• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.811-818
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• 2005

Stability analyses on the 17 railroad cut-off soil slopes were carried out. The influences of rainfall infiltration on the slope stabilities were taken into account by seepage analyses using finite element method and by assuming ground water tables to be located adjacent to soil surface. The validity of those analyses were evaluated by comparing the slope failure characteristics between analysis results and the past failure records. The analyses were not appropriate to estimate the failure surface and the method considering only the increase of pore-water pressure (reduction of matric suction) as the influence of rainfall cannot appropriately estimate the surficial failures that occurred most of the cut-off soil slopes. For the better estimation of the surficial failure, the influence of water flows over slope surface which erode soil mass and/or increase driving force, should be evaluated and considered.

• Geomechanics and Engineering
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• 제30권3호
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• pp.219-231
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• 2022

Geotechnical materials such as silt, fine sand, or coarse granular soils may be unstable under undrained shearing or during rainfall infiltration starting an unsaturated state. Some researches are available describing the instability of coarse granular soils in drained or undrained conditions. However, there is a need to investigate the instability mechanism of unsaturated silty soil considering the effect of degree of compaction and net confining stress under partially and fully drained conditions. The specimens in the current study are compacted at 65%, 75%, & 85% degree of compaction, confined at pressures of 60, 80 & 120 kPa, and tested in partially and fully drained conditions. The tests have been performed in two steps. In Step-I, the specimens were sheared in constant water content conditions (a type of partially drained test) to the maximum shear stress. In Step-II, shearing was carried in constant suction conditions (a type of fully undrained test) by keeping shear stress constant. At the start of Step-II, PWP was increased in steps to decrease matric suction (which was then kept constant) and start water infiltration. The test results showed that soil instability is affected much by variation in the degree of compaction and confining stresses. It is also observed that loose and medium dense soils are vulnerable to pre-failure instability i.e., instability occurs before reaching the failure state, whereas, instability in dense soils instigates together with the failure i.e., failure line (FL) and instability line (IL) are found to be unique.

• Geomechanics and Engineering
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• 제16권4호
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• pp.423-433
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• 2018

A three-dimensional model is constructed to simulate water infiltration in an unsaturated slope from a leaking pipe. Adaptive mesh refinement and time stepping are used, assisted by an automatic procedure for progressive steepening of the hydraulic property function for better convergence. The model is justified by comparing the simulated results with experimental data. Steady-state flow is investigated considering various pipe water pressures, locations and sizes of the opening, and soil layering. The opening size significantly affects the soaked zone around the pipe. Preferential flow dominates along the pipe longitudinal direction in the presence of a loose backfill around the pipe.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.129-130
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• 2023

This study proposes rainwater infiltration retention blocks as a solution to the flooding problems caused by recent climate change and developed a flood prediction simulation program to select the optimal site for installing rainwater infiltration retention blocks that can minimize damage from floods. By applying the existing 2D flood analysis model G2D and adding a reservoir function, the volume of water before and after installation can be determined through simulation results.

• 한국조경학회지
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• 제40권5호
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• pp.140-147
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• 2012

본 연구에서는 우수 유출량을 일정수준 이하로 제어할 수 있는 화단형 침투시설을 개발하여 이의 적정 설계침투량을 산정하고 적용효과를 분석하였다. 침투시설의 설계침투량을 산정하고 성능을 분석하는 것은 지구단위계획과 같은 공간계획에 구체적으로 빗물침투시설을 계획할 경우에 적용 후 효과를 예측하는데 있어 반드시 검토되어야 할 사항이다. 이에 본 연구에서는 한국건설기술연구원 실험동 옆 주차장을 대상으로 본 시설의 단위설계침투량에 변화를 주어 물수지 분석 프로그램을 이용, 유출량 감소효과를 분석하였다. 침투시설의 설계침투량을 $0.1{\sim}3m^3/m^2.day$로 각각 변화를 주어 유출율 변화를 분석한 결과, $1.0m^3/m^2.day$에서 유출량 80%를 침투시키는 것으로 분석되었으며, 이때의 단위설계침투량이 0.0416($m^3/m^2.hr$)이었다. 또한 개발한 시스템을 현장침투실험한 결과, 단위설계침투량이 약 $0.045m^3/m^2.hr$으로 나타났다. 이 값은 시뮬레이션한 단위설계침투량과 유사한 것으로 분석되었다. 본 연구결과를 토대로 경제적인 규모와 환경적 효과를 최대한 고려한 침투량 산정이 가능하였으며, 또한 도시에서의 녹색인프라로서 빗물침투시설을 공간계획에 적용할 때 고려할 수 있는 근거를 마련했다는 데 의의를 갖는다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2001년도 학술발표회 논문집(II)
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• pp.1195-1199
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• 2001

