기초저면의 조도가 기초의 침하 특성에 미치는 영향

유남재,김영길,박병수 강원대학교 산업기술연구소 1992 産業技術硏究 Vol.12 No.-

This research is to investigate the effect of base roughness of footing on characteristics of load-settlement curve. Parametric experiments of small scaled model test were performed with changing the properties of base roughness of model footing ; Gluing the vinyl, aluminum, sand paper, sand beneath the model footing surface. The width of model footing and relative density of soil foundation were also changed to investigate their effects on settlement characteristics of footing. The ultimate bearing capacity as well as the initial slope of load-settlement curve obtained from test results were compared with those from limit equilibrium methods proposed by Terzaghi, Hansen and Meyerhof. From test results, it was confirmed that the base roughness affected the failure mechanisms of showing different shapes of slip lines formed beneath the footing.

원심모형시험에 의한 편심하중을 받는 얕은기초의 거동

유남재,이명욱,박병수,정길수 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

This paper is an experimental and numerical work of investigating the bearing capacity of shallow foundation of rubble mound under eccentric loads. Parametric centrifuge model tests at the 50g level environments with the model footings in the form of strip footing were performed by changing the loading location of model footing, relative density and materials for ground foundation. For the model ground, crushed rock sampled from a rocky mountain was prepared with a grain size distribution of having an identical coefficient of uniformity to the field condition. Model ground was also prepared with relative densities of 50 % and 80 %. For loading condition, model tests with and without eccentric load were carried out to investigate the effect of eccentric loads and a numerical analysis with the commertially available software of FLAC was performed. For numerical estimation with FLAC, the hyperbolic model of a nonlinear elastic constitutive relationship was used to simulate the stress-strain constitutive relationship of model ground and a series of triaxial compression test were carried out to find the parameters for this model. Test results were analyzed and compared with Meyerhof method (1963), effective area method based on the limit equilibrium method, and a numerical analysis with FLAC.

水稻作 耕地의 區劃規模에 따른 農業機械의 作業性能(Ⅱ) : 乾畓直播 栽培 Direct-Seeding in dry Land

유수남,구자웅 全南大學校 農業科學技術硏究所 1997 農業科學技術硏究 Vol.32 No.-

본 연구는 건답직파 수도재배의 경우 농업기계 이용측면에서 포장의 대구획화에 따른 경지정리의 적정 구획규모 결정을 위한 기초자료와 영농의 효율화와 생산성 향상을 위한 영농방법 및 이에 따른 기계화 작업체계 수립의 기초자료를 제공하고자 경지구획(경구)의 규모와 형상에 따른 대형 고성능 농업기계의 포장작업능률, 포장작업효율 등을 분석하였으며, 그 연구결과를 요약하면 다음과 같다. 1. 장변 길이가 길어짐에 따라 이앙작업을 제외한 모든 작업에서 포장작업능률과 포장작업효율은 높아지는 것으로 나타났으며, 이에 따라 ha당 총작업소요시간도 줄어들었다. 2. 단변의 길이 증가에 따른 포장작업능률과 포장작업효율은 구동경운, 정지, 파종작업 등에서는 약간씩 증가하였으며, 수확작업에서는 거의 일정하게 나타난 반면, 제초제 살포와 병충해약제 살포 등 방제작업과 추비살포작업에서는 약간씩 낮아지는 것으로 나타났다. 한편 시비작업(기비살포)에서는 단변의 길이 변화에 따라 크게 변동하였다. ha당 총작업소요시간은 대체적으로 방제작업의 비중이 상대적으로 크기 때문에 단변의 길이 증가에 따라 약간씩 감소하는 것으로 나타났다. 3. 포장작업능률은 거의 모든 작업에서 동일한 구획규모에서는 장단변비의 증가에 따라 대체적으로 증가하였으며, 또한 같은 장단변비에서는 구획규모가 클수록 증가하는 것으로 나타났다. 총작업소요시간은 동일한 구획에서는 장단변비가 커질수록 감소하며, 같은 장단변비에서는 구획규모가 클수록 적어짐을 보였다. 그러나 장단변비가 커질수록 포장작업능률 증가율과 총작업소요시간의 감소율은 떨어지는 것으로 나타났다. 4. 대구획화를 위하여 장변의 길이를 길게하는 것은 단변을 길게하는 것보다 거의 모든 작업에서 효과적으로 포장작업능률과 포장작업효율을 높일수 있는 것으로 나타났다. 현행 농업기계 체계를 고려해 볼 때 장변의 길이는 100∼150 m, 단변의 길이는 60∼80 m로 각각 제한되어 적정 구획규모는 약 0.6∼1.2 ha 정도인 것으로 판단되며, 포장의 배수성 개선, 대형 트랙터에 적합한 부착작업기의 채용,포장주행이 가능한 방제 및 추비살포기계의 개발이 이루어진다면 농업기계능률을 높이기 위하여 1.2∼1.6 ha의 구획규모로 경지를 대구획화하는 것이 바람직 할 것으로 보인다. This study was carried out to evaluate the effect of field size on field capacities of farm machines and their operating times for determining the optimum field size in direct-seeding of rice in dry land. As long side length increases, the field capacities and field efficiencies increased and total operating time per ha of the machines decreased in most works. As short side length increases, the field capacities and field efficiencies increased slightly in rotary tilling, pulverizing, and seeding works, and were almost constant in harvesting work. But those were changed irregularly due to the wide effective working width in fertilizing work, and were decreased slightly owing to the time loss for resting in weedicide and pesticide application works. Total operating time per ha of the machines decreased slightly as the short side length increases. As the ratio of long side length to short side length increases under same field size, the field capacities of the machines increased and total operating time per ha of the machines decreased. But, increasing rates of field capacities and decreasing rate of operating time per ha were reduced gradually. In the case of same ratio, field capacities increased and total operating time per ha decreased as the field size increases. Increase of the long side length is more effective than that of the short side length for improving the field capacities of machines and reducing their operating times. Long side length is limited by the loading capacities of chemical distributers and short side length is limited by the effective working width of machines. And therefore long side and short side can be lengthende up to 100 - 150 m and 60 - 80 m, respectively and optimum field size is in the range of 0.6 - 1.2 ha under the current farm machine system. But, if improvement of drainage, and development of chemical distributer which can run in the field are achieved, field size in the range of 1.2 - 1.6 ha is desirable for improving field capacities of machines.

