We study the geotechnical parameters (void ratio and hydraulic conductivity) of two types of mixtures of particles (crushed gravel and rounded gravel), and determine the porosity n (or the void ratio e) along with the permeability or hydraulic conductivity by the weight mass method. A progressive evolution of the void ratio of the three granular classes is established starting with completely crushed gravel to the fully rounded gravel. We establish a dependency of the void ratio in function of the size range for each grain size.

The study of the permeability or the hydraulic conductivity enables to see a decrease in the evolution of the permeability of different granular classes in function of the shape of the grains. Fully crushed gravels have a higher permeability. We rely on the fact that the values of permeabilities do not follow that of the void ratio and we have established a difference between porosity and drainage which is a function of the stack and grain shape. And then we have established a relationship between the measured values and the predictive values of Chapuis [4].

void ratio, permeability, rounded gravel, crushed gravel, weight mass.