• The Journal of Engineering Geology
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• v.25 no.2
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• pp.227-235
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• 2015

In recent years, owing to the frequent occurrence of natural disasters, the inspection and maintenance of structures have become increasingly important on a national scale. However, because most structural inspections are carried out manually, and due to the lack of objectivity in data acquisition, quantitative data are not always available. As a result, researchers are seeking ways to collect and standardize survey data using terrestrial laser scanning, thereby bypassing the limitations associated with visual investigations. However, field data acquired using a laser scanner have been required to measure changes in structure geometry resulting from passive deterioration. In this study, we demonstrate that it is possible to identify the processes of structural deterioration (e.g., efflorescence, leakage, delamination) using intensity data from terrestrial laser scanning. Additionally, we confirm the viability of automated classification of alteration type and objectification of the polygon area by establishing intensity characteristics. Finally, we show that our method is effective for structural inspection and maintenance.

• The Journal of Engineering Geology
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• v.25 no.2
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• pp.201-213
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• 2015

Site effects resulting in the amplification of earthquake ground motion are strongly influenced not only by the subsurface soil conditions and structure, but also by the surface topography. Yet, over the last several decades, most studies of site-specific seismic responses in Korea have focused primarily on the seismic amplification associated with geologic and soil conditions. For example, the effects of local geology are now well established and have been incorporated into current Korean seismic design codes, whereas topographic effects have not been considered. To help address this shortcoming, two-dimensional (2D) seismic site response analyses, using finite element (FE) ground modeling with three different slope angles, were performed in order to assess the site effects of surface topography. We then compared our results, specifically peak ground acceleration (PGA) and acceleration response spectrum, to those of one-dimensional (1D) FE model analyses conducted alongside our study. Throughout much of the upper slope region, PGAs and spectral accelerations are larger in the 2D analyses than in the 1D analyses as a result of the topographic effect.

• The Journal of Engineering Geology
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• v.25 no.1
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• pp.45-55
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• 2015

Purifying leachate discharged from animal carcass disposal sites requires decisions regarding the locations and numbers of boreholes. An electrical resistivity survey, known to be effective for investigating leachate distribution, was performed to evaluate the range extent of contamination due to local hydrological properties, such as groundwater flow direction, and geological structure. Results of the survey at four sites at a landfill near Icheon and Anseong, Gyeonggi Province, showed low-resistivity zones (20-200 ohm-m) at a depth of 8 m from the surface. Sites 1-4, which contain 5, 2, 4, and 2 boreholes, respectively, were estimated to have a contaminated groundwater acquisition capability of 12.9 m, 13.7 m, 10.1 m, and 18.0 m, and measured pumping capacity of 2,040 m³, 479.8 m³, 1,492.3 m³, and 691.9 m³, respectively.

• The Journal of Engineering Geology
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• v.17 no.1 s.50
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• pp.101-113
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• 2007

A landslide was occurred due to soil cutting for construction to expand the Donghae express highway in Dong-hae-City, Korea. The total area of the landslide was about $9,550m^2$ with 100 m of width and 87m of height. The landslide was occurred due to the internal factor of the unstable geological structure including the clay layer and the external factor of continuous heavy rainfalls. As the result of field instrumentation during the landslide, the horizontal displacement of the slope ground increases with increasing the accumulated rainfall by continuous rainfall during the rainy season. Also, the depth of sliding failure was decided by the horizontal displacement distribution during landslide occurrence. It makes sure that the horizontal displacement starts from the depth of sliding failure and the depth of sliding failure matches well with the location of the clay layer. As the slope stability analysis using Bishop's Simplified Method at the landslide area, the safety factor of slope during the rainy season was 0.53. This safety factor of slope was enough to trigger the landslide at this area. The depth of sliding failure obtained by analytical method matches well with the depth of the clay layer.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.329-338
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• 2010

The foundation area for tram contains biotite gneiss, quartzo-feldspathic gneiss, calc-silicate rock, and porphyroblastic gneiss of the pre-Cambrian Kyeonggi gneiss complex. These rocks record at least three stages of deformation, as indicated by fold sets of contrasting orientations (D1-D3). Joints are generally steeply dipping and strike NW-SE to WNW-ESE. The Gonjiam Fault, which strikes WNW-ESE, follows a river in the area. The fault possesses a 3-m-wide fracture zone, a 10-m-wide damage zone, and is 15 km long. Two tunnels have been constructed through the biotite gneiss. The geometric relationship between discontinuities (e.g., joints and foliation) and tunneling direction reveals that set 3 of the AA tunnel is unstable but that BB tunnel is relatively safe.

