• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1285-1289
• /
• 2008

Increasing the flood control capacity's link that is enforcing to existing dam by unusual change of weather, While build planing construction by exiting spillway of tunnel type to dam, could know that part bed rock is formed as is different with design. Grasped topography of research area and geology state to definite distribution aspect of different bed rock, Place that achieved Surface geological Survey and correct Survey is difficult in some section enforced Electrical resistivity dipole-dipole investigation. Grasped stratigraphy distribution confirmation and fracture or weathering zone making out siding 2D-Resistivity Electrical resistivity diagram and Reverse analysis diagram, examining closely soil weathered rock rock's distribution state, established stability countermeasure plan

• Proceedings of the KSRS Conference
• /
• v.2
• /
• pp.728-731
• /
• 2006

Ground subsidence near abandoned underground coal mines has become a serious social problem in Korea. The purpose of this study is to perform a comparative analysis between the ground subsidence area and the electrical resistivity measured by field survey at Samcheok City. A raster database composed of ground subsidence areas and electrical resistivity data was constructed for GIS. To analyze correlation between the two constructed raster datasets, we used a frequency ratio model. The results show that low and high electrical resistivity anomaly zones coincide with the existing subsidence areas. We infer that the high anomaly zone means saturated and low anomaly zone means vacant. It suggests that electrical resistivity might be a useful factor for analyzing ground subsidence hazard zone.

• Journal of the Korean earth science society
• /
• v.36 no.1
• /
• pp.59-67
• /
• 2015

An electrical resistivity survey is widely conducted for the safety management of embankment. In this study we investigated how a tidal variation affects the interpretation of electrical resistivity monitoring data of the embankment located in west coast. We monitored the variation of electrical resistivity on the coastal embankment where there was a high tidal variation for 3 days in every 3 hours. Electrical resistivity monitoring data showed a variation of resistivity distribution in specific area according to the time, which demonstrated some correlation with a tidal height variation. Therefore, we highly recommend that a tidal effect be considered when electrical resistivity survey is conducted on the embankment where there is a high tidal variation. For further study, we need a long term electrical resistivity monitoring and analyzing on tidal variation.

• Tunnel and Underground Space
• /
• v.13 no.4
• /
• pp.279-286
• /
• 2003

Many trials to set up the correlation between the rock mass classification and the earth resistivity have been carried out to design tunnel support type based on the interpreted electrical resistivity acquired by surface electrical survey. But it is hard to find reports on the comparison of the real rock support type determined during the excavation with the electrical resistivity by the inversion of the survey data acquired before the tunneling. In this study, the rock mass classification based on the face mapping data and the resistivity inversion data are investigated to see if it is possible to design reliably the rock support type based on the surface electrical survey. To get the quantitative correlation, rock engineering indices such as RCR(rock condition rating), N(Rock mass number), Q-system and RMR(rock mass rating) are calculated. Since resistivity data has low resolution, Kriging method as a post processing technique which minimizes the estimated variance is used to improve resolution. The result of correlation analysis shows that the 2D electrical resistivity survey is appropriate to see the general trend of the geology in the sense of rock type, though there might be some local area where these two factors do not coincide. But the correlation between the result of 3D survey and the rock mass classification turns out to be very high, and then 3D electrical resistivity survey can make it possible to set up more reliable rock support type.

• Journal of the Korean Geophysical Society
• /
• v.9 no.4
• /
• pp.455-462
• /
• 2006

In this paper, we used the electrical resistivity survey as a simple and reasonable technique to evaluate the effectiveness of grouting. And, a mechanism was also analyzed to understand how the electrical resistivity is affected by the loss of fine material in the core of a dam. From this mechanism, it was confirmed that electrical resistivity value of the damage section may be up or down depending on the survey conditions. This result seems to be contrary to the previous study that electrical resistivity of the damage zone become alway low. To clarify what was investigated, the electrical resistivity before and after grouting was compared and analyzed. As the result, it was concluded that grouting effectiveness was successfully assessed by electrical resistivity survey.

