Sandy Soil Compression Test Data to compute Compression Index

Abstract In this research, they have been studied sandy soils with granulometry obtained mixing three granulometry types A,B, C, and considering percentage ranged between 0 and 100 %, with increasing of the 20 %, with moisture content of 0, 5, 10%. The soils granulometry were: type A (0.5-1 mm), B(0.25-0.5mm), C(less than 0.25 mm). Therefore, 24 soil different typologies were obtained. The considered samples were submitted to hydrostatic compression test (HCT) and pressure-void index (p-e) diagrams were obtained. The (p-e) diagrams have allowed to determine the compression index, Cc, by the Gompertz model. Then we fitted the raw data with the Gompertz model because of its ability to describe the compression phenomenon of a soil. The modulus of the slope of the virgin compression curves - the compression index “Cc” – have been estimated as the modulus of the slope at the first inflection point of the Gompertz curve. The Cc value characterized the soil mechanical behavior of the considered soil, denoting the soil capability to be compacted. By mean these experimental data 3 D diagrams were obtained that allowed a better description of the mechanical behavior of a family set of soils considered. This approach has the advantage of being objectively defined by a straightforward procedure. The estimates of the Gompertz model parameters was performed with a nonlinear regression method. The model fitted the raw data closely, with mean R2 values greater than 0.99.