Modelos descontínuos na análise tridimensional do comportamento hidromecânico de fundações de barragens de betão
DOI:
https://doi.org/10.24849/j.geot.2021.151.02Palavras-chave:
fundações de barragens de betão, comportamento hidromecânico, modelação numérica tridimensionalResumo
Neste artigo apresenta-se a formulação e resultados da aplicação de dois modelos descontínuos tridimensionais que simulam a interação hidromecânica. Nestes modelos o comportamento mecânico é simulado de forma idêntica mas o comportamento hidráulico é simulado com duas abordagens diferentes. O primeiro modelo baseia-se numa formulação que admite o escoamento através de elementos planos de interface. O segundo modelo, que se propõe neste artigo, baseia-se numa discretização unidimensional, ocorrendo o escoamento através de elementos de canais. Os modelos hidromecânicos implementados no módulo computacional Parmac3D-Fflow são verificados e validados através de exemplos simples, e o modelo proposto é calibrado de modo a serem obtidos, com os dois modelos, os mesmos valores de pressão e de caudal.Foi desenvolvido um modelo hidromecânico de um conjunto barragem/fundação, tendo em consideração a existência de cortina de impermeabilização e de sistema de drenagem na fundação. Salientam-se as vantagens do modelo proposto no estudo do comportamento hidromecânico de fundações de barragens.
Downloads
Referências
Azevedo, N.M. (2003). A rigid particle discrete element model for the fracture analysis of plain and reinforced concrete. Ph.D Thesis. Heriot-Watt University, Scotland.
Azevedo N.M., Candeias, M., Gouveia, F. (2015) A Rigid Particle Model for Rock Fracture Following the Voronoi Tessellation of the Grain Structure: Formulation and Validation, Rock Mechanics and Rock Engineering, vol. 48, pp. 535-557, DOI 10.1007/s00603-014-0601-1.
Azevedo, N.M.; Farinha, M.L.B. (2015). Um modelo hidromecânico para análise de fundações de barragens gravidade em betão. Geotecnia, vol. 133, nº março, pp. 5–33.
Bear, J. (1988). Dynamics of fluids in porous media. Dover Publications, Inc., New York.
Bretas, E.; Lemos, J.V.; Lourenço, P. (2013). Hydromechanical analysis of masonry gravity dams and their foundations. Rock Mechanics and Rock Engineering, vol. 46, pp. 327–339.
Bustamante, L.; Radisic, A. (2006). Structural design and RCC zoning in Ralco dam. Proceedings of the 22nd International Congress on Large Dams. Barcelona, Spain, 18-23 June 2006. ICOLD, Paris, Vol.1, Q84-R3, pp. 33-45.
Damjanac, B. (1996). A three-dimensional numerical model of water flow in a fractured rock mass. Ph.D. Thesis, University of Minnesota.
Erban, P., Gell, K. (1988) Consideration of the interaction between dam and bedrock in a coupled mechanic-hydraulic FE-program. Rock Mechanics and Rock Engineering, vol. 21, nº2, pp. 99–117.
Farinha, M.L.B.; Azevedo, N.M.; Candeias, M. (2017). Small displacement coupled analysis of concrete gravity dam foundations: static and dynamic conditions. Rock Mechanics and Rock Engineering, vol. 50, nº 2, pp. 439-464.
Farinha, M.L.B.; Lemos, J.V.; Maranha das Neves, E. (2011). Numerical modelling of borehole water-inflow tests in the foundation of the Alqueva arch dam. Canadian Geotechnical Journal, vol. 48, nº 1, pp. 72-88.
Farinha, M.L.B.; Lemos, J.V.; Maranha das Neves, E. (2012). Analysis of foundation sliding of an arch dam considering the hydromechanical behaviour. Frontiers of Structural and Civil Engineering, vol.6, nº1, pp. 35-43.
Farinha, M.L.B.; Azevedo, N.M.; Leitão, N. S.; Castilho, E.; Câmara, R. (2018). 3D coupled hydromechanical analysis of dam foundations. Proceedings of the 9th European Conference on Numerical Methods in Geotechnical Engineering (NUMGE 2018), Porto.
Freitas, G..; Farinha, M.L.B.; Azevedo, N.M., Almeida, J.R.; Sá, M.; Leitão, N.S. (2020). Discontinuous hydromechanical modelling of concrete dam foundations. Proceedings of the Fourth International Dam World Conference, Lisboa, Portugal, 21-25 September. Vol 1.
Gell K. (1983). Influence of seepage in the underground to the calculation of stresses and deformations of arch dams. Ph.D Thesis. RWTH, Germany (em Alemão).
