The Measurement of Gas Bubble Size Distributions in a Three Phase Laboratory Gassy Soil

The technique developed can be used to measure the total void, gas void, or particle size distribution in both gassy and saturated sediments provided the void spaces, or particles, can be approximated to spheres. Here the technique is demonstrated for measuring gas bubble size distribution in a reconstituted estuarine silty clay, which has been impregnated with methane gas using the method described by Nagaswaran. The process involves specimen preparation of a resin impregnated specimen to provide images using a scanning electron microscope (SEM). An average planar size distribution is obtained from the SEM images by computerized measurement of pixels on a monitor distinguished by luminance intensity phasing. Conversion from the planar to a spherical size distribution is carried out by a statistical method of probability. Results are presented that illustrate the consistency and accuracy of the measurement technique as a whole. Observations are made regarding the structure of the laboratory gassy soil which may be relevant to an in-situ sea bed gassy soil.