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2016 Vol.32, Issue 6 Preview Page
Slope Stability Assessment on a Landslide Risk Area in Ulsan During Rainfall

울산 산사태 위험지역의 강우 침투 안정성 평가

Jinwook Kim1
,
Hosung Shin2*
김 진욱1
,
신 호성2*
1Master Student, Dept. of Civil & Environmental Engrg., Univ. of Ulsan
2Associate Prof., Dept. of Civil & Environmental Engrg., Univ. of Ulsan
1울산대학교 건설환경공학부 석사과정
2울산대학교 건설환경공학부 부교수
*교신저자. *Corresponding Author. 
30 June 2016. pp. 27-40
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Abstract

Conventional warning criteria for landslides due to rainfall in broad regions have limitations, because they did not have proper reflection of topography, forest physiognomy, and unsaturated soil properties, et al. This study suggested a new stability model for unsaturated slope analyses during rainfall, considering rainfall pattern, geomorphological characteristics (slope angle, soil depth), engineering properties of unsaturated soils, and tree surcharge and root reinforcement. Stability analysis not considering root reinforcement and tree surcharge tends to over-predict a factor of safety in unsaturated slopes. Developed slope stability model was used to build database on the factor of safety in unsaturated slopes during rainfall, and it was integrated with GIS to do quantitative risk analysis in landslide risk areas specified in Ulju. Landslide risk areas were located at downstream of the point with sudden drop in safety factor, as well as at regions with low safety factor during rainfall.

Keywords
Landslide risk assessment
Unsaturated infinite slope stability
GIS

기존의 강우에 의한 사면붕괴 기준들은 지형학적 특성, 임상특성, 불포화 지반 조건 등을 반영하지 않아 사면 파괴 예측 지표로 활용하기에는 많은 문제점을 가지고 있다. 본 연구에서는 강우패턴, 지형학적 특성(경사, 토심), 공학적 특성(불포화 지반 특성), 임상특성(식생 뿌리에 의한 영향, 수목하중) 등을 반영할 수 있는 불포화 사면 안정성 해석 방법을 제안하였다. 뿌리보강과 수목하중을 고려하지 않는 사면의 안전율 평가는 안전율을 과다 평가하는 것으로 나타났다. 제안된 안정성 해석 방법에 의하여 강우에 의한 불포화사면의 안전율에 대한 데이터베이스를 구축하고, 이를 GIS와 연계하여 울주군 산사태위험 지정지역에 적용하여 강우에 대한 사면 위험성을 정량적으로 분석하였다. 산사태위험지역은 강우에 의한 사면의 안전율이 낮거나, 대부분 안전율 감소가 급격하게 발생한 지점의 하류에 위치하고 있음을 알 수 있다.

