Comparison of Geoacoustic Models for Unfrozen Water Content Estimation. Issue 10 (7th October 2020)

• Record Type: Journal Article
• Authors: Lyu, Chuangxin; Amiri, Seyed Ali Ghoreishian; Grimstad, Gustav; Høyland, Knut Vilhelm; Ingeman‐Nielsen, Thomas
• Is Part Of: Journal of geophysical research. Volume 125:Issue 10(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-10-07
• Subjects: frozen soil -- unfrozen water content -- geoacoustic model -- ice crystal growth; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2020JB019766
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: This paper reviews eight geoacoustic models applied to frozen soils: crystal growth models (grain cementing, grain coating, matrix supporting, and pore filling), the weighted equation (WE) model, Zimmerman and King's model (KT), the Biot‐Gassmann theory modified by Lee (BGTL), and a two‐end member model. We verify the capacity of these models to estimate unfrozen water content (UWC) based on "reference" UWC results and joint P and S wave velocities for different soil types. The satisfactory UWC estimates of saline unconsolidated sand and overconsolidated clay based on V p data prove that the KT, BGTL, and two‐end member models are capable of modeling "smooth" transitions in the ice crystal growth mode, while they may provide less accurate UWC values when abrupt change of crystallization mode occurs. None of the tested soil types show a single crystallization mode throughout the freezing process, as assumed by individual crystal growth models. V s ‐based UWC estimates are less accurate due to significant but difficult‐to‐estimate influence of effective stress and soil initial cementation. All models, except pore filling and matrix supporting, can match V s versus V p measurement results for sands and silts but gradually provide inconsistent estimates with increasing clay content. We conclude that model validation by independent UWC measurements is necessary and that consistency between UWC values estimated from V s and V p is insufficient to ensure proper model validation. Key Points: Review of combined laboratory data shows that geoacoustic models can estimate the unfrozen water content for saline frozen soils Joint analysis of data and models indicates the dependency of ice crystallization mode on the unbound water content and salinity of the soil Salt precipitation and dissolution are interpreted as the likely cause of freeze‐thaw hysteresis near the eutectic temperature in frozen soil