• 한국농공학회지
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• 제21권2호
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• pp.81-103
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• 1979

The weathered granite soil involves problems in its stability in soil structures depending upon the reduction of soil strength due to the water absorption, crushability, and content of colored mineral and feldspar. As an attemt to solve the problems associated with soil stability, the crushability of weathered granite soil was investigated by conducting tests such as compaction test, CBR test, unconfined compression test, direct shear test, triaxial compression test, and permeability test on the five soil samples different in weathering and mineral compositions. The experimental results are summarized as follows: The ratio of increasing dry density in the weathered granite soil was high as the compaction energy was low, while it was low as the compaction energy was increased. The unconfined compressive strength. and CBR value were highest in the dry side rather than in the soil with the optimum moisture content, when the soil was compacted by adjusting water content. However, the unconfined compressive strength of smples, which were compacted and oven dried, were highest in the wet side rather than in soil with the optimum moisture content. As the soil becomes coarse grain, the ratio of specific surface area increased due to increased crushability, and the increasing ratio of the specific surface area decreased as the compaction energy was increased. The highest ratio of grain crushability was attained in the wet side rather than in the soil with the optimum moisture content. Such tendency was transforming to the dry side as the compaction energy was increased. The effect of water on the grain crushability of soil was high in the coarse grained soil. The specific surface area of WK soil sample, when compacted under the condition of air dried and under the optimum moisture content, was constant regardless of the compaction energy. When the weathered granite soil and river sand with the same grain size were compacted with low compaction energy, the weathered granite soil with crushability had higher dry density than river sand. However, when the compaction energy reached to certain point over limitation, the river sand had higher dry density than the weathered granite soil. The coefficient of permeability was lowest in the wet side rather than in the optimum moisture content, when the soil was compacted by adjusting soil water content. The reduction of permeability of soil due to the compaction was more apparent in the weathered granite soil than in the river sand. The highly significant correlation coefficient was obtained between the amount of particle breakage and dry density of the compacted soil.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.13-17
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• 2002

Ultrasonic waves have several mechanical, chemical, and biological effects on a saturated soil medium. Their mechanical effects, popularly known as cavitation. Cavitation is the rapid and repeated formation, and resulting implosion, of imcrobubbles in a liquid, resulting in the propagation of microscopic shock waves. In a soil-liquid system, their mechanical effects generate high differntial fluid-particle velocities and microscopic shock waves. The velocity perturbations are capable of dislodging oil in the system by overcoming the forces binding oil to sand particles. In this study, a series of laboratory experiments involving the simple flushing and ultrasonic flushing were carried out. An increase in permeability and oil removal rate were observed in ultrasonic flushing tests. Some practical implications of these results are discussed in terms of technical feasibility of in situ implementation of ultrasonics.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.210-214
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• 2002

In this study, the coupled effect of electrokinetic and ultrasonic remediation technology was investigated for removing of heavy metal and organic matter at the same time. The laboratory tests were conducted using specially designed and fabricated electrokinetic and ultrasonic devices. The electrokinetic technique was applied to remove mainly the heavy metal and the ultrasonic technique was applied to remove mainly organic substance in contaminated soil. Diesel fuel and Cd were used as a surrogate contaminant for this test. A series of laboratory experiments involving electrokinetic and electrokinetic+ultrasonic flushing test were carried out. An increase in permeability and contaminant removal rate was observed in electrokinetic+ultrasonic flushing test.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.318-321
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• 2003

This study explored the feasibility of applying Electrokinetic-Fenton process(EK-Fenton process) to remediation of contaminant sorbed on the soil possessed low-permeability. The addition of 0.01 N H$_2$SO$_4$ in the anode reservoir for the $H_2O$$_2$stabilization improved the stabilization of $H_2O$$_2$and the treatment effect of phenanthrene across the entire soil specimen. The use of $H_2O$$_2$and dilute acid as anode purging solution is a promising method treating of HOCs in low-permeability subsurface environments.

• 한국지반공학회지:지반
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• 제6권2호
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• pp.21-34
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• 1990

국내에서 여과용도로 폭넓게 사용되고 있는 Geotextile인 단섬유부직포를 대상으로 교번류상태에서의 흙/Geoteztile 시스템에 대한 실내 여과특성실험을 수행하였다. 실험을 통하여 교번주기, 교번동수경사, 수직하중 및 지반흙의 입도와 밀도등 여러 영향인자들이 흙/Geotextile시스템의 여과구조,수직투수성 및 흙 보유성에 미치는 효과를 규명하였으며, 국내생산 단섬유부직포에 대한 교번류 작용시의 보유성 기준과 투수성 기준을 제시하였다.