집중호우시 산사태 원인분석에 관한 사례연구

유남재,박병수 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

This study is a research result of investigating causes of landslides occurred at Uijongbu in Kyonggi Province, Korea. For works of this research, informations and data about landslides occurred at the site, geological and topographical informations were collected to analyze causes of landslides, and mapping landslides was performed by using results of field investigation. Data about rainfall during occurrence of landslides around Uijongbu was also used to fond the effect of intense rainfall on occurrence of landslides. Based on informations obtained from field investigation and collected data, the scale and the pattern of landslides were analyzed and influencing factors on landslide such as intensity and duration of rainfall, topography, geologic condition, geotechnical engineering properties of ground, forestry were investigated statistically to find causes of landslides. On the other hands, for geotechnical engineering respects, slope stability analysis was performed for the typical sites chosen from the sires where the landslides occurred, using informations obtained from detailed topographical survey with total stations, field reconnaissance and results from laboratory tests.

해조류 내 Na+ 챈널 차단 생리활성물질의 측정

유종수,천병수,김남길 한국해양대학교 해양과학기술연구소 2001 硏究論文集 Vol.10 No.1

A tissue biosensor was developed for the continuous determination of Na+ channel blockers. The proposed sensor was applied to the determination of Na+ channel blockers in seaweed. It was found that Na+ channel blocker content displayed seasonal variation; it was high from February to April and decreased thereafter (May∼August). From theme results the present proposed method may be used for high sensitive determination of Na+ channel blockers contained in the seaweed organisms and environments. Therefore, it may be important to monitor Na+ channel blocker content of seaweed throughout the year.

슬래그 다짐말뚝의 원심모델링

유남재,박병수,정길수,이명욱 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.B

This paper is experimental and numerical research results of performing centrifuge model tests to investigate the geotechnical engineering behavior of slag compaction pile as a substitute of sand compaction pile. In order to find the geotechnical engineering characteristics of the soft clay and the slag used in centrifuge model experiments, basic soil property tests, consolidation test, permeability tests and triaxial compression tests were performed. For centrifuge model tests, slags with changing relative density were used and their bearing capacity, stress concentrations in between pile and soft clay, settlement characteristics, and failure modes were investigated. As a results of centrifuge model tests, it was found that the bearing, capacity of model was increased with increasing density of slag pile and general shear failures were occured. Miniature soil pressure gauges were installed on model pile and soft ground respectively and thus vertical stress acting on them were measured. Stress concentration ratio was found to be in the range of 2.0∼3.0. Bearing capacity obtained from the model test with slag was greater than that from the model test with a sand having the identical layout to each other. Thus it was confirmed the slag was an appropriate substitution of pile for sand.

