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Research Article

Landslide Susceptibility Assessment Considering the Saturation Depth Ratio by Rainfall Change

강우변화에 따른 토층 내 침투깊이를 고려한 산사태위험지수 개발

Jae Hwan Kwak1
,
Man-Il Kim2*
,
Seung-Jae Lee3
곽 재환1
,
김 만일2*
,
이 승재3
1Forest Engineering Research Institute, National Forestry Cooperative Federation, Researcher
2Forest Engineering Research Institute, National Forestry Cooperative Federation, Principal Researcher
3National Center for AgroMeteorology, Dept. Head
1산림조합중앙회 산림공학연구소, 연구원
2산림조합중앙회 산림공학연구소, 책임연구원
3(재)국가농림기상센터, 부장
* Corresponding Author
31 December 2018. pp. 687-699
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Abstract

Understanding rain infiltration into the ground is an important feature of landslide risk evaluation. In this study, a landslide risk index for the study area is suggested, wherein the result of the landslide risk evaluation, based on the factor of safety (FS), is used. The landslide risk index is a landslide risk prediction index that utilizes the saturated depth ratio of the ground. Based on the landslide risk result for the study area, it was found that the FS was first to decrease. However, it gradually became convergent over the 50-year rainfall intensity study period, a result that is similar to the relationship between the saturated depth ratio and soil thickness. Moreover, saturated depth was also found to be deeper on gentle slopes than steep slopes. As such, the landslide risk index, based on the Inhu-ri study result, is thus suggested. Additionally, the suggested landslide risk index was compared and analyzed against the rainfall intensity of previous landslide experience. Results thus revealed that almost all landslides that occurred were over 0.7, which is the second grade, based on the landslide risk index.

Keywords
Infinite slope model
Rainfall intensity
GIS
Saturation depth ratio
landslide risk index

강우변화에 따라 토층 내로 침투되는 강우양상을 파악하는 것은 산사태 위험도 평가에 있어 매우 중요한 요소라 할 수 있다. 본 연구에서는 재현기간 별 강우변화에 따른 안전율 기반의 산사태 위험도를 평가하고 이를 바탕으로 연구지역 내 산사태 위험지수를 제안하고자 하였다. 산사태 위험지수는 토층으로 침투되는 강우양상을 침투깊이비로 추정하고 이를 기반으로 산사태 위험도를 사전에 파악할 수 있도록 지수로 표현한 것이다. 연구지역에 대한 산사태 위험도 분석결과, 빈도 별 강우강도가 증가하면서 연구지역 전체 안전율은 감소하는 경향을 보였으나 50년 빈도 이상의 강우조건에서는 점차 수렴하는 경향을 보였다. 이러한 현상은 침투깊이비와 토층깊이에서도 유사하게 나타났으며 경사가 완만할수록 침투깊이가 깊은 것으로 분석되었다. 분석결과를 바탕으로 연구지역 내 복수의 산사태가 발생된 인후리 지역에 대하여 산사태위험지수를 제안하였다. 제안된 산사태위험지수는 과거 산사태 발생 시 강우조건과 비교, 분석한 결과 대부분의 산사태 발생 강우강도 조건에서는 산사태위험지수 2등급, 0.7이상에서 발생된 것으로 분석되었다.

키워드
무한사면 안정해석
강우강도
GIS
침투깊이비
산사태위험지수
References
1
Beven K. J. and Kirkby M.J., 1979, A physically-based variable contributing area model of basin hydrology. Hydrological Sciences Bulletin, 24(1), 43-69.
10.1080/02626667909491834
2
Burrough, P.A., McDonnell, R.A., and Lloyd, C.D., 2013, Principles of Geographical Information Systems. OUP Oxford.
3
Chae, B-G., Park, K-B., Park, H-J., Choi, J-H. and Kim, M-I., 2012, Analysis of slope stability considering the saturation depth ratio by rainfall infiltration in unsaturated soil, The Journal of Engineering Geology, 22(3), 343-351.
10.9720/kseg.2012.3.343
4
Ha mmond, C., Hall, D., Miller, S., and Swetik, P., 1992, Level I Stability Analysis (LISA) Documentation for Version 2.0, General Technical Report INT-285, USDA Forest Service Intermountain Research Station 20p.
5
Jaafari, A., Najafi, A., Pourghasemi, H. R., Rezaeian, J., and Sattarian, A., 2014, GIS-based frequency ratio and index of entropy models for landslide susceptibility assessment in the Caspian forest, northern Iran, International Journal of Environmental Science and Technology, 11(4), 909-926.
10.1007/s13762-013-0464-0
6
Kim, J-W. and Shin, H-S, 2016, Slope stability assessment on a landslide risk area in ulsan during rainfall, Journal of the Korean Geotechnical Society, 32(6), 27-40.
10.7843/kgs.2016.32.6.27
7
Longley, P., 2005, Geographic information System and Science, Wiley.
8
Mehnatkesh, A., Ayoubi, S., Jalaliani, A., and Sahrawat, K., 2013, Relationships between Soil Depth and Terrain Attributes in a Semi Arid Hilly Region in Western Iran, Science Press and Institute of Mountain Hazards and Environment, CAS and Springer-Verlag Berlin Heidelberg, 10, 163-172.
9
Moore, I., Burch, G., 1986 Physical basis of the length-slope factor in the Universal Soil Loss Equation, Soil Science Society of America Journal, 50(5), 1294-1298.
10.2136/sssaj1986.03615995005000050042x
10
Moore, I., Grayson, R., Ladson, A., 1991, Digital terrain modeling: a review of hydrological, geomorphological, and biological applications. Hydrological Processes, 5(1), 3-30.
10.1002/hyp.3360050103
11
Olivares, L. and Picarelli, L., 2003, Shallow flowslides triggered by intense rainfalls in natural slopes covered by loose unsaturated pyroclastic soils, Geotechnique, 53(2), 283-287.
10.1680/geot.2003.53.2.283
12
Springman, S.M., Jo mmi, C. and Teysseire P., 2003, Instability on moraine slopes induced by loss of suction: a case history, Geotechnique, 53(1), 3-10.
10.1680/geot.2003.53.1.3
13
Xue, J. and Gavin, K., 2008, Effect of rainfall intensity on infiltration into partly saturated slopes, Geotech Geology Engineering, 26(1), 199-209.
10.1007/s10706-007-9157-0
14
Yu, J-S., Muha mmad, W., Shin, J-Y., and Kim T-W., 2015, Evaluation of Extended Inverse Distance Weighting Method for Constructing a Flow Duration Curve at Ungauged Basin, J. Korean Soc. Hazard Miting, 15(3), 329-337.
10.9798/KOSHAM.2015.15.3.329
Information
  • Publisher :Korean Society of Engineering Geology
  • Publisher(Ko) :대한지질공학회
  • Journal Title :The Journal of Engineering Geology
  • Journal Title(Ko) :지질공학
  • Volume : 28
  • No :4
  • Pages :687-699
  • Received Date : 2018-11-20
  • Revised Date : 2018-12-18
  • Accepted Date : 2018-12-21
  • DOI :https://doi.org/10.9720/kseg.2018.4.687
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