Triaxial tests on undisturbed gravelly soils from the Sicilian shore of the Messina Strait

The paper reports the results of laboratory testing of dense sandy gravel carried out on large dimension undisturbed samples, obtained by means of in situ freezing technique. The specimens, 290 mm in diameter and 600 mm high, have been subjected to undrained cyclic triaxial tests carried out in isotropically and anisotropically consolidated conditions aimed at investigating sandy gravel susceptibility to cyclic mobility and plastic strain accumulation during earthquakes induced vibrations. The quality of the undisturbed samples was corroborated by comparing the field shear wave velocities against those inferred from bender element tests, carried out in the triaxial apparatus after the specimens consolidation. The cyclic tests were supported by a series of monotonic undrained and drained triaxial tests performed on isotropically and anisotropically consolidated specimens to help in their more rational interpretation. The tests yielded valuable information as to the susceptibility of the sandy gravel in hands to cyclic mobility and plastic strain accumulation during earthquake loading.