Comportamento hidráulico de um perfil de solo não saturado de Aparecida de Goiânia-GO
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Data
2010-04-30
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Universidade Federal de Goiás
Resumo
The hydraulic behavior of a tropical and unsaturated soil profile of Aparecida de Goiânia-GO
is presented. The main objective of this research was to contribute to the understanding of
hydraulic properties of a tropical soil, with special emphasis on the soil-water characteristic
curves and its hysteresis. The research work done was divided into two main parts: physical,
chemical and mineralogical characterization; and hydraulic behavior for the unsaturated
condition. The characterization tests indicate that the soil profile studied is formed by two
horizons. The top layer of 1,50 m comprised of transported material and a bottom layer
comprised of young residual soil. The results of particle size analysis have shown that the
various sample preparation conditions (i.e., with or without drying, chemical and physical
disaggregation) produce different grain-size distribution curves. A varying state of
disaggregation can be achieved, that state being dependent on the stability of the soil
aggregates. A fairly good correspondence between conventional hydrometer and laser
diffraction analysis was achieved, considering supposedly equivalent aggregation conditions.
The soil-water characteristic curve (SWCC) was measured for both the natural and the soil
reconstituted by mud consolidation. The role played by the soil fabric on the hydraulic
behavior of the soil was analyzed. The SWCC was obtained for drying, wetting, and mixed
paths, both in terms of total and matric suction. It was determined that the natural and
reconstituted soils have distinct SWCCs. The disaggregation achieved with the reconstituted
soil results in higher air-entry values and a unimodal SWCC, even when the natural soil
presents a bimodal SWCC. Therefore, the pore-size distribution if affected by the different
soil structures. The procedure for wetting and drying soil samples used along with the filter
paper technique resulted in a number of SWCCs showing absence of hysteresis. The study of
the moisture content along the specimen s heights revealed non-homogeneous moisture
content distributions, even after 14 day of equilibrium of water potential. It was concluded
that it is the very existence of SWCC hysteresis, along with a not sufficiently slow wetting
and drying from the specimen surface that results in a non-homogeneous moisture content.
Descrição
Citação
BORGES, Camilla Rodrigues. Hydraulic behavior of an unsaturated soil profile of Aparecida de Goiania-GO. 2010. 272 f. Dissertação (Mestrado em Engenharias) - Universidade Federal de Goiás, Goiânia, 2010.