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http://dx.doi.org/10.12989/gae.2020.23.5.419

Influence of spatial variability on unsaturated hydraulic properties  

Tan, Xiaohui (School of Resources and Environmental Engineering, Hefei University of Technology)
Fei, Suozhu (School of Resources and Environmental Engineering, Hefei University of Technology)
Shen, Mengfen (Zhejiang University of Technology)
Hou, Xiaoliang (School of Resources and Environmental Engineering, Hefei University of Technology)
Ma, Haichun (School of Resources and Environmental Engineering, Hefei University of Technology)
Publication Information
Geomechanics and Engineering / v.23, no.5, 2020 , pp. 419-429 More about this Journal
Abstract
To investigate the effect of spatial variability on hydraulic properties of unsaturated soils, a numerical model is set up which can simulate seepage process in an unsaturated heterogeneous soil. The unsaturated heterogeneous soil is composed of matrix sand embedded with a small proportion of clay for simulating the heterogeneity. Soil-water characteristic curve and unsaturated hydraulic conductivity curve of the unsaturated soil are expressed by Van Genuchten model. Hydraulic parameters of the matrix sand are considered as random fields. Different autocorrelation lengths (ACLs) of hydraulic parameter of the matrix sand and different proportions of clay are assumed to investigate the influence of spatial variability on the equivalent hydraulic properties of the heterogeneous soil. Four model sizes are used in the numerical experiments to investigate the influence of scale effects and to determine the sizes of representative volume element (RVE) in the numerical simulations. Through a number of Monte Carlo simulations of unsaturated seepage analysis, the means and the coefficients of variations (COVs) of the equivalent hydraulic parameters of the heterogeneous soil are calculated. Simulations show that the ACL and model size has little influence on the means of the equivalent hydraulic parameters, but they have a large influence on the COVs of the equivalent hydraulic parameters. The size of an RVE is mainly affected by the ACL and the proportion of heterogeneity. The influence of spatial variability on the hydraulic parameters of the heterogeneous unsaturated soil can be used as a guidance for geotechnical reliability analysis and design related to unsaturated soils.
Keywords
spatial variability; autocorrelation; random field; hydraulic parameters; van Genuchten model;
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Times Cited By KSCI : 8  (Citation Analysis)
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1 Van Genuchten, M.T. (1980), "A closed form equation predicting the hydraulic conductivity of unsaturated soils", Soil Sci. Soc. Am. J., 44(5), 892-898. http://doi.org/10.2136/sssaj1980.03615995004400050002x.   DOI
2 Vanapalli, S.K., Fredlund, D.G. and Pufahl, D.E. (1996), "The relationship between the soil-water characteristic curve and the unsaturated shear strength of a compacted glacial till", Geotech. Test. J., 19(3), 259-268. http://doi.org/10.1520/GTJ10351J.   DOI
3 Vanmarke, E.H. (1977), "Probabilistic modeling of soil profiles", J. Geotech. Eng., 103(11), 1227 -1246.
4 Vogel, T., van Genuchten, M.T.H. and Cislerova, M. (2001), "Effect of the shape of the soil hydraulic functions near saturation on variably-saturated flow predictions", Adv. Water Resour., 24, 133-144. https://doi.org/10.1016/S0309-1708(00)00037-3.   DOI
