Strength characteristics of crushable volcanic soils at various degrees of saturation

The objective of this study is to evaluate the effect of degree of saturation on the strength characteristics of volcanic coarse-grained soils, wherein particle breakage significantly takes place during loading and deformation processes, under various degrees of saturation conditions. In this paper, a series of monotonic triaxial compression tests for two kinds of volcanic coarse-grained soils are performed under various degrees of saturation conditions, and the relationships between degree of saturation, degree of particle breakage and strength are examined based on experimental results. As the result, the following conclusions are obtained: The shear strength of crushable coarse-grained volcanic soils decreases with an increase in the amount of particle breakage. Particle breakage is strongly influenced by the degree of saturation of the soil matrix. Accordingly, as the crushable volcanic coarse-grained soil becomes saturated, particle breakage becomes more dominant, thereby decreasing the shear strength of the soil.