Abstract
This paper presents a set of triaxial compression tests on partially saturated dense sands to clarify the microscopic characteristics and their link to the macroscopic responses. Constant suction tests (CS tests) and constant water content tests (CW tests) are conducted under low confining pressure to observe microscopic and macroscopic behaviors of the sands associated with dilative shear bands. X-ray micro-tomography and image analysis techniques are applied to investigate the continuity as a defined index to evaluate the morphology of the pore water, the number of liquid bridges and the principal curvature of the air–water interface. The number of liquid bridges decreases for both the CS and CW tests, particularly during the strain softening process, while it decreases greater in the CW test than in the CS test. The curvature of the air–water interface remains at almost the same value under the CS test, while it tends to decrease under the CW test. The tendency of decreasing curvature corresponds to that of decreasing suction in the CW test. The peak deviator stress is higher in the CS test than in the CW test when the pore water is initially discontinuous, whereas it is identical between the two tests when the pore water is initially continuous. The residual stress is lower in the CW test than in the CS test, independent of the initial water retention states. The macroscopic responses at the different initial water retention states are qualitatively identical between poorly graded sand and well-graded sand.
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References
Bear J (1979) Hydraulics of groundwater. McGraw-Hill, New York
Bishop AW, Alpan I, Blight, GE, Donald, IB (1960) Factors controlling the shear strength of partly saturated cohesive soil. In: Proceedings of the ASCE research conference on shear strength of cohesive soils, pp 503–532
Bruchon JF, Pereira JM, Vandamme M, Lenoir N, Delage P, Bornert M (2013) Full 3D investigation and characterisation of capillary collapse of a loose unsaturated sand using X-ray CT. Granul Matter 15(6):783–800
Cui YJ, Delage P (1996) Yielding and plastic behavior of an unsaturated compacted silt. Géotechnique 46(2):291–311
Cunningham MR, Ridley AM, Dineen K, Burland JB (2003) The mechanical behavior of a reconstituted unsaturated silty clay. Géotechnique 53(2):183–194
Dallavalle JM (1943) Micrometrics. Pitman Inc., London
Desrues J, Chambon R, Mokni M, Mazerolle F (1996) Void ratio evolution inside shear bands in triaxial sand specimens studied by computed tomography. Géotechnique 46(3):539–546
Escario V (1980) Suction controlled penetration and shear tests. In: Proceedings of the 4th international conference on expansive soils, vol 2. ASCE, Denver, pp 781–797
Escario V, Saez J (1986) The shear strength of partly saturated soils. Géotechnique 36:453–456
Fredlund DG, Morgenstern NR, Widger RA (1978) The shear strength of unsaturated soils. Can Geotech J 15:313–321
Fredlund DG, Rahardjo H (1993) Soil mechanics for unsaturated soils. Wiley, New York
Gan JKM, Fredlund DG, Rahardjo H (1988) Determination of the shear strength parameters of an unsaturated soil using the direct shear test. Can Geotech J 25:500–510
Geiser F, Laloui L, Vulliet L (2006) Elasto-plasticity of unsaturated soils: laboratory test results on a remoulded silt. Soils Found 46(5):545–556
Hall SA, Bornert M, Desrues J, Pannier Y, Lenoir N, Viggiani G, Bésuelle P (2010) Discrete and continuum analysis of localised deformation in sand using X-ray μCT and volumetric digital image correlation. Géotechnique 60(5):315–322
Haralick RM, Sternberg SR, Zhuang X (1987) Image analysis using mathematical morphology. IEEE Trans Pattern Anal Mach Intell 9(4):532–550
Higo Y, Oka F, Kimoto S, Sanagawa T, Matsushima Y (2011) Study of strain localization and microstructural changes in partially saturated sand during triaxial tests using microfocus X-ray CT. Soils Found 51(1):95–111
Higo Y, Oka F, Sato T, Matsushima Y, Kimoto S (2013) Investigation of localized deformation in partially saturated sand under triaxial compression using microfocus X-ray CT with digital image correlation. Soils Found 53(2):181–198
Higo Y, Oka F, Morishita R, Matsushima Y, Yoshida T (2014) Trinarization of μX-ray CT images of partially saturated sand at different water retention states using a region growing method. Nucl Instrum Methods Phys Res B 324:63–69
Higo Y, Oka F, Morishita R, Matsushima Y (2015) Quantitative observation of strain localisation in a partially saturated triaxial specimen using microfocus X-ray CT with image analysis. In: Proceedings of the 10th international workshop on bifurcation and degradation in geomaterials, pp 325–330
Higo Y, Kido R, Takamura F, Fukushima Y (2018) Pore-scale investigations of partially water-saturated granular soil. Mech Res Commun 94:1–7
Karube D, Kawai K (2001) The role of pore water in the mechanical behavior of unsaturated soils. Geotech Geol Eng 19:211–241
