Evolution of Small Strain Soil Stiffness during Freeze-Thaw Cycle: Transition from Capillarity to Cementation Examined Using Magnetic and Piezo Crystal Sensors

• Published in: Sensors (Basel, Switzerland) Vol. 21; no. 9; p. 2992
• Main Authors: Park, Junghee, Lee, Jong-Sub, Won, Jongmuk, Kim, Jongchan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 24.04.2021; MDPI
• Subjects: Capillarity; capillary pressure; Capillary waves; Cementation; Cooling; Data acquisition systems; degree of water saturation; Density; Drying; Elastic properties; elastic wave; Elastic waves; freeze-thaw cycle; Geotechnical engineering; Grain size; Measurement techniques; NMR; Nuclear magnetic resonance; P waves; Percolation; S waves; Saturation; Sediments; Sensors; Soil properties; Stiffness; Water distribution; water distribution patterns; Water engineering; elastic wave; degree of water saturation; water distribution patterns; cementation; freeze-thaw cycle; capillary pressure
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s21092992

Freeze-thaw cycles caused by seasonal temperature fluctuations significantly affect the geotechnical engineering properties. This study investigated the crucial role of water distribution patterns in the characterization of elastic wave properties for the fine F-110 sand during a freeze-thaw cycle. Sand specimens with four different water distribution patterns were prepared, namely homogeneously-mixed, evaporation-driven, vertically-, and horizontally-layered specimens. The - and -wave signatures of the specimens were monitored using piezo crystal sensors. Results indicated the criticality of water distribution patterns in the determination of small-strain soil properties even though the specimens had identical global water saturation. The nuclear magnetic resonance-based water volume depth profiles indicated that the evaporation-driven specimens had more heterogeneous pore-invasive ice-bonding layers at a high water saturation region; by contrast, the drying process facilitated uniform meniscuses around the particle contacts near the air percolation threshold. Elastic wave measurements for laboratory-prepared specimens might over/underestimate the small-strain soil stiffness of sediments in nature, wherein the drying processes prevailed to control the water saturation. This study highlighted a clear transition from capillary-controlled to cementation-controlled elastic wave properties during temperature oscillations.