| Coupling phenomena in soil mechanics: Beyond failure of slopes Manuel Pastor1; Diego Manzanal2; Miguel Martin Stickle3; Ángel Yagüe3; Saeed S.m. Tayyebi4; Miguel Molinos3; Jose Antonio Fernandez Merodo5; Pablo Mira6; Pedro Navas3; 1UNIVERSIDAD POLITéCNICA DE MADRID, Madrid, Spain; 2ETS CAMNOS UPM, madrid, Spain; 3ETS CAMINOS UPM, Madrid, Spain; 4ETS INGENIEROS DE CAMINOS UPM, Madrid, Spain; 5IGME, Madrid, Spain; 6CEDEX, CENTRO DE ESTUDIOS Y EXPERIMENTACION DE OBRAS PUBLICAS, Madrid, Spain; PAPER: 179/Geomechanics/Keynote (Oral) SCHEDULED: 14:25/Thu. 24 Oct. 2019/Athena (105/Mezz. F) ABSTRACT: Geotechnical engineers have been concerned for many years to determine the conditions under which a geostructure would fail. In order to determine the failure load and the mechanism type, mathematical, constitutive and numerical models have been used. As an example, we can consider the case of a slope subjected to seismic loading. Here, the mathematical model has to describe the coupling between the solid skeleton and the pore fluids. The contributions of Olek Zienkiewicz and Bernardo Schrefler have been of paramount importance for both saturated and unsaturated soils. To describe soil behaviour, constitutive relations are used. We will consider here Generalized Plasticity models for both saturated and unsaturated soils where we have included a state parameter. Regarding numerical models, most of practical cases have been modelled using coupled finite elements. Special techniques have been proposed in the past years to improve the accuracy of the models. Once failure has been triggered, large deformations and displacements can occur. New mathematical models enlarging the domain of application of the classical pre-failure models have been derived, taking into account large relative displacements between phases. Regarding the rheological behaviour of fluidized soil, the progress has been much slower, and much work lies ahead of the concerned researchers. During last years, we have explored the similarity between rheological models and viscoplastic constitutive equations of Perzyna's type, which seem to provide a suitable bridge between solid and fluidized geomaterials behaviour. Regarding numerical modelling, lagrangian meshless techniques such as SPH provide a suitable framework. In cases of landslides propagating distances much larger than their initial length, thin layer approximations provide suitable compromises between accuracy and cost of computation. References: Haddad, B; Pastor, M; Palacios & D; Munoz-Salinas, E A depth-integrated, coupled SPH model for flow-like landslides and related phenomena Engng.Geology 114 (3-4), 312-339, 2010 Hutter, K., Siegel, M., Savage, S. B. & Nohguchi, Y. 1993 Two dimensional spreading of a granular avalanche down an inclined plane. Part 1. Theory. Acta Mech. 100, 37-68 Hutter, K., Wang, Y. & Pudasaini, S. P. (2005) The Savage-Hutter avalanche model: how far can itbe pushed?. Phil. Trans. R. Soc. A 363. Laigle, D. & Coussot, P. (1997): Numerical modelling of mudflows. Journal of Hydraulic Engineering, ASCE, 123 (7): 617-623. McDougall, S. & Hungr,O. (2004). "A model for the analysis of rapid landslide motion across three-dimensional terrain." Canadian Geotechnical Journal 41.6 (2004): 1084-1097 Pastor, M., Quecedo, M., Fernández Merodo, J.A., Herreros, M.I., Gonzalez, E. & Mira, P.: Modelling tailings dams and mine waste dumps failures. Geotechnique. 52, 579-591 (2002). Pastor, M., Haddad, B., Sorbino, G., Cuomo, S., Drempetic, V.: A depth-integrated, coupled SPH model for flow-like landslides and related phenomena. Int. J. Numer. Anal. Methods Geomech. 33, 143-172 (2009). Pastor, M., Quecedo, M., Gonzalez, E., Herreros, I., Fernandez Merodo, J.A. & Mira, P., "Simple Approximation to Bottom Friction for Bingham Fluid Depth Integrated Models," J. Hydraul. Eng., vol. 130, no. 2, pp. 149-155, Feb. 2004. M. Pastor, M. Martin Stickle, P. Dutto, P. Mira, J. A. Fernández Merodo, T. Blanc, S. Sancho& A. S. Benítez, "A viscoplastic approach to the behaviour of fluidized geomaterials with application to fast landslides," Contin. Mech. Thermodyn., Nov. 2013.M. Pastor, T. Blanc, B. Haddad, S. Petrone, M. Sanchez Morles, V. Drempetic, D. Issler, G.B. Crosta, L. Cascini, G. Sorbino & S. Cuomo (2014), Application of a SPH depth-integrated model to landslide run-out analysis Landslides (DOI) 10 http://dx.doi.org/10.1007/s10346-014-0484-y Pastor, M., Blanc, T., Haddad, B., Drempetic, V., Morles, M. S., Dutto, P., & Merodo, J. F. (2015b). Depth Averaged Models for Fast Landslide Propagation: Mathematical, Rheological and Numerical Aspects. Archives of Computational Methods in Engineering, 22(1), 67-104. Pastor, M., Yague,A., Martin Stickle, M, Manzanal,D. & Mira, P. "A two-phase SPH model for debris flow propagation", Int J Numer Anal Methods Geomech. 2018 DOI: 10.1002/nag.2748 Pitman EB & Le L. A two-fluid model for avalanche and debris flows. Philos Trans A Math Phys Eng Sci. 2005; 363: 1573-601. Pudasaini SP. A general two-phase debris flow model. Journal of Geophysical Research. 2012; 117, F03010 Pudasaini, S. P. & K. Hutter (2007), Avalanche Dynamics: Dynamics of Rapid Flows of Dense Granular Avalanches, 602 pp., Springer, New York. Zienkiewicz, O.C. & Shiomi, T. (1984). Dynamic behaviour of saturated porous media: The generalised Biot formulation and its numerical solution. International Journal of Numerical and Analythical Methods in Geomechanics,8, pp. 71-96 |
