• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2003년도 추계학술대회 논문집(II)
• /
• pp.397-402
• /
• 2003

Infiltration of rainfall causes railway embankment to be unstable and may result in failure. Basic relationship between the rainfall and stability of railway embankment are defined to analyze the stability of embankment by rainfall. An experimental study for defining of infiltration rate of rainfall into slope is conducted in the lab. The results of Rainfall infiltration show that rainfall infiltration is not equal to infiltration as like reservoir because rate of rainfall infiltration is controlled by slope angle. Based on these results, boundary condition of rainfall is altered and various numerical analysis are performed. The variation of shear strength, the degree of saturation and pore-water pressure for railway slope during rainfall can be predicted and the safety factor of railway slope can be expressed as the function of rainfall amount, namely rainfall index. Therefore, it is judged that this rainfall index can be a good tool for the rail-transport operation control.

• 한국주조공학회지
• /
• 제12권2호
• /
• pp.149-154
• /
• 1992

The wetting behaviour of SiC/Al-Li composite interface has been investigated by using an infiltration method. The critical pressure for melt infiltration into SiC particulate preform has been determined by measuring the melt infiltration distance changes with the variation of applied pressure. The threshold pressure of pure Al, Al-0.2wt%Li, Al-0.5wt%Li for melt infiltration are 3.94, 3.93, $3.7Kg/cm^2$ respectively, which implies a slight improvement in wettability of SiC/Al composite by addition of Li. The threshold pressure for melt infiltration also changes with the variation of other parameters such SiC particulate size, SiC particulate fraction and melt temperature.

• 한국방재학회 논문집
• /
• 제7권4호
• /
• pp.85-95
• /
• 2007

우리나라의 계절별 편차가 큰 강우 특성과 도시화에 따른 도시유역 수리 수문 양상의 변화로 인해 도시의 유출변화를 초래하여 홍수피해가 증가하고 수자원 관리 측면에서도 매우 불리한 형편에 있다. 현재 이러한 문제를 해결하기 위해 각종 개발 사업으로 인해 가중되는 홍수유출량을 처리할 수 있는 우수유출 저감시설을 설치하고 있다. 본 연구에서는 보다 효율적인 우수유출저감 기능을 가진 침투-저류 시스템을 제안하고, 수리모형 실험을 통해 침투-저류 시스템의 저감효과를 분석하였다. 각종 개발 사업이나 도시화에 따른 영향을 고려할 수 있도록 표면재료를 고려하여 인공강우 실험장치와 상 하부층으로 구성된 침투-저류 시스템을 이용하여 수리모형실험을 수행하였다. 상부와 하부 침투율을 비교한 결과, 대체적으로 하부의 침투율이 더 크게 나타났으며, 이러한 결과로 침투-저류시스템의 효과가 침투율을 증가시켜 기존 침투형 우수유출저감시설보다 더 효율적인 것으로 판단되었다. 본 연구의 침투-저류시스템 저감효과 분석내용은 침투-저류시스템 및 침투형 우수유출저감시설의 기초 연구 자료로 활용될 수 있을 것이다.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2010년도 추계 학술발표회
• /
• pp.71-78
• /
• 2010

The stability analysis of unsaturated infinite slope under rainfall-induced infiltration condition was performed using the generalized effective stress that unifies both saturated and unsaturated condition recently proposed by Lu and Likos(2004, 2006). The Soil-Water Characteristic Curve (SWCC) of the sand with the relative density of 75% was first measured for both drying and wetting processes. The Hydraulic Conductivity Function (HCF) and Suction Stress Characteristic Curve (SSCC) were subsequently estimated. Also, under the rainfall-induced infiltration condition transient seepage analysis of unsaturated infinite slope was performed using the finite element program, SEEP/W. Based on these results, the stability of unsaturated infinite slope under rainfall-induced infiltration condition was examined considering the suction stress. According to the results, the negative pore water pressure and water content within the soil changed with time due to the infiltration. Also, the variation of those caused the variation of suction stress and then the factor of safety of slope changed consequently during the rainfall period.

