• Title/Summary/Keyword: Mountain slope

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Analysis of Rainfall Infiltration and Slope Stability in Deforested and Forested Areas Using Real-Time Water Content Monitoring (실시간 함수비 모니터링을 통한 벌목지역과 수풀지역의 강우침투 경향 분석)

  • Park, Sung-Il;Yoo, Hyung-Sik;Kim, Jae-Hong;Kim, Tae-Wan
    • Journal of the Korean Geotechnical Society
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    • v.40 no.6
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    • pp.45-55
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    • 2024
  • Due to ongoing climate change, large-scale landslides are occurring in many regions because of extreme rainfall, causing enormous human and property damage. In addition, expanding deforestation driven by indiscriminate development and insect pests in urban mountain areas contributes substantially to landslide occurrence. Predicting the likelihood of landslides is necessary to reduce damage and, where possible, prevent them. In this study, the flow of water in the ground was analyzed by measuring water content using a wireless sensor network in the deforested and forested areas of a natural slope, where shallow slope failures occurred during the rainy season. The results showed that water content in the forested area remained consistent, even during dry and rainy periods; preventing extreme drying and wetting cycles. In contrast, in the deforested area, considerable fluctuations in water content led to the formation of tensile cracks on the soil surface layer, creating water flow paths and influencing factors that compromise slope stability.

Umyeon Mountain Debris Flow Movement Analysis Using Random Walk Model (Random Walk Model을 활용한 우면산 토석류 거동 분석)

  • Kim, Gihong;Won, Sangyeon;Mo, Sehwan
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.5
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    • pp.515-525
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    • 2014
  • Recently, because of increasing in downpour and typhoon, which are caused by climate changes, those sedimentation disasters, such as landslide and debris flow, have become frequent. Those sedimentation disasters take place in natural slope. In order to predict debris flow damage range within wide area, the response model is more appropriate than numerical analysis. However, to make a prediction using Random Walk Model, the regional parameters is needed to be decided, since the regional environments conditions are not always same. This random Walk Model is a probability model with easy calculation method, and simplified slope factor. The objective of this study is to calculate the optimal parameters of Random Walk Model for Umyeon mountain in Seoul, where the large debris flow has occurred in 2011. Debris flow initiation zones and sedimentation zones were extracted through field survey, aerial photograph and visual reading of debris flow before and after its occurrence via LiDAR DEM.

Volcanic Geomorphology of Gonaengisool-oreum, Bonggae-dong, Jeju (제주시 봉개동 고냉이술 오름의 화산형태학적 특성)

  • Lee, Jeong-Hyun;Yun, Sung-Hyo
    • The Journal of the Petrological Society of Korea
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    • v.20 no.3
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    • pp.151-159
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    • 2011
  • The geology of the Gonaengisool-oreum, Bonggae-dong, Jeju consists of Yeongpyeong-dong basalt, Shinan-dong basalt, Bonggae-dong basalt and cinder in ascending order. Yeongpyeong-dong and Shinan-dong basalt is situated at the mid-mountain slope in southern part of the Gonaengisool-oreum, and Bonggae-dong basalt is located at the Gonaengisool-oreum area and nortgbern low foot of the mountain. Bonggae-dong basalt is aa lava flows with thick clinker. The Gonaengisool-oreum is isolated small volcano, that is, a lava shield having wide crater in the summit with several small pit craters. The average basal elevation of the Gonaengisool-oreum cone is 297.5 m(highest 300 m and lowest 295 m), and the highest summit is 304.5 m, average cone basal width is 597.5 m and cone height is 7.9 m, and mean slope of 1.5 for the flank of the shield cone.

Detection of forest Free - South Slope Features from Land Cover Classification in Mongolia

  • Bayarsaikhan, Uudus;Boldgiv, Bazartseren;Kim, Kyung-Ryul;Park, Kyung-Ae;Lee, Don-Koo
    • Proceedings of the KSRS Conference
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    • 2009.03a
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    • pp.354-359
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    • 2009
  • Land cover types of Hustai National Park (HNP) in Mongolia, a hotspot area with rare species, were classified and their temporal changes were evaluated using Landsat MSS TM/ETM data between 1994 and 2000. Maximum likelihood classification analysis showed an overall accuracy of 88.0% and 85.0% for the 1994 and 2000 images, respectively. Kappa coefficients associated with the classification were resulted to 0.85 for 1994 and 0.82 for 2000 image. Land cover types revealed significant temporal changes in the classification maps between 1994 and 2000. The area has increased considerably by 166.5km2 for mountain steppe. By contrast, agricultural areas and degraded areas affected by human being activity were decreased by 46.1km2 and 194.8km2 over the six year span, respectively. These areas were replaced by mountain steppe area. Specifically, forest area was noticeably fragmented, accompanied by the decrease of 400 ha. The forest area revealed a pattern with systematic gain and loss associated with the specific phenomenon called as forest free-south slope. We discussed the potential environmental conditions responsible for the systematic pattern and addressed other biological impacts by outbreaks of forest pests and ungulates.

