• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.05a
• /
• pp.55-58
• /
• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.

• Journal of the Korean Geophysical Society
• /
• v.8 no.4
• /
• pp.211-214
• /
• 2005

Low resistivity zone is observed at the lower part of a CFRD (Concrete Face Rockfill Dam). Generally, CFRD tends not to have any saturated zone within the body, but the result of resistivity survey shows that it is possible for the dam to be saturated under 20m depth with water. The level of reservoir was under 10 m from the crest. We suspect that this result may come from the wrong 2D inversion process ignoring the 3D geometry of dams. For the analysis of possibility of distortion by different geometry, we perform the 3D forward modeling for the dam and apply the 2D inversion process. And then we check the point of traditional interpretation of resistivity data. By the analysis, it is found that the result of 2D inversion process of 3D geometry of dams, seems to have deep relation with the reservoir level, and the complex 3D structure hide some internal electrical anomaly of dams from resistivity information.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.09a
• /
• pp.446-449
• /
• 2004

High resolution geophysical imaging to delineate costal aquifer and seawater- freshwater interface has been applied in Baesu-eup, Yeonggwang-gun, Jeolla province Electrical resistivity information from vertical electrical sounding and 2-D electrical resistivity survey is key parameter to map equivalent Nacl concentration map over the survey area. Seismic velocity from refraction tomographic survey, on the other hand, gives more reliable information on the subsurface stratagraphy than electrical resistivity methods which frequently suffer from low resolution due to masking effect. We imaged high-resolution 3-D structure of costal aquifer by correlating the electrical resistivity with seismic velocity, and mapped equivalent NaCl concentration map using resistivity and hydro-geological information from well logging.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2005.05a
• /
• pp.129-136
• /
• 2005

The groundwater survey was carried out by electrical resistivity and resistivity tomography using several kinds of electrode array to delineate the depth of the saturated zone and basement complex, the aquifer system of fractured rock, and the 2-D resistivity structure was obtained by inversion technique. And the hole-to-surface and crosshole tomography were applied for two boreholes and the inverted resistivity tomogram are obtained. The comparison of those data with core logging data was performed and those results were relatively well correlated. And it was possible to find out the configuration of basement and the fracture zone and the aquifer system from the 2-D resistivity structure and resistivity tomogram.

• Geophysics and Geophysical Exploration
• /
• v.4 no.4
• /
• pp.124-132
• /
• 2001

Electrical resistivity survey has been conducted for delineating geological fault structure in Kaekok-ri near Kyungju. In general, electrical resistivity survey has an advantage of searching buried faults and its traces compared with other geophysical survey methods. Distribution of electrical conductivity in the ground is influenced by the ratio of pores, groundwater and clay minerals. These properties are evidenced indirectly to explain for weathering condition, faults and fracture Bones. Thus the electrical resistivity survey can be an effective method to find buried faults. We have carried out two dimensional (2-D) interpretation by means of smoothness-constrained least-squares and finite element method. Field data used in this paper was acquired at Kaekok-ri, Wuedong-eup, Kyungju-si, where is Ulsan Fault and is close to the region in which debatable quaternary fault traces were found recently. The dipole-dipole array resistivity survey which could show the 2-D subsurface electrical resistivity structure, was carried out in the area with three lines. The results showed good property of fault, fracture zone and fault traces which we estimated were congruous with the results. Through this study, 2-D electrical resistivity survey interpretation for fault is useful to apply.

• Journal of Environmental Impact Assessment
• /
• v.13 no.5
• /
• pp.223-230
• /
• 2004

The electrical resistivity prospecting method with dipole-dipole array were applied in order to survey 3-D structure characteristics of the Noen landfill site. For the electrical resistivity prospecting, 3 line of measurements were established parallel to the main boundary of the Noen landfill site and additional 2 lines were also established perpendicular to the existing 3 lines for the effective investigation of the landfill site. The results showed that the uppermost layer of the landfill site is believed to be stabilized generally based on the characteristics of electrical resistivity distribution. Lowest layer was partially polluted by the leachate.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.7
• /
• pp.37-45
• /
• 2007

Recently, there has been an increase of the use of ground system for lightning protection called deeply driven grounding electrode. In the case of deeply driven grounding electrode, the rod electrode is equipped perpendicularly and deeply, therefore, it has a benefit to have less restriction of place compared to mesh grid electrode. However, ground impedance is largely changed by the local earth resistivity, so it requires a detailed analysis of the ground structure when planning. The measurement of earth resistivity by existing Wenner's method has been widely used, however, this method can not find out a change in the local ground resistance and it shows the result outwardly to be difficult to estimate exact depth. Therefore, this study analyzed the ground structure as 2-D image using 96 channels measurement facility and tried to analyze change in the local ground resistance and depth of the ground in order to design a deeply driven electrode effectively for lightning protection. It used Wenner alpha method dipole-dipole method and Schlumberger method for 2-D image analysis of the ground resistivity ma based on, it the result was compared with the ground structure analyzed with the result using the CDEGS and Wenner 1-D method.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1318-1327
• /
• 2008

Geotechnical sites in urban areas may have embedded structures such as utility lines and underground concrete structures, which cause difficulties in site investigation. This study is a preliminary research to establish knowledge base for developing an optimal technique for site investigation in urban areas. Surface-wave method and resistivity survey, which are frequently adopted for non-destructive site-investigation for geotechnical sites, were investigated to characterize effects of adjacent structures. In case of surface wave method, patterns of wave propagation were investigated for typical sets of multi-layered geotechnical profiles by numerical simulation based on forward modeling theory and field experiments for small-size model tests and real-scale tests in the field. In case of resistivity survey, 3-D finite element analyses and field tests were performed to investigate effects of adjacent concrete structures. These theoretical and experimental researches for surface-wave method and resistivity survey resulted in establishing physical criteria to cause interference of adjacent structures in site investigation at urban areas.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.03b
• /
• pp.199-206
• /
• 2000

The grout-effect evaluation of the ground reinforcement technique, which has been widely applied to civil engineering and construction fields, is not established for the guidelines of choosing the efficient evaluation method, and in fact the experts have little effort to determine the reinforcement effect quantitatively. The evaluation of the grout was carried out by experiments on core specimen and drilling, which is impossible to evaluate grout-reinforcement effect quantitatively. This paper presents an example on verification of FRP grout-effect using geophysical prospecting on ground surface, which is 2D resistivity survey that easily visualize survey results with color graphics and seismic refraction method that interprets the subsurface seismic velocity structure.

• Journal of IKEEE
• /
• v.22 no.4
• /
• pp.1152-1157
• /
• 2018

In this paper, we try to solve the difficulties of the location of the structure for the movement of the wire - based pesticide spraying equipment designed for field farming. To do this, we apply earth resistivity measurement method and analysis technique which can indirectly grasp the earth structure. Electrodes are installed on the field in a selected farming area, and multi-switches built in the control board are driven to automatically acquire ground resistivity data. Then, the optimal point suitable for the actual structure installation is selected through the site analysis using the 2D image restoration algorithm.