• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1241-1245
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• 2006

절 성토사면에 구조물을 설치할 경우 가장 중요하게 고려되어야 하는 점은 사면의 안정성 여부이다. 특히, 절 성토사면에 설치된 구조물이 붕괴되는 가장 큰 원인은 뒷채움재 내에 존재하는 수압의 영향이라는 것을 우리는 이미 많은 연구와 경험을 통해 알고 있다. 만일 지하수위가 존재하는 상태에서 단시간에 발생되는 집중호우로 인해 수위가 갑자기 상승하였을 경우, 구조물을 통해 전혀 배수되지 않는다면 절 성토사면의 안정성은 급격히 저하될 것이다. 이러한 사면의 배수압을 소산시킬 수 있는 공법은 여러 가지가 있으나, 본 연구에서는 특히 제주도의 지역적 특성을 고려하여 화산석을 채움재로 사용한 Mattress/Filter를 절 성토사면에 설치함으로써 배수압을 소산시킬 수 있는 방법을 연구하였다. Mattress/Filter는 제방 또는 절 성토사면의 파괴와 침식을 방지하기 위해 사면에 설치하는 육각형의 철망구조로서 유연성, 다공성, 배수성 및 식생성과 같은 특징이 있으며, 콘크리트 구조물과 달리 별도의 배수시설을 필요로 하지 않는 장점이 있다. 또한 본 연구에 사용된 Mattress/Filter의 채움재인 화산석은 현재 제주도 지역에 방대하게 분포되어 있다. 특히 현무암은 제주도 암석 전체의 90%이상을 차지하고 있으며, 투수성이 매우 큰 암석이다. 현무암의 공극률은 그 종류에 따라 $0.02{\sim}0.36$의 범위로 나타난다. 특히, 표선리현무암의 경우 평균 공극률이 0.23으로 나타나 모래의 공극률인 $0.3{\sim}0.8$에 비교하여 볼 때, 연구에 사용된 재료는 아주 우수한 투수성을 가진 것으로 판명된다. 또한 현무암의 경우 암석의 겉 표면이 미세한 다공질 조직으로 이루어져 있다. 따라서 암석자체에 물이 정체될 수 있어 구조물을 통해 배수될 때 암석이 머금고 있는 물로 인해 추가적으로 발생하는 중력은 다른 재료가 가지지 못한 화산석의 또 다른 장점이라 할 수 있다.서는 자료변환 및 가공이 필요하다. 즉, 각 상습침수지구에 필요한 지형도는 국립지리원에서 제작된 1:5,000 수치지형도가 있으나 이는 자료가 방대하고 상습침수지구에 필요하지 않은 자료들을 많이 포함하고 있으므로 상습침수지구의 데이터를 인터넷을 통해 서비스하기 위해서는 많은 불필요한 레이어의 삭제, 서비스 속도를 고려한 데이터의 일반화작업, 지도의 축소.확대 등 자료제공 방식에 따른 작업 그리고 가시성을 고려한 심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전략이고, 이 전략의 유용성은 투자자가 설정한 투자기간보다 더욱 긴 분석기간의 주식가격정보에 의하여 최대한 발휘될 수 있음을 확인하였다.(M1), 무역적자의 폭, 산업

• Geophysics and Geophysical Exploration
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• v.17 no.1
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• pp.1-10
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• 2014

To reveal and classify site characteristics in densely populated areas in Chuncheon, Korea, Rayleigh-waves were recorded at 50 sites including four sites in the forest area using four 1-Hz velocity sensors and 24 4.5-Hz vertical geophones during the period of January 2011 to May 2013. Dispersion curves of the Rayleigh waves obtained by the extended spatial autocorrelation method were inverted to derive shear-wave velocity ($v_s$) models comprising 40 horizontal layers of 1-m thickness. Depths to weathered rocks ($D_b$), shear wave velocities of these basement rocks ($v_s^b$), average velocities of the overburden layer ($\bar{v}_s^s$), and the average velocity to a depth of 30 m ($v_s30$), were then derived from those models. The estimated values of $D_b$, $v_s^b$, $\bar{v}_s^s$, and $v_s30$ for 46 sites at lower altitudes were in the ranges of 5 to 29 m, 404 to 561 m/s, 208 to 375 ms/s, and 226 to 583 m/s, respectively. According to the Korean building code for seismic design, the estimated $v_s30$ indicates that the lower altitude areas in Chuncheon are classified as $S_C$ (very dense soil and soft rock) or $S_D$ (stiff soil). To determine adequate proxies for $v_s30$, we compared the computed values with land cover, lithology, topographic slope, and surface elevation at each of the measurement sites. Due to a weak correlation (r = 0.41) between $v_s30$ and elevation, the best proxy of them, applications of this proxy to Chuncheon of a relatively small area seem to be limited.

