Effect of Soft Viscoelastic Biopolymer on the Undrained Shear Behavior of Loose Sands
KAUST DepartmentEarth Science and Engineering Program
Physical Science and Engineering (PSE) Division
Energy Resources and Petroleum Engineering Program
Ali I. Al-Naimi Petroleum Engineering Research Center (ANPERC)
Permanent link to this recordhttp://hdl.handle.net/10754/669406
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AbstractSoft viscoelastic biological products such as biopolymers and biofilms have recently garnered significant interest as alternative biogrout materials for ground improvement because of their nontoxic and biodegradable characteristics. However, the impact of soft gel-like viscoelastic pore fillers on the undrained response of treated soils remains poorly understood. This study involves undrained triaxial compression tests with concurrent shear wave velocity measurements of loose contractive sands treated with soft gelatin. The specimens experience two distinct loading-gelation sequences, either consolidation before gelation (CbG) or confinement after gelation (CaG). Results reveal that the shear wave velocity can be used as an indicator of the effective stress carried by the granular skeleton. The inclusion of the viscoelastic biopolymer hinders the contractive tendency, diminishes postpeak softening, and increases the undrained shear strength of loose contractive sands. These effects become more pronounced for stiffer biopolymers because they provide an enhanced skeletal support against chain buckling and contraction. The presence of biopolymers increases the normalized undrained shear strength from Su=σ 0o ¼ ∼0.1 to ∼1.4, particularly at low effective confining stress. The biopolymers alter the terminal state in the p0-q-e space. Therefore, critical states should be reconsidered for biopolymer-treated sands. The confinement-gelation sequence affects the effective stress supported by the granular frame and thus has pronounced effects on the undrained shear strength. This suggests the potential use of viscoelastic pore fillers as an effective treatment of loose sands prone to liquefaction
CitationNoh, D.-H., Cha, W., Santamarina, J. C., Cho, G.-C., & Kwon, T.-H. (2021). Effect of Soft Viscoelastic Biopolymer on the Undrained Shear Behavior of Loose Sands. Journal of Geotechnical and Geoenvironmental Engineering, 147(8), 04021072. doi:10.1061/(asce)gt.1943-5606.0002582
SponsorsWe would like to thank two anonymous reviewers, the associate editor, and the editor Dr. John McCartney for providing valuable comments and suggestions. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (Ministry of Science, ICT and Future Planning) (No. 2020R1A2C4002358), a grant (19CTAP-C151917-01) from the Technology Advancement Research Program (TARP) funded by the Ministry of Land, Infrastructure, and Transport of the Korean government, and the KAUST Endowment. Gabrielle E. Abelskamp edited this manuscript.
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