Influence of Salinity-Based Osmotic Suction on the Shear Strength of a Compacted Clay
Publication: International Journal of Geomechanics
Volume 21, Issue 5
Abstract
As most previous studies have neglected the positive influence of salinity (osmotic suction) on most coastal soils in Australia, the design of transport infrastructure involving these soils has often been overly conservative. In this study, a laboratory approach based on direct shear testing was explained to determine the stress–strain behavior of compacted coastal silty clay (CL) at different levels of osmotic suction generated by various salinity (NaCl) concentrations. A broad data set for a total of 147 direct shear tests conducted on remolded and recompacted test specimens at seven different initial matric suction conditions was analyzed to develop a semiempirical model that captures the effect of osmotic suction on the soil shear strength. The results suggested that the greater the initial matric suction, the more pronounced the role of osmotic suction. The proposed semiempirical model was governed by an electrical conductivity relationship with the osmotic suction generated by soil salinity. A new parameter χ2 was introduced to quantify the role of soil salinity in the apparent soil shear strength corresponding to different levels of osmotic suction. When this novel relationship was coupled with the conventional matric suction theory, the overall unsaturated shear strength of a saline soil could be properly evaluated, as proven by the close proximity of the predictions to the measurements.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The authors acknowledge the financial support provided by the Australian Government Research Training Program Scholarship and ARC Industry Transformation Training Centre for Advanced Rail Track Technologies (ITTC-Rail). The authors also appreciate the assistance provided by the University of Wollongong (UOW) technical staff member, Richard Berndt. The authors also acknowledge the contributions of previous Ph.D. students and Research Associates at UOW who have conducted research on native vegetation and unsaturated soil mechanics, namely, Dr. Behzad Fatahi, Dr. Shiran Gunasena, Dr. Udeshini Pathirage, and Dr. Muditha Pallewatha.
References
Abedi-Koupai, J., and H. Mehdizadeh. 2007. “Estimation of osmotic suction from electrical conductivity and water content measurements in unsaturated soils.” Geotech. Test. J. 31: 142–148. https://doi.org/10.1520/GTJ100322.
Adam, I., D. Michot, Y. Guero, B. Soubega, I. Moussa, G. Dutin, and C. Walter. 2012. “Detecting soil salinity changes in irrigated vertisols by electrical resistivity prospection during a desalinisation experiment.” Agric. Water Manage. 109: 1–10. https://doi.org/10.1016/j.agwat.2012.01.017.
Arora, S. 2017. “Diagnostic properties and constraints of salt-affected soils.” In Bioremediation of salt affected soils: An Indian perspective, edited by S. Arora, A. K. Singh, and Y. P. Singh, 44–52. Cham, Switzerland: Springer.
AS1289.3.1.1. 2009. Determination of the liquid limit of a soil-Four-point Casagrande method. Sydney, Australia: Standards Australia.
AS1289.3.2.1. 2009. Determination of the plastic limit of a soil-Standard method. Sydney, Australia: Standards Australia.
AS1289.3.5.2. 2009. Determination of the soil particle density of combined soil fractions-Vacuum Pycnometer method. Sydney, Australia: Standards Australia.
AS1289.3.6.1. 2009. Determination of the particle size distribution of a soil-standard method of analysis by sieving. Sydney, Australia: Standards Australia.
AS1289.5.1.1. 2009. Determination of the dry density/moisture content relation of a soil using standard compaction effort. Sydney, Australia: Standards Australia.
ASTM. 2003. Standard test method for measurement of soil potential (suction) using filter paper. D5298, ASTM, West Conshohocken, PA, USA.
ASTM. 2010. Test method for classification of soils for engineering purposes, unified soil classification system. D2487. West Conshohocken, PA: ASTM.
Barbour, S. L., and D. G. Fredlund. 1989. “Mechanisms of osmotic flow and volume change in clay soils.” Can. Geotech. J. 26 (4): 551–562. https://doi.org/10.1139/t89-068.
Bishop, A. W. 1960. The principles of effective stress. Oslo, Norway: Norges Geotekniske Institute.
Di Maio, C., L. Santoli, and P. Schiavone. 2004. “Volume change behaviour of clays: The influence of mineral composition, pore fluid composition and stress state.” Mech. Mater. 36 (5–6): 435–451. https://doi.org/10.1016/S0167-6636(03)00070-X.
Di Maio, C., and G. Scaringi. 2016. “Shear displacements induced by decrease in pore solution concentration on a pre-existing slip surface.” Eng. Geol. 200: 1–9. https://doi.org/10.1016/j.enggeo.2015.11.007.
Fredlund, D. G., H. Rahardjo, and M. D. Fredlund. 2012. Unsaturated soil mechanics in engineering practice. Hoboken, NJ: Wiley.
Graham, J., J. M. Oswell, and M. N. Gray. 1992. “The effective stress concept in saturated sand-clay buffer.” Can. Geotech. J. 29 (6): 1033–1043. https://doi.org/10.1139/t92-121.
Hen-Jones, R., P. Hughes, S. Glendinning, D. Gunn, J. Chambers, P. Wilkinson, and S. Uhlemann. 2014. Determination of moisture content and soil suction in engineered fills using electrical resistivity. Leiden, Netherlands: CRC Press.