Kido R, Higo Y (2017) Evaluation of distribution of void ratio and degree of saturation in partially saturated triaxial sand specimen using micro X-ray tomography. JGS Spec Publi 5(2):22–27
Kido R, Higo Y (2019) Distribution changes of grain contacts and menisci in shear band during triaxial compression test for unsaturated sand. Jpn Geotech Soc Spec Publ 7(2):627–635
Kido R, Higo Y, Takamura F, Morishita R, Khaddour G, Salager S (2020) Morphological transitions for pore water and pore air during drying and wetting processes in partially saturated sand. Acta Geotech 15:1745–1761
Kimoto S, Oka F, Fukutani J, Yabuki T, Nakashima K (2011) Monotonic and cyclic behavior of unsaturated sandy soil under drained and fully undrained conditions. Soils Found 51(4):663–681
Kohgo Y, Nakano M, Miyazaki T (1993) Theoretical aspects of constitutive modelling for unsaturated soils. Soils Found 33(4):49–63
Kreyszig E (2013) Differential geometory. Dover, New York
Liu X, Zhou A, Shen SI, Li J, Sheng D (2020) A micro-mechanical model for unsaturated soils based on DEM. Comput Methods Appl Mech Eng 368(15):113183
Lu N, Likos WJ (2004) Unsaturated soil mechanics. Wiley, Hoboken
Manahiloh KN, Meehan CL (2017) Determining the soil water characteristic curve and interfacial contact angle from microstructural analysis of X-ray CT images. J Geotech Geoenviron Eng 143(8):1–11
Rahardjo H, Lim TT, Chang MF, Fredlund DG (1995) Shear-strength characteristics of a residual soil. Can Geotech J 32:60–77
Rahardjo H, Heng OB, Choon LE (2004) Shear strength of a compacted residual soil from consolidated drained and constant water content triaxial tests. Can Geotech J 41:421–436
Richards LA (1948) Porous plate apparatus for measuring moisture retention and transmission by soil. Soil Sci 66(2):105–110
Rieger B, Timmermans FJ, van Vliet LJ, Verbeek PW (2004) On curvature estimation of ISO surfaces in 3D gray-value images and the computation of shape descriptors. IEEE Trans Pattern Anal Mach Intell 26(8):1088–1094
Takano D, Lenoir N, Otani J, Hall SA (2015) Localised deformation in a wide-grained sand under triaxial compression revealed by X-ray tomography and digital image correlation. Soils Found 55(4):906–915
Than VD, Aimedieu P, Pereira JM, Roux JN, Tang AM (2020) Experimental investigation on the grain-scale compression behavior of loose wet granular material. Acta Geotech 15:1039–1055
Thu TM, Rahardjo H, Leong EC (2006) Shear strength and pore-water pressure characteristics during constant water content triaxial tests. J Geotech Geoenviron Eng 132(3):411–419
Urso MED, Lawrence CJ, Adams MJ (1999) Pendular, funicular, and capillary bridges: results for two dimensions. J Colloid Interface Sci 220:42–56
Vanapalli SK, Fredlund DG, Pufahl DE, Clifton AW (1996) Model for the prediction of shear strength with respect to soil suction. Can Geotech J 33:379–392
Vanapalli SK, Nicotera MV, Sharma RS (2008) Axis translation and negative water column techniques for suction control. Geotech Geol Eng 26:645–660
Wang JP, Lambert P, De Kock T, Cnudde V, François B (2019) Investigation of the effect of specific interfacial area on strength of unsaturated granular materials by X-ray tomography. Acta Geotech. https://doi.org/10.1007/s11440-019-00765-2
Wang JP, Li X, Yu HS (2018) A micro–macro investigation of the capillary strengthening effect in wet granular materials. Acta Geotech 13:513–533
Wheeler SJ, Sivakumar V (2000) Influence of compaction procedure on the mechanical behaviour of an unsaturated compacted clay. Part 2: shearing and constitutive modelling. Géotechnique 50(4):369–376
Wheeler SJ, Sharma RS, Buisson MS (2003) Coupling of hydraulic hysteresis and stress-strain behaviour in unsaturated soils. Géotechnique 53(1):41–54
Willson CS, Lu N, Likos WJ (2012) Quantification of grain, pore, and fluid microstructure of unsaturated sand from X-ray computed tomography images. Geotech Test J 35(6):911–923
Wulfsohn D, Adams BA, Fredlund DG (1998) Triaxial testing of unsaturated agricultural soils. J Agric Eng Res 69(4):317–330
Acknowledgements
This research was supported by the Japan Society for the Promotion of Science (JSPS) Grant-in-Aids for JSPS Fellows (Subject No. 17J06250) and Research Activity start-up (Subject No. 19K23534). The authors would like to express their sincere gratitude to Professor Makoto Kimura of Kyoto University, Japan, for his great support and valuable suggestions during this work. The authors also gratefully acknowledge the support of Mr. Takanobu Ishimura (Maxnet Co., Ltd, Japan) who assisted in performing the image analysis using 3D image analysis software Avizo 9.4.0 (FEI) in the present study.
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Kido, R., Higo, Y. Microscopic characteristics of partially saturated dense sand and their link to macroscopic responses under triaxial compression conditions. Acta Geotech. 15, 3055–3073 (2020). https://doi.org/10.1007/s11440-020-01049-w
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DOI: https://doi.org/10.1007/s11440-020-01049-w