References
1
1.Caine, N. (1980), “The Rainfall Intensity-duration Control of Shallow Landslides and Debris Flows”, Geografiska Annaler. Series A. Physical Geography, Vol.62, pp.23-27.
2
2.Chacón, J., Irigeray, C., Fernandez, T., and El Hamdouni, R., (2006), “Engineering Geology Maps: Landslides and Geographical Information Systems”, Bull. Eng. Geol. Environ, Vol.65, No.4, pp.341-411.
3
3.Cho, S.E. and Lee, S.R. (2000), “Surficial Stability Evaluation of Homogeneous Slopes Considering Rainfall Characteristics”, Journal of the Korean geotechnical society, Vol.16, No.5, pp.107-116.
4
4.Gray, D.H. and Al-Refeai, T. (1986), “Behavior of Fabric Versus Fiber-reinforced Sand”, J. Geotech. Eng. Div., ASCE, Vol.112, No. 8, pp.804-820.
5
5.Green, W.H. and Ampt, G. (1911), “Studies on Soil Physics, 1. The Flow of Air and Water through Soils”, The Journal of Agricultural Science, Vol.4, pp.1-24.
6
6.Iida, T. (1999), “A Stochastic Hydro-geomorphological Model for Shallow Landsliding due to Rainstorm”, CATENA, Vol.34, No.34, pp.293-313.
7
7.Jeon, J.S. (2015), “Stability Assessment of the Landslide Considering Unsaturated Characteristics under Rainfall based on GIS”, MS Thesis, Yeungnam University.
8
8.Kim, J.H., Jeong, S.S., and Bae, D.H. (2013), “Predicting Rainfall Infiltration-groundwater Flow based on GIS for a Landslide Analysis”, Journal of Korean Geotechnical Society, Vol.29, No.7, pp.75-89.
9
9.Kim, J.S. (2014), “Analysis of Landslide Susceptibility in Physically based Model Considering Characteristics of Unsaturated Soil and Rainfall”, MS Thesis, University of Sejong.
10
10.Kim. Y.M. (2013), “Influence of Soil Characteristic and Rainfall Intensity on Matric Suction of Unsaturated Weathered Soil Slope”, Journal of the Korean society of civil engineers, Vol.33, No.3, pp.1017-1025.
11
11.Kim, Y.S. (2002), “Analysis of Landslide Susceptibility Area Using GIS”, MS thesis, Seoul National University.
12
12.Koean Institute of Landscape Architecture (2013), Landscape design standards, pp.59.
13
13.Lee, I.M. (1991), “An Experimental Study on the Effect of Vegetation Roots on Slope Stability of Hillside Slopes”, Journal of the Korean geotechnical society, Vol.7, No.2, pp.51-66.
14
14.Lee. S.J. (2005), “Soil Water Characteristic Curve for Weathered Ganite Soils a Test Method”, Journal of the Korean Geoenvironmental Society, Vol.21, pp.17-26.
15
15.Lee, S.R. (1999), “Development and Application of Landslide Susceptibility Analysis Techniques Using Geographic Information System (GIS)”, MS Thesis, Yonsei University.
16
16.Lee, S.R., Oh, T.K., Kim, Y.K., and Kim, H.C., (2009), “Influence of Rainfall Intensity and Saturated Permeability on Slope Stability during Rainfall Infiltration”, Journal of the Korean Geoenvironmental Society Vol.25, No.1, pp.65-76.
17
17.Lee, Y.H., Oh, S.B., Kim, K.H., and Seong, Y.H. (2012), “The Relationship between Effective Stress and Shear Strength of Weathered Granite Soils based on Matric Suctions”, Journal of the Korean Geoenvironmental Society, Vol.13, No.4, pp.45-51.
18
18.Lu, N. and Likos, W.J. (2006), “Suction Stress Characteristic Curve for Unsaturated Soil”, Journal of Geotechnical and Geoenvironmental Engineering, Vol.132, No.2, pp.131-142.
19
19.Lu, N. and Godt, J. (2008), “Infinite-slope Stability under Steady Unsaturated Seepage Conditions”, Water Resources Research, Vol.44, No.11, pp.1-13.10.1029/2008WR006976
20
20.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, pp.163-172.
21
21.Mein, R.G. and Larson, C.L. (1973), “Modeling Infiltration during a Steady Rain”, Water Resource Research, Vol.9, No.2, pp.384-394.
22
22.National Disaster Management Institute (2012), Re-establishment of rainfall criteria for steep slope failures, p146, 11-1311526- 000073-01.
23
23.Penizek, V. (2005), “Soil Depth Prediction Supported by Primary Terrain Attributes: A Comparison of Methods”, Plant Soil Environ., 52, pp.424-430.
24
24.Rahardjo, H., Lim, T.T., Chang, M.F., and Fredlund, D.G. (1995), “Shear-strength Characteristics of a Residual Soil”, Canadian Geotechnical Journal, Vol.32, No.1, pp.160-77.
25
25.Saito, H., Nakayama, D., and Matsuyama, H. (2010), “Relationship between the Initiation of a Shallow Landslide and Rainfall Intensity- duration Thresholds in Japan”, Geomorphology, Vol.118, No.1-2, pp.167-175.
26
26.Saulnier, G. M., Beven, K., and Obled, C. (1997), “Including Spatially Variable Effective Soil Depths in TOPMODEL”, Journal of hydrology, Vol.202, No.1/4, pp.158-172.
27
27.Shin, B.W. (2003), “Soil-water Characteristics of Unsaturated Decomposed Granite Soils”, Journal of the Korean Geoenvironmental Society, Vol.4, No.1, pp.49-58.
28
28.Shin, H., Kim, Y. T., and Park, D. K. (2013), “Development of Rainfall Hazard Envelope for Unsaturated Infinite Slope”, KSCE Journal of Civil Engineering, Vol.17, No.2, pp.351-356.
29
29.Song, Y.K. (2013), “Failure Prediction of Unsaturated Steep Slope Considering Rainfall Infiltration Characteristics”, Ph.D. Thesis, Myongji University.
30
30.Trigila, A., Iadanza, C., and Spizzichino, D. (2010), “Quality Assessment of the Italian Landslide Inventory Using GIS Processing”, Landslides, Vol.7, pp.455-470.
31
31.Van Genuchten, M.T. (1980), “A Closed form Equation Predicting the Hydraulic Conductivity of Unsaturated Soils”, Soil Science Society of America Journal, Vol.44, No.5, pp.892-898.
32
32.Waldron, L.J. and Dakessian, S. (1981), “Soil Reinforcement by Roots: Calculation of Increased Soil Shear Resistance from Root Properties”, Soil Sci., Vol.132, No.6, pp.427-435
33
33.Wu, T.H., McKinnell, W.P., and Swanston, D.N. (1979), “Strength of Tree Roots and Landslides on Prince of Wales Island, Alaska”, Can. Geotech., J., Vol.16, pp.19-33.
Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 32
  • No :6
  • Pages :27-40
  • Received Date : 2016-04-12
  • Revised Date : 2016-05-23
  • Accepted Date : 2016-06-03
  • DOI :https://doi.org/10.7843/kgs.2016.32.6.27
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