Fine grain soils have a complex engineering
behaviour which depends but not limited to moisture content, changes in
external pressure and characteristics of the pore medium. Sand often contains a
considerable percent of silt which is expected to alter its natural behaviour.
This composite matrix is referred to as silty-sand. To understand the behaviour
of this matrix under varying moisture conditions, some of the factors
influencing the soil-water characteristics of unsaturated silty sands were
investigated. Representative samples were collected from a river bank after its
index properties were predetermined in the laboratory. The samples were
compacted at different moisture conditions and compactive efforts. With the
pressure plate extractor device, the Soil-Water Characteristic (SWC) was obtained and SWC Curves plotted. Compaction at greater compactive effort
(modified proctor) and optimum moisture content produced the largest air entry
value and reduced air voids. The air entry values of the soils obtained ranged
from 21 kPa to 57 kPa. Also changes in the shape of the SWCC were consistent
with changes in pore size which occur by varying compaction conditions. Result
shows that soil structure, compaction water content, compactive effort and
percentage of fine particles are factors affecting the Soil-Water Characteristics.
References
[1]
Acar, Y. B., & Oliveri, I. (1990). Pore Fluids Effects on the Fabric and Hydraulic Conductivity of Laboratory-Compacted Clay. Transportation Research Record, No. 1219, 144-159.
[2]
Barbour, S. L. (1998). Nineteenth Canadian Geotechnical Colloquium: The Soil-Water Characteristics Curve: A Historical Perspective. Canadian Geotechnical Journal, 35, 873-894. https://doi.org/10.1139/t98-040
[3]
Diamond, S. (1971). Microstructure and Pore Structure of Impact-Compacted Clays. Clays and Clay Mineral, 19, 239-249. https://doi.org/10.1346/CCMN.1971.0190405
[4]
Fredlund, D. G. (2000). The Implementation of Unsaturated Soil Mechanics into Geotechnical Engineering. Canadian Geotechnical Journal, 37, 963-986. https://doi.org/10.1139/t00-026
[5]
Fredlund, D. G., & Morgenstern, N. R. (1977). Stress State Variables for Unsaturated Soils. Journal of Geotechnical Engineering, 103, 447-466.
[6]
Garcia-Bengochea, I., Lovell, C., & Altschaeffl, A. (1979). Pore-Distribution and Permeability of Silty Clays. Journal of Geotechnical Engineering Division, 105, 839-856.
[7]
Han, Z., & Vanapalli, S. K. (2016). Stiffness and Shear Strength of Unsaturated Soils in Relation to Soil-Water Characteristic Curve. Géotechnique, 66, 627-647. https://doi.org/10.1680/jgeot.15.P.104
[8]
Holtz, R. D., & Kovacs, W. D. (1981). An Introduction to Geotechnical Engineering (733 p.). Eaglewood Cliff, NJ: Prentice-Hall, Inc.
[9]
Miller, C. J., Yesiller, N., Yaldo, K., & Merayyan, S. (2002). Impact of Soil Type and Compaction Conditions on Soil Water Characteristics. Journal of Geotechnical and Geoenvironmental Engineering, 128, 733-742. https://doi.org/10.1061/(ASCE)1090-0241(2002)128:9(733)
[10]
Mitchell, J. K. (1976). Fundamental of Soil Behavior (422 pp.). New York: John Wiley and Sons, Inc.
[11]
Nwaiwu, C. M. O. (2004). Evaluation of Compacted Lateritic Soils as Hydraulic Barriers in Municipal Solid Waste Containment Systems. Unpublished Ph.D. Thesis, Zaria, Nigeria: Ahmadu Bello University.
[12]
Osinubi, K. J., & Bello, A. A. (2011). Soil-Water Characteristics Curves for Reddish Brown Tropical Soil. Electronic Journal of Geotechnical Engineering, 16, 1-25.
[13]
Tinjum, J. M., Benson. C. H., & Blotz, L. R. (1997). Soil Water Characteristics Curves for Compacted Clays. Journals of Geotechnical and Geoenvironmental Engineering, 123, 1060-1069. https://doi.org/10.1061/(ASCE)1090-0241(1997)123:11(1060)
[14]
Vanapalli, S. K., Fredlund, D. G., & Pufahi, D. E. (1999). The Influence of Soil Structure and Stress History on the Soil-Water Characteristics of a Compacted Till. Géotechnique, 49, 143-159. https://doi.org/10.1680/geot.1999.49.2.143
