• Title/Summary/Keyword: LANDSLIDE AFFECTING FACTOR

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An Assessment of Ecological Risk by Landslide Susceptibility in Bukhansan National Park (산사태취약성 분석을 통한 북한산국립공원의 생태적 위험도 평가)

  • Kim, Kyung-Tae;Jung, Sung-Gwan;You, Ju-Han;Jang, Gab-Sue
    • Korean Journal of Environment and Ecology
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    • v.22 no.2
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    • pp.119-127
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    • 2008
  • This research managed to establish the space information on incidence factors of landslide targeting Bukhansan National Park and aimed at suggesting a basic data for disaster prevention of a landslide for the period to come in Bukhansan National Park through drawing up the map indicating vulnerability to a landslide and ecological risks by the use of overlay analysis and adding-up estimation matrix analysis methods. This research selected slope angle, slope aspect, slope length, drainage, vegetation index(NDVI) and land use as an assessment factor of a landslide and constructed the spatial database at a level of '$30m\times30m$' resolution. The analysis result was that there existed high vulnerability to a landslide almost all over Uidong and Dobong valleys. As for ecological risks, Dobong valley, Yongueocheon valley, Jeongneung valley and Pyeongchang valley were analyzed to be higher, so it is judged that the impact on a landslide risk should be also considered in time of establishing a management plan for these districts for the time to come.

Comparison between Models for Thickness of Soils (토심추정 모형의 비교)

  • Min, Chang-Sik;Jang, Byeong-Uk;Cha, Gyeong-Seop
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2005.10a
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    • pp.399-403
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    • 2005
  • Slope angle, ground water table and thickness of soils are the key factors affecting landslide stability. However examining the factors such as thickness of soils; geological structure, slope angle, and height, in order to use the global landslide susceptibility forecasting analysis is very expensive and time consuming effort. So most researchers prefer to use the simplest methods such as the C strata and the USGS methods. In this research thickness of soils was calculated using these two methods and stability analysis was performed with the thickness of soils calculated by the two methods at the SINMAP based on ArcView 3.2. The two safety factor maps were compared with the past landslide records. The thickness of soils calculated by USGS method showed more unstable safety factors.

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Prediction and Evaluation of Landslide Hazard Based on Regional Forest Environment (지역산림환경을 기반으로 한 산사태 발생 위험성의 예측 및 평가)

  • Ma, Ho-Seop;Kang, Won-Seok;Lee, Sung-Jae
    • Journal of Korean Society of Forest Science
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    • v.103 no.2
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    • pp.233-239
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    • 2014
  • This study was carried out to propose the criteria for the prediction of landslide occurrence through analysis the influence of each factor by using the quantification theory. The results obtained from this study are summarized as follows. From a stepwise regression analysis between the landslide area($m^2$) and environmental factors, the factors strongly affecting the landslide sediment($m^2$) were the Parents rock (igneous), cross slope(complex), coniferous forests (forest type) and slope gradient ($21{\sim}30^{\circ}$). According to the range, it was shown in order of Cross slope (0.2922), Parents rock (0.2691), Forest type (0.2631) and Slope gradient (0.2312). The range of prediction score of landslide occurrence has been distributed between score 0 and score 1.0556, the median value was score 0.5278. The prediction for class I was over 0.7818, for class II was 0.5279 to 0.7917, for class III 0.2694 to 0.5278 and for class IV was below 0.2693. The prediction on landslide occurrence appeared relatively high accuracy rate as 72% for class I and II. Therefore, this score table for landslide will be very useful for judgement of dangerous slope.

Analysis of Landslide Hazard Map during Earthquake with Various Degrees of Saturation and Cohesion Values (포화도 및 점착력 변화에 따른 지진시 산사태 위험도 분석)

  • Lee, Joonyong;Han, Jin-Tae
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.3
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    • pp.599-606
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    • 2015
  • Damage of landslide due to earthquake covers a considerable part of total damage due to earthquake. Landslide due to earthquake affects direct damage of human lives and structures, and social system can be paralyzed by losing functions of roads, basic industries, and so on. Therefore, systematic and specialized research examining the factors affecting the slope stability by earthquakes should be needed. However, method of evaluation of slope stability problems due to earthquake contains somewhat uncertainty since many soil properties are predicted or assumed. In this study, influences of change of soil properties such as degree of saturation and cohesion value are analyzed in factor of safety and displacement using seismic landslide hazard maps based on GIS. As the degree of saturation increases or cohesion decreases, it is found that seismic landslide hazard area marked with factors of safety or displacements tends to increase. Therefore, to draw more exact landslide hazard map during earthquake, it is necessary to obtain accurate soil property information preferentially from site investigation data in the field.