• 지질공학
• /
• 제24권1호
• /
• pp.1-8
• /
• 2014

Numerical stability analysis of an unsaturated infinite slope under rainfall-induced infiltration conditions was performed using generalized effective stress to unify both saturated and unsaturated conditions The soil-water characteristic curve (SWCC) of sand with a relative density of 75% was initially measured for both drying and wetting processes. The hydraulic conductivity function (HCF) and suction stress characteristic curve (SSCC) were subsequently estimated. Under the rainfall-induced infiltration conditions, transient seepage analysis of an unsaturated infinite slope was performed using the finite element analysis program, SEEP/W. Based on these results, the stability of an unsaturated infinite slope under rainfall-induced infiltration conditions was examined in relation to suction stress. According to the results, the negative pore-water pressure and water content within the slope soil changed over time due to the infiltration. In addition, the variation of the negative pore-water pressure and water content led to a variation in suction stress and a subsequent change in the slope's factor of safety during the rainfall period.

• 한국농공학회지
• /
• 제35권3호
• /
• pp.36-46
• /
• 1993

The purposes of this study are to develop three-layered Green-Ampt infiltration model considering temporal variation of physical properties of soil and to evaluate the model with field experiment on bare-tilled and soybean-growing soil plots under natural rainfalls. Infiltration tests were conducted on a sandy loam soil. The model has three-layered soil profile including a surface crust, a tilled layer, a subsoil and considers temporal variation of porosity, hydraulic conductivity, capillary pressure head on a tilled layer by natural rainfalls and canopy density variation of crop. Field measurement of porosity, average hydraulic conductivity and average capillary presure head on a tilled layer were conducted by soil sampler and air-entry permeameter at regular intervals-after tillage. It was found that temporal variation of porosity and average hydraulic conductivity might be expressed as a function of cumulative rainfall energy and average capillary pressure head might be expressed as a function of porosity of a tilled soil. The model was calibrated by an optimization technique, Hooke and Jeeves method using hourly surface runoff data. With the calibrated parameters, the model was verified satisfactorily.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
• /
• pp.163-167
• /
• 2003

Based on the transient finite difference solution of Richards' equation, an infiltration model is developed to analyze temporal variation of precipitation recharge in the region of monsoon climates. Simulation results obtained by using time series data of 20-year daily precipitation and pan evaporation indicate that a linear relationship between the annual precipitation and the annual recharge holds for the soils under the monsoon climates with varying degrees of the correlation coefficient depending on the soil types. A sensitivity analysis reveals that the water table depth has little effects on the recharge for the sandy soil, whereas, for the loamy and silty soils, rise of the water table at shallow depths causes increase of evaporation by approximately 100㎜/yr and a corresponding decrease in recharge. A series of simulations for two-layered soils illustrate that the amount of recharge is dominantly determined by the soil properties of the upper layer, although the temporal variation of recharge is affected by both layers.

• 지질공학
• /
• 제20권2호
• /
• pp.137-146
• /
• 2010

강우시 침투량 산정을 위하여 일반적으로 기존의 침투능 산정식인 Horton 공식 및 Green-Ampt 공식으로 지반 내 침투능을 산정해 왔다. 하지만, 실제 강우로 인한 지반 침투는 연속적으로 침투가 이루어지므로, 이와 같은 불연속적인 침투량 산정공식의 단점을 보완하고자 연속적인 침투능 산정공식을 새로이 유도하여, 침투능 및 침투량을 비교 분석하고자 하였다. 유도된 식 및 기존의 침투공식을 검증하기 위한 침투실험을 행하여 각 식의 결과들을 비교 분석하였다. 함수비 혹은 포화도의 함수인 불포화투수계수는 직접적으로 침투능 및 침투량에 영향을 끼치므로, 새로이 유도된 식은 침투과정에 따른 불포화투수계수의 변화를 이용하여 보다 정확한 침투능 및 침투량을 산정하고자 하였으며, 침투로 인한 구조물의 안정 및 지하수 거동을 보다 정확히 해석하기 위한 것이다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2002년도 추계학술대회 논문집(I)
• /
• pp.601-607
• /
• 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.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
• /
• pp.225-232
• /
• 2009

Infiltration of rainfall causes railway slopes to be unstable and may result in failure. Basic relationship between the rainfall and stability of railway embankment is defined to analyze its stability by rainfall. An experimental study for defining of infiltration rate of rainfall into slope is conducted in the lab. The results of Rainfall infiltration show that rainfall infiltration is not equal to infiltration as like reservoir because rate of rainfall infiltration is controlled by slope angle. Based on these results, boundary condition of rainfall is altered and various numerical analysis are performed. The variation of shear strength, the degree of saturation and pore-water pressure for railway slope during rainfall can be predicted and the safety factor of railway slope can be expressed as the function of rainfall amount, namely rainfall index. And suggested rainfall index is compared with the rail transport operation control which is used in KORAIL. It is judged that this rainfall index can be a good tool for the rail-transport operation control.