• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.58-63
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• 2007

We developed a new algorithm for jointly inverting dc resistivity and seismic travel time tomography data based on the multiple constraints: (1) structural similarity based on cross-gradient, (2) correlation between two different material properties, and (3) a priori information on the material property distribution. Through the numerical experiments of surface dc resistivity and seismic refraction surveys, the performance of the proposed algorithm was demonstrated and the effects of different regularizations were analyzed.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1487-1493
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• 2008

The frost heaving is related with thermal conduction rate and permeability. If the thermal conduction rate can be controlled, it is effective to prevent from frost heaving. If soil mixed with shredded tire which has relatively lower thermal conduction rate than soil, it helps preventing from frost heaving. However, in this case, the shear strength can get weak. In this study, we compared thermal conduction rate of soil and shredded tire, and test uniaxial compression strength of soil which is mixed with shredded tire and cement in different ratio.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.388-392
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• 2003

In this study, various railroad geotechnical informations were standardized. The standardization was progressed by classifying the informations as basic properties, railroad vibrations and design plans. Basic informations included soil properties(27), dynamic property(1), geophysical prospecting(1), and elastic wave prospecting(4). Specification for 'human exposure to whole-body vibration' was used to construct the information of railroad vibration. And in the case of the information of design plan, the way to save by graphic files was chosen. Thus standardized informations examined their application by setting up database. Entity-Relation(E-R) model was used in the design of database and by this, the database system was constructed. This database system will be able to serve the performance enhancement of railroad system.

• Journal of Industrial Technology
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• v.18
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• pp.77-86
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• 1998

This study is to provide the useful data for the design and construction of the geotechnical engineering works by collecting and analyzing the soil properties of granite soil in the Kangwon Province. Data base was obtained from 92 field sites in the Kangwon province divided into 15 areas based on administration district. Total numbers of data were 478. Correlations between soil constants, especially compaction properties, were obtained by performing statistical analysis. Analyzed results were as follows. 1. Most of granite soil consists of SM and GM based on United Soil Classification System. 2. Mean gravity of granite soil is 2.65 3. High correlations between optimum moisture content and the maximum dry density, plasticity index and liquid limit are obtained. 4. Analyzed results between other soil constants show relatively low correlation. However, they show consistent trends matchable to geotechnical engineering senses.

• Wind and Structures
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• v.3 no.4
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• pp.221-241
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• 2000

Structural dynamics usually applies modal transformation rules aimed at de-coupling and/or minimizing the equations of motion. Proper orthogonal decomposition provides mathematical and conceptual tools to define suitable transformed spaces where a multi-variate and/or multi-dimensional random process is represented as a linear combination of one-variate and one-dimensional uncorrelated processes. Double modal transformation is the joint application of modal analysis and proper orthogonal decomposition applied to the loading process. By adopting this method the structural response is expressed as a double series expansion in which structural and loading mode contributions are superimposed. The simultaneous use of the structural modal truncation, the loading modal truncation and the cross-modal orthogonality property leads to efficient solutions that take into account only a few structural and loading modes. In addition the physical mechanisms of the dynamic response are clarified and interpreted.

• Journal of the Korean Association of Geographic Information Studies
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• v.11 no.2
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• pp.38-50
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• 2008

The site-specific seismic responses and corresponding seismic hazards are influenced mainly by the subsurface geologic and geotechnical dynamic characteristics. To estimate reliably the seismic responses in this study, a geotechnical information system (GTIS) within GIS framework was developed by introducing new concepts, which consist of the extended area containing the study area and the additional site visit for acquiring surface geo-knowledge data. The GIS-based GTIS was built for Gyeongju area, which has records of abundant historical seismic hazards reflecting the high potential of future earthquakes. At the study area, Gyeongju, intensive site investigations and pre-existing geotechnical data collections were performed and the site visits were additionally carried out for assessing geotechnical characteristics and shear wave velocity ($V_S$) representing dynamic property. Within the GTIS for Gyeongju area, the spatially distributed geotechnical layers and $V_S$ in the entire study area were reliably predicted from the site investigation data using the geostatistical kriging method. Based on the spatial geotechnical layers and $V_S$ predicted within the GTIS, a seismic zoning map on site period ($T_G$) from which the site-specific seismic responses according to the site effects can be estimated was created across the study area of Gyeongju. The spatial $T_G$ map at Gyeongju indicated seismic vulnerability of two- to five-storied buildings. In this study, the seismic zonation based on $T_G$ within the GIS-based GTIS was presented as regional efficient strategy for seismic hazard prediction and mitigation.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.03a
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• pp.277-284
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• 1999

This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.311-318
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• 2000

In constructions of dams and ports structure, gravels are used as principle structural materials. Gravels have different material property compared with other materials like soil and concretes, etc. For example, material properties of gravels obtained from normal triaxial compression test are usually overestimated due to scale and penetration effects. Also, material properties of gravels under dynamic loads are the main interest when structural behavior of rockfill dam under earthquake loads is analyzed. The development of large triaxial compression apparatus is needed for the better estimation of material property of gravel. This paper reports work in progress to development of large triaxial compression apparatus.

• Journal of the Korean Geotechnical Society
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• v.26 no.12
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• pp.71-79
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• 2010

The reliable evaluation of the coefficient of variation (COV) of soil properties is required for the determination of adequate design values and the application of a probabilistic method for the design of geotechnical structures. In this paper, the applicability of methods for estimating the standard deviation, such as the. Three-Sigma Rule and a statistical method, is evaluated by using site investigation data of the Songdo area. It is found that the Three-Sigma Rule provides similar results to those of a statistical method when using $N_{\sigma}$=6 for the property with small variability and $N_{\sigma}$=4.2~5.3 for the property with large variability. It is also observed that, for the undrained shear strength that has an increasing trend with depth, a $N_{\sigma}$ value of 4 is adequate for the evaluation of the variability by the Three-Sigma Rule. The COVs of soil properties determined in this paper could be used in the estimation of the confidence interval and characteristic values of soil properties.

• Proceedings of the Korean Geotechical Society Conference
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• 2001.11a
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• pp.122-142
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• 2001

Mudstone which is in po-hang area, made from bedrock under a tropical ocean environment, The mudstone has a tendency to be weathered and swelled when it is exposed to the atmosphere. In addition the clay material on the surface shows highly compressive property that causes a lot of engineers problem during embanking and cutting. This report covers alternative methods to solve those problems by understanding engineering characteristics of the site through precise filed investigations and predicting the problems during construction.