• 한국지반환경공학회 논문집
• /
• 제2권1호
• /
• pp.57-65
• /
• 2001

본 연구에서는 증축하천제방의 침투거동과 안정성을 평가하기 위하여, 증축부의 투수계수와 홍수시 강우로 인한 수위상승속도를 3가지 경우로 변화시켜 가면서 평행흐름조건에서 침투모형실험과 유한요소해석을 통한 침윤선 변화와 홍수직후의 수위급상승시 제체사면의 안정성을 분석하여 제체침식에 대한 사면의 불안정성을 검토하였다. 침투모형실험은 평행흐름조건에서 서로 다른 증축재료의 투수계수 $k_1$, $k_2$, $k_3$와 홍수시 발생 가능한 수위상승속도 $v_1$, $v_2$, $v_3$를 각각 변화시키며 수행되었다. 증축체제의 침투거동은 증축부의 투수계수가 클수록 초기 침투거리가 길고, 제체하류사면에 유출점이 점차로 상승하며 시간에 따른 안전율이 감소하면서 국부적인 붕괴로 이어지는 불안정한 침투거동을 보여준다. 또한, 제체사면의 붕괴양상은 수위상승속도가 증가할수록 붕괴발생높이와 붕괴깊이가 증가함을 보여준다.

• 한국농공학회논문집
• /
• 제55권6호
• /
• pp.37-46
• /
• 2013

Many factors about the stability for the reservoir embankments is determined when the facility is completed. Therefore the initial design of the embankment is important. Many researchers focused the effect of soil parameters although the cross section greatly affects the stability and can be controlled in design step. The objective of this research is to analysis of the effects for the safety factor of slope and seepage according to change cross-section in embankment. As a result, the quantity of seepage decreased as the gradient of downstream slope decreased and was proportional to the height of embankments. There was a linear relationship between the gradient of slope and the safety factor of slope. However the gradient of slope did not affect other side slope. All in a relationship, regressive equations with a high correlation coefficient were calculated and can be applied the simple estimation method of the stability using the cross-section. As results of analyzing the sensitivity, the friction angle and permeability critically effect for the slope stability and the seepage, respectively. The effect of the slope gradient was similar to major soil properties.

• 농업과학연구
• /
• 제39권1호
• /
• pp.97-110
• /
• 2012

This study was carried out for safety evaluation, the practical application and improvement of design method of the agricultural reservoir embankment according to backside extension. Seepage analysis, slope stability analysis and finite element analysis were performed for steady state and transient conditions. Also, the pore water pressure, seepage quantity, safety factor and stress-strain behavior according to high water level and rapid drawdown were compared and analyzed. The pore water pressure at contact region between backside extension and old embankment was kept high after rapid drawdown. Therefore, backside extension is recommended that design method is required to be improved and reinforced more than the others raising embankment. The hydraulic gradients before and after backside extension showed high value at the base of the core, but they showed stable state at the upstream slope and downstream slope. The seepage quantity per 1 day and the leakage per 100 m for the steady state and transient conditions appeared to be safe against the piping. The safety factor of slope stability showed high at the steady state, and transient conditions did not show differences depending on the rapid drawdown. The safety factor was appeared high at the upstream slope before backside extension and downstream slope after extension. The excess pore water pressure for steady state and transient conditions showed negative(-) at the upstream slope, it was small at the downstream slope. The mean effective stress (p') showed high at the base of the core and to be wild distribution after the extension. The displacement after extension showed 0.02-0.06 m in the upstream slope, the maximum shear strain after extension was smaller than that before extension.

• 한국안전학회지
• /
• 제22권4호
• /
• pp.57-65
• /
• 2007

Effects on the stiffness of the embankment and sandmat on the construction safety of road embankment was investigated in this study by the numerical experiments using FEM. Two points was mainly focused in this study especially. First the deformation characteristics by the change of the stiffness of sand mat and embankment was investigated by the analyzing the consolidation settlement at the center of the embankment and the lateral displacement at the toe of the embankment. And, the effect of the stiffness on the stress distribution characteristics was also investigated in this study. Furthermore, slope stability analysis was carried out to gain the safe factor by change the stiffness of the sandmat and the embankment. The objective of the study is supplying the result of the numerical experiments for the geotechnical engineers who use the FEM for the safety design of the soil structures. As a result, the stiffness of the superstructures greatly affects on the deformation characteristics both in consolidation settlement and lateral displacement. However, it can be aware that it is not dominants to the stress distribution in the aspect that the no changes in the residual excess pore water pressure. Therefore, the decision of the stiffness has to be carried out deliberately considering not only the consolidation the magnitude of the settlement and the lateral displacement, but the slope stability.

• 한국재난관리표준학회지
• /
• 제1권4호
• /
• pp.65-71
• /
• 2008

본 논문은 국지성 호우에 따른 성토사변의 내부 침식의 특성에 대한 것이다. 기존 성토재료의 필터조건 분석방법에 대하여 검토하였다. 근접 성토재료로부터 재료업자의 이동을 억제하기 위한 필터층의 조건을 이론적 배경을 기초로 새로운 분석법을 제안하였다. 이러한 필터거동에 대한 새로운 분석기법에 따라 성토재료 내 침식에 의한 입자간의 거동 특성을 규명하기 위하여 사면의 내부 침식에 영향을 주는 주요원인인자(강우강도, 사면구배, 성토재료 특성 등)를 변화하여 총 3가지 Case의 축소모형실험을 실시하였다. 본 연구로부터 새로운 필터조건 분석법이 실질적인 성토구배 내의 성토재료에 대한 필터 설계시보다 더 적용성이 높은 방법이라는 결론을 얻었다. 이에 따라 새로운 필터조건검토 기준 또는 방법을 제안하였다.

