Stiffness of a granular base under optimum and saturated water contents

Abstract

Objective: This research work addressed the comparison of the stiffness of a granular base under optimum water content and total saturation conditions. Methodology: The methodology focused in the development of an experimental program and the computation of a function, which permits to assess the elastic moduli of the material. A triaxial cell equipped by local LVDT transducers, capable of managing different stress paths, was used to measure the small-strain stiffness of a granular base under two different conditions of moisture. The material was compacted with optimum water content and subjected to a series of loading-unloading cycles under isotropic conditions. In addition, identical specimens were prepared to be saturated and the experimental procedure was repeated to obtain the moduli in these new circumstances. The moduli were assessed by a hyperbolic model, and its relationship with the confining pressure was computed. Results: The results indicated that numerical model was adjusted to the experimental results. In addition, it was found that the elastic moduli decrease 3% to 8% in conditions of total saturation versus the condition of optimum water contents. Conclusions: The small-strain stiffness in the granular base depends on the water content, and the moisture can affect the deformation in the pavement structures.

Keywords

• granular bases, hyperbolic model, local transducers, small-strain stiffness, unload-reload moduli.