The behavior of loose gassy sand

Grozic, J. L. H.; Robertson, P.K.; Morgenstern, N.R.

doi:10.1139/cgj-36-3-482

Cited by 17 publications

(26 citation statements)

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“…And it is shown that the undrained shear strength of the gassy soil (fabricated by using the methane‐saturated zeolite) is a function of the initial degree of saturation as well as initial operating stress (Sills et al, ). Laboratory experiments show that gassy specimen (prepared by depressurization of CO 2 ‐dissolved water) shows strain‐softening, quasi steady state, or strain‐hardening behavior depending on initial water saturation and void ratio before the shearing test (Grozic et al, ). In addition, the sediment desaturated by microbial denitrification process shows that undrained shear strength and cyclic shear resistance can be improved by lowering water saturation, and the undrained stress‐strain behavior can change from strain‐softening to strain‐hardening via desaturation (He & Chu, ; O'Donnell et al, ; van Paassen et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…Sometimes, methane bubbles burst out and form a crater in the permafrost subject to gradually thawing by the climate change (Moskvitch, ). The gas bubble formation in the shallow ocean sediment, called gassy soils, also affects the mechanical properties of the sediment (Grozic et al, ; Sills et al, ). In addition, the small gas bubbles trapped in porous media could dramatically reduce hydraulic conductivity without the significant reduction in water saturation (Ronen et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Gas Bubble Migration and Trapping in Porous Media: Pore‐Scale Simulation

Mahabadi

Zheng²,

Yun

et al. 2018

JGR Solid Earth

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Gas bubbles can be naturally generated or intentionally introduced in sediments. Gas bubble migration and trapping affect the rate of gas emission into the atmosphere or modify the sediment properties such as hydraulic and mechanical properties. In this study, the migration and trapping of gas bubbles are simulated using the pore‐network model extracted from the 3D X‐ray image of in situ sediment. Two types of bubble size distribution (mono‐sized and distributed‐sized cases) are used in the simulation. The spatial and statistical bubble size distribution, residual gas saturation, and hydraulic conductivity reduction due to the bubble trapping are investigated. The results show that the bubble size distribution becomes wider during the gas bubble migration due to bubble coalescence for both mono‐sized and distributed‐sized cases. And the trapped bubble fraction and the residual gas saturation increase as the bubble size increases. The hydraulic conductivity is reduced as a result of the gas bubble trapping. The reduction in hydraulic conductivity is apparently observed as bubble size and the number of nucleation points increase.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gas Bubble Migration and Trapping in Porous Media: Pore‐Scale Simulation

Mahabadi

Zheng²,

Yun

et al. 2018

JGR Solid Earth

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“…The effect of the presence of natural gases on the geotechnical properties of soils has been investigated by a number of researchers and a good summary of the work done to date is found in Grozic et al (1999).…”

Section: Effect Of Gases On Soil Behaviourmentioning

confidence: 99%

Influence of exsolved gases on slope performance at the Sarnia approach cut to the St. Clair Tunnel

et al. 2010

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In 1993, over 100 years after the completion of the original St. Clair Tunnel and its approach cuts, work commenced on the new St. Clair Tunnel. The new tunnel used the existing approaches, but required additional excavation to widen and deepen the original cuts. In Sarnia, the new work initiated unusual deep-seated deformations on the south slope of the approach. Effective stress finite element analysis (FEA), using an elliptical cap soil model coupled with Biot consolidation theory, was used to model the 1993 construction, but initial predictions were unable to capture the trend of deformations noted in the field. Naturally occurring gases are frequently encountered near the base of the overburden in the Sarnia area and this phenomenon was observed during drilling investigations in the Sarnia approach cut. Including the effects of the presence of exsolved natural gases in fine-grained soils subjected to unloading in the FEA results in substantially better predictions in the trend of deformations on the slopes of the approach cut.Résumé : En 1993, plus de 100 ans après la fin du tunnel original de St. Clair et ses coupes d'approche, le travail a dé-buté sur le nouveau tunnel de St. Clair. Le nouveau tunnel a employé les approches existantes mais a exigé l'excavation additionnelle pour élargir et approfondir les coupes d'original. À Sarnia, le nouveau travail a lancé des déformations peu communes situées en profondeur sur la pente du sud de l'approche. L'analyse par éléments finis (« FEA ») en contrainte effective utilisant un modèle elliptique de sol couplé à la théorie de consolidation de Biot est employée pour modéliser la construction de 1993 mais les prévisions initiales ne peuvent pas prendre en compte la tendance des déformations observées sur le chantier. Des gaz naturels sont fréquemment produits près de la base des terrains de recouvrement dans la ré-gion de Sarnia et ce phénomène a été observé pendant les investigations par forage dans la coupe d'approche de Sarnia. L'inclusion des effets de la présence des gaz naturels ex-résolus dans les sols granuleux fins soumis au déchargement dans le FEA a donné des prévisions sensiblement meilleures de la tendance des déformations sur les pentes de la coupe d'approche.Mots-clés : gaz naturels, excavation, déformations de la pente, plaine d'argile de St. Clair, analyse par éléments finis.

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“…This has been shown by a number of researchers via a number of different testing techniques including cyclic triaxial tests (Bouferra et al 2007;Okamura and Soga 2006;Pietruszczak et al 2003;Tamura et al 2002;Tsukamoto et al 2002;Xia and Hu 1991), cyclic torsional shear tests (Altun and Goktepe 2006;Sherif et al 1977;Yoshimi et al 1989) and shaking table tests (Eseller-Bayat 2009; He 2013; Lee and Santamarina 2007;Okamura and Teraoka 2006;Yegian et al 2006Yegian et al , 2007. Grozic et al (1999) observed that under conventional isotropically undrained triaxial compression tests, loose sand with a degree of saturation lower than about 90% exhibited strain hardening behavior. They also observed that samples with a DOS > 90% loose sand exhibited complete strain softening behavior.…”

Section: 1backgroundmentioning

confidence: 92%

“…Under monotonic loading, the behavior has been shown to depend on the density of the sand and stability of the gas. Grozic et al (1999) observed that under conventional isotropically undrained triaxial compression tests, loose sand with a degree of saturation lower than about 90% exhibited strain hardening behavior. They also observed that loose samples with a DOS > 90% exhibited complete strain softening behavior.…”

Section: 32effects Of Gas On the Stress-strain Behavior Of Sandmentioning

confidence: 99%

Engineering properties of saturated and biogas desaturated sand

Hansen

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The behavior of loose gassy sand

Cited by 17 publications

References 0 publications

Gas Bubble Migration and Trapping in Porous Media: Pore‐Scale Simulation

Gas Bubble Migration and Trapping in Porous Media: Pore‐Scale Simulation

Influence of exsolved gases on slope performance at the Sarnia approach cut to the St. Clair Tunnel

Engineering properties of saturated and biogas desaturated sand

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