5 Wang, T., Zhou, G.Q., Wang, J.Z., Zhao, X.D. and Yin, L.J. (2018), "Stochastic analysis for uncertain deformation of foundations in permafrost regions", Geomech. Eng., 14(6), 589-600. http://doi.org/10.12989/gae.2018.14.6.589.   DOI
6 Wang, Y.Q., Shao, M.A., Han, X.W. and Liu, Z.P. (2015), "Spatial variability of soil parameters of the van Genuchten model at a regional scale", Clean-soil Air Water, 43(2), 271-278. https://doi.org/10.1002/clen.201300903.   DOI
7 Wu, C.M., Chen, P.Y., Chen, C.H., Hsu, N.S. and Wen, J.C. (2012), "Influence of heterogeneity on unsaturated hydraulic properties (2) - percentage and shape of heterogeneity", Hydrol. Process, 26, 3604-3613. http://doi.org/10.1002/hyp.8448.   DOI
8 Wu, L.Z., Huang, R.Q. and Xu, Q. (2012), "Incorporating Hysteresis in One-dimensional Seepage Modeling in Unsaturated Soils", KSCE J. Civ. Eng., 16(1), 69-77. http://doi.org/10.1007/s12665-015-4890-9.   DOI
9 Ahmed, A.A. (2009), "Stochastic analysis of free surface flow through earth dams", Comput. Geotech., 36(7), 1186-1190. http://doi.org/10.1016/j.compgeo.2009.05.005.   DOI
10 Botros, F.E., Harter, T., Onsoy, Y.S., Tuli, A. and Hopmans, J.W. (2009), "Spatial variability of hydraulic properties and sediment characteristics in a deep alluvial unsaturated zone", Vadose Zone J., 8(2), 276-289. http://doi.org/10.2136/vzj2008.0087.   DOI
11 Chen, P.Y., Chen, C.H., Hsu, N.S., Wu, C.M. and Wen, J.C. (2012), "Influence of heterogeneity on unsaturated hydraulic properties:(1) local heterogeneity and scale effect", Hydrol. Process., 26, 3593-3603. http://doi.org/10.1002/hyp.8449.   DOI
12 Ching, J.Y. and Phoon, K.K. (2013), "Effect of element sizes in random field finite element simulations of soil shear strength", Comput. Struct., 126(1), 120-134. http://doi.org/10.1016/j.compstruc.2012.11.008.   DOI
13 Cho, S.E. (2007), "Effects of spatial variability of soil properties on slope stability", Eng. Geol., 92(3), 97-109. http://doi.org/10.1016/j.enggeo.2007.03.006.   DOI
14 Fei, S.Z., Tan, X.H., Wang, X., Du, L.F. and Sun, Z.H. (2019), "Evaluation of soil spatial variability by micro-structure simulation", Geomech. Eng., 17(6), 565-572. http://doi.org/10.12989/gae.2019.17.6.565.   DOI
15 Cho, S.E. (2012), "Probabilistic analysis of seepage that considers the spatial variability of permeability for an embankment on soil foundation", Eng. Geol., 133-134(3), 30-39. http://doi.org/10.1016/j.enggeo.2012.02.013.   DOI
16 Dou, H.Q., Han, T.C., Gong, X.N. and Zhang, J. (2014), "Probabilistic slope stability analysis considering the variability of hydraulic conductivity under rainfall infiltrationredistribution conditions", Eng. Geol., 183(1-13), 1-13. http://doi.org/10.1016/j.enggeo.2014.09.005.   DOI
17 Fan, H. and Liang, R. (2013), "Reliability-based design of axially loaded drilled shafts using Monte Carlo method", Int. J. Numer. Anal. Meth. Geomech., 37(14), 2223-2238. https://doi.org/10.1002/nag.2131.   DOI
18 Firouzianbandpey, S., Griffiths, D.V., Ibsen, L.B. and Andersen, L.V. (2014), "Spatial correlation length of normalized cone data in sand: case study in the north of Denmark", Can. Geotech. J., 51(8), 844-857. http://doi.org/10.1139/cgj-2013-0294.   DOI
19 Fredlund, D.G. and Houston, S.L. (2009), "Protocol for the assessment of unsaturated soil properties in geotechnical engineering practice", Can. Geotech. J., 46(6), 694-707. http://doi.org/10.1139/T09-010.   DOI
20 Fredlund, D.G. and Xing, A. (1994), "Equations for the soil-water characteristic curve", Can. Geotech. J., 31(521-32), 521-532. https://doi.org/10.1139/t94-061.   DOI
21 Fredlund, D.G., Sheng, D.C. and Zhao, J.D. (2011), "Estimation of soil suction from the soil-water characteristic curve", Can. Geotech. J., 48(2), 186-198. https://doi.org/10.1139/T10-060.   DOI
