ABSTRACT: This paper aims to clarify static and cyclic deformation-strength properties and evaluation method for volcanic coarse-grained soils with particle crushing, based on site investigations which were conducted using standard penetration test (SPT), cone penetration test (CPT) and seismic cone penetration test (SCP). In addition to these in-situ tests, a series of laboratory tests on disturbed and undisturbed samples was also carried out to obtain the mechanical proper ties such as shear strength, cyclic undrained triaxial strength, pseudo elastic shear modulus and damping ratio. From the results of drained and undrained triaxial compression tests, plane strain compression test and cyclic undrained triaxial test on volcanic soils, it was understood that the effect of particle crushing and fabric anisotropy on the cyclic and static strength-deformation behavior of volcanic coarse-grained soils could not be ignored. Furthermore, the effect of particle breakage on results of dynamic penetration test was also discussed based on the correlation between the sounding data and triaxial test results.

Key words:  anisotropy, in-situ test, laboratory test, liquefaction, particle breakage, shear modulus, stress-strain relation, volcanic coarse-grained soil (IGC: D6/D7)