Effect of Water Content and Sea Salt on Seismoacoustic Waves in Beach Sand
Abstract
New findings are presented providing physical insight on the effect of moisture and sea salt on high-frequency seismoacoustic waves in beach sand. Quantitative results reveal that the velocity of high-frequency compressional waves increases by about 8% as the water content is decreased by 18% from full saturation 1-3. This increase in velocity is in contrast with the Biot-Gassmann theory which predicts that the velocity of low-frequency compressional waves decreases by 85% as the water content is decreased by only 1% from saturation 4. Velocity plots as function of water saturation are compared for different sands and spherical glass beads. The effect of sea salt on grain to grain acoustic coupling is demonstrated. Salt crystallization and transport can lead to the &formation of hard sand/salt layers with a compressional velocity increasing from 200 m/s to 2887 m/s, and a shear velocity increasing from 10 m/s to 1885 m/s 3. A hypothesis is discussed with preliminary results on the potential existence of a suction-cup effect increasing the rigidity of unconsolidated compacted sediments, in the absence of roughness, due to the formation of cavitation microbubbles as the tensile strength of the thin capillary water film between compressed sand grains is exceeded 5.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2001
- Accession Number
- ADA395391
Entities
People
- Jacques R. Chamuel