• Journal of Engineering Education Research
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• v.12 no.4
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• pp.75-83
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• 2009

The purpose of this study was to verify factor structure and validation of Oddi Continuing Learning Inventory (OCLI) and prove up possibility of usage as an evaluation tool for evaluating life-long learning. 330 students in school of engineering of I university at Incheon province were responded for OCLI. Data were analyzed using descriptive statistics, exploratory factor analysis and confirmatory factor analysis. As the exploratory factor analysis results, 24 items in original version were converted to 19 items. The total reliability was .774 and the total covariance was 40.57%. As the confirmatory factor analysis results, four items were removed and GFI .938, AGFI .915, CFI .908 appeared to fit all the criteria. The RMSEA index 0.054 also appeared to fit significantly higher.

• The Journal of Engineering Geology
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• v.20 no.4
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• pp.381-390
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• 2010

This study assessed the hydrogeological characteristics of a seepage area of white leachate. The geological characteristics of the leachate were determined by a surface survey, and an electrical resistivity survey and borehole image processing system (BIPS) were applied to estimate the distribution of discontinuities, to assess the geological structure of the seepage areas. Fluctuations in groundwater level within boreholes were measured during periods of precipitation in the dry and wet seasons. The results show that electrical resistivity is lower in the seepage section than in non-seepage sections. The distribution of fracture zones and limestone cavities was inferred from the logging data and BIPS data. Variations in groundwater level and groundwater recharge, related to rainfall events, show the direct effect of rainfall events during the rainy season. We obtained a strong relationship between seepage amount and rainfall (correlation coefficients of 0.83-0.97).

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.257-269
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• 2010

We analyzed patent trends regarding stabilization technology for steep slope hazards, focusing on patents applied for and registered in Korea, the USA, Japan, and Europe. The technology was classified into four groups at the second classification step: prediction techniques, instrumentation techniques, countermeasure/reinforcement/mitigation techniques, and laboratory tests. A total of 2,134 patents were selected for the final effective analysis. As a result of portfolio analysis using the correlation between the number of patents and the applicant for each patent, the Korean and USA situations were classified as belonging to the developing period, and the Japanese and European situations were classified as belonging to the ebbing period. In particular, patent activity in Korea has been enlivened by government-led research. As a result of technology analysis at the second classification step, prediction techniques arising from Japan are evaluated as a competitive power technique, and laboratory tests arising from the USA are evaluated as a competitive power technique. However, prediction techniques and laboratory tests arising from Korea are evaluated as a blank technique. According to the prediction results regarding future research and developments, a new finite element analysis method and a numerical model should be established as part of prediction techniques, as well as sensors, and hazard prediction should be developed by integrating information and equipment using IT technology as part of instrumentation techniques. In addition, improvements to existing structures for erosion control and the development of new slope-reinforcement methods are required as part of countermeasure/reinforcement/mitigation techniques, and new laboratory apparatus and methods with an optimizing structure should be developed as part of laboratory tests.

• The Journal of Engineering Geology
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• v.20 no.2
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• pp.169-181
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• 2010

This study aimed at simulating several responses to stresses caused by the ground water level variations around the K-1 oil stockpile. For this simulation, we considered the characteristic hydrogeological condition including the special occurrence of long and thick acidic dyke, which is regarded as the main geological structure dominating the ground water flow system at this study area. We activated twenty-four imaginary wells which are located in northern and southern area around central K-1 site. Each neighboring distance is altogether 300 m and whole distance between K-1 site and remote wells is 1,200 m. Through the modeling, we operated the long-term and continuous pumping tests and finally categorized five zones based on maximum pumping rates for the imaginary wells; zone I within 300 meter distance from K-1 site with a pumping rate of 50 $m^3/day$; zone II between 300 to 600 meter distance from K-1 site with a pumping rate of 75 $m^3/day$; zone III between 600 to 900 meter distance from K-1 site with 150 $m^3/day$; zone IV between 900 to 1,200 meter distance from K-1 site with 300 $m^3/day$; and zone V of acidic dyke area. At zone V, especially because of their possibility of high transmissivity for groundwater flow, it is necessary to control and restrict groundwater discharge.

• The Journal of Engineering Geology
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• v.18 no.1
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• pp.55-68
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• 2008

At present underground structures such as road tunnels, railway tunnels, underground petroleum storages and radioactive waste storages are being constructed in numerous places in Korea. For the construction of underground structrues, it should be accounted for natural factors (geology, hydrogeology, soil, vegetation, topography and drainage patterns) and human-social factors (land use, urbanization, population, culture and transportation). Especially, hydrogeology should be regarded as an important factor for evaluating the safety of underground structures and their impact to groundwater system around the structures. This study aimed to recognize hydrogeological characteristics of shallow formations in the area from Dongrae crossway to Seo-Dong where 45 boreholes were drilled for the construction of Line-3 subway in Busan Megacity. Slug tests for unsaturated and saturated zones were conducted on 30 boreholes in the study area. From the result of the slug tests, it was identified that average zonal hydraulic conductivity in the unsaturated zone was higher than that in the saturated zone. Besides, the slug test result in the saturated zones may reflect hydraulic properties of the upper most part of the saturated zones.