Gell K., Wittke W. (1986) A new design concept for arch dams taking into account seepage forces. Rock Mechanics and Rock Engineering, vol. 19, nº4, pp.187–204.
Gomes de Mendonça T. (1989) Three-dimensional finite element model for the analysis of the hydromechanical behaviour of concrete dam foundations. LNEC, Relatório 158/99, pp. 1–67 (em Português)
Goodman, R.; Taylor, R.; Brekke, T. (1968) A model for the mechanics of jointed rock. Journal of the Soil Mechanics and Foundations Division (ASCE), vol. 94(SM3), pp. 637-659.
Hohberg, J. (1992) A joint element for the nonlinear dynamic analysis of arch dams. Ph.D. Thesis. Institute of Structural Engineering, ETH, Zurich, Switzerland.
Itasca (2004). UDEC - Universal Distinct Element Code, Version 4.0, Itasca Consulting Group, Minneapolis.
Jing, L. (2003) A review of techniques, advances and outstanding issues in numerical modelling for rock mechanics and rock engineering. International Journal of Rock Mechanics and Mining Sciences, vol. 40(3), pp. 283-353, DOI:10.1016/S1365-1609(03)00013-3.
Lemos, J.V. (2011). Discontinuum models for dam foundation failure analysis. Keynote Lecture, 12th International Congress on Rock Mechanics, Beijing, China, 16-21 October 2011.
Lemos, J.V.; Cundall, P. (1999). Earthquake analysis of concrete gravity dams on jointed rock foundations. In Distinct element modelling in geomechanics. Oxford and IBH Publishing, New Delhi, pp. 117–143.
Lisjak, A.; Kaifosh, P.; He, L.; Tatone, B.S.A.; Mahabadi, O.K.; Grasseli, G. (2017). A 2D, fully coupled, hydro-mechanical, FDEM formulation for modelling fracturing processes in discontinuous porous rocks masses. Computers and Geotechnics, vol. 81,nº January, pp. 1 18. https://doi.org/10.1016/j.compgeo.2016.07.009.
Lombardi, G. (2007). 3-D analysis of gravity dams. International Journal Hydropower and Dams 14(1), pp. 98-102.
Louis, C. (1969). A study of groundwater flow in jointed rock and its influence on the stability of rock masses. Ph.D. Thesis, University of Karlsruhe (in German), English translation, Imperial College Rock Mechanics Research Report nº10, London.
Louis, C.; Maini, Y.N. (1970). Determination of in situ hydraulic parameters in jointed rock. Proceedings of the 2nd International Congress on Rock Mechanics. vol.I, pp. 235-245, Belgrade.
Noorishad J., Ayatollahi M.S., Witherspoon P.A. (1982) A finite-element method for coupled stress and fluid flow analysis in fractured rock masses. International Journal of Rock Mechanics and Mining Sciences and Geomechanics Abstracts, vol. 19, pp.185-193.
Rutqvist J., Stephansson O. (2003). The role of hydromechanical coupling in fractured rock engineering. Hydrogeology Journal, vol. 11, nº1, pp.7-40.
Sá, M. (2019). Análise tridimensional do comportamento hidromecânico de fundações de barragens gravidade. Dissertação de mestrado, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, Portugal.
Snow, D.T. (1965). A parallel plate model of fractured permeable media. Ph.D. Thesis, University of California, Berkeley.
Sun, Y. (1994). A three-dimensional model for transient fluid flow through deformable fractured porous media. Ph.D. Thesis, University of Minnesota.
Underwoord, P. (1983). Dynamic relaxation. In Computational methods for transient analysis. New York: North Holland, 9 p.
Wittke, W., Gell, K. (1984) Wechselwirkung zwischen Staumauer und Untergrund. Wasserwirtschaft 74(3): 137-141
Yan, C.; Zheng, H. (2017). FDEM-flow3D: A 3D hydro-mechanical coupled model considering the pore seepage of rock matrix for simulating three-dimensional hydraulic fracturing. Computers and Geotechnics, vol. 81, nº January pp. 212–228. https://doi.org/10.1016/j.compgeo.2016.08.014
Yan, C.; Zheng, H.; Sun, G.; Ge, X. (2016). Combined finite-discrete element method for simulation of hydraulic fracturing. Rock Mechanics Rock Engineering, vol. 49, pp. 1389–1410. https://doi.org/10.1007/s.00603-015-0816-9.
Yan, C.; Jiao, Y.-Y.; Zheng, H. (2018). A fully coupled three-dimensional hydro-mechanical finite discrete element approach with real porous seepage for simulating 3D hydraulic fracturing. Computers and Geotechnics, vol. 96, nº November pp. 73–89. https://doi.org/10.1016/j.compgeo.2017.10.008.