Jayathilaka, P., B. Indraratna, and A. Heitor. 2019. “Influence that osmotic suction and tree roots has on the stability of coastal soils.” In Geotechnics for transportation infrastructure, edited by R. Sundaram, J. T. Shahu, and V. Havanagi, 669–680. Singapore: Springer.
Jiao-Jun, Z., K. Hong-Zhang, and Y. Gonda. 2007. “Application of Wenner configuration to estimate soil water content in pine plantations on sandy land.” Pedosphere 17 (6): 801–812. https://doi.org/10.1016/S1002-0160(07)60096-4.
Khabbaz, N., and M. H. Khalili. 1998. “A unique relationship for χ for the determination of the shear strength of unsaturated soils.” Géotechnique 48 (5): 681–687. https://doi.org/10.1680/geot.1998.48.5.681.
Khalili, N. 2018. “Guidelines for the application of effective stress principle to shear strength and volume change determination in unsaturated soils.” Aust. Geomech. J. 53: 37–47.
Khalili, N., F. Geiser, and G. E. Blight. 2004. “Effective stress in unsaturated soils: Review with new evidence.” Int. J. Geomech. 4 (2): 115–126. https://doi.org/10.1061/(ASCE)1532-3641(2004)4:2(115).
Li, S., H. Li, C.-Y. Xu, X.-R. Huang, D.-T. Xie, and J.-P. Ni. 2013. “Particle interaction forces induce soil particle transport during rainfall.” Soil Sci. Soc. Am. J. 77 (5): 1563–1571. https://doi.org/10.2136/sssaj2013.01.0009.
Liang, Y., N. Hilal, P. Langston, and V. Starov. 2007. “Interaction forces between colloidal particles in liquid: Theory and experiment.” Adv. Colloid Interface Sci. 134–135: 151–166. https://doi.org/10.1016/j.cis.2007.04.003.
Lu, N., and W. J. Likos. 2006. “Suction stress characteristic curve for unsaturated soil.” J. Geotech. Geoenviron. Eng. 132 (2): 131–142. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:2(131).
Murray, E. J., and V. Sivakumar. 2010. Unsaturated soils: A fundamental interpretation of soil behaviour. Hoboken, NJ: Wiley.
Pathirage, U., B. Indraratna, M. Pallewattha, and A. Heitor. 2017. “A theoretical model for total suction effects by tree roots.” Environ. Geotech. 6 (6): 353–360. https://doi.org/10.1680/jenge.15.00065.
Piegari, E., and R. Di Maio. 2013. “Estimating soil suction from electrical resistivity.” Nat. Hazards Earth Syst. Sci. 13 (9): 2369–2379. https://doi.org/10.5194/nhess-13-2369-2013.
Rao, S. M., and T. Thyagaraj. 2007. “Swell–compression behaviour of compacted clays under chemical gradients.” Can. Geotech. J. 44 (5): 520–532. https://doi.org/10.1139/t07-002.
Read, D. W. L., and R. Cameron. 1979. “Relationship between salinity and Wenner resistivity for some dryland soils.” Can. J. Soil Sci. 59 (4): 381–385. https://doi.org/10.4141/cjss79-043.
Rengasamy, P. 2006. “World salinization with emphasis on Australia.” J. Exp. Bot. 57 (5): 1017–1023. https://doi.org/10.1093/jxb/erj108.
Shah, P. H., and D. Singh. 2004. “A simple methodology for determining electrical conductivity of soils.” J. ASTM Int. 1 (5): 1–11. https://doi.org/10.1520/JAI12128.
Shevnin, V. A., H. Peinado, O. Delgado, and A. A. Ryjov. 2010. “Petrophysical and electrical study of soil properties in Sinaloa, Mexico.” In Near Surface 2010-16th EAGE European Meeting of Environmental and Engineering Geophysics, 164. Houten, Netherlands: European Association of Geoscientists & Engineers.
Tarantino, A., and S. Tombolato. 2005. “Coupling of hydraulic and mechanical behaviour in unsaturated compacted clay.” Géotechnique 55 (4): 307–317. https://doi.org/10.1680/geot.2005.55.4.307.
Tiwari, B., and B. Ajmera. 2015. “Reduction in fully softened shear strength of natural clays with NaCl leaching and its effect on slope stability.” J. Geotech. Geoenviron. Eng. 141 (1): 04014086. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001197.
Vanapalli, S. K., D. G. Fredlund, D. E. Pufahl, and A. W. Clifton. 1996. “Model for the prediction of shear strength with respect to soil suction.” Can. Geotech. J. 33 (3): 379–392. https://doi.org/10.1139/t96-060.
van Genuchten, M. T. 1980. “A closed-form equation for predicting the hydraulic conductivity of unsaturated soils.” Soil Sci. Soc. Am. J. 44 (5): 892–898. https://doi.org/10.2136/sssaj1980.03615995004400050002x.
Xu, Y. 2019. “Peak shear strength of compacted GMZ bentonites in saline solution.” Eng. Geol. 251: 93–99. https://doi.org/10.1016/j.enggeo.2019.02.009.
Information & Authors
Information
Published In
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Jun 10, 2020
Accepted: Nov 27, 2020
Published online: Feb 22, 2021
Published in print: May 1, 2021
Discussion open until: Jul 22, 2021
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.