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http://dx.doi.org/10.7843/kgs.2013.29.9.5

Stability Analysis of the Unsaturated Infinite Slope Considering Suction Stress under Steady Infiltration Condition  

Song, Young-Suk (Geologic Environment Division, Korea Institute of Geoscience and Mineral Resources)
Publication Information
Journal of the Korean Geotechnical Society / v.29, no.9, 2013 , pp. 5-15 More about this Journal
Abstract
In this paper, the unsaturated slope stability analysis considering suction stress (Lu and Godt, 2008) was introduced and the results applied for a certain sand slope were analyzed. The unsaturated slope stability analysis considering suction stress can analyze both conditions of steady infiltration and no infiltration, and it can estimate the safety factor of slope as a function of soil depth. Also, the influence of weathering phenomenon at a certain depth from the ground surface can be considered. The stability analysis considering suction stress was applied to the unsaturated infinite slope composed of sand with the relative density of 60%. The suction stress under no infiltration condition was affected by ground water table until a certain influencing depth. However, the suction stress under steady infiltration condition was affected by seepage throughout the soils. Especially, the maximum suction stress was displayed around ground surface. The factor of safety in the infinite slope under no infiltration condition rapidly increased and decreased within the influence zone of ground water table. As a result of slope stability analysis, the factor of safety is less than 1 at the depth of 2.4 m below the ground surface. It means that the probability of slope failure is too high within the range of depths. The factor of safety under steady infiltration condition is greater than that under no infiltration condition due to the change of suction stress induced by seepage. As the steady infiltration rate of precipitation was getting closer to the saturated hydraulic conductivity, the factor of safety decreased. In case of the steady infiltration rate of precipitation with $-1.8{\times}10^{-3}cm/s$, the factor of safety is less than 1 at the depths between 0.2 m and 3 m below the ground surface. It means that the probability of slope failure is too high within the range of depths, and type of slope failure is likely to be shallow landslides.
Keywords
Infinite slope stability analysis; Suction stress; Steady infiltration condition; Factor of safety; Unsaturated soil;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
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1 Terzaghi, K. (1943), Theoretical soil mechanics, John Wiley & Sons Inc., New York.
2 van Genuchten, M.T. (1980), "A closed-form equation for predicting the hydraulic conductivity of unsaturated soils", Soil Science Society of America Journal, Vol.44, pp.892-898.   DOI   ScienceOn
3 Lu, N. and Likos, W.J. (2006), "Suction stress characteristic curve for unsaturated soil", Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.132, No.2, pp.131-142.   DOI   ScienceOn
4 Bishop, A.W. (1959), "The principle of effective stress", Teknisk Ukeblad I Samarbeide Med Teknikk, Vol.106, No.39, pp.859-863.
5 Cornforth, D.H. (1973), "Prediction of drained strength of sands from relative density measurement", ASTM STP 523, pp.281-303.
6 Cornforth, D.H. (2005), Landslides in Practice; Investigation, Analysis, and Remedial/Preventative Options in Soils, John Wiley and Sons, 569p.
7 Marachi, N.D., Chan, C.K., Seed, H.B., and Duncan, J.M. (1969), Strength and deformation characteristics of rockfill materials, University fo California, Report TE-69-5, Berkeley, California.
8 Wayllace, A. and Lu, N. (2012), "A transient water release and imbibitions method for rapidly measuring wetting and drying soil water retention and hydraulic conductivity functions", Geotechnical Testing Journal, ASTM, Vol.35, GTJ103596.   DOI
9 Wolle, C.M. and Hachich, W. (1989), "Rain-induced landslides in southeastern Brazil", Proc. of the 12th International Conference on Soil Mechanics and Foundation Engineering, Roi de Janeiro, pp. 1639-1644.
10 Lu, N., Godt, J.W., and Wu, D.T. (2010), "A closed-form equation for effective stress in unsaturated soil", Water Resources Research, Vol.46, W05515.
