• Title/Summary/Keyword: soil model

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Evaluation on the Landslide Stability Triggered by Rainfall (강우로 인한 사면활동의 안정성 평가)

  • Sagong Myung
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.1101-1106
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    • 2004
  • Rainfall induced landslides are disasters causing sever damage on the human life and the infrastructures. In this paper, a simplified procedure to evaluate the slope stability problems induced by rainfall by modifying the Iverson's pressure head dispersion model. The proposed approach extends the applicability of the Iverson's model in to the cases of higher rainfall intensity than the permeability of the soil by incorporating the existence of overland flow. In addition, the Manning equation is applied to calculated the depth of overland flow. From the calculated depth of overland flow, shear stress acting on the surface is included for the driving component triggering the landslides. From the analysis of a case study, the long term rainfall alters the stability of slope.

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Analyses on Consolidation Characteristics of Dredged and Reclaimed Soils in Busan Area (부산지역 준설매립지반의 압밀거동 특성 분석)

  • Yoo, Nam-Jae;Kim, Dong-Gun;Hwang, Hee-Seok
    • Journal of Industrial Technology
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    • v.32 no.A
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    • pp.87-94
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    • 2012
  • For soils with high void ratios, the inverse method of utilizing results obtained from centrifuge model test was used to find the constitutive relation of effective stress - void ratio - permeability whereas conventional oedometer test and constant rate of strain consolidation(CRS) test about settlement of interface and pore pressure and distribution with time were compared with numerically estimated values to confirm such a constitutive relation as obtained from the inverse method. As results of numerical method, the volumetric ratio and reclamation velocity were obtained for the reclamation condition.

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Application of Scale Effect in Estimating Bearing Capacity and Settlement of Footing from Plate-Load Test (평판재하시험으로부터 실제기초의 지지력 및 침하량 산정시 Scale Effect)

  • 정형식;김도열
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.350-357
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    • 2002
  • The scale effect should be considered to determine the bearing capacity and settlement of footings from Plate-Load Test, because of the size difference between a footing and a loading plate. To analyze characteristics of bearing capacity and settlement according to the difference of loading plate sizes, model tests were peformed with four different sizes of square plate, which is B=10, 15, 20 and 25cm respectively, on five different kinds of subsoil, which is pure sand(100:0), sand-clay mixed soil(75:25, 50:50, 25:75), and pure clay(0:100). Based on the analyzed results, this paper also proposed a method of bearing capacity and settlement determination, where scale effect is considered depending on the mixing ratio of sand and clay. Applying the formular proposed in this research to field problems, it is expected that evaluation of bearing capacity and settlement of footings can be more reliable and more economic construction can be achieved.

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Application of Porous Medium Theory in Slope Stability Analysis (다공체 이론을 사용한 사면안정해석)

  • 서영교
    • Journal of the Korean Geotechnical Society
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    • v.17 no.2
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    • pp.135-142
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    • 2001
  • 사면안정해석을 위해 다공체(porous medium) 이론이 제시되었다. 다공체 이론은 간극수압, 토질입자 및 간극수의 상호작용을 포함하는 여러 가지 지반관련 문제의 이해에 있어 매우 중요하다. 이러한 상호작용은 토질강도 및 변형에 중요한 영향을 미친다. 압밀 예제로서 이러한 모델의 정확도를 첫째로 검증하였다. 사면안정해석에 있어서 토질의 응력 및 강도는 일반적인 구성모델을 포함한 비선형 유한요소해석을 사용하여 정확히 계산되었다. 사면안정해석은 한계상태를 표시하는 파괴면이 나타날 때까지 점차적인 중력의 증가로 실행되었다. 안전율은 증가시킨 중력과 실제사면 중력의 비로서 계산되었다. 제시된 사면 안정 해석 방법의 자세한 사항은 예제를 통하여 설명되었다.

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A Study on PBD Improvement Effect depending on disturbance by Laboratory Model Tests failure. (실내 모형시험을 통한 교란에 따른 PBD개량효과 연구)

  • Lim, Jin-Gyu;Kim, Woo-Jin;Hwang, Sung-Won;Kang, Kwon-Soo;Kim, Jong-Ryeol
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1132-1135
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    • 2008
  • In this study, a circular and indoor soil tank foundation was manufactured to study the improvement according to the degree of turbulence arising from PBD penetration, using the existing plate-type shoe and improved V-type shoe to change the degree of turbulence. Furthermore, to study the foundation improvement effect, the strength, settlement speed in the turbulence area were compared according to the shoe penetration. The results of the study showed that the V-type shoe reduced the strength coefficient decrease effect, and the foundation improvement effect according to the degree of turbulence was identified.

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Settlement Behavior Of High Rock Embankment With Construction Path (시공이력을 반영한 고성토 암버력 지반의 침하거동 분석)

  • Bae, Kyung-Tae;Kim, Tae-Hoon;Kang, In-Kyu;Lee, Won-Je;Yu, Nam-Jae;Lee, Kang-Il
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.956-962
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    • 2009
  • A high embankment is generally constructed by dividing into several sub-embankments. Unlike any soil embankment, a rock embankment is constructed by means of dynamic compaction. Such a sub-embankment and dynamic compaction may induce an increase of pressure at the lower part of embankment and cause a different behavior of ground from initial status. In this study, settlement of a high rock embankment is estimated using a hyperbolic model taking into construction history. The results from prediction are compared with those obtained from field measurements and large plate loading tests.

