• The Journal of Engineering Geology
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• v.18 no.1
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• pp.27-36
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• 2008

To derive easily the coefficient of permeability from several other soil properties, the estimation model of coefficient of permeability was proposed using linear regression analysis. The coefficient of permeability is one of the major factors to evaluate the soil characteristics. The study area is located in Kangwon-do Pyeongchang-gun Jinbu-Myeon. Soil samples of 45 spots were taken from the study area and various soil tests were carried out in laboratory. After selecting the soil factor influenced by the coefficient of permeability through the correlation analysis, the estimation model of coefficient of permeability was developed using the linear regression analysis between the selected soil factor and the coefficient of permeability from permeability test. Also, the estimation model of coefficient of permeability was compared with the results from permeability test and empirical equation, and the suitability of proposed model was proved. As the result of correlation analysis between various soil factors and the coefficient of permeability using SPSS(statistical package for the social sciences), the largest influence factor of coefficient of permeability were the effective grain size, porosity and dry unit weight. The coefficient of permeability calculated from the proposed model was similar to that resulted from permeability test. Therefore, the proposed model can be used in case of estimating the coefficient of permeability at the same soil condition like study area.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4B
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• pp.345-354
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• 2006

Drought brings on long term damage in contrast to flood, on economic loss in the region, and on ecologic and environmental disruptions. Drought is one of major natural disasters and gives a painful hardship to human beings. So we have tried to quantify the droughts for reducing drought damage and developed the drought indices for drought monitoring and management. The Palmer's drought severity index (PDSI) is widely used for the drought monitoring but it has the disadvanges and limitations in that the PDSI is estimated by considering just climate conditions as pointed out by many researchers. Thus this study uses the SWAT model which can consider soil conditions like soil type and land use in addition to climate conditions. We estimate soil water (SW) and soil moisture index (SMI) by SWAT which is a long term runoff simulation model. We apply the SWAT model to Soyang dam watershed for SMI estimation and compare SMI with PDSI for drought analysis. Say, we calibrate and validate the SWAT model by daily inflows of Soyang dam site and we estimate long term daily soil water. The estimated soil water is used for the computation of SMI based on the soil moisture deficit and we compare SMI with PDSI. As the results, we obtained the determination coefficient of 0.651 which means the SWAT model is applicable for drought monitoring and we can monitor drought in more high resolution by using GIS. So, we suggest that SMI based on the soil moisture deficit can be used for the drought monitoring and management.

• Geomechanics and Engineering
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• v.6 no.5
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• pp.487-502
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• 2014

A three dimensional finite element model was used to simulate rapid impact compaction (RIC) in loose granular soils using ABAQUS software for one impact point. The behavior of soil under impact loading was expressed using a cap-plasticity model. Numerical modeling was done for a site in Assalouyeh petrochemical complex in southern Iran to verify the results. In-situ settlements per blow were compared to those in the numerical model. Measurements of improvement by depth were obtained from the in-situ standard penetration, plate loading, and large density tests and were compared with the numerical model results. Contours of the equal relative density clearly showed the efficiency of RIC laterally and at depth. Plastic volumetric strains below the anvil and the effect of RIC set indicated that a set of 10 mm can be considered to be a threshold value for soil improvement using this method. The results showed that RIC strongly improved the soil up to 2 m in depth and commonly influenced the soil up to depths of 4 m.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.85-88
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• 2002

This paper presents the result of the Water Erosion Prediction Project(WEPP) watershed scale model's application for prediction of sediment yield from a watershed which is comprised of hillslopes and channels and analyses of the soil loss from hillslopes and channels with crop practice and shape. To evaluate the model's application, the model is applied to a watershed that comprised of six hillslope and one channel, and the result was a good agreement with the observed values. The soil loss from hillslope was increased as the hills lope was under fallow conditions and slope length was longer. The soil loss from the channel was increased at the downstream for the concentration of flow.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.6
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• pp.248-257
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• 1999

A mathematical model was developed to investigate the mechanical interrelation between soil characteristics and main design factors of a tracked vehicles , and predict the tractive performance of the tracked vehicles. Based on the mathematical model, a computer simulation program(TPPMTV98) was developed in this study. The effectiveness of the developed model was verified by comparing the predicted drawbar pulls using TPPMTV98 with measured ones from traction tests with a tracked vehicle reconstructed for test in loam soil with moisture content of 18.92%(d.b). The drawbar pulls measured by the TPPMTV98 were well matched to the measured ones. Such results implied that the model developed in this study could estimate the drawbar pulls well at various soil conditions , and would be very useful as a simulation tool for designing a tracked vehicle and predicting its tractive performance.

