• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.84-89
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• 2000

Parametric studies based on laboratory pilot tests were performed to investigate the relationships between electrical resistivity and contaminated soil properties. Three kinds of sandy soils sampled and leachates from a industrial waste landfill were mixed to model the contaminated soils. Electrical resistivity of soils were measured by using a simulated resistivity cone penetrometer probe. In the experiments, the electrical resistivity were observed with changing the water content, void ratio, unit weight, degree of saturation, and concentration of the leachate. The test results show that the electrical resistivity of soils depends largely on the water content and the electrical property of pore water rather than unit weight and types of soils.

• Steel and Composite Structures
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• 제27권4호
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• pp.465-477
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• 2018

In this research, vibration and smart control analysis of a concrete foundation reinforced by $SiO_2$ nanoparticles and covered by piezoelectric layer on soil medium is investigated. The soil medium is simulated with spring constants and the Mori-Tanaka low is used for obtaining the material properties of nano-composite structure and considering agglomeration effects. With considering first order shear deformation theory, the total potential energy of system is calculated and by means of Hamilton's principle in three displacement directions and electric potential, the six coupled equilibrium equations are obtained. Also, based an analytical method, the frequency of system is calculated. The effects of applied voltage, volume percent and agglomeration of $SiO_2$ nanoparticles, soil medium and geometrical parameters of structure are shown on the frequency of system. Results show that with applying negative voltage, the frequency of structure is increased.

• Coupled systems mechanics
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• 제3권2호
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• pp.213-232
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• 2014

Pounding is a major cause of bridge damage during earthquakes. In an extreme situation, it can even contribute to the unseating of bridge girders. Long-span bridges will inevitably experience spatially varying ground motions. Soil-structure interaction (SSI) may play a significant role in the structural response of these structures. The objective of this research is to experimentally investigate the effect of spatially varying ground motions on the response of a three-segment bridge considering SSI and pounding. To incorporate SSI, the model was placed on sand contained in sandboxes. The sandboxes were fabricated using soft rubber in order to minimise the rigid wall effect. The spatially varying ground motion inputs were simulated based on the New Zealand design spectra for soft soil, shallow soil and strong rock conditions, using an empirical coherency loss function. The results show that with pounding, SSI can amplify the pier bending moments and the relative opening displacements.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 총회 및 춘계 학술발표회 논문집
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• pp.22-26
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• 1998

토양오염 정화방법의 하나인 토양증기추출법(soil vapor extraction, SVE)은 오염된 토양에 진공 또는 가압의 공기를 공급하여 연속적인 공기 흐름을 유도함으로써 토양의 기공에 잔류하는 유해화합물의 증발을 촉진하여 오염물질을 제거하는 공정이다. 본 연구에서는 토양증기추출법의 효율에 영향을 주는 인자들 가운데에서 토양의 수분함량과 오염물질의 종류가 오염물질의 제거효율에 미치는 영향에 대한 실험과 계산을 수행하였다. 인공토양으로 glass bead, sand, molecular sieve가 사용되었으며. 오염물질로는 톨루엔. 메틸에틸케톤, 트리클로로에틸렌이 사용되었다. 각 실험에 대하여 프로인들리히 등온식과 기공확산모델 등을 고려하여 계산을 수행한 결과, 수분이 없는 경우에는 탈착식에 의해, 수분이 있는 경우에는 interparticle에서의 확산 현상에 의해 오염물질의 제거속도가 지배됨을 알 수 있었다. 이러한 연구결과는 정화대상지역에 SVE를 이용한 적절한 정화방법을 설계하는데 기초자료로 이용할 수 있을 것이다.

• Advances in concrete construction
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• 제6권6호
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• pp.585-610
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• 2018

In this study, vibration analysis of a concrete foundation-reinforced by $SiO_2$ nanoparticles resting on soil bed is investigated. The soil medium is simulated with spring constants. Furthermore, the Mori-Tanaka low is used for obtaining the material properties of nano-composite structure and considering agglomeration effects. Using third order shear deformation theory or Reddy theory, the total potential energy of system is calculated and by means of the Hamilton's principle, the coupled motion equations are obtained. Also, based an analytical method, the frequency of system is calculated. The effects of volume percent and agglomeration of $SiO_2$ nanoparticles, soil medium and geometrical parameters of structure are shown on the frequency of system. Results show that with increasing the volume percent of $SiO_2$ nanoparticles, the frequency of structure is increased.

