Novel Methodology for Determining the Mechanical Characteristics of Coarse-Grained Soils

Coarse-grained soils are a type of soil frequently found in civil engineering projects, and their mechanical characterization still presents a real challenge. They are composed by elements of different dimensions (from a few microns to tens of centimeters), and can be of very varied nature (clay, sand, gravel, pebbles, etc.). The mechanical characterization of coarse-grained soils is very difficult because of the presence of large elements. In order to be able to characterize them in the laboratory by means of conventional size devices, it is very important to study the influence of significant parameters on the mechanical behavior of coarse-grained soils (the volume fraction, particle size distribution and spread, consolidation level and initial state of the matrix), using the large-sized triaxial testing device. In this paper, we will propose a methodology for evaluating the mechanical characteristics of coarse-grained soils based on soil granulometric reconstruction procedures. The method we have named GALA is based on the use of polynomial correlations between the strength increase due to inclusions and the volume fraction f_v and the particle spread (d_min/d_max) of inclusions. We were able to apply this new method to a natural soil. The results showed the relevance of our method.