11 Mualem, Y. (1976), "A new model for predicting the hydraulic conductivity of unsaturated porous media", Water Resources Research, Vol.12, No.3, pp.513-522.   DOI   ScienceOn
12 Ng, C.W.W. and Shi, Q. (1998), "A numerical investigation of the stability of unsaturated soil slopes subjected to transient seepage", Computers and Geotechnics, Vol.22, No.1, pp.1-28.   DOI   ScienceOn
13 Park, D.K., Oh, J.R., Son, Y.J., Park, J.H., and Lee, M.S. (2008), "Steep slope management system in Korea", Proc. the 2nd East Asia Landslides Symposium, Seoul, pp.7-11.
14 Song, Y.S. and Choi, J.S. (2012), "Hysteresis of the suction stress in unsaturated weathered mudstone soils", Journal of Korean Geotechnical Society, Vol.28, No.3, pp.91-100. (in Korean)   DOI   ScienceOn
15 Song, Y.S., Choi, J.S., and Kim, G.W. (2012a), "Experimental study on the hysteresis of suction stress in unsaturated sand" Journal of Engineering Geology, Vol.22, No.2, pp.145-155. (in Korean)   과학기술학회마을   DOI   ScienceOn
16 Song, Y.S., Hong, W.P., and Woo, K.S. (2012b), "Behavior and analysis of stabilizing piles installed in a cut slope during heavy rainfall", Engineering Geology, Vol.129-130, pp.56-67.   DOI   ScienceOn
17 Song, Y.S., Hwang, W.K., Jung, S.J., and Kim, T.H. (2012c), "A comparative study of suction stress between sand and silt under unsaturated conditions", Engineering Geology, Vol.124, pp.90-97.   DOI   ScienceOn
18 Song, Y.S., Lee, N.W., Hwang, W.K., and Kim, T.H. (2010), "Construction and application of an automated apparatus for calculating the Soil-Water Characteristic Curve", Journal of Engineering Geology, Vol.20, No.3, pp.281-295. (in Korean)   과학기술학회마을
19 Godt, J.W., Baum, R.L., and Chleborad, A.F. (2006), "Rainfall characteristics for shallow landsliding in Seattle, Washington, USA". Earth Surface Processes and Landforms, Vol.31, No.1, pp.97-110.   DOI   ScienceOn
20 Gallipoli, D., Gens, A., Sharma, R., and Vaunat, J. (2003), "An elasto-plastic model for unsaturated soil incorporating the effects of suction and degree of saturation on mechanical behaviour", Geotechnique, Vol.53, No.1, pp.123-135.   DOI   ScienceOn
21 Hilf, J.W. (1956), An investigation of pore water pressure in compacted cohesive soils, Technical Memorandum No.654, U.S. Department of the interior, Bureau of Reclamation, Design and Construction Division, Denver, Colorado.
22 Karube, D. and Kato, S. (1994), "An ideal unsaturated soil and the Bishop's soil", Proc. 13th nternational Conference on Soil Mechanics and Foundation Engineering, New Delhi, India, Vol.1, pp.43-46.
23 Kim, J.H., Jeong, S.S., Park, S.W., and Sharma, J. (2004), "Influence of rainfall-induced wetting on the stability of slopes in weathered soils", Engineering Geology, Vol.75, pp.251-262.   DOI   ScienceOn
24 Kim, K.S., Song, Y.S., Chae, B.G., Cho, Y.C., and Lee, C.O. (2007), "Geometric characteristics of landslides on natural terrain according to the geological condition", Journal of Engineering Geology, Vol.17, No.1, pp.75-87. (in Korean)   과학기술학회마을
25 Lu, N. and Godt., J. (2008), "Infinite-Slope Stability under Steady Unsaturated Seepage Conditions", Water Resources Research, W11404, Vol.44, pp.1-13.
26 Lu, N. and Griffiths, D.V. (2004), "Suction stress profiles in unsaturated soils", Journal of Geotechnical and Geoenvironmental Engineering, ASCE, Vol.130, No.10, pp.1063-1076.   DOI   ScienceOn
27 Lu, N. and Likos, W.J. (2004), Unsaturated soil mechanics, John Wiley & Sons Inc., New York. 556p.
28 de Campos, T.M.P., Andrade, M.H.N., and Vargas, E.A., Jr. (1991), "Unsaturated colluvium over rock slide in a forested site in Rio de Janeiro, Brazil", Proc. 6th Int. Symp. on landslides, Christchurch, New Zealand, Vol.2, pp.1357-1364.