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Evaluation of Slope Stability of Taebaeksan National Park using Detailed Soil Map

정밀토양도를 이용한 태백산국립공원의 사면안정성 평가

  • Kim, Young-Hwan (Graduate School of Disaster Prevention, Kangwon National University) ;
  • Jun, Byong-Hee (Graduate School of Disaster Prevention, Kangwon National University) ;
  • Jun, Kye-Won (Graduate School of Disaster Prevention, Kangwon National University)
  • 김영환 (강원대학교 방재전문대학원) ;
  • 전병희 (강원대학교 방재전문대학원) ;
  • 전계원 (강원대학교 방재전문대학원)
  • Received : 2019.05.14
  • Accepted : 2019.06.14
  • Published : 2019.06.30

Abstract

More than 64% of Korea's land is occupied by mountain regions, which have terrain characteristics that make it vulnerable to mountain disasters. The trails of Taebaeksan Mountain National Park-the region considered in this study-are located in the vicinity of steep slopes, and therefore, the region is vulnerable to landslides and debris flow during heavy storms. In this study, a slope stability model, which is a deterministic analysis method, was used to examine the potential occurrence of landslides. According to the soil classification of the detailed soil map, the specific weight of soil, effective cohesion, internal friction angle of soil, effective soil depth, and ground slope were used as the parameters of the model, and slope stability was evaluated based on the DEM of a 1 m grid. The results of the slope stability analysis showed that the more hazardous the area was, the closer the ratio of groundwater/effective soil depth is to 1.0. Further, many of the private houses and commercial facilities in the lower part of the national park were shown to be exposed to danger.

한국은 국토의 64%이상이 산지로 구성되어 있어 산지재해에 취약한 지형적 특성을 가진다. 연구대상지역인 태백산국립공원 당골유역은 탐방로 대부분이 급경사지와 인접해 있어 집중호우 시 산사태와 토석류에 취약한 지역이다. 본 연구에서는 결정론적 분석방법인 사면안정성 모델을 이용하여 사면재해 발생예측 가능성을 검토하였다. 모델의 매개변수는 정밀토양도의 토양분류에 따라 토질의 단위중량, 유효점착력, 흙의 내부마찰각, 유효토심, 지표경사 등을 이용하였고 1 m격자의 DEM을 바탕으로 사면안정성 평가를 실시하였다. 사면안정성평가 분석결과 지하수/ 유효토심과의 비가 1.0에 가까워질수록 위험지역이 높게 나타났으며, 국립공원 하류지역의 민가와 상업시설 상당수가 위험에 노출된 것으로 나타났다.

Keywords

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Fig. 1. Infinite slope stability analysis diagram

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Fig. 2. Study area

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Fig. 3. Slope and histogram from 1 m grid

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Fig. 4. Soil distribution in the study area

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Fig. 5. Parameters extracted from detailed soil map

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Fig. 6. Slope stability result (a) m=1.0; (b) m=0.5

Table 1. Total soil content by surface soil, specific weight, cohesion, and internal friction angle

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Table 2. Area of different soils in the study area

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