• Structural Engineering and Mechanics
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• 제69권5호
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• pp.547-555
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• 2019

In this study, vibration analysis of a concrete foundation-reinforced by $SiO_2$ nanoparticles resting on soil bed is investigated. The soil medium is simulated with spring constants. Furthermore, the Mori-Tanaka low is used for obtaining the material properties of nano-composite structure and considering agglomeration effects. Using third order shear deformation theory or Reddy theory, the total potential energy of system is calculated and by means of the Hamilton's principle, the coupled motion equations are obtained. Also, based an analytical method, the frequency of system is calculated. The effects of volume percent and agglomeration of $SiO_2$ nanoparticles, soil medium and geometrical parameters of structure are shown on the frequency of system. Results show that with increasing the volume percent of $SiO_2$ nanoparticles, the frequency of structure is increased.

• Earthquakes and Structures
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• 제22권6호
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• pp.549-559
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• 2022

The quasi-static finite element (FE) approaches are widely used for the seismic analysis of tunnels. However, the conventional quasi-static approaches may cause significant deviations when the tunnel excavation process is simulated prior to the quasi-static analysis. In addition, they cannot account for vertical excitations. Therefore, this paper first highlights the limitations of conventional approaches. A hybrid quasi-static FE approach is subsequently proposed and extensively validated for various conditions. The hybrid approach is simple and not time consuming, and it can be used for the preliminary seismic design of tunnels, especially when the tunnel excavation and vertically propagating P-waves are considered.

• Journal of the Korean Wood Science and Technology
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• 제45권4호
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• pp.419-431
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• 2017

The forest slopes cause substantial local changes in soil properties and an increase in soil erosion after extreme rainstorms. The high soil erosion rates on forest slopes need the effective use of growing media to control the soil runoff. Therefore, we prepared six different lignocellulosic growing media such as peat, perlite, and wood meal as the base materials and carboxymethyl cellulose (CMC), glucomannan, starch, old corrugated containerboard, and computer printout as the additional materials for the prevention of simulated rainfall-induced runoff. The growing media containing old corrugated containerboard efficiently reduced the percentage of soil runoff; however, it could not completely cushion the influence of crust. The best results for plant growth, except in the leaf area, were also obtained with the growing media containing old corrugated containerboard, suggesting an interesting way of paper recycling and an economic benefit for plant or crop growth in forest slope.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.183-186
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• 2002

The objective of this study is to predict behavior of a contaminant plume and concentration of contaminants in soil through tile relations between the concentrations of contaminants in groundwater and in soil on the shallow sandy aquifer contaminated with petroleum hydrocarbons. The current state of the plume and its fate in the study area was simulated by using the MODFLOW-RT3D model and geochemical parameters of grounwater had been monitored and measured during 3 years (1999~2001). The relations between the concentrations of contaminants in each medium were taken from the investigation of site characterization conducted in 1999. Simulation results showed the center of the plume would migrate 407m twenty years later. At that time, the concentration would be decreased down to about 26 mg/$\ell$(93%). In comparison TEX concentration in the groundwater with that in the soil, the value of correlation coefficient (r=0.876) was as high as it could be used. Based on the high r-value, the linear equation was obtained from regression analysis. The results of model simulation by RT3D engine showed that the highest TEX concentration in the groundwater would be 58.8 mg/$\ell$ 16 years later, and then the TEX concentration in soil would be below the alarming level (80 mg/kg) of regulation criteria.

• Water Engineering Research
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• 제2권1호
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• pp.49-61
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• 2001

A grid-based KIneMatic wave soil-water EROsion and deposition Model(KIMEROM) that predicts temporal variation and spatial distribution of sediment transport in a watershed was developed. This model uses ASCII-formatted map data supported from the regular gridded map of GRASS (U.S. Army CERL, 1993)-GIS(Geographic Information Systems), and generates the distributed results by ASCII-formatted map data. For hydrologic process, the kinematic wave equation and Darcy equation were used to simulated surface and subsurface flow, respectively (Kim, 1998; Kim et al., 1998). For soil erosion process, the physically-based soil erosion concept by Rose and Hairsine (1988) was used to simulate soil-water erosion and deposition. The model adopts single overland flowpath algorithm and simulates surface and subsurface water depth, and sediment concentration at each grid element for a given time increment. The model was tested to a 162.3 $\textrm{km}^2$ watershed located in the tideland reclaimed ares of South Korea. After the hydrologic calibration for two storm events in 1999, the results of sediment transport were presented for the same storm events. The results of temporal variation and spatial distribution of overland flow and sediment areas are shown using GRASS.