Anisotropy of Small Strain Stiffness in Undisturbed and Reconstituted Clays

This paper concerns the assessment of the elastic shear modulus Go of reconstituted and undisturbed clays by means of seismic measurements performed dunng tria,rial compression tests. The experiments were performed by means of a triaxial celì equipped with local gauges for a-rial and radial strain measurements and with piezoceramic bender elements for the measurement of the propagatìon velocity of differentiy polarised shear waves. The tests were performed on reconstituted specimens of Fujiromori (Japan) clay and on intact specimens of two Italian clays (Pisa and Augusta). Seismic tests were performed during saturation process. consoJidation and shearing. These measurements allowed to determine the small strair she:u modulus in the vertical and horizontal plane (Gvh, , Ghh ). ln particular the paper deals with the followmg topics: i) assessment of the stiffness anisotropy at smal1 strains, iì) assessment of the decay of Go during shealing in order to dehne the sensitivity of this parameter to sample disturbance.