• Journal of Korean Society of Forest Science
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• v.52 no.1
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• pp.72-78
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• 1981

On August 25, 1979 a heavy daily rainfall of 465 mm pured into Jinhae area by the influence of Typhoon Judy. In consequence of the typhoon, 38 persons were killed, houses and arable land were demolished and caused wide ranges of landslides in the area. According to the previous investigation, there had been five cases of such typhoons accompanied a daily precipitation over 300 mm for 27 years, however, there had not occurred any landslides before, even though it is reported that any typhoon accompanied by heavy daily rainfalls over 300 mm is normally known to cause various kinds of landslides. This phonomenon was described to the fact that there has been a qualitative change in the agents of landslides such as precipitation, geology, topography and forest. Thus, in this report, the relations of the agents to the development of landslides were to be analysed and brought forth the following confirmation: 1. In the district, 71 landslides of which area covered 15.3 ha were observed. 2. In terms of geology of the landslided sites. 89 and 11% in numbers were observed in the andesite and the granite respectively, and the areas of those landslide estimated 45 and 55% respectively. 3. In a topographical point of view, 44% of the numbers of landslides(55% in area basis) were occurred within the slopes of $26-35^{\circ}$, while no landslides were observed in either lower (below $9^{\circ}$) or upper (above $41^{\circ}$) slopes. In terms of slope patterns, 39 and 33% in numbers (52 and 46% on the basis of area) were observed in concave slopes and compound slopes respectively. 4. In terms of forest ages, the most landslides were observed in 5-15 year-old forest, of which averages were 2.19 landslides per 100 ha and 0.47 ha per 100 ha. However, no landslides were observed in the forest of over 26 years old. 5. Among the agents, precipitation, geology, topography are considered not to be controlled but the only agent, the forest, to be controlled by human beings. Thus, this firstly observed landslides at Jinhae District are conclusively considered as the result of qualitative changes of one agent, the forest, in the area.

• Journal of Korea Water Resources Association
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• v.45 no.6
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• pp.569-581
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• 2012

The levee is the facility which is constructed along with river for the protection of landside and for passage of water when there is a flood. When the seepage is exposed to the atmosphere on the landside surface of levee, it may eventually lead to levee failure. The seepage water may be removed from the landside surface by a properly designed drainage system. The purpose of the study is to show seepage control effect of a pervious toe drain, and to compare two drainage methods of a pervious toe drain. One is the pervious toe drain suggested by U.S. Army Corps of Engineers (USACE) and the other is that suggested by Japan Institute of Construction Engineering (JICE). The levee model constructed has the following dimension: the base width is 2.6 m; the crest width is 0.4 m; the side slope 1 : 2. The water depth in the riverside is 0.5 m. The shape of the toe drain by USACE is triangular. The shape of the toe drain by JICE is rectangular. They were installed with the base length of 0.4 m. The levee model without the toe drain showed saturation surface on the land side in the experiment but not with the toe drain. The experiment results was applied to a numerical analysis model using SEEP/W to calibrate and verify. The numerical analysis results for 35 cm and 30 cm drain width showed that the drain by JICE is a little bit safer than the drain by USACE. It is also easier to construct the toe drain by JICE. The results in the study would be applied to plan the seepage control for a levee with pervious toe drain.