• Ocean and Polar Research
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• v.26 no.2
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• pp.323-332
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• 2004

This paper concerns about a study on dynamic responses of tracked vehicle on soft cohesive soil. For dynamic analyses of tracked vehicle, two different models were adopted, i.e. a single-body model and a multi-body model. The single-body vehicle model was assumed as a rigid body with 6-dof. The multi-body vehicle was modeled by using a commercial software, RecurDyn-LM. For the both models properties of cohesive soft soil were modeled by means of three relationships: pressure to sinkage, shear displacement to shear stress, and shear displacement to dynamic sinkage. Traveling performances of the two tracked vehicle models were compared through dynamic analyses in time domain.

• Water Engineering Research
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• v.5 no.3
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• pp.133-146
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• 2004

Soil and water assessment tool (SWAT) was simulated based on the default parameters and a priori soil parameter estimation method in Bocheong watershed of Korea. The performance of the model was tested against the measured daily runoff data for 5 years between 1993 and 1997. The sensitivity analysis of SWAT model parameters was conducted to identify the most sensitive model parameters affecting the model output. The results of SWAT simulation indicate that the overall performance of SWAT in calculating daily runoff is reasonably acceptable. However, there is a problem in estimating the low flow components of streamflow since the low flow components simulated by SWAT are significantly different from the measured low flow. The sensitivity analysis with SWAT points out that soil related parameters are the most sensitive parameters affecting surface and ground water balance components and groundwater flow related parameters exhibit negligible sensitivity.

• Journal of the Korean Institute of Landscape Architecture
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• v.30 no.1
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• pp.96-104
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• 2002

This study was conducted to investigate physical properties of soil and turfgrass wear characteristics within turfgrasses inside or outside the stadium A 1/1000 scale model Inchon world cup soccer d[me was constructed for this test. Turfgrasses planted inside and outside the model dome were; Kentucky bluegrass(KB), Kentucky bluegrass + perennial ryegrass mixture (KB+PR), Kentucky bluegrass + tall fescue + perennial ryegrass mixture (KB+TF+PR), Zoysia japonica 'Anyangjungzii'(ZA) and Zoysia japonica 'Zenith\`(ZZ). The rootzone was constructed by the multi-layer method (United States Golf Association method). Traffic on turfgrasses was treated with a 120kg roller. Surface soil hardness, soil penetration and water infiltration values on cool-season grasses(KB, KB+PR, KB+TF+PR) was found to be better for soccer play compared to zoysiagrasses(ZA, ZZ). No big differences in surface soil hardness, soil penetration and water infiltration values were found between inside and outside of the model dome. Wear damage on cool-season grasses caused by the traffic treatment was low compared to zoysiagrasses. However, there was no difference in wear damage by the traffic treatment within cool-season grasses while wear damage on ZA was higher than on ZZ within zoysiagrasses. It could be concluded that physical properties and wear characteristics on cool-season grasses were much better for soccer play than on zoysiagrasses.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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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.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.361-364
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• 2005

The use of remotely sensed data and geographic information system (GIS) to develop conservation-oriented watershed management strategies on Imha Dam, Korea, is presented. The change of land use for study area was analyzed using multi-temporal Landsat imagery. A soil loss model was executed within a GIS environment to evaluate watershed management strategies in terms of soil loss. In general, remotely sensed data provide efficient means of generating the input data required for the soil loss model. Also, GIS allowed for easy assessment of the relative erosion hazard over the watershed under the different land use change options. The soil loss model predicted substantial declines in soil loss under conservation-oriented land management compared to current land management for Imha Dam. The results of this study indicate that soil loss potential (5,782,829 ton/yr) on Imha Dam in 2003 is approximately 1.27 times higher than that (4,557,151 ton/yr) in 1989. This study represents the first attempt in the application of GIS technology to watershed conservation planning for Imha Dam. The procedures developed will contribute to the evolution of a decision support system to guide the land planning and dam management in Imha Dam.