22 Gui, S.X., Zhang, R.D., Turner, J.P. and Xue, X.Z. (2000), "Probabilistic slope stability analysis with stochastic soil hydraulic conductivity", J. Geotech. Geoenviron. Eng., 126(1), 1-9. http://doi.org/10.1061/(ASCE)1090-0241.   DOI
23 Zhu, H., Zhang, L.M., Zhang, L.L. and Zhou, C.B. (2013), "Twodimensional probabilistic infiltration analysis with a spatially varying permeability function", Comput. Geotech., 48(4), 249-259. http://doi.org/10.1016/j.compgeo.2012.07.010.   DOI
24 Fredlund, D.G., Xing, A., Fredlund, M.D. and Barbour, S.L. (1995), "The relationship of the unsaturated soil shear strength to the soil-water characteristic curve", Can. Geotech. J., 33(3), 440-448. https://doi.org/10.1139/t96-065.   DOI
25 Fredlund, M. and Gitirana, J.G. (2011), "Probabilistic methods applied to unsaturated numerical modeling", Geotech. Geol. Eng., 29(2), 217-223. http://doi.org/10.1007/s10706-011-9391-3.   DOI
26 Gong, W., Juang, C.H., Khoshnevisan, S. and Phoon, K.K. (2016), "R-LRFD: Load and resistance factor design considering robustness", Comput. Geotech., 74, 74-87. https://doi.org/10.1016/j.compgeo.2015.12.017.   DOI
27 Griffiths, D.V., Paiboon, J., Huang, J. and Fenton, G.A. (2012), "Homogenization of geomaterials containing voids by random fields and finite elements", Int. J. Solids Struct., 49(14), 2006-2014. http://doi.org/10.1016/j.ijsolstr.2012.04.006.   DOI
28 Heshmati, A.A. and Motahari, M.R. (2015), "Modeling the dependency of suction stress characteristic curve on void ratio in unsaturated soils", KSCE J. Civ. Eng., 19(1), 91-97. http://doi.org/10.1007/s12205-013-1185-0.   DOI
29 Itasca Consulting Group, Inc. (2008), FLAC Version 6.0 Manual, Minneapolis, Minnesota, U.S.A.
30 Sillers, W.S. and Fredlund, D.G. (2001), "Statistical assessment of soil-water characteristic curve models for geotechnical engineering", Can. Geotech. J., 38(6), 1297-1313. http://doi.org/10.1139/t01-066.   DOI
31 Srivastava, A., Babu, G.L.S. and Halda, S. (2010), "Influence of spatial variability of permeability property on steady state seepage flow and slope stability analysis", Eng. Geol., 110(3-4), 93-101. http://doi.org/10.1016/j.enggeo.2009.11.006.   DOI
32 Tan, X.H., Wang, X., Khoshnevisan, S., Hou, X.L. and Zha, F.S. (2017), "Seepage analysis of earth dams considering spatial variability of hydraulic parameters", Eng. Geol., 228, 260-269. http://doi.org/10.1016/j.enggeo.2017.08.018.   DOI
33 Javankhoshdel, S., Bathurst, R.J. and Cami, B. (2018), "Influence of model type, bias and input parameter variability on reliability analysis for simple limit states with two load terms", Comput. Geotech., 97, 78-89. https://doi.org/10.1016/j.compgeo.2018.01.002.   DOI
34 Stefanou, G. (2008), "The stochastic finite element method: Past, present and future", Comput. Method Appl. M., 198(9-12), 1031-1051. http://doi.org/10.1016/j.cma.2008.11.007.   DOI
35 Sudret, B. and Kiureghian, A.D. (2002), "Comparison of finite element reliability methods", Probabilist. Eng. Mech., 17(4), 337-348. http://doi.org/10.1016/S0266-8920(02)00031-0.   DOI
36 Tan, X.H., Bi, W.H., Hou, X.L. and Wang, W. (2011), "Reliability analysis using radial basis function networks and support vector machines", Comput. Geotech., 38(2), 178-186. https://doi.org/10.1016/j.compgeo.2010.11.002.   DOI
37 Tan, X.H., Hu, M.Z., Juang, C.H., Li, P. and Shen, M.F. (2018), "Evaluation of the Autocorrelation Distance of Unsaturated Soils", Proceedings of the GeoShanghai 2018 International Conference: Multi-physics Processes in Soil Mechanics and Advances in Geotechnical Testing, Shanghai, China, May.