• 한국안전학회지
• /
• 제15권1호
• /
• pp.146-152
• /
• 2000

To estimate the behavior of reinforced and unreinforced embankment constructed on a impermeable foundation ground, a laboratory model test was performed for two types of soils and water level increasing velocity of a flood period. The experiment models were constructed with slopes of water level is 1.25cm/min, 2.5cm/min each. From model test results, as the slope of reinforced and unreinforced embankment was the slower, the more seepage line rised. In the unreinforced embankment, the rising velocity of water level was the faster, the larger the embankment failure was. And the reinforced embankment with geotextile was the more safe than the unreinforced embankment for seepage force.

• 한국농공학회지
• /
• 제35권3호
• /
• pp.47-62
• /
• 1993

The laboratorv model test was carried out to investigate the behavior of pore water pressure, the critical amount of rainfall for slope failure, the pattern of failure, and the variation of seepage line at the slope with the uniform material of embankment by changing the slope angles and rainfall intensities. The results were was summarised as follows : 1.At the beginning stage of rainfall, the negative pore pressure appeared at the surface of slope and the positive pore pressure at the deep parts. But, the negative one turned into the positive one as the rainfall continued and this rapidly increased about 50 to 100 minutes before the slope failure. 2.The heavier the rainfall intensity, the shorter the time, and the milder the slope, the longer the time took to reach the failure of slope. 3.As the angle of the slope became milder, the critical amount of rainfall for slope failure became greater. 4.Maximum pore water pressure was 10 to 40g/cm$^2$ at the toe of slope and 50 to 90g/cm$^2$at the deep parts. 5.In the respect of the pattern of slope failure, surface failure of slope occurred locally at the toe of slope at the A-soil and failure of slope by surface flow occurred gradually at the top part of slope at the B-soil. 6.As the rainfall continued and the saturation zone in the embankment was formed, the seepage line went rapidly up and also the time to reach the total collapse of slope took longer at the B-soil. 7.As the position of the seepage line went up and the strength parameter accordingly down, the safety factor was 2.108 at the A-soil and 2.150 at the B-soil when the slope occured toe failure. Minimum safety factor was rapidly down to 0.831 at the A-soil and to 0.936 at the B-soil when the slope collapsed totally at the top part of slope.

• 복합신소재구조학회 논문집
• /
• 제6권3호
• /
• pp.8-13
• /
• 2015

This study investigates the application of a synthetic resine based net-hose system to sustain vegetated embankment slope reinforcement. The net-hose system is designated to improve water supply to the vegetation that can suffer the lack of water in case of extreme drying condition or rock slope where water supply is relatively insufficient to ensure the growth of vegetation. A series of laboratory tests were conducted to check the structural adequacy and effectiveness of net-hose system. The results indicated that the model slope equipped with net-hose system seemed to provide better water supply resulting in more vegetated areas and higher matric suction due to active water uptake capacity, which might be contributed to greater shear strength of slope surface. A limited numerical analysis was conducted to verify the effect of water uptake on vegetated root system that generally yields better slope stability.

• 한국지반환경공학회 논문집
• /
• 제2권2호
• /
• pp.51-58
• /
• 2001

본 연구에서는 보강제체와 무보강제체의 침투거동을 평가하기 위하여 실내모형실험을 실시하였다. 제체침투시험은 사면경사가 1:1.5, 1:2.0이고 수위상승속도가 1.25cm/min, 2.5cm/min, 수위는 15cm, 25cm, 35cm인 조건에서 실시하였다. 모형실험결과 보강재를 사용한 제체의 경우 지하수의 흐름과 상승 때문에 어느 정도의 침하와 수평방향변위가 발생하였으나, 무보강제체에서 나타난 커다란 활동파괴는 발생되지 않았다. 그리고 수위상승속도 변화에 따른 제체의 침투거동분석결과 Geotextile로 보강된 제체가 무보강제체보다 최종침하량이 감소하는 것으로 나타나 Geotextile을 설치한 제체가 비교적 물의 침투력에 대해 안정한 것으로 나타났다.

• Geomechanics and Engineering
• /
• 제10권1호
• /
• pp.59-76
• /
• 2016

The non-linear Hoek-Brown failure criterion has been widely accepted and applied to evaluate the stability of rock slopes under plane-strain conditions. This paper presents a kinematic approach of limit analysis to assessing the static and seismic stability of three-dimensional (3D) rock slopes using the generalized Hoek-Brown failure criterion. A tangential technique is employed to obtain the equivalent Mohr-Coulomb strength parameters of rock material from the generalized Hoek-Brown criterion. The least upper bounds to the stability number are obtained in an optimization procedure and presented in the form of graphs and tables for a wide range of parameters. The calculated results demonstrate the influences of 3D geometrical constraint, non-linear strength parameters and seismic acceleration on the stability number and equivalent strength parameters. The presented upper-bound solutions can be used for preliminary assessment on the 3D rock slope stability in design and assessing other solutions from the developing methods in the stability analysis of 3D rock slopes.