• 한국약용작물학회지
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• 제17권3호
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• pp.204-209
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• 2009

This study was conducted to assess water movement in paddy-upland rotation soil scheduled for ginseng cultivation through the measurement of infiltration and permeability of soil water. Soil sample was divided with four soil layers. The first soil layer (to 30cm from top soil) was loamy sand, the second and the third soil layers (30$\sim$70 ㎝) were sand, and the fourth (< 120 ㎝) was sandy loam. The soil below 130 ㎝ of fourth soil layer was submerged under water. The shear strength, which represents the resisting power of soil against external force, was 3.1 kPa in the first soil layer. This corresponded to 1/8 of those of another soil layer and this value could result in soil erosion by small amount of rainfall. The rates of infiltration and permeability depending on soil layers were 39.86 cm $hr^{-1}$ in top soil, 2.34 cm $hr^{-1}$ in 30$\sim$70 ㎝ soil layer, 5.23 cm $hr^{-1}$ and 0.18 cm $hr^{-1}$ in 70$\sim$120 ㎝ soil layer, with drain tile, and without drain tile, respectively. We consider that ground water pooled in paddy soil and artificial formation of soil layer could interrupt water canal within soil and affect negatively on water movement. Therefore, we suggest that to drain at 5 m intervals be preferable when it makes soil dressing or soil accumulation to cultivate ginseng in paddy-upland rotation soil to reduce failure risk of ginseng cultivation.

• 한국지반환경공학회 논문집
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• 제8권3호
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• pp.59-65
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• 2007

투수성이 낮은 흙에서 과잉간극수압은 빨리 소산되지 못하므로 유효응력을 감소시키게 되며, 이는 보강토 옹벽에서 보강재와 흙 사이의 인터페이스 전단강도를 감소시키는 결과를 가져온다. 이러한 조건에서는 간극수압의 소산속도가 매우 중요하며, 이는 벽체의 크기, 뒤채움 흙의 투수성 그리고 보강재의 길이 등에 의해 영향을 받는다. 본 논문에서는 이러한 영향요소의 효과를 조사하기 위하여 유한요소해석을 실시하였고, 그 결과 투수계수 $10^{-3}cm/sec$ 이하부터는 간극수압 소산시간이 점차 증가하기 시작함을 알 수 있었다. 간극수압 소산시간의 증가는 유효응력의 감소를 의미하여 보강재 인발력의 감소로 이어질 것이며, 이는 본 논문에서 수행된 수치해석으로 확인되었다. 또한, 보강재의 길이가 길수록 간극수압 소산시간이 더 많이 필요한 것으로 나타났는데 이는 배수거리의 증가에 기인한다.

• 한국지반공학회논문집
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• 제16권4호
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• pp.107-116
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• 2000

흙 필터를 대신한 토목섬유의 사용량이 점차 증가하고 있다. 따라서 흙과 결합된 복합체계에 대한 메카니즘 연구가 활발히 진행되고는 있지만 이러한 복합체의 거동은 흙과 사용 필터재의 상호작용으로 인한 여러 가지 영향 인자들 때문에 실제의 필터 설계는 경험적인 방법에 의존하고 있다. 본 연구에서는 흙/부직포 시스템에서 세립자 이동에 의한 폐색 현상을 규명하고자 하였다. 국내의 대표적인 풍화잔적토 지반에 속하는 서울의 신내동과 포이동 지역의 흘을 시료로 이용한 본 실험은 필터재 내에서의 흐름방향에 따라 수평흐름과 수직흐름으로 나누어 실내 시험을 실시하였다. 필터재로서는 현장에서 배수재로 광범위하게 쓰이는 토목섬유를 사용하였다. 흙 모체와 필터가 결합된 복합체의 적합성 여부를 필터재의 흐름에 따라 비교, 분석하고 기존에 제안된 폐색 방지 기준을 적용하여 보았다. 이러한 실험결과를 토대로 하여 수평 흐름시 발생하는 공간적 투수 계수 변화를 예측할 수 있는 모델을 제안하고 실내에서 실시한 모형실험과 이론적 모델예측의 비교를 통하여 투수능 저하 현상의 시각적, 공간적 변화 양상을 파악하였다.

• 한국농공학회지
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• 제23권3호
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• pp.65-77
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• 1981

The Compaction of fill dam is very important for increasing of the safty of dam. Vibration roller is used for the compaction of pervious materials such as sand and gravel. The principal objects of this study are to give a comstruction criteria of vibration roller and to find out the relationship between dry density and permeabity of pervious soil after compaction. The results in this study are summerized as follows. 1.The relationship between maximum dry density (Υdmax) and optimum moisture content(Wo) of modified compaction test is Υdmax=2. 74-0. 064w0 2.The maximum dry density decrease with increasing fine particle(n) and the relative formular is n==ae-brdmax 3.The maximum dry density is influenced more by passing rate of number 200 sieve than 4 sieve. 4.The coefficient of permeability are similar when the degrees of compaction are equal even though the spreading thickness of soil are different. 5.The coefficient of permeability(K)is greatly influence by fine particle passing number 200 sieve, and those relationship is inversely proportionate. 6.The K values of pervious soil are from 10-0 cm/sec to 10-4 cm/sec when degree of compaction by a modified method is from 90 to 95percent. 7.The coarser material is little influenced on the permeability with different density. 8.The increasing rate of permeability with decreasing degree of compaction is more influened by fine pacticle than number 200 sieve. When degree of compaction decrease from 100 percent to 90 percent the K values of SM and GM increase about 20 times but GW increase 6 times only. 9.The effect of compaction by vibration roller is greatly influenced by 6 passes and the increasing rate of the effect is decraased at 8 passes. 10. In order to get the degree of compaction of 95 percent or more, 6 to 8 passes of roller are generall required with 30 cm thickeness of soil for 4.5 ton to 6.5 ton vibration roller and 7 to 8 passes is required with 50cm thickness for 8 to 12 ton roller.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1998년도 가을 학술발표회 논문집
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• pp.65-72
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• 1998