ABSTRACT
This paper presents the results of a series of triaxial CIU tests performed with a compacted residual soil following two different initial procedures to increase saturation prior the shear.
2 QUASI-SATURATED STATE
Many authors have studied the behavior of soils under a quasi-saturated state (e.g. Vaughan, 1982; Cruz & Maiolino, 1985; Sandroni, 1985; Lins & Sandroni, 1994; Shahu et al., 1999; Marinho et al., 2002, among others). The usual way to infer the saturation state is by using the pore-water pressure parameter B (Δu/Δσ3) that increases with the increment in the degree of saturation reaching the value of one when the soil is fully saturated. Casagrande & Poulos (1964) and more recently Shahu et al. (1999) showed that for the soil to behave as a quasi-saturated material, the initial B value should be higher than 0.3 or 0.4, with a degree of saturation above 93 or 95%. However, the relation between B and the degree of saturation is nonlinear and soils with high stiffness may present B values close to zero even at degrees of saturation above 95% (Black & Lee, 1973). This aspect put
1 INTRODUCTION
Compaction is one of the most common processes used to improve the geotechnical characteristics of the natural soil. Normally, this activity is performed in the vicinity of the optimum water content of the compaction curve. However, in tropical regions where the rain season is too long, compaction on the wet side of the optimum is the only solution that can meet the deadlines of construction. This combination determines to work with a lower dry density and higher water content.