• Journal of Korean Society of Forest Science
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• v.27 no.1
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• pp.5-14
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• 1975

Eroded sloping faces in hillsides including cut-bank slopes are liable to both surface erosion and land-slides and the key to control of these form of erosion lies with drainages of excessive run-off and dense vegetation establishment including surface mulching on the slopes. Micro-plots having $1.6m^2$ (1 metre in width and 1.6 metres in slope length, and 1:1.2 in gradient) of banking slopes on coarse sand soil are used to establish the order of magnititude of the difference in controlling of soil erosion and water runoff, and in rating of survival, performed on the repetetions of three-experiment plots consisted of such three levels as 90% (Dense), 70% (Moderate), and 50% Sparse of the density of the coarse straw-mat mulchings. The main results obtained may be summarized as follows: 1. The rates of surface runoff are calculated as 13.13% from the dense mulchings, 14.21% from the moderate mulchings, and 15.57% from the sparse mulchings respectively. 2. The total amounts of soil loss are measured as about 1.24 tons/ha. from the dense mulchings, about 1.33 tons/ha. from the moderate mulchings, and about 1.44 tons/ha. from the sparse mulchings respectively. The amounts of soil loss under these treatments are much lower than the standard of erosion in USDA (1939 Bennet). 3. Average numbers of germination by treatment are counted as 80 seedlings at the dense mulchings. 132 at the moderates and 121 at the sparse respectively. Large numbers of seedling are suppressed and died during the growing at the dense mulchings due to mainly mechanical obstruction. 4. Coarse straw-mat having about 70% of coverage density is the most suitable mulches in both soil erosion control and vegetation establishment. 5. The method of coarse straw-mat mulching is the most recommendable measure for establishing the vegetation cover with less soil erosion on the denuded gentle slopes in hillsides at present in Korea.

• Korean Journal of Environment and Ecology
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• v.20 no.4
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• pp.436-447
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• 2006

Recently, there is increasing demand on enhancing the efficiency of hydro-seed spraying in afforestation for damaged or degraded land including forest road slopes. In this study, we focus on how seed coating and molding may affect seed germination and seedling growth. Plant species used in the study are Lespedeza cyrtobotrya, Indigofera pseudotinctoria, Arudineila hirta, Poa pratensis, and Lolium perenne. The results of seed germination and seedling growth with and without seed coating and molding are analyzed as follows: 1. For all the species and in both seeding with molding covered with soil and seeding without molding in which seeds were over sown, the increment of germination ratio by seed coating method is greater than by non·coating one. Seed coating increases average germination ratios observed in seeding with molding and without molding by 11.2% and 21.4%, respectively. Germination force may decrease from 0.8 to 3.7 days depending on the plant species and the treatments. The $LD_{50}$ decreased by $0.8{\sim}2.6$ days. However, seed coating delays the start of germination by approximate 1 day for all of the observed plants. 2. Seed coating may have the effect of accelerating the growth of stem and leaf and root. The experimental result shows that seed coating leads to 21.7% and 34.8% increment of average stem and leaf growth by seeding with molding and without molding, respectively. In terms of root growth, seeding with molding results in 22.0% increment while seeding without molding produces 26.2% increased root growth. 3: Compared to seeding without molding, germination starts on an average of 1.3 days later in seeding coated seeds with molding. However. the germination ratio is increased by 5%, and germination force and $LD_{50}$ are observed to shorten by 1.0 day and 1.4 days, respectively. Meanwhile, whether seeds are coated or not may be more related with germination and seedling growth in seeding without molding than with those in seeding with molding. 4. In this study, coating materials are examined to look at which ones are better in each treatment. Coating with Vermiculite+Talcum is the most effective in germination and seedling growth for overall plants. Seed coating using Bentonite, Calcium Carbonate, and Calcium Hydroxide shows better results than non-coating does. 5. When seeds are coated, the greatest enhancement of seed germinations was observed in Indigofera pseudotinctoria and, in the case of seedling growth, Lespedeza cyrtobotrya has the most increasing observation value among the 5 examined species. These results may indicate that woody plant seeds, having greater sizes of seeds than ones of grass seeds, may have greater relation with seed coating than grass plant seeds may have. 6. Therefore, if seeds cannot be molded up after hydro-seeding on forest road slopes, it is recommended that seeds for restoration be pre-coated with Vermiculite+Talcum and then be sowed, in order to quickly stabilize the damaged slope and achieve successful afforestation.

