OBSERVATION OF 2 LONGITUDINAL AND 2 TRANSVERSE-WAVES IN A FROZEN POROUS-MEDIUM

Experimental results on the transmission of elastic waves in a water-saturated sample of glass powder are presented. Both longitudinal and transverse waves are studied in a temperature range of [-30, 0 °C]. Two longitudinal and two transverse waves are detected. For a temperature of -28 °C and a frequency of 500 kHz, the measured velocities are of the order of 4000 and 2300 m/s for the two longitudinal waves and of 2400 and 1400 m/s for the two transverse waves. The two supplementary signals detected (one longitudinal and one transverse) are very unlikely the result of spurious reflections or electromagnetic coupling since such phenomena were not observed when replacing the porous sample by water. The values of the experimental velocities are in good agreement with the predictions of the extension of Biot's theory to frozen porous media developed by Leclaire et al. [J. Acoust. Soc. Am. 96, 3753-3768 (1994)]. © 1995, Acoustical Society of America. All rights reserved.