Soil-water Characteristic Curves Obtained Through The Wetting Paths For A Tropical Soil Profile

This research presents the soil water characteristic curves (SWCC) for a tropical soil profile, typical of 14% of the region of Campinas, in the state of São Paulo, Brazil. This profile consists of colluvial, lateritic and collapsible silty clay, with an approximate 6.5 m thickness and present in a clayed silt soil. The water level is approximately at 17 m. To determine the curves, the filter paper and axis-translation method with wetting paths were used. Impregnated thin-layer plates were prepared with collected undisturbed samples, so as to obtain their structures in the field along the profile, until a 4.5 m depth. Geotechnical characterization tests and chemical-mineralogical tests were carried out on the disturbed samples. The SWCCs for the soil profile until a 4.5 m depth were the bimodal type, typical of tropical soils with macro and micro-aggregated structures. There were differences between the curves obtained with the different methods, mainly due to the way the wetting paths were carried out on the specimens. These differences are very clear for suctions below 100 kPa, where the influence of macropores is more expressive. © 2011 Taylor & Francis Group, London.1441446Spanish Society for Soil Mechanics and Geotechnical Engineering(2004) Test Method for Measurement of Soil Potential Suction Using Filter Paper, 4 (8). , ASTM D 5298-03Bonder, B.H., (2008) Curvas de Retencao de Agua de Um Solo Coluvionar de Campinas Obtidas Mediante Tecnicas de Laboratorio e de Campo, p. 130. , Dissertao de Mestrado Universidade Estadual de Campinas, Brasil. (in Portuguese)Boocking, Fredlund, D.J., Limitation of axis translation technique (1980) 4o International Conference on Expansive Soils, pp. 117-135. , Denver, EUACalle, J.A.C., (2000) Analise de Ruptura de Talude de Um SSolo Nao Saturado, , Tese de Mestrado, EESC-USP/ São Carlos. (in Portuguese)Cavalcante, E.H., Giachetti, H.L., Danziger, F.A.B., Coutinho, R.Q., Souza, A., Kormann, A.C.M., Belincanta, A., Lacerda, W.A., Campos experimentais brasileiros (2007) Revista Luso Brasileira de Geotecnia, 111, pp. 99-205. , in PortugueseChandler, R.J., Gutierrez, C.I., The filter paper method of suction measurement (1986) Geotechnique, 36 (2), pp. 265-268Chandler, R.J., Crilly, M.S., Montgomery-Smith, G., A low-cost method of assessing clay desiccation for low-rise buildings (1992) Proc. of the Institution of Civil Engineering, 92 (2), pp. 89-89(1985) Peculiarities of Geotechnical Behavior of Tropical Lateritic and Saprolitic Soils Progress, , Committee on Tropical Soils of ISSMFE. Edile: São Paulo/SPFeuerharmel, C., Gehling, W.Y.Y., Bica, A.V.D., The use of filter-paper and suction-plate methods for determining the soil-water characteristic curve of undisturbed colluvium soils (2006) Geotechnical Testing Journal, 29 (5), pp. 419-425. , GTJ14004Gardner, W.R., A method of measuring the capillary tension of soil moisture over a wide moisture range (1937) Soil Science, 43 (4), pp. 277-283Gidigasu, M.D., Laterite soil engineering: Pedogenesis and engineering principles (1976) Developments in Geotechnical Engineering, 9. , Elsevier Scientific Publishing CompanyLibardi, P.L., (1995) Dinamica da Agua No Solo, p. 497. , Edio do Autor, ESALQ, Departamento de Física e Meteorologia, (in Portuguese)Marinho, F.A.M., Técnica do papel filtro para medio de suco (1994) Encontro Sobre Solos Nao Saturados, 1, pp. 112-125. , Porto Alegre/RS. (in Portuguese)Marinho, F.A.M., Medição de suc ção em solos (1997) III Simposio Brasileiro de Solos Não Saturados, 1, pp. 373-397. , Rio de Janeiro/RJ, (in Portuguese)Miguel, M.G., Albuquerque, P.J.R., Azevedo, G.S., Silva, G.S.V., De Carvalho, D., Lateritic behaviour of the colluvial soil from Campinas-SP-Brasil (2007) XIII Pan American Conference on Soil Mechanics and Geotechnical Engineering, , Isla de Margarita. CDRom. (in Portuguese)Miguel, M.G., Vilar, O.M., Study of the water retention properties of a tropical soil (2009) Canadian Geotechnical Journal, 46, pp. 1084-1092Rojas, E., Modeling the soil water characteristic curve during wetting e drying cycles (2002) Proc. of the Third International Conference on Unsaturated Soil, 1, pp. 215-219. , Recife, BrazilSoto, M.A., (2004) Comparacao de Metodos de Imposicao e de Controle de Succao em Ensaios de Solos Nao Saturados, , Tese de Doutorado, Escola Politécnica da Universidade de São Paulo, São Paulo. (in Portuguese