Unified Consolidation-Creep-Collapse Phenomena in an Unsaturated Sand-Bentonite Mixture
Publication: Geo-Congress 2023
ABSTRACT
Unsaturated soils that exhibit significant volume reduction under wetting or mechanical loading are referred to as collapsible soils. The main objective of this study is to investigate the time-dependent response of an unsaturated sand-bentonite mixture under coupled hydro-mechanical loading conditions. For this purpose, a modified osmotic oedometer device was employed to determine soil volume change properties such as the compressibility coefficient, creep index, and collapse potential under controlled matric suctions. The results demonstrate the interaction of the stress history and the long-term behavior of the tested soil, suggesting that creep and consolidation deformations strongly depend on the preceding hydraulic loadings. Incomplete collapse incidents were observed in the specimens confined in the oedometer ring in which the specimens did not collapse laterally. As a result, the volume states of the collapsed samples were located above the saturated normal consolidation line. The higher void ratios led to higher creep deformations in saturated samples that experienced the collapse phenomenon. This behavior is attributed to the meta-stable condition of samples, which eventually tends to evolve toward the stable virgin consolidation curve. Moreover, the creep index and collapse potential increased with the net stresses within the range of applied loads. Findings confirm the reverse relationship between the creep index and applied matric suction.
Get full access to this article
View all available purchase options and get full access to this chapter.
REFERENCES
Ajdari, M., Habibagahi, G., and Ghahramani, A. (2012). Predicting effective stress parameter of unsaturated soils using neural networks. Computers and Geotechnics, 40, 89–96.
Ajdari, M., Habibagahi, G., and Masrouri, F. (2013). The role of suction and degree of saturation on the hydro-mechanical response of a dual porosity silt–bentonite mixture. Appl. Clay Sci., 83–84, 83–90.
Ajdari, M., Monghassem, M., and Lari, H. R. (2016). A modified osmotic diaphragmatic oedometer for investigating the hydro-mechanical response of unsaturated soils. Geotech. Test. J., 39, 20150142.
Ajdari, M., Niknam, E., Bahmyari, H., and Esfandiari, Z. (2020). Consolidation and creep phenomena in a sand-bentonite mixture under controlled suctions. Geomechanics and Geoengineering, DOI: https://doi.org/10.1080/17486025.2020.1714082, 1–12.
Alonso, E. E., Gens, A., and Josa, A. (1990). A constitutive model for partially saturated soils. Geotechnique, 40(3), 405–430.
Alonso, E. E., Romero, E., Hoffmann, C., and García-Escudero, E. (2005). Expansive bentonite-sand mixtures in cyclic controlled-suction drying and wetting. Eng. Geol., 81, 213–226.
ASTM. ASTM-D2487-17. (2017). Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System). ASTM Stand. Guid. 11. https://doi.org/10.1520/D2487-11.
ASTM. ASTM-D422-63. (2007). Standard Test Method for Particle-Size Analysis of Soils (Withdrawn 2016). ASTM Int. 1–8. https://doi.org/10.1520/D0422-63R07E02.
ASTM. ASTM-D4318-17e1. (2017). Standard Test Methods for Liquid Limit, Plastic Limit, and Plasticity Index of Soils. Des. D 4318–00 Stand. 04, 1–14. https://doi.org/10.1520/D4318-10.
ASTM. ASTM-D854-14. (2014). Standard Test Methods for Specific Gravity of Soil Solids by Water Pycnometer. ASTM Stand. Guid. 1–8. https://doi.org/10.1190/segam2013-1251.1.
Boso, M., Tarantino, A., and Mongiovì, L. (2005). A direct shear box improved with the osmotic technique. Int. Symp. Adv. Exp. Unsaturated Soil Mech. 85–91.
Budhu, M. (2010). Soil mechanics and foundation. 3rd edition, John Wiley and Sons, Inc., 781 pages.
Chen, F., Marinelli, Y., and Buscarnera, G. (2020). Influence of clay anisotropy on model simulations of wetting collapse. J. Eng. Mech., ASCE, 146(2), 04019130.
Delage, P., and Cui, Y. J. (2008). An evaluation of the osmotic method of controlling suction. Geomech. Geoengin. 3, 1–11.
Esfandiari, Z., Ajdari, M., and Vahedifard, F. (2021). Time-dependent deformation characteristics of an unsaturated sand-bentonite mixture under drying-wetting cycles. J. Geotech. Geoenv. Eng., ASCE, 147(3), 04020172.
Fox, P. J., Edil, T. B., and Lan, L. T. (1992). Cα/Cc concept applied to compression of peat. Journal of Geotechnical Engineering, 118 (8), Published online.
Grimstad, G., et al. (2017). Creep of geomaterials – some finding from the EU project CREEP. European Journal of Environmental and Civil Engineering, Published online.
Hamidi, A., Habibagahi, G., and Ajdari, M. (2013). A modified osmotic direct shear apparatus for testing unsaturated soils. Geotech. Test. J., 36, https://doi.org/10.1520/GTJ20120092.
Khalili, N., Geiser, F., and Blight, G. E. (2004). Effective stress in unsaturated soils. Int. J. Geomech. 4, 115–126.
Lai, X. L., Wang, S. M., Ye, W. M., and Cui, Y. J. (2014). Experimental investigation on the creep behavior of an unsaturated clay. Can. Geotech. J., 51, 621–628.
Lee, J., and Aubeny, C. P. (2022). Lateral Undrained Capacity of a Multiline Ring Anchor in Clay. Int. J. Geomech., 2021, 21(5): 04021047.
Loret, B., and Khalili, N. (2002). An effective stress elastic-plastic model for unsaturated porous media. Mech. Mater., 34, 97–116.
Lu, N. (2008). Is Matric suction a stress variable? J. Geotech. Geoenviron. Eng., ASCE, 134(7): 899–905.
Lu, N. (2020). Unsaturated soil mechanics: fundamental challenges, breakthroughs, and opportunities. J. Geotech. Geoenviron. Eng., ASCE, 146(5), 02520001.
Mesri, G., and Godlewski, P. M. (1977). Time-and stress-compressibility interrelationship Title. J. Geotech. Eng. Div. ASCE, 103, 417–430.
Monghassem, M., Ajdari, M., Binesh, S. M., and Vahedifard, F. (2021). Effect of suction and drying-wetting cycles on shearing response of adobe. J. Mater. Civ. Eng., ASCE, 33 (7), 04021173.
Russel, A., and Khalili, N. (2005). A unified bounding surface plasticity model for unsaturated soils. Numerical and Analytical Methods in Geomechanics, 30(3), https://doi.org/10.1002/nag.475.
Rezania, M., Bagheri, M., and Mousavi Nezhad, M. (2020). Creep and consolidation of a stiff clay under saturated and unsaturated conditions. Can. Geotech. J., 57(5), 728–741.
Seiphoori, A., and Zamanian, M. (2022). Improving mechanical behaviour of collapsible soils by grouting clay nanoparticles, Engineering Geology, 298, 106538.
Wheeler, S. J., Sharma, R. S., and Buisson, M. S. R. (2003). Coupling of hydraulic hysteresis and stress–strain behaviour in unsaturated soils. Géotechnique, 53(1), 41–54.
Yuan, S., Liu, X., and Buzzi, O. (2021). A microstructural perspective into soil collapse. 71 (2), pp. 132–140.
Zou, L., Wang, S., and Lai, X. (2013). Creep model for unsaturated soils in sliding zone of Qianjiangping landslide. Journal of Rock Mechanics and Geotechnical Engineering, 5, 162–167.
Information & Authors
Information
Published In
History
Published online: Mar 23, 2023
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.