Stochastic Analysis of Seepage through Natural Alluvial Deposits Considering Mechanical Anisotropy

Document Type : Research Papers


The University of Guilan


The soil is a heterogeneous and anisotropic medium. Hydraulic conductivity, an intrinsic property of natural alluvial deposits varies both deterministically and randomly in space and has different values in various directions. In the present study, the permeability of natural deposits and its influence on the seepage flow through a natural alluvial deposit is studied. The 2D Finite Difference code, FLAC 5.0, is used for modeling permeability as a random variable with lognormal distribution and correlated structure. Effect of spatially varying permeability on the seepage flow through deposit is investigated for both isotropic and anisotropic conditions. Results show that in isotropic condition, the mean discharge flow rate calculated from stochastic analyses is less than the equivalent deterministic value and this reduction depends on the coefficient of variation, COV of permeability and the correlation length. The directionality of permeability introduced as mechanical anisotropy was also studied along with the heterogeneity. It was found that increasing the anisotropy ratio of permeability leads to the formation of horizontal flow canals and increasing the seepage flow consequently at a constant vertical permeability. Variation of permeability coefficient was found to have almost no impact on mean discharge flow rate for anisotropic fields in comparison to the isotropic condition.


Main Subjects

Ahmed, A.A. (2012). “Stochastic analysis of seepage under hydraulic structures resting on anisotropic heterogeneous soils”, Journal of Geotechnical and Geoenvironmental Engineering, 139(6), 1001-1004.
Budhu, M. (2011). Soil Mechanics and Foundations (3rd Edition), John Wiley & Sons.
Benson, C. H. (1993). “Probability Distributions for Hydraulic Conductivity of Compacted Soil Liners”, Journal of Geotechnical and Geoenvironmental Engineering, 119(3), 471–486.
Cho, S.E. (2012). “Probabilistic analysis of seepage that considers the spatial variability of permeability for an embankment on soil foundation”, Engineering Geology, 133-134, 30–39.
Clennell, M.B., Dewhurst, D.N., Brown, K.M. and Westbrook, G.K. (1999). Permeability anisotropy of consolidated clays, Geological Society, London, Special Publications, 158(1), 79-96.
Dagan, G. (1989). Flow and Transport in Porous Formations, Springer-Verlag, New York, NY.
Duncan, J.M. (2000). “Factors of safety and reliability in geotechnical engineering”, Journal of Geotechnical and Geoenvironmental Engineering, 126(4), 307-316.
Fenton, G. A. and Griffiths, D.V. (1995). “Flow through earth dams with spatially random permeability”, Proceedings of the 10th ASCE Engineering Mechanics Conference, Boulder, Colorado.
Fenton, G.A. and Griffiths, D.V. (1996). “Statistics of free surface flow through stochastic earth dam”, Journal of Geotechnical Engineering, 122(6), 427-436.
Fenton, G.A. and Griffiths, D.V. (1997). “Extreme hydraulic gradient statistics in stochastic earth dam”, Journal of Geotechnical and Geoenvironmental Engineering, 123(11), 995-1000.
Griffiths, D.V. and Fenton, G.A. (1993). “Seepage beneath water retaining structures founded on spatially random soil”, Geotechnique, 43(4), 577-87.
Griffiths, D.V. and Fenton, G.A. (1997), “Three-dimensional seepage through spatially random soil”, Journal of Geotechnical and Geoenvironmental Engineering, 123(2), 153-160.
Jamshidi Chenari, R., and Seyed Noori, N. (2016). “Uncoupled consolidation analysis of clay deposits with linearly varying characteristics with depth”, Iranian Journal of Science and Technology, Transactions of Civil Engineering, 41(1), 49-53.
Jamshidi Chenari, R. and Alaie, R. (2015). “Effects of anisotropy in correlation structure on the stability of an undrained clay slope”, Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 9(2), 109-123.
Jamshidi Chenari, R. and Mahigir, A. (2014). “The effect of spatial variability and anisotropy of soils on bearing capacity of shallow foundations”, Civil Engineering Infrastructures Journal, 47(2), 199-213.
Le, T.M.H., Gallipoli, D., Sanchez, M. and Wheeler, S.J. (2012). “Stochastic analysis of unsaturated seepage through randomly heterogeneous earth embankments”, International Journal for Numerical and Analytical Methods in Geomechanics, 36(8), 1056-1076.
Lumb, P. (1974). Application of statistics in soil mechanics, Soil Mechanics New Horizons, IK Lee, (ed.).
Oda, M. (1972). “Initial fabrics and their relations to mechanical properties of granular material”, Soils and Foundations, 12(1), 17-36.
Rafiezadeh, K. and Ataie-Ashtiani, B. (2013). “Three dimensional flow in anisotropic zoned porous media using boundary element method”, Engineering Analysis with Boundary Elements, 36 (5), 812-824.
Salmasi, F., Mansuri, B., and Raufi, A. (2015). “Use of numerical simulation to measure the effect of relief wells for decreasing uplift in a homogeneous earth dam”, Civil Engineering Infrastructures Journal, 48(1), 35-45.
Seyed Noori, N. (2014). “Analytical investigation on consolidation of heterogeneous natural alluvial deposits”, M.Sc. Thesis, Faculty of Pardis, The University of Guilan, Guilan, Iran.
Scholes, O.N., Clayton, S.A., Hoadley, A.F. and Tiu, C. (2007). “Permeability anisotropy due to consolidation of compressible porous media”, Transport in Porous Media, 68(3), 365-387.
Srivastava, A., Babu, G.S. and Haldar, S. (2010). “Influence of spatial variability of permeability property on steady state seepage flow and slope stability analysis”, Engineering Geology, 110(3), 93-101.
Yu, C., Deng, S.C., Li, H.B., Li, J.C. and Xia, X. (2013). “The anisotropic seepage analysis of water-sealed underground oil storage caverns”, Tunneling and Underground Space Technology, 38 (September), 26-37.
Zhang, F., Cosson, B., Comas-Cardona, S. and Binetruy C. (2011). “Efficient stochastic simulation approach for RTM process with random fibrous permeability”, Composites Science and Technology, 71 (12), 1478.