모래다짐말뚝으로 개량된 연약지반의 응력분담특성

유남재,박병수,정길수,김상진 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

This paper is results of extensive centrifuge model experiments about design factors influencing the bearing capacity and the settlement behaviors of SCP (Sand Compaction Pile). Centrifuge model tests were carried out changing design factors for SCP method such as replacement area ratio (as= 20, 40, 70%), improvement ratio to footing width (W/B = 1, 2, 3), and amount of fines in sand pile (#200 = 5, 10, 15). Therefore, the effects of these design factors on the bearing capacity and the settlement behavior of SCP were investigated and changes of stress concentratio rato due to such an design factors were also investigated. Centrifuge model testing technique for preparing and installing centrifuge model of sand compaction pile, using freezing them, was also developed. As results of centrifuge model tests, more fines in sand compaction pile increases the bearing capacity of SCP. Optimum improvement ratio to footing width was found to be 2. Values of stress concentration ratio was in the ranges of 1.5 - 3.5. The depth of bulging in sand piles was found in the range of 2.0 - 2.5 times of pile diameter.

토사 절토사면 안정성 영향인자의 민감도 분석

유남재,박병수,전상현,조한기 강원대학교 산업기술연구소 2006 産業技術硏究 Vol.26 No.B

A sensitivity analysis about effects of influencing factors on the stability of Soil cut slope was performed. Slope stability analyses were carried out under dry, rainy and seismic conditions. Dominant factors controlling the slope stability were chosen such as cohesion and internal friction angle, unit weight of soil, water table and seismic horizontal coefficient used for the slope stability during eurthquake. Parametric stability analysis with those factors was performed for sensitivity analysis. As results of analyzing the sensitivity of factors under dry and rainy conditions, effects of cohesion, internal friction angle and unit weight of soil on the stability of slope are more critical in the dry condition than in the rainy condition. Cohesion and internal friction angle are more dominant factors influencing the slope stability irrespective of dry or rainy conditions than unit weight of soil and the horizontal seismic coefficient. The unit weight and the horizontal seismic coefficient affects crucially the stability according to conditions of slope formation and dry or rainy seasons. For the effect of horizontal seismic coefficient on stability of slope, safety factor of slope is not affected significantly by dry or rainy conditions, However, increase of the horizontal seismic coefficient under the rainy condition does reduce the safety factor significantly rather than the dry condition. Therefore, it is needed that the location of the water table is assigned appropriately to satisfy the required safety factor of stability in the case of checking slope stability for the rainy and seismic conditions.

원심모형시험에 의한 사석재의 내부마찰각 추정

유남재,박병수,정길수,이종호 江原大學校 産業技術硏究所 2002 産業技術硏究 Vol.22 No.A

This paper is an experimental work of estimating friction angle of very coarse grained soil such as rubble mound by performing laboratory experiments. Two crushed rocks of rubble mound were used for tests. Triaxial compression tests with drained conditions were performed to measure friction angles of soils prepared by mixing the crushed soil having an identical coefficient of uniformity with different maximum grain size distribution. Centrifuge model experiments with those soils were also performed to measure angle of repose and to estimate friction angle of soil from measuring the slope of slip line in the active stress state. Model tests were carried out by changing the G-levels of 1G and 50G. From triaxial compression tests, the measured value of friction angle of soil is in the range of 41∼57˚. The measured value of repose angle is in the range of 32∼35˚. The values of friction angle are found not so sensitive to the maximum grain size of soil as long as the coefficient of uniformity is identical. Estimated value of friction angle from measuring the slope of slip line in the active stress state is in the range of 30~46˚. Thus, the estimated angle of friction are found to be greater in the order of the measured angle of repose, the estimated value from the slope of active state, and triaxial compression test results. On the other hand, the measured values of friction angle from triaxial tests were compared with empirical equations, based on the relation between friction angle and void ratio. Equations proposed by Helenelund(1966) and Hansen(1967) found to be relatively reliable to estimate friction angles of soil.

나팔꽃 피해를 지표로 한 광화학 옥시단트 오염의 평가

유영식,권우택,채수권,김남천 서울保健大學 1992 論文集 Vol.12 No.1