A correlation technique is developed which enables acoustic transmission measurements to be made in a laboratory tank on air- free samples of real and artificial marine sediments. Measurements of acoustic velocity and transmission loss are presented over a frequency range of 80 kHz to 320 kHz for water saturated granular materials having mean grain diameters ranging from 50 mu to 8000 mus. The transmission loss figures are converted into a surface transmission loss, which is shown to be frequency independent and a volume transmission loss, which is shown to be linearly dependent on frequency over the range where the wavelength of the acoustic energy is greater than the particle size. The acoustic velocity, the surface transmission loss and the volume transmission loss are related to the physical properties of the samples, the mean grain size, phi-deviation, porosity, permeability and solid density. Velocity is shown to be directly related to mean grain size, porosity and phi-deviation and inter-grain friction is shown to be the dominant attenuation mechanism.
|Date of Award||1978|