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A numerical study on the influence of small underground cavities for estimation of slope safety factor (소규모 지하공동이 사면안전율 산정에 미치는 영향에 관한 수치해석 연구)

  • An, Joon-Sang;Kang, Kyung-Nam;Song, Ki-Il;Kim, Byung-Chan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.5
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    • pp.621-640
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    • 2019
  • Quantitative stability assessment of underground cavities can be presented as a factor of safety based on the Shear Strength Reduction Method (SSRM). Also, SSRM is one of the stability evaluation methods commonly used in slope stability analysis. However, there is a lack of research that considers the relationship between the probability of occurrence of cavities in the ground and the potential failure surface of the slope at the same time. In this study, the effect of small underground cavities on the failure behavior of the slope was analyzed by using SSRM. Considering some of the glaciology studies, there is a case that suggests that there is a cavity effect inside the glacier in the condition that the glacier slides. In this study, the stability evaluation of underground cavities and slope stability analysis, where SSRM is used in geotechnical engineering field, was carried out considering simultaneous conditions. The slope stability analysis according to the shape and position change of underground cavities which are likely to occur in the lower part of a mountain road was analyzed by using SSRM in FLAC3D software and the influence of underground cavities on the slope factor of safety was confirmed. If there are underground cavities near slope potential failure surface, it will affect the calculation of a factor of safety. The results of this study are expected to be basic data on slope stability analysis with small underground cavities.

An Analysis on Site, Soil and Cultivation Characteristics of Korean Mountain Cultivated Ginseng (Panax ginseng) Field (산양삼 재배지의 입지, 토양 및 재배특성 분석)

  • Kwon, Su-Deok;Kang, Jeong-Hee;Yoon, Jun-Hyuck;Moon, Hyun-Shik
    • Journal of agriculture & life science
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    • v.45 no.6
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    • pp.81-88
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    • 2011
  • This study was carried out to provide basic information for standard cultivation guideline of Korean mountain cultivated ginseng (Panax ginseng). Environmental conditions, soil properties, growth process, cultivation methods and sowing timing were investigated in cultivations of Korean mountain cultivated ginseng in Korea (18 region in 9 province). Most of Korean mountain cultivated ginseng was cultivated to north, north-east, east or north-west direction in broad-leaved forest, IV age group, and 500~1,000 trees/ha. Elevation was below 500 m and slope was below 25 in cultivation. There were significant differences in soil properties by region and cultivation based on organic matter (3.43~24.07%) and pH level (3.8~5.7). Sprouting, leaf unfolding, flowering, fruiting, red ripening, fruit drop and leaf drop of Korean mountain cultivated ginseng was investigated in cultivation. The results show that it took 98 days on average for the whole growth process. There were two methods, sowing and transplant for cultivation. Sowing methods were classified in sowing after opening-testa treatment and direct sowing. and it was 70% and 30%, respectively.

On the Determination of Slope Stability to Landslide by Quantification(II) (수량화(數量化)(II)에 의한 산사태사면(山沙汰斜面)의 위험도(危險度) 판별(判別))

  • Kang, Wee Pyeong;Murai, Hiroshi;Omura, Hiroshi;Ma, Ho Seop
    • Journal of Korean Society of Forest Science
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    • v.75 no.1
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    • pp.32-37
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    • 1986
  • In order to get the fundamental information that could be useful to judge the potentiality of occurrence of rapid shallow landslide in the objective slope, factors selected on Jinhae regions in Korea, where many landslides were caused by heavy rainfall of daily 465 mm and hourly 52mm in August 1979, was carried out through the multiple statistics of quantification method (II) by the electronic computer. The net system with 2×2cm unit mesh was overlayed with the contour map of scale 1:5000. 74 meshes of landslides and 119 meshes of non-landslide were sampled out to survey the state of vegetative cover and geomorphological conditions, those were divided into 6 items arid 27 categories. As a result, main factors that would lead to landslide were shown in order of vegetation, slope type, slope position, slope, aspect and numbers of stream. Particularly, coniferous forest of 10 years old, concave slope and foot of mountain were main factors making slope instability. On the contrary, coniferous forest of 20-30 years old, deciduous forest, convex slope and summit contributed to the stable against Landslide. The boundary value between two groups of existence and none of landslides was -0.123, and its prediction was 72%. It was well predicted to divide into two groups of them.

