TY - JOUR
T1 - Effect of Soft Viscoelastic Biopolymer on the Undrained Shear Behavior of Loose Sands
AU - Noh, Dong-Hwa
AU - Cha, Wonjun
AU - Santamarina, Carlos
AU - Cho, Gye-Chun
AU - Kwon, Tae-Hyuk
N1 - KAUST Repository Item: Exported on 2021-06-07
Acknowledgements: We 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.
PY - 2021/6/3
Y1 - 2021/6/3
N2 - Soft 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
AB - Soft 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
UR - http://hdl.handle.net/10754/669406
UR - http://ascelibrary.org/doi/10.1061/%28ASCE%29GT.1943-5606.0002582
U2 - 10.1061/(asce)gt.1943-5606.0002582
DO - 10.1061/(asce)gt.1943-5606.0002582
M3 - Article
SN - 1090-0241
VL - 147
SP - 04021072
JO - Journal of Geotechnical and Geoenvironmental Engineering
JF - Journal of Geotechnical and Geoenvironmental Engineering
IS - 8
ER -