Interface wave studies on a laboratory test facility

• Published in: The Journal of the Acoustical Society of America Vol. 141; no. 5; p. 3532
• Main Authors: Potty, Gopu R., Sapiie, Rendhy M., Small, Chris J., Miller, James H.
• Format: Journal Article
• Language: English
• Published: 01-05-2017
• ISSN: 0001-4966; 1520-8524
• DOI: 10.1121/1.4987461

Rayleigh wave measurements were made in the Interface Wave Test Facility at the University of Rhode Island to develop techniques to estimate the shear wave properties of near surface sediment. Repeating source events at various ranges spaced equally at 0.15 m from a fixed receiver (accelerometer) created a virtual source array. The source events consisted of dropping a tennis ball thereby exciting Rayleigh waves. A monitoring accelerometer was used to record each source event at a fixed distance from the source location in order to time it. This enabled to calculate the travel time of the Rayleigh waves from the monitoring receiver to the fixed receiver. The phase velocity dispersion is calculated using high resolution frequency-wavenumber processing. The shear wave speed of the sediment layers in the “sand tank” is estimated using an inversion scheme. The shear wave speed estimates is compared to direct measurements using a calibrated bender element system at selected depths. The bender element system was placed in a test tank initially filled with mason sand and the Rayleigh wave inversion system was deployed on the surface of the sand in the tank. [Work supported by Army Research Office and ONR.]