Location
Arlington, Virginia
Date
14 Aug 2008, 4:30pm - 6:00pm
Abstract
In this paper, we examine the role of grain mineralogy and compressibility, sample preparation, and shear strain/displacement levels on the shearing behavior of sands using undrained triaxial and constant volume ring shear tests in an attempt to explain some discrepancies observed between field and laboratory behavior. As expected, preparation by moist tamping can produce specimens that are contractive throughout shear, while counterparts prepared using pluviation exhibit dilative behavior at intermediate shear strain/displacement levels (i.e., after initial yield). However, both triaxial and ring shear tests illustrate that some sands consisting of more compressible minerals can exhibit entirely contractive behavior regardless of the sample preparation method. These preliminary tests suggest that laboratory testing of pure quartz sands may result in potentially misleading conclusions regarding the field behavior of mixed mineral soils involved in many liquefaction flow failures and long run-out landslides. Furthermore, grain crushing at larger displacements (larger than those that can be achieved in the triaxial device) results in net contractive response regardless of the sample preparation method or the grain mineralogy. Grain crushing has been observed in shear zones formed during a few well-documented long run-out landslides. The combination of these factors: grain mineralogy and compressibility, particle damage and crushing, and shear zone formation may help to explain some discrepancies observed between field and laboratory behavior of sands.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
6th Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
Missouri University of Science and Technology
Document Version
Final Version
Rights
© 2008 Missouri University of Science and Technology, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Sadrekarimi, Abouzar and Olson, Scott M., "The Importance of Mineralogy and Grain Compressibility in Understanding Field Behavior of Failures" (2008). International Conference on Case Histories in Geotechnical Engineering. 55.
https://scholarsmine.mst.edu/icchge/6icchge/session02/55
The Importance of Mineralogy and Grain Compressibility in Understanding Field Behavior of Failures
Arlington, Virginia
In this paper, we examine the role of grain mineralogy and compressibility, sample preparation, and shear strain/displacement levels on the shearing behavior of sands using undrained triaxial and constant volume ring shear tests in an attempt to explain some discrepancies observed between field and laboratory behavior. As expected, preparation by moist tamping can produce specimens that are contractive throughout shear, while counterparts prepared using pluviation exhibit dilative behavior at intermediate shear strain/displacement levels (i.e., after initial yield). However, both triaxial and ring shear tests illustrate that some sands consisting of more compressible minerals can exhibit entirely contractive behavior regardless of the sample preparation method. These preliminary tests suggest that laboratory testing of pure quartz sands may result in potentially misleading conclusions regarding the field behavior of mixed mineral soils involved in many liquefaction flow failures and long run-out landslides. Furthermore, grain crushing at larger displacements (larger than those that can be achieved in the triaxial device) results in net contractive response regardless of the sample preparation method or the grain mineralogy. Grain crushing has been observed in shear zones formed during a few well-documented long run-out landslides. The combination of these factors: grain mineralogy and compressibility, particle damage and crushing, and shear zone formation may help to explain some discrepancies observed between field and laboratory behavior of sands.