38 Tan, X.H., Xin, Z.Y., Shen, M.F., Wang, X.E. and Xu, Q. (2014), "Study of soil-water characteristics of expansive soil under moisture adsorption and expansion condition", Rock Soil Mech., 35(12), 3352-3360. http://doi.org/10.11779/CJGE201507004.   DOI
39 Jimenez, R. and Sitar, R. (2009), "The importance of distribution types on finite element analyses of foundation settlement", Comput. Geotech., 36(3), 474-483. https://doi.org/10.1016/j.compgeo.2008.05.003.   DOI
40 Jiang, S.H., Li, D.Q., Zhou, C.B. and Phoon, K.K. (2014), "Slope reliability analysis considering effect of autocorrelation functions", Chin. J. Geotech. Eng., 36(3), 508-518. http://doi.org/10.11779/CJGE201403014.   DOI
41 Johari, A. and Mehrabani, L.A. (2016), "System reliability analysis of rock wedge stability considering correlated failure modes using sequential compounding method", Int. J. Rock Mech. Min. Sci., 82, 61-70. http://doi.org/10.1016/j.ijrmms.2015.12.002.   DOI
42 Kim, Y.M. and Jeong, S.S. (2017), "Modeling of shallow landslides in an unsaturated soil slope using a coupled model", Geomech. Eng., 13(2), 353-370. http://doi.org/10.12989/gae.2017.13.2.353.   DOI
43 Le, T.MH., Gallipoli, D., Sanchez, M. and Wheeler, S.J. (2012), "Stochastic analysis of unsaturated seepage through randomly heterogeneous earth embankments", Int. J. Numer. Anal. Met., 36(8), 1056-1076. http://dx.doi.org/10.1002/nag.1047.   DOI
44 Lombardi, M., Cardarilli, M. and Raspa, G. (2017), "Spatial variability analysis of soil strength to slope stability assessment", Geomech. Eng., 12(3), 565-572. http://doi.org/10.12989/gae.2019.17.6.565.   DOI
45 Paiboon, J., Griffiths, D.V., Huang, J. and Fenton, G.A. (2013), "Numerical analysis of effective elastic properties of geomaterials containing voids using 3D random fields and finite elements", Int. J. Solids Struct., 50(20-21), 3233-3241. http://doi.org/10.1016/j.ijsolstr.2013.05.031.   DOI
46 Mahmood, K., Kim, J.M., Khan, H., Safdar, M. and Khan, U. (2018), "The probabilistic stability analysis of saturatedunsaturated MH and CL soil slope with rainfall infiltration", KSCE J. Civ. Eng., 22(5), 1742-1749. http://doi.org/10.1007/s12205-017-1052-5.   DOI
47 Ji, J., Liao, H.L. and Low, B.K. (2012), "Modeling 2-D spatial variation in slope reliability analysis using interpolated autocorrelations", Comput. Geotech., 40(3), 135-146. http://doi.org/10.1016/j.compgeo.2011.11.002.   DOI
48 Mualem, Y. (1976), "A new model for predicting the hydraulic conductivity of unsaturated porous media", Water Resour. Res., 12(3), 513-522. https://doi.org/10.1029/WR012i003p00513.   DOI
49 Nemes, A., Schaap, M.G., Leij, F.J. and Wosten, J.H.M. (2001), "Description of the unsaturated ydraulic database UNSODA version 2.0", J. Hydrol., 251, 151-162. https://doi.org/10.1016/S0022-1694(01)00465-6.   DOI
50 Onyejekwe, S., Kang, X. and Ge, L. (2016), "Evaluation of the scale of fluctuation of geotechnical parameters by autocorrelation function and semivariogram function", Eng. Geol., 214, 43-49. http://doi.org/10.1016/j.enggeo.2016.09.014.   DOI
51 Papaioannou, I. and Straub, D. (2012), "Reliability updating in geotechnical engineering including spatial variability of soil", Comput. Geotech., 42, 44-51. http://doi.org/10.1016/j.compgeo.2011.12.004.   DOI
52 Moradi, F., Moosavi, A.A. and Moghaddam, B.K. (2016), "Spatial variability of water retention parameters and saturated hydraulic conductivity in a calcareous Inceptisols (Khuzestan province of Iran) under sugarcane cropping", Arch. Agron. Soil Sci., 62(12), 1686-1699. https://doi.org/10.1080/03650340.2016.1164308.   DOI
53 Pereiral, J.H. and Fredlund, D.G. (2000), "Volume change behavior of collapsible compacted gneiss soil", J. Geotech. Geoenviron. Eng., 126(10), 907-916. http://doi.org/10.1061/(ASCE)10900241(2000)126:10(907).   DOI
54 Phoon, K.K., Santoso, A. and Quek, S.T. (2010), "Probabilistic Analysis of Soil-Water Characteristic Curves", J. Geotech. Geoenviron. Eng., 136(3), 445-455. http://doi.org/10.1061/(ASCE)GT.1943-5606.0000222.   DOI