• Journal of Korean Tunnelling and Underground Space Association
• /
• v.24 no.3
• /
• pp.279-292
• /
• 2022

Unexpected anomalies in the geotechnical investigation at design stage may cause problems during tunnel excavation. Therefore, it is important to predict the ground condition ahead of a tunnel face during tunnel excavation in order to prevent tunnel collapse. Despite the fulfillment of an electrical resistivity survey at the tunnel face, the existing electrical resistivity survey program can produce distorted results by the limitation of tunnel modelling. In this background, this study develops a modelling program for an electrical resistivity survey considering the tunnel shape. Numerical simulation and inverse calculation were performed for the electrical resistivity survey in the tunnel using the developed program. As a result, it was proved that the developed program could predict accurately the anomalous object's location and condition ahead of the tunnel face.

• The Journal of Engineering Geology
• /
• v.22 no.4
• /
• pp.409-416
• /
• 2012

In this study, an electrical resistivity survey and a drilling investigation were conducted at an animal carcass disposal site. Chemical analysis of leachate collected from the site was also performed (sampling times: May 2011 and June 2012). Five lines of dipole-dipole electrical resistivity surveys were carried out, along with drilling investigations at 3 points within the disposal areas and 11 points near the disposal site. Two-dimensional inverse modeling of the collected resistivity data was performed to evaluate the properties (size, depth, and form) of the disposal site. Leachate analysis showed that pH of leachate decreased from 7.4 to 6.7, while Eh changed from -358 mV to -48 mV over time. In addition, dissolved ions increased due to the progression of carcass decomposition. Results of the electrical resistivity survey indicated that low resistivity zones (minimum value, $0.64{\Omega}m$) existed at a depth of 8 m from the surface. Considering the bedrock location and carcass disposal depth, there was no evidence of bedrock contamination by leachate. The results of the electrical resistivity survey are consistent with those of the drilling investigation, which indicates that electrical resistivity effectively depicted the properties of the disposal site. This study demonstrates that electrical resistivity survey is a suitable technique for investigation of animal carcass disposal sites.

• 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.

• Geophysics and Geophysical Exploration
• /
• v.19 no.2
• /
• pp.59-66
• /
• 2016

The electrical resistivity method is an effective geophysical tool to detect subsurface contamination because the contaminated zones show generally lower electrical resistivity. In this study, the electrical resistivity surveys were applied to a waste landfill site to image the subsurface structure around the landfill and to identify the contaminated zones. First, the dipole-dipole 2D resistivity surveys were conducted along the boundaries of landfill to define the developed contaminated zones. Then the crosshole resistivity tomography was applied to confirm the suspected contaminated zones at depth. The results of drilling and geochemical analysis of ground water supported that the low resistivity zones coincide well with the contaminated zones and the leachate pathways could be delineated effectively from the resistivity survey.

• Economic and Environmental Geology
• /
• v.23 no.2
• /
• pp.215-219
• /
• 1990

Geological and electrical resistivity surveys along the survey line of about 3 km between Kyungsangbukdo Youngilgun Hodong and Gwangmyungdong using by dipole-dipole electrode array method were carried out to examine the boundary and structural relationship between Tertiary Pohang and Janggi basins. Electrical resistivity data were interpreted qualitatively and quantitatively by means of pseudosection of apparent electrical resitivity distribution and finite difference method for two dimensional geologic structure model. The nearly vertical fault zone with low electrical resistivity value of 1-5 Ohm-m and widths of about 200m at the surface and 400 m at depth exists around 1.2 km west of national road between Ocheoneup and Yangbukmyun. Mudrocks, sandstones and tuffaceous rocks are widely distributed with electrical resistivity values of 6-77 Ohm-m. Especially, tuffaceous rocks with relatively high electrical resistivity value are predominant at eastern side of fault zone. Consequently, it is known that Pohang and Janggi basins are in fault contact.