Influence of Excavation Time, Tension Crack, and Rainfall on the Stability of Unsupported Vertical Cuts in Unsaturated Soil
Publication: International Journal of Geomechanics
Volume 21, Issue 10
Abstract
This study focuses on the stability of unsupported vertical cuts in unsaturated soil. For this, a series of numerical analyses were carried out to estimate the stability of unsupported vertical cuts excavated in an unsaturated glacial till considering three possible practical scenarios: (1) excavation time, (2) depth and location of a tension crack, and (3) rainfall infiltration into a tension crack. The results showed that the influence of excavation time and rainfall infiltration into a tension crack may not be significant if an unsupported vertical cut is made with a certain safety margin (i.e., safe height). A tension crack did not affect the overall safety of an unsupported vertical cut in a case where the location and depth of the tension crack are within 30% and 20% of safe height, respectively. The proposed approaches were then applied to the deep unsupported vertical cut made into a clay (9.75 m; Kwan 1971) for the validation. The failure in the vertical cut was initiated due to the development of a tension crack, which matched the numerical analyses results obtained extending both effective and total stress approaches considering the influence of matric suction.
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Acknowledgments
The second author acknowledges the support of the Natural Sciences and Engineering Research Council of Canada (NSERC).
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International Journal of Geomechanics
Volume 21 • Issue 10 • October 2021
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© 2021 American Society of Civil Engineers.
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Received: Jun 23, 2020
Accepted: May 30, 2021
Published online: Aug 9, 2021
Published in print: Oct 1, 2021
Discussion open until: Jan 9, 2022
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