Suction-Monitored Direct Shear Testing of Residual Soils from Landslide-Prone Areas
This article has been corrected.
VIEW CORRECTIONPublication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 136, Issue 3
Abstract
The apparent cohesion due to soil suction plays an important role in maintaining the stability of steep unsaturated soil slopes with deep ground water table. In this paper, a modified direct shear box is used to determine the relationships between the value of this additional cohesion and the associated soil suction. The apparatus incorporates a miniature tensiometer which allows for the simple and direct measurement of suction during shearing. The soil-water characteristic curves and shearing behavior of intact residual soils, being low-to-medium plasticity silts, as well as silty sand, taken from four landslide-prone areas in Thailand, have been investigated. The relatively low air-entry suctions (0–7 kPa) and bimodality of the soil-water characteristic curves gives an indication of the structured pore size distribution of the materials tested. Samples with higher suction tend to display stronger bonding at particle contacts and thus are more brittle. The shear strength is found to increase nonlinearly with suction, though linearization can be reasonably assumed for suction below around 30 kPa. Prediction of shear strength based on soil-water characteristic curves agrees better with ultimate than peak values. A simple equation is proposed for the minimum ultimate strength that can be expected in an unsaturated residual soil with a suction lower than about 30 kPa.
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Acknowledgments
The writers gratefully acknowledge the research Grant No. UNSPECIFIEDMRG4980086 of the Thailand Research Fund and Commissions of Higher Education, Thailand, and thank Mr. Narin Hansachainun, Mr. Nattapong Paiboonsombat, and Mr. Lerdchao Kenganantanon for their assistance in performing some direct shear tests in this research project. The writers also thank Dr. Auckpath Sawangsuriya, Dr. Rafael Monroy, and other anonymous reviewers for their invaluable comments.UNSPECIFIED
References
Bishop, A. W., Alpan, I., Blight, G. E., and Donald, I. B. (1960). “Factors controlling the strength of partly saturated cohesive soils.” Proc., Res. Conf. on Shear Strength of Cohesive Soils, Univ. of Colorado, Boulder, 503–532.
Collins, B. D., and Znidarcic, D. (2004). “Stability analyses of rainfall-induced landslides.” J. Geotech. Geoenviron. Eng., 130(4), 362–372.
Fredlund, D. G., and Rahardjo, H. (1993). Soil mechanics for unsaturated soils, Wiley, New York.
Gitirana, G. de F. N., and Fredlund, D. G. (2004). “Soil-water characteristic curve equation with independent properties.” J. Geotech. Geoenviron. Eng., 130(2), 209–212.
Godt, J. W., Baum, R. L., and Lu, N. (2009). “Landsliding in partially saturated materials.” Geophys. Res. Lett., 36(L02403), 1–5.
Jotisankasa, A., Porlila, W., Soralump, S., and Mairiang, W. (2007). “Development of a low cost miniature tensiometer and its applications.” Proc., 3rd Asian Conf. on Unsaturated Soils (Unsat-Asia 2007), Science Press, Nanjing, China, 475–480.
Leroueil, S. (2001). “Natural slopes and cuts: Movement and failure mechanisms. The 39th Rankine lecture.” Geotechnique, 51(3), 197–243.
Lu, N., and Godt, J. W. (2008). “Infinite slope stability under steady unsaturated seepage conditions.” Water Resour. Res., 44(W11404), 1–13.
Lu, N., and Likos, W. J. (2006). “Suction stress characteristic curve for unsaturated soil.” J. Geotech. Geoenviron. Eng., 132(2), 131–142.
Mesri, G., and Shahien, M. (2003). “Residual shear strength mobilized in first-time slope failures.” J. Geotech. Geoenviron. Eng., 129(1), 12–31.
Vaughan, P. R. (1988). “Keynote paper: Characterising the mechanical properties of in situ residual soil.” Proc., 2nd Conf. Geomechanics in Tropical Soils, Balkema, Rotterdam, The Netherlands, 2, 469–487.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 136 • Issue 3 • March 2010
Pages: 533 - 537
Copyright
© 2010 ASCE.
History
Received: Aug 19, 2008
Accepted: Aug 13, 2009
Published online: Aug 26, 2009
Published in print: Mar 2010
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