depth and the electrical conductivity of the water are simultaneously measured and inserted into the inverse restriction condition, thereby enabling a quick and accurate analysis of the bottom ground structure.

Embodiments have been disclosed in the drawings and the specification as above. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Streamer electrical resistivity exploration system according to the present invention and a method for analyzing the bottom soil structure using the same can be applied to the analysis of underground structures, such as the bottom bedrock boundary.

1 is a block diagram showing a streamer electrical resistivity exploration system according to an embodiment of the present invention.

2 is a view showing the device configuration of the streamer electrical resistivity exploration system according to an embodiment of the present invention.

3 is a diagram illustrating an algorithm for analyzing a bottom ground structure using a streamer electrical resistivity survey system according to an embodiment of the present invention.

<Codes and explanations of the main parts of the drawings>

100: probe 110: streamer cable

112 electrode 114 buoy

116: terminal buoy 120: second RTK GPS

130: electrical conductivity meter 140: side scan sonar

150: 1st RTK GPS 160: multi-channel electrical resistivity probe

200: operation unit 210: memory

220: control unit 230: underground structure analysis unit

Claims (9)

In the electrical resistivity exploration system for exploring the structure of the underwater ground using a probe, A streamer cable connected to the probe and attached with a plurality of electrodes; A multi-channel electrical resistivity probe for measuring electrical resistivity from a plurality of electrodes mounted on the probe and attached to the streamer cable; A first real time kinematic GPS (RTK GPS) mounted on the probe to measure the position of the probe in real time; A second RTK GPS installed at the end of the streamer cable and measuring the position of the streamer cable end in real time; An conductivity meter and a side scan sonar mounted to the lower portion of the probe; And An arithmetic device for imaging the bottom ground structure through electrical resistivity inversion; It is made, including The computing device, Generating electrical conductivity data of water measured by the conductivity meter and water depth data measured by the side scan sonar as geographic information system (GIS) data using position data measured by the first RTK GPS; Calculating GPS data of a precise measurement position based on the position data measured by the first RTK GPS and the position data measured by the second RTK GPS; A streamer characterized in that a two-dimensional inversion is performed on the electrical resistivity data measured by the multi-channel electrical resistivity probe based on the GPS data of the measurement position, and the bottom ground structure is imaged using the inversion result. Electrical resistivity exploration system. In the electrical resistivity exploration system for exploring the structure of the underwater ground using a probe, A streamer cable connected to the probe and attached with a plurality of electrodes; A multi-channel electrical resistivity probe for measuring electrical resistivity from a plurality of electrodes mounted on the probe and attached to the streamer cable; A first real time kinematic GPS (RTK GPS) mounted on the probe to measure the position of the probe in real time; A second RTK GPS installed at the end of the streamer cable and measuring the position of the streamer cable end in real time; And An arithmetic device for imaging the bottom ground structure through electrical resistivity inversion; It is made, including The computing device, Calculating GPS data of a precise measurement position based on the position data measured by the first RTK GPS and the position data measured by the second RTK GPS; An inversion result performed by performing two-dimensional inversion on the electrical resistivity data measured by the multi-channel electrical resistivity probe based on the GPS data of the measurement position, and inputting the depth data of the exploration area and the electrical conductivity data of the water as a constraint condition. Streamer electrical resistivity exploration system, characterized in that for performing an operation to image the bottom ground structure using. The method according to claim 1 or 2, The streamer cable, Streamer electrical resistivity exploration system, characterized in that by connecting the tail buoy at its end to keep the streamer cable in a straight line. The method according to claim 1 or 2, The streamer cable, A buoy is installed between the plurality of electrodes to enable the electrode to float while maintaining contact with the water. The method according to claim 1 or 2, The second RTK GPS, Streamer electrical resistivity exploration system comprising a radio modem, through which the location information of the streamer cable terminal is transmitted to the probe. delete The method according to claim 1, In the computing device, In performing the two-dimensional inversion, the streamer electrical resistivity exploration system, characterized in that the depth data and the electrical conductivity data of the water is input as a constraint condition. (a) a streamer cable connected to the probe and attached with a plurality of electrodes, a multi-channel electric resistivity probe mounted on the probe and measuring electrical resistivity from a plurality of electrodes attached to the streamer cable, mounted on the probe and Streamer electrical including a first RTK GPS (Real Time Kinematic GPS) for measuring the position of the probe in real time, a second RTK GPS installed at the end of the streamer cable and measuring the position of the streamer cable end in real time Measuring the resistivity and position data in a resistivity exploration system; (b) in a computing device including a memory, a data computing unit, an underground structural analysis unit and a control unit, (b-1) generating the precision measurement position data by receiving the probe position data and the streamer cable end position data from the memory in the data calculating unit; (b-2) performing two-dimensional inversion on the electrical resistivity measurement data according to the precise position data in the underground structure analyzing unit; And (b-3) imaging the bottom soil structure using the inversion result in the underground structure analyzing unit; Including; In the step (b-2), the bottom of the ground structure analysis method using the streamer electrical resistivity exploration system, characterized in that the electrical conductivity of the water depth and the water of the exploration zone is input as a restriction condition. (c) a streamer cable having a probe and a plurality of electrodes connected thereto, a multi-channel resistivity probe mounted on the probe and measuring electrical resistivity from a plurality of electrodes attached to the streamer cable, mounted on the probe And a first RTK GPS (Real Time Kinematic GPS) for measuring the position of the probe in real time, a second RTK GPS installed at the end of the streamer cable and measuring the position of the streamer cable in real time, the probe In a streamer electrical resistivity exploration system including a conductivity meter and a side scan sonar mounted on the bottom, measuring electrical resistivity, position, electrical conductivity of water, and depth data; (d) in a computing device including a memory, a data computing unit, an underground structural analysis unit and a control unit, (d-1) receiving the electrical conductivity data of the water and the position data of the probe from the memory in the data calculating unit and generating an electrical conductivity map of the water according to the position; (d-2) receiving depth data from the memory and position data of the probe from the memory to generate a depth map according to a position; (d-3) generating precision measurement position data by receiving the probe position data and streamer cable end position data from the memory at the data calculating unit; (d-4) performing two-dimensional inversion on the electrical resistivity measurement data according to the precise position data in the underground structure analyzing unit; And (d-5) imaging the bottom soil structure by using the inversion result in the underground structure analyzing unit; Including; In the step (d-4), the electrical conductivity data of the water according to the position obtained in the step (d-1) and the water depth data according to the position obtained in the step (d-2) is input as a constraint condition Analysis of Underground Soil Structure Using Streamer Electrical Resistivity Exploration System.

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