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Variation of Slope Stability under rainfall considering Train Speed (열차의 속도 하중을 고려한 강우시 성토사면의 안정성 변화)

  • 김정기;김현기;박영곤;신민호;김수삼
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.601-607
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    • 2002
  • Infiltration of rainfall causes railway embankment to be unstable and may result in failure. Basic relationship between the stability of railway embankment and rainfall introducing the partial saturation concept of ground are defined to analyze the stability of embankment by rainfall. A pressure plate test is also peformed to obtain soil-water characteristic curve of unsaturated soils. Based on this curve, the variables in the shear strength function and permeability function are also defined. These functions are used fur the numerical model for evaluation of railway embankments under rainfall. As comparing the model and case studies, the variation of shear strength, the degree of saturation and pore-water pressure for railway embankment during rainfall can be predicted and the safety factor of railway embankment can be expressed as the function of rainfall amount namely rainfall index. Therefore, the research on safety factor on railway embankment considering train speed and rainfall infiltration with the variation of rainfall intensity and rainfall duration was carried out in this paper.

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Effect of Loading Rate to Bearing Capacities (지지력에 미치는 재하속도에 관한 해석적 연구)

  • 박중배
    • Geotechnical Engineering
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    • v.13 no.1
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    • pp.147-158
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    • 1997
  • In this study, it is examined that partial drain has an effect of bearing capacities and deformations on intermediate soils. To compare the numerical and experimental results, this study uses CRISP90 which is composed of Modify Cam-Clay Model for calculation and Geotechnical Centrifuge in model test. As the results of analysis, we can classify relative loading rate into three ranges which are drain, undrain and partial drain. Besides it is proved that partial drain range is about 103.

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Estimation of Spatial Evapotranspiration using the Relationship between MODIS NDVI and Morton ET - For Chungjudam Watershed - (MODIS NDVI와 Morton 증발산량의 관계를 이용한 공간증발산량 산정 기법 연구 - 충주댐유역을 대상으로 -)

  • Shin, Hyung-Jin;Ha, Rim;Park, Min-Ji;Kim, Seong-Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.52 no.1
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    • pp.19-24
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    • 2010
  • The purpose of this study is to estimate monthly Morton evapotranspiration (ET) using normalized difference vegetation index (NDVI) from MODIS satellite images. Morton ET for land surface conditions was evaluated by using daily meteorological data, and the monthly averaged Morton ETs for each land cover were compared with the monthly NDVIs of three years (2000-2002) at Chungjudam Watershed. There was a high correlation between monthly NDVI and Morton ET for the watershed with average coefficient of determination, 0.80. By comparing the MODIS NDVI ET with SLURP Morton ET, the SLURP ET was smaller than the MODIS NDVI ET. This was estimated from the consideration of soil moisture condition for the ET occurrence in the SLURP model, the limited information from the monthly NDVI values, and the errors from the derived regression equations.

Application of Hydrological Model for Nakdong River Basin Using Assimilation System (자료동화를 이용한 낙동강 유역에 대한 수문 모형 적용)

  • Kim, Da-Eun;Choi, Min-Ha
    • Proceedings of the Korea Water Resources Association Conference
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    • 2012.05a
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    • pp.84-87
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    • 2012
  • 수자원 분야에서 지표와 대기 사이의 물과 에너지 교환에 대한 해석을 위하여 다양한 수문 모형이 이용되고 있다. 이 과정은 물 순환 과정을 이해하기 위한 한 방법으로 본 연구에서는 Common Land Model (CLM)을 이용해 수문 기상학적 인자를 모의하였다. CLM은 Soil-Vegetation-Atmosphere Transfer (SVAT) 모형 중 하나이며, 본 모형을 이용한 연구들이 활발히 이루어지고 있다. 그러나 한반도를 포함한 영역에서의 참고할만한 결과가 부족한 실정이며, 국내에서의 사용 가능한 기초자료도 부족하여 모형 구동을 위해 본 연구에서는 1 km의 높은 해상도의 강제입력자료를 Weather Research Forecast (WRF) 모형을 통하여 생산하여 사용하였다. 이 자료는 관측자료 및 위성 자료 등을 이용한 자료동화방법을 통하여 산출하였으며, 이를 이용하여 낙동강 유역에 대하여 CLM의 수문 기상학적 인자들을 산정하였다. 향후 보다 넓은 범위의 연구 지역을 설정하여 국내 관측 자료와의 비교를 통해 본 자료에 대한 사용 가능성을 검증할 계획이다. 또한 이를 바탕으로 수문 모형을 이용한 아시아 지역의 높은 해상도의 수문 기상학적 인자에 대한 연구를 진행할 예정이다.

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