• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.1
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• pp.57-65
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• 2007

In Korea, most landslides occurr during the rainy season and have shallow failure planes parallel to the slope. For these types of rainfall-induced failures, the most important factor triggering slope unstability is decrease in the matric suction of unsaturated soils with increasing saturation depth by rainfall infiltration. For this reason, estimation of cumulative infiltration has a significance. In this study, infiltration rate and cumulative infiltration are estimated by using both Mein & Larson model based on Green-Ampt infiltration model and using modified Mein & Larson model to which unsteady rainfall is applied. According to the results, the modified model is more reasonable than Mein & Larson method itself in estimation of infiltration rate and saturation depth because of considering real pending condition.

• Journal of the Korean Geotechnical Society
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• v.16 no.5
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• pp.107-116
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• 2000

강우에 의한 얕은 사면파괴는 우리 나라에서 흔히 볼수 있는 사면파괴의 형태이다. 본 연구에서는 재현기간에 따른 강우강도와 지속시간을 고려한 한계평형법에 의하여 이러한 얕은 사면파괴의 가능성을 평가하기 위함 방법에 대하여 논의하였다. 이를 위해 일차원 침투모델인 Green-Ampt 모델에 바탕을 둔 두 방법을 고려하였다. 즉 침투능에 따른 침투깊이를 산정하는 Pradel과 Raad의 방법과 일정한(uniform) 강우강도가 작용할 경우 폰딩(ponding)에 대해 해를 주는 Mein과 Larson의 방법을 고려하여 함수특성이 알려진 화강풍화토사면에 적용하였다. 연구결과에 의하며 Pradel과 Raad 방법은 실제 적용된 강우강도가 아닌 침투능을 바탕으로 침투깊이를 산정하므로 Mein과 Larson 방법에 비해 보수적인 사면안정 해석결과를 예측한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6B
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• pp.697-707
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• 2008

The grid-based KIneMatic wave STOrm Runoff Model (KIMSTORM) by Kim (1998) predicts the temporal variation and spatial distribution of overland flow, subsurface flow and stream flow in a watershed. The model programmed with C++ language on Unix operating system adopts single flowpath algorithm for water balance simulation of flow at each grid element. In this study, we attempted to improve the model by converting the code into FORTRAN 90 on MS Windows operating system and named as ModKIMSTORM. The improved functions are the addition of GAML (Green-Ampt & Mein-Larson) infiltration model, control of paddy runoff rate by flow depth and Manning's roughness coefficient, addition of baseflow layer, treatment of both spatial and point rainfall data, development of the pre- and post-processor, and development of automatic model evaluation function using five evaluation criteria (Pearson's coefficient of determination, Nash and Sutcliffe model efficiency, the deviation of runoff volume, relative error of the peak runoff rate, and absolute error of the time to peak runoff). The modified model adopts Shell Sort algorithm to enhance the computational performance. Input data formats are accepted as raster and MS Excel, and model outputs viz. soil moisture, discharge, flow depth and velocity are generated as BSQ, ASCII grid, binary grid and raster formats.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.254-258
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• 2008

본 연구는 격자기반 운동파 강우유출모형 KIMSTORM(grid-based KIneMatic wave STOrm Runoff Model)의 기능을 개선하고 적용성을 평가하는 것이다. KIMSTORM은 김성준(1998)이 개발한 분포형 강우유출모형으로 포화상태의 지표흐름 및 토양수분상태의 시공간적인 분포를 파악할 수 있다. UNIX C++ 언어로 개발되었으며, GRASS 형태의 ASCII Grid를 입출력하도록 구성되어 있는 모형으로 UNIX 운영체제에서 구동이 가능하다. 그러나 UNIX와 GRASS는 최근에 많이 이용되지 않는 추세로 KIMSTORM 모형을 이용한 홍수유출해석이 적극적으로 활용되는데 주요 제약사항이 되어 왔다. 본 연구에서는 KIMSTORM을 윈도우즈 환경에서 운영될 수 있도록 FORTRAN 90을 이용하여 재개발하였으며 주요개선 사항으로, ESRI ASCII Grid 형태의 GIS(geographic information system) 자료 입력, 물리적 침투모의 방법인 GAML (Green-Ampt and Mein- Larson) 적용, 공간강우 입력가능, 정렬 알고리즘을 이용한 계산속도의 개선, 모형 자료입력 등 전처리 기능개선, 계산결과의 자동평가 및 분포도출력 등 후처리 방식개선으로 요약할 수 있다. 개선된 모형 GAML에 의한 침투방법을 적용하여, 남강댐유역($2,293\;km^2$)의 6개 강우사상을 대상으로 결정계수, Nash & Sutcliffe 모형효율계수, 용적편차, 첨두유량의 상대오차, 첨두시간의 절대오차를 이용하여 적용성을 평가하였으며, 민감도분석결과 초기토양수분조건과 하천조도계수가 가장 큰 민감도를 나타내었다.

• Journal of the Korean Geotechnical Society
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• v.21 no.8
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• pp.45-53
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• 2005

Shallow slope failures in residual soil during periods of prolonged infiltration are common over the world. Therefore, this study examines an approximate method to estimate the influence of infiltration on surficial stability of slopes by one-dimensional infiltration model. Modified GAML model based on the Green-Ampt model was extended to predict the infiltration behavior of two-layered slope. Then, the model has been considered to evaluate the likelihood of shallow slope failure which is induced by a particular rainfall event that accounts for the rainfall intensity and duration for various return periods in two-layered soil profile. The results obtained from the approximate method were compared with those obtained from numerical analyses. According to the results, with the use of properly estimated input parameters, the proposed method was found to give good results that agree reasonably well to those of the more rigorous finite element analyses.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.6
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• pp.823-827
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• 2010

This study was conducted to assess the propriety of models for soil water characteristics estimation in anthropogenic soil through the measurement of soil water content and soil water matric potential. Soil profile was characterized with four different soil layers. Soil texture was loamy sand for the first soil layer (from soil surface to 30 cm soil depth), sand for the second (30~70 cm soil depth) and the third soil layers (70~120 cm soil depth), and sandy loam for the fourth soil layer (120 cm < soil depth). Soil water retention curve (SWRC), the relation between soil water content and soil water matric potential, took a similar trend between different layers except the layer of below 120 cm soil depth. The estimation of SWRC and air entry value was better in van Genuchten model by analytical method than in Brooks-Corey model with power function. Therefore, it could be concluded that van Genuchten model is more desirable than Brook-Corey model for estimating soil water characteristics of anthropogenic soil accumulated with saprolite.