Abstract
To investigate the soil–water retention curves of undisturbed and compacted lateritic clay specimens in the full suction range, suction is imposed or measured by using the pressure plate method, filter paper and vapor equilibrium technique with a saturated salt solution. The mercury intrusion porosimetry (MIP) tests were also performed to observe the pore size distribution (PSD) of undisturbed and compacted samples. The test results show that the undisturbed samples have lower gravimetric water content and degree of saturation than the compacted samples at the same density in the suction ranging from 0 kPa to 10 MPa. According to the study on microstructures, the observed phenomenon can be explained by internal cracks of undisturbed samples continuing to develop along with an increase in suction. When the suction is higher than 10 MPa, the soil–water retention curves (SWRCs) coincide with each other for both undisturbed and compacted samples. Undisturbed samples exhibit a unimodal PSD, while unsaturated, compacted samples have a distinct bimodal PSD. The structural degradation of the clay aggregate due to the moisture change leads to the change of the inter-aggregate pores (the intra-aggregate pores remain almost unchanged). For unsaturated, compacted samples with different void ratios, the intra-aggregate PSDs are almost the same, while the inter-aggregate PSD varies with the void ratio. This can be adopted to explain that the wetting branches of the SWRCs are independent of the dry density in the high suction range when the SWRC is expressed by the relation between suction and gravimetric water content. The results of MIP tests on a saturated sample are used to predict the SWRC of the same soil in the main drying.
Similar content being viewed by others
References
Bello AA (2011) Analysis of shear strength of compacted lateritic soils. Pac J Sci Technol 12(1):425–434
Blatz JA, Cui YJ, Oldecop L (2008) Vapour equilibrium and osmotic technique for suction control. Geotech Geol Eng 26:661–673
Bulut R, Leong EC (2008) Indirect measurement of suction. Geotech Geol Eng 26:633–644
Costa YD, Cintra JC, Zornberg JG (2003) Influence of matric suction on the results of plate load tests performed on a lateritic soil deposit. Geotech Test J 26(2):1–9
Delage P, Audiguier M, Cui YJ, Howat MD (1996) Microstructure of a compacted silt. Can Geotech J 33(1):150–158
Delage P, Howat M, Cui YJ (1998) The relationship between suction and swelling properties in a heavily compacted unsaturated clay. Eng Geol 50(1–2):31–48
Fredlund DG (2000) The 1999 R.M. Hardy Lecture: the implementation of unsaturated soil mechanics into geotechnical engineering. Can Geotech J 37(5):963–985
Fredlund DG, Rahardjo H (1993) Soil mechanics for unsaturated soils. John Wiley & Sons, Inc
Gao GR (1996) The distribution and geotechnical properties of loess soils, lateritic soils and clayey soils in China. Eng Geol 42(1):95–104
Gidigasu MD (1976) Laterite soil engineering, paedogenesis and engineering principles. Developments in geotechnical engineering, vol 9. Elsevier, Amsterdam
Greenspan L (1977) Humidity fixed points of binary saturated aqueous solutions. J Res Natl Bur Stand 81(1):89–96
Kolawole J, Osinubi M, Charles MO, Nwaiwu AM (2006) Design of compacted lateritic soil liners and covers. J Geotech Geoenviron Eng 132(2):203–213
Leong EC, He L, Rahardj H (2002) Factors affecting the filter paper method for total and matric suction measurements. Geotech Test J 25(3):1–12
Nayak S, Sunil BM, Shrihari V (2007) Hydraulic and compaction characteristics of leachate-contaminated lateritic soil. Eng Geol 94(2):137–144
Péron H, Hueckel T, Laloui L (2007) An improved volume measurement for determining soil water retention curves. Geotech Test J 30(1):1–8
Sasanian S, Newson TA (2013) Use of mercury intrusion porosimetry for microstructural investigation of reconstituted clays at high water contents. Eng Geol 158:15–22
Simms PH, Yanful EK (2005) A pore-network model for hydromechanical coupling in unsaturated compacted clayey soils. Can Geotech J 42(2):499–514
Tang AM, Cui YJ (2005) Controlling suction by the vapour equilibrium technique at different temperatures and its application in determining the water retention properties of MX80 clay. Can Geotech J 42:287–296
Townsend FC (1985) Geotechnical characteristics of residual soils. J Geotech Eng 111(1):77–94
Washburn EW (1921) Note on a method of determining the distribution of pore sizes in a porous material. Proc Natl Acad Sci USA 7(4):115–116
Acknowledgments
The authors express their gratitude for the grants provided by the National Basic Research Program of China (2014CB047001) and the National Natural Science Foundation of China (11272194).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Sun, D., You, G., Annan, Z. et al. Soil–water retention curves and microstructures of undisturbed and compacted Guilin lateritic clay. Bull Eng Geol Environ 75, 781–791 (2016). https://doi.org/10.1007/s10064-015-0765-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10064-015-0765-2