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Analysis on the Spatial Characteristics Caused by the Cropland Increase Using Multitemporal Landsat Images in Lower Reach of Duman River, Northeast Korea (다시기 위성영상을 이용한 두만강 하류지역의 농경지 개간의 공간적 특성분석)

  • Lee, Min-Boo;Han, Uk;Kim, Nam-Shin;Han, Ju-Youn;Shin, Keun-Ha;Kang, Chul-Sung
    • Journal of the Korean Geographical Society
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    • v.38 no.4
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    • pp.630-639
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    • 2003
  • This study aims to analysis the distribution and change of cropland and forest, the Onseong, Saebyeol, and Eundeok counties on the lower reach of Duman(Tumen) river, northeast Korea, using 1992 year Landsat TM data, 2000 year Landsat ETM data, and digital terrain elevation data(DTED). Land cover and land use of the study areas are classified into cropland, forest, village, and water body, using the supervised classification method including 1:50,000 DTED analysis, image band composition, and principal component analysis(PCA). Results of quantitative analysis present that each growth rate of cropland of Onseong and Eundeok are 22.8% and 14.7% corresponding to decreasing rates of forest, 8% and 13.6% during 8 years from 1992 to 2000. In Onseong, Saebyeol, and Eundeok, each values of mean elevations and slope gradients increased to 192m, 95m, and 91m from 157m, 85m, and 78m, and to 6.6, 3.0, and 4.4 from 5.2, 2.5, and 3.0. Especially, in case of newly developed cropland, the values of mean elevation and mean gradient have 225m, 122m, and 127m, and 9.4, 5.1, and 8.0, in above three regions. These new croplands were developing along to deeper valleys and toward lower hill and mountain slope up to knickpoint zone of gradient change. Deforested lands for cropland have formed irregular pattern of patch-type, and become sources for the sheet erosion, rilling and gulleying in mountain slope and sedimentation in local river channel. Though there were no field checking, analysis using landsat images and GIS mapping can help understand actual environmental problems relating to cropland development of mountain slope in North Korea.

A Study on the Pollutant Dispersion over a Mountain Valley Region (I) : Wind Tunnel Experiments (산악 계곡지형에서의 오염확산에 관한 연구(I) :풍동실험)

  • Yoo Seong-Yeon;Shim Woo-Sup;Kim Seogcheol
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.17 no.11
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    • pp.1050-1059
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    • 2005
  • Heat and SF6 gas dispersions over a complex terrain were investigated using wind tunnel. The wind speed, temperature and concentration profiles were measured for the 1/1000 scale complicated terrain model in an Eiffel type boundary layer wind tunnel with test section of 2.5m in height and 4.5m in width. The scale model was mounted on the top of a plate which can rotate with respect to the approaching wind. Dispersion processes from a continuous emission source driven by various wind direction were investigated, including plume climbing over the steep up-slope of the mountain and down-spreading toward the lower level of the valley. Extensive dispersion experiment data (wind speeds and concentration profiles) were provided for verification and validation of dispersion models. Under the identical flow and emission conditions, the independently measured profiles of the temperature and SF6 concentration showed an excellent agreement which ensured the credibility of the results.

Landslide Susceptibility Analysis in Baekdu Mountain Area Using ANN and AHP Method

  • Quan, Hechun;Moon, Hongduk;Jin, Guangri;Park, Sungsik
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.12
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    • pp.79-85
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    • 2014
  • To analyze the landslide susceptibility in Baekdu mountain area in china, we get two susceptibility maps using AcrView software through weighted overlay GIS (Geographic Information System) method in this paper. To assess the landslide susceptibility, five factors which affect the landslide occurrence were selected as: slope, aspect, soil type, geological type, and land use. The weight value and rating value of each factor were calculated by the two different methods of AHP (Analytic Hierarchy Process) and ANN (Artificial Neural Network). Then, the weight and rating value was used to obtain the susceptibility maps. Finally, the susceptibility map shows that the very dangerous areas (0.9 or higher) were mainly distributed in the mountainous areas around JiAnShi, LinJiangShi, and HeLongShi near the china-north Korea border and in the mountainous area between the WangQingXian and AnTuXian. From the contrast two susceptibility map, we also Knew that The accuracy of landslide susceptibility map drew by ANN method was better than AHP method.