João Paulo Martins

Comparison between laboratory and field stiffness by wave measurements

The present work aims to establish a relationship between field and laboratory moduli obtained from mechanical wave measurements. Spectral analysis of surface waves was performed on a clayey sand trial layer during tests in a full-scale trial. Laboratory triaxial tests involving S-wave measurements with bender elements and accelerometers were conducted on specimens under similar conditions, and the shear modulus was determined. Both laboratory and field methodologies for the determination of the shear modulus were based on S-wave propagation through the tested material; thus they involved similar stress and strain levels. A reasonable relationship was observed between field and laboratory moduli, taking into account field conditions (moisture content and void ratio) and stress state.