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2001년도 학술발표회 논문집(I)
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• pp.170-175
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• 2001

No Abstract (See Full-text)

• 한국농공학회논문집
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• 제54권3호
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• pp.11-17
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• 2012

In this study, an experiment with large-scale model was performed according to raising embankment in order to investigate the cause of collapse by a change in water level of reservoir. Also, the settlement and pore water pressure by high water level and a rapid drawdown were compared and analyzed. After raising embankment for inclined core, there was no infiltration by leakage. For the vertical core, the pore water pressure showed a largely change by faster infiltration of pore water than in the inclined core. In a rapid drawdown, inclined core was remained stable but vertical core showed a largely change in pore water pressure. A settlement after a raising embankment showed a larger measure of settlement than before the raising embankment. The leakage quantity before a raising embankment and an inclined extension showed no leakage. Leakage in vertical extension was measured 160 $l$. From the result, a instrument system that can accurately estimate a change of pore water pressure shall be established for a rational maintenance and stabilization of raising embankment for agricultural reservoir.

• 농업과학연구
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• 제48권3호
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• pp.629-642
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• 2021

Land-use change has an important role in the hydrologic characteristics of watersheds because it alters various hydrologic components such as interception, infiltration, and evapotranspiration. For example, rapid urbanization in a watershed reduces infiltration rates and increases peak flow which lead to changes in the hydrologic responses. In this study, a physical hydrologic model the soil and water assessment tool (SWAT) was used to assess long-term continuous daily streamflow corresponding to land-use changes that occurred in the Naesungchun river watershed. For a 30-year model simulation, 3 different land-use maps of the 1990s, 2000s, and 2010s were used to identify the impacts of the land-use changes. Using SWAT-CUP (calibration and uncertainty program), an automated parameter calibration tool, 23 parameters were selected, optimized and compared with the daily streamflow data observed at the upstream, midstream and downstream locations of the watershed. The statistical indexes used for the model calibration and validation show that the model performance is improved at the downstream location of the Naesungchun river. The simulated streamflow in the mainstream considering land-use change increases up to -2 - 30 cm compared with the results simulated with the single land-use map. However, the difference was not significant in the tributaries with or without the impact of land-use change.

• 상하수도학회지
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• 제34권3호
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• pp.191-200
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• 2020

This study is to improve the efficiency of BTL (Build Transfer Lease) project operation by comparing the infiltration rate based on the data of 5 years of infiltration of the separate sewer system and combined sewer system. In the survey site, the separate sewer system area consists of eight flowmeters in seven treatment basins, and the combined sewer system area consists of eight flowmeters in five treatment basins. The infillration rate was analyzed by night-time domestic flow evaluation method, and the average infiltration rates of the separate sewer system and combined sewer system were 13% and 16%, respectively. Combined sewer system was about 1.3 times higher than the separate sewer system. The average BOD of separate sewer system was 233 mg/L, which was about 2.4 times higher than the combined sewer system was 107 mg/L. In the comparison of the average pipe diameter-length infiltration of separate sewer system and combined sewer system, the separate sewer system and the combined sewer system were about 0.150 ㎥/d/mm/km and about 0.109 ㎥/d/mm/km, respectively. The floating population in mixed residential and commercial areas has been identified as the cause. Therefore, we propose a method to calculate the infiltration rate in consideration of the margin ratio in the area where the night active population is concentrated.