Relationship between sound velocity and physical mechanical properties of seafloor sediments in controlled three axis stress - strain

Abstract

Relationship between seafloor sediment sound velocity and the physical and mechanical properties is the foundation of forecasting the sound velocity of seabed sediment or inversing seabed sediment attributes by sound parameters. The relation between sound velocity and the physical and mechanical properties expressed as: a polynomial function of n(1−K w /K s ), the modulus change ratio; and, n(1−ρ w /ρ s ), density change ratio, was presented in the previous paper by this writer. To verify the model, data from measuring experiments in the three axis stress-strain / sound velocity instruments are reported for columnar samples of seafloor sediments at depths of 100–400 meters from the southern South China Sea. The result shows that both the porosity and modulus change have influence on the sound velocity of sediment. Moreover, a sound velocity polynomial formula of modulus change ratio and density change ratio; and, a porosity-velocity formula have been established. By comparison of the errors between sound velocities forecasted with the two formulae and ones measured in experiments, the errors made by the sound velocity formula of double parameters is a quarter of the ones made by the porosity-velocity formula.