• Journal of the Korean association of regional geographers
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• v.4 no.2
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• pp.15-30
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• 1998

Physical geography is the discipline which deals with the relationship between man and natural environment. Therefore, it should be studied as the organized unity. In this paper I recognize the drainage basin as a framework outlining physical geography, describe the difference of inhabitant's life style due to the difference of natural environment in the drainage basin, and consider the meaning of drainage basin as a unit of life(and unit of regional geography). Munkyung is divided into three regions(intermontane basin region, middle mountainous region, marginal hilly region of the great basin) owing to the topographic characteristics. Subdivision in these regions is related closely to drainage network distribution, specially in intermontane basin region. And small regions have developed with the confluence point of $3{\sim}4$ order streams as the central figure. Intermontane basin region is the valley floor of Sinbuk-Soya-Kauun-Nongam stream located in the limestone region which is exposed according to Munkyung fault at its northern part. Small streams are affected strongly by the influence of the NNE-SSE or WNW-ESE tectolineament. Thus Kaeripryungro(鷄立嶺路), Saejaegil(새재길), Ewharyungro(伊火嶺路) and so on are constructed through the tectolineament. In the valley floors of small streams which flow into the intermontane basin, there are large floodplains. Floodplain in Sinbuk, Joryung, and Yangsan stream is used to paddy field or orchard, and in Nongam stream is used to paddy field or vegetable field. Hills are distributed largely in the periphery of intermontane basin. Limestone hills in Kauun and Masung basin are not continuous to the present low and flat floodplain, and most of those are used to forest land and field. On the other side. granite hills in Koyori are continuous to be used to the present floodplain, and they are used to residential area and field. In the middle mountainous region are there hilly mountains constructed in the geology of Palaeozoic Pyeongan System in northern area and Chosun System's Limestone Series in southern area, and banded gneiss and schist among Sobaeksan Gneiss Complex. In Palaeozoic Pyeongan System region are there relatively rugged mountains and ingrown meanders developed along tectolineaments. Chosun System's Limestone Series region builds up a geomorphic surface, develops various karst landforms. Mountainous area is used to field. On the other hand, especially in case of Hogye, valley bottom is wide, long, and discontinuous to slope, is used to paddy field dominantly. And schist region in Youngnam Block of Pre-Cambrian is rugged mountainous. Marginal hilly region of the great basin is hilly zone located in the margin of erosional basin(Bonghwa-Youngju-Yechon-Hamchang-Sangju). This region is lower geomorphic surface which is consisted of hills of $50{\sim}100$m height. Hills are used to field or orchard, and dissected gentle depression is used to paddy field.

• The Korean Journal of Pesticide Science
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• v.10 no.4
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• pp.279-288
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• 2006

Three different experiments were undertaken to investigate the runoff and erosion loss of diazinon and metolachlor from sloped-field by rainfall. The mobility of two pesticides and which phase they were transported by were examined in adsorption study, the influence of rainfall pattern and slope degree on the pesticide losses were evaluated in simulated rainfall study, and the pesticide losses from soybean field comparing with bare soil were measured in field lysimeter study. Freundlich adsorption parameter (K) ranged $1.6{\sim}2.0$ for metolachlor and $4.0{\sim}5.5$ for diazinon. The K values of pesticides by the desorption method were higher than those ones by the adsorption method. Another parameter (1/n) in Freundlich equation for the pesticides tested ranged $0.96{\sim}1.02$ by desorption method and $0.87{\sim}1.02$ by adsorption method. By the SSLRC's classification for pesticide mobility of diazinon and metolachlor were classified as moderately mobile ($75{\leq}Koc$ <500). Runoff and erosion losses of pesticides by three rainfall scenarios were $0.5{\sim}1.0%$ and $0.1{\sim}0.7%$ for metolachlor and $0.1{\sim}0.6%$ and $0.1{\sim}0.2%$ for diazinon. Distribution of pesticides in soil polite were investigated after the simulated rainfall events. Metolachlor was leached to $10{\sim}15$ cm soil layer and diazinon was leached to $5{\sim}10$ cm soil layer. Losses of each pesticide in the 30% of sloping degree treatment were $0.2{\sim}1.9$ times higher than those ones in the 10% of sloping degree treatment. Pesticide losses from a series of lysimeter plots in sloped land by rainfall ranged $1.0{\sim}3.1%$ for metolachlor and $0.23{\sim}0.50%$ for diazinon, and were $1/3{\sim}2.5$ times to the ones in the simulated rainfall study. The erosion rates of pesticides from soybean-plots were $21{\sim}75%$ lower than the ones from bare soil plots. The peak runoff concentration in soybean-plots and bare soil plots were $1{\sim}9{\mu}gL^{-1}$ and $3{\sim}16{\mu}gL^{-1}$ for diazinon, $7{\sim}31{\mu}gL^{-1}$ and $5{\sim}40{\mu}gL^{-1}$ for metolachlor, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.5
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• pp.259-267
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• 2006

