Shear moduli of volcanic soils

The shear modulus of soils is one of the important parameters in small strain level geotechnical problems (i.e. the study of earthquake effects and soil-structure interaction). In this paper, the shear moduli of crushable volcanic soils at small strain level were investigated in bender element and cyclic undrained triaxial tests. Comparison of results shows that the shear moduli from bender element tests agree well with those determined in cyclic triaxial tests. The influence of particle breakage, effective confining pressure, consolidation time, void ratio and fines content on the shear modulus are also discussed. In the present study, empirical equations for evaluating the shear modulus of granular materials with particle breakage are proposed based on the test results.