Investigation of Suction Effects Due to Stress Release with Compacted MX80 BentoniteSource: Journal of Geotechnical and Geoenvironmental Engineering:;2022:;Volume ( 148 ):;issue: 009::page 04022070DOI: 10.1061/(ASCE)GT.1943-5606.0002849Publisher: ASCE
Abstract: In this study, the suction induced by stress release was investigated by measuring the suction of instantaneously unloaded MX80 bentonite specimens after wetting in an oedometer either under different vertical stresses or under a constant-volume condition. Swell-consolidation tests were also performed, and the results were compared with those of specimens wetted under different vertical stresses or a constant-volume condition. The microstructure of the unloaded specimens was investigated using mercury intrusion porosimetry (MIP). The water content and void ratio as well as the degree of saturation of specimens were also determined. Results showed that in the case of limited water exchange between macropores and micropores during stress release, the change in suction was equal to that of stress (−ds/dσv=1). By contrast, with water exchange between macropores and micropores, soil swelling occurred, and the variation of suction was higher than that of stress (−ds/dσv>1). A method was proposed allowing such water exchange between macropores and micropores to be determined (−ds/dσv−modified=1, where σv−modified is the modified stress considering water exchange), evidencing the macropore drying due to stress release. Comparison of results from MX80 bentonite and other clayey soils showed that when the nonclay (grains such as quartz, calcite, and so on) fraction (NCF) was lower than 35% by mass, NCF had an insignificant effect on −ds/dσv−modified (equal to 1). By contrast, in the case of higher NCF (>35%), −ds/dσv−modified became lower than 1, and the higher the NCF, the lower the −ds/dσv−modified value. These findings provide useful information for better understanding the mechanism involved at the microstructure level in the stress/suction coupling during stress release in clayey soils.
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contributor author | Feng Zhang | |
contributor author | Yu-Jun Cui | |
contributor author | Bo Chen | |
date accessioned | 2022-08-18T12:17:50Z | |
date available | 2022-08-18T12:17:50Z | |
date issued | 2022/07/01 | |
identifier other | %28ASCE%29GT.1943-5606.0002849.pdf | |
identifier uri | http://yetl.yabesh.ir/yetl1/handle/yetl/4286375 | |
description abstract | In this study, the suction induced by stress release was investigated by measuring the suction of instantaneously unloaded MX80 bentonite specimens after wetting in an oedometer either under different vertical stresses or under a constant-volume condition. Swell-consolidation tests were also performed, and the results were compared with those of specimens wetted under different vertical stresses or a constant-volume condition. The microstructure of the unloaded specimens was investigated using mercury intrusion porosimetry (MIP). The water content and void ratio as well as the degree of saturation of specimens were also determined. Results showed that in the case of limited water exchange between macropores and micropores during stress release, the change in suction was equal to that of stress (−ds/dσv=1). By contrast, with water exchange between macropores and micropores, soil swelling occurred, and the variation of suction was higher than that of stress (−ds/dσv>1). A method was proposed allowing such water exchange between macropores and micropores to be determined (−ds/dσv−modified=1, where σv−modified is the modified stress considering water exchange), evidencing the macropore drying due to stress release. Comparison of results from MX80 bentonite and other clayey soils showed that when the nonclay (grains such as quartz, calcite, and so on) fraction (NCF) was lower than 35% by mass, NCF had an insignificant effect on −ds/dσv−modified (equal to 1). By contrast, in the case of higher NCF (>35%), −ds/dσv−modified became lower than 1, and the higher the NCF, the lower the −ds/dσv−modified value. These findings provide useful information for better understanding the mechanism involved at the microstructure level in the stress/suction coupling during stress release in clayey soils. | |
publisher | ASCE | |
title | Investigation of Suction Effects Due to Stress Release with Compacted MX80 Bentonite | |
type | Journal Article | |
journal volume | 148 | |
journal issue | 9 | |
journal title | Journal of Geotechnical and Geoenvironmental Engineering | |
identifier doi | 10.1061/(ASCE)GT.1943-5606.0002849 | |
journal fristpage | 04022070 | |
journal lastpage | 04022070-10 | |
page | 10 | |
tree | Journal of Geotechnical and Geoenvironmental Engineering:;2022:;Volume ( 148 ):;issue: 009 | |
contenttype | Fulltext |