Critical state, dilatancy and particle breakage of mine waste rock
| dc.contributor.author | Fox, Zachary P., author | |
| dc.contributor.author | Carraro, J. Antonio H., advisor | |
| dc.contributor.author | Shackelford, Charles D., committee member | |
| dc.contributor.author | Borch, Thomas, committee member | |
| dc.contributor.author | Overton, Daniel D., committee member | |
| dc.date.accessioned | 2007-01-03T05:00:48Z | |
| dc.date.available | 2007-01-03T05:00:48Z | |
| dc.date.issued | 2011 | |
| dc.description.abstract | Critical state, dilatancy and particle breakage characteristics of two mine waste rock (MWR) materials were systematically studied in drained isotropic and axisymmetric compression. A specimen preparation technique that simulated material dumping in the field was adopted and the technique is shown to be suitable for reconstitution of uniform and repeatable specimens of MWR for element testing. The MWR types tested were unoxidized and oxidized sedimentary argillite taken from the Ordovician Vinini formation in northeastern Nevada. Acid-base accounting results indicate that the neutralization potential (NP) and acid-producing potential (AP) values decreased for the oxidized material. Static, monotonic, isotropically compressed drained triaxial tests were performed on 150-mm-diameter, 300-mm-tall cylindrical specimens with maximum particle size equal to 25.4 mm. Laboratory particle size distributions were modeled to be parallel to the collected field gradation in order to create specimens with appropriate maximum particle sizes for the testing apparatus. The intrinsic parameters that characterize critical-state, dilatancy and particle breakage of each MWR material tested were determined allowing analysis of constitutive behavior to be carried out using an appropriate theoretical framework for granular soils experiencing particle breakage during testing. While the critical state friction angles were very similar between the two MWR types (unoxidized = 38.3° and oxidized = 36.7°), dilatancy is much greater in the unoxidized specimens than in the oxidized specimens. Bolton's (1986) fitting parameters Q and R were determined and values agree well with those found in the literature for geomaterials with similar stress-dilatancy behavior and grain tensile strengths. Grain tensile strength was evaluated through point load strength index testing giving values for grain tensile strength for the unoxidized material that are 10 times greater than observed for the oxidized material. Particle size distributions were determined before and after testing to evaluate particle breakage due to the combined effects of isotropic and axisymmetric compression as well as evaluate the increase in surface area due to particle breakage. The fractal dimension (D) was evaluated before and after testing in order to assess the validity of the underlying assumptions of the modified work equation presented by McDowell et al. (1996). The surface energy of the materials tested was found to be in the range of 5-24 J/m2. All of these results indicate that in situ weathering may degrade the shear strength characteristics of a quarried sedimentary mine waste rockfill by weakening the intrinsic shear strength parameters of the MWR. The only rigorous way to properly assess the strength degradation of the MWR materials tested involves careful assessment of the critical state, dilatancy and particle breakage characteristics. | |
| dc.format.medium | born digital | |
| dc.format.medium | masters theses | |
| dc.identifier | Fox_colostate_0053N_10648.pdf | |
| dc.identifier.uri | http://hdl.handle.net/10217/46900 | |
| dc.language | English | |
| dc.language.iso | eng | |
| dc.publisher | Colorado State University. Libraries | |
| dc.relation.ispartof | 2000-2019 | |
| dc.rights | Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. | |
| dc.subject | critical state | |
| dc.subject | dilatancy | |
| dc.subject | mine waste rock | |
| dc.subject | particle breakage | |
| dc.subject | particle strength | |
| dc.subject | triaxial | |
| dc.title | Critical state, dilatancy and particle breakage of mine waste rock | |
| dc.type | Text | |
| dcterms.rights.dpla | This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). | |
| thesis.degree.discipline | Civil and Environmental Engineering | |
| thesis.degree.grantor | Colorado State University | |
| thesis.degree.level | Masters | |
| thesis.degree.name | Master of Science (M.S.) |
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