Hydraulic conductivity is the rate of water flux on hydraulic gradient. The van Genuchten Mualem (VGM) model is frequently used for describing unsaturated state of soils, that is composed with the function of soil water potential and soil water content and requests various parameters. This study is to get the value of VGM parameters used Rosetta computer program based on neural network analysis method and to calculate VGM parameters. VGM parameters included Ko(effective saturated hydraulic conductivity), ${\theta}r$(residual soil water content), ${\theta}s$(saturated soil water content), L, n and m. The unsaturated hydraulic conductivity at 10 kPa was calculated by using Rosetta program. Unsaturated hydraulic conductivities of 17 soil series at 1, 3, 5, 7 kPa were also obtained by applying saturated hydraulic conductivity by disk tension infiltrometer based on Gardner and Wooding's equation. Water flow at the water potential of 3 kPa was very low except Namgye, Hagog, Baegsan, Sangju, Seogcheon, Yesan soil series. Unsaturated hydraulic conductivity at 1 kPa showed the highest value for Samgag soil series and was in order of Yesan, Hwabong, Hagog and Baegsan soil series. Those of Gacheon, Seocheon and Ugog soil series were very low. When the value by VGM was compared with the value by disc tension infiltrometer, there was a tendency with exponential function to soils without gravel but there was no tendency to soils including gravel. Conclusively, it would be limited that VGM model for unsaturated hydraulic conductivity analysis applies to Korean agricultural land including gravel and having steep slope, shallow soil depth.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.139-144
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• 2000

This study was conducted to obtain the basic information to increase the practical use of soil survey data through the subdividing of valley shapes with soil sequences due to different parent rocks, and to study the relationship between the valley shapes and parent rock. The various rocks such as sedimentary(gray shale and sand stone) and igneous rocks(granite, granite gneiss and andesite porphyry) which are the major parent rocks in Yeongnam area were investigated. The characteristics of valleys formed and the kinds of soils derived from different rocks were analysed by using aerial photographs and topographical maps scaled 1:5,000. The rill density in igneous rock area was as high as 40. But the rill bifurcation ratio of first order stream was higher in the sedimentary than the igneous rocks except granite area. The mean slope of valleys in igneous areas was about 8%, which was higher than that of the sedimentary areas. The variability of valley width in the complexly metamorphosed rock, such as granite gneiss, and andesite porphyry, was greater than in sedimentary and in granite rocks. Based on the variability of valley widths and valley slopes, it was possible to classify the valleys into two types. The "Uterus-shaped valleys" had wide variability of valley width and were located in the areas of granite gneiss and andesite porphry rocks. while the "Roots-shaped valleys" had narrow variability of valley width and were located in the sedimentary areas. "Uterus-shaped valleys" were typified by having land forms of mountain foot slopes and alluvial fans, and the soil drainage sequences also had complexities. So that, we concluded that the variability of valley width and valley slopes was associated with kinds of parent rocks and metamorphism which influences soil sequence and characteristics.