Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review
Determining the shear strength of rockfill is a key task for the design and stability analysis of rockfill structures. When direct shear tests are performed, the well-established ASTM standard requires that specimen width and thickness must be at least 10 and 6 times the maximum particle size (dmax)...
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| Format: | Article |
| Language: | English |
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Wiley
2020-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2020/8890237 |
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| author | Akram Deiminiat Li Li Feitao Zeng Thomas Pabst Paul Chiasson Robert Chapuis |
| author_facet | Akram Deiminiat Li Li Feitao Zeng Thomas Pabst Paul Chiasson Robert Chapuis |
| author_sort | Akram Deiminiat |
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| description | Determining the shear strength of rockfill is a key task for the design and stability analysis of rockfill structures. When direct shear tests are performed, the well-established ASTM standard requires that specimen width and thickness must be at least 10 and 6 times the maximum particle size (dmax), respectively. When the value of dmax is very large, performing such tests in laboratory with field rockfill becomes difficult or impossible. Four scaling-down techniques were proposed in the past to obtain a modeled sample excluding oversize particles: scalping, parallel, replacement, and quadratic. It remains unclear which of the four scaling-down techniques yields reliable shear strength of field rockfill. In this paper, an extensive review is presented on existing experimental results to analyze the capacity of each scaling-down technique to determine the field rockfill shear strength. The analyses show that previous researches followed an inappropriate methodology to validate or invalidate a scaling-down technique through a direct comparison between the shear strengths of modeled and field samples. None of the four scaling-down techniques was shown to be able or unable to predict the field rockfill shear strength by extrapolation. The analyses further show that the minimum ratios of specimen size to dmax dictated by well-established standards are largely used but are too small to eliminate the specimen size effect. In most cases, this practice results in shear strength overestimation. The validity or invalidity of scaling-down techniques based on experimental results obtained by using the minimum ratios is uncertain. Recommendations are given for future studies. |
| format | Article |
| id | doaj-art-22f41276cece43db92e8ee4fcea211e2 |
| institution | Kabale University |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2020-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Advances in Civil Engineering |
| spelling | doaj-art-22f41276cece43db92e8ee4fcea211e22025-08-20T03:54:48ZengWileyAdvances in Civil Engineering1687-80861687-80942020-01-01202010.1155/2020/88902378890237Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical ReviewAkram Deiminiat0Li Li1Feitao Zeng2Thomas Pabst3Paul Chiasson4Robert Chapuis5Research Institute on Mining and Environment (RIME UQAT-Polytechnique), Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montréal, CanadaResearch Institute on Mining and Environment (RIME UQAT-Polytechnique), Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montréal, CanadaResearch Institute on Mining and Environment (RIME UQAT-Polytechnique), Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montréal, CanadaResearch Institute on Mining and Environment (RIME UQAT-Polytechnique), Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montréal, CanadaFaculty of Engineering, Université de Moncton, Moncton, CanadaResearch Institute on Mining and Environment (RIME UQAT-Polytechnique), Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montréal, CanadaDetermining the shear strength of rockfill is a key task for the design and stability analysis of rockfill structures. When direct shear tests are performed, the well-established ASTM standard requires that specimen width and thickness must be at least 10 and 6 times the maximum particle size (dmax), respectively. When the value of dmax is very large, performing such tests in laboratory with field rockfill becomes difficult or impossible. Four scaling-down techniques were proposed in the past to obtain a modeled sample excluding oversize particles: scalping, parallel, replacement, and quadratic. It remains unclear which of the four scaling-down techniques yields reliable shear strength of field rockfill. In this paper, an extensive review is presented on existing experimental results to analyze the capacity of each scaling-down technique to determine the field rockfill shear strength. The analyses show that previous researches followed an inappropriate methodology to validate or invalidate a scaling-down technique through a direct comparison between the shear strengths of modeled and field samples. None of the four scaling-down techniques was shown to be able or unable to predict the field rockfill shear strength by extrapolation. The analyses further show that the minimum ratios of specimen size to dmax dictated by well-established standards are largely used but are too small to eliminate the specimen size effect. In most cases, this practice results in shear strength overestimation. The validity or invalidity of scaling-down techniques based on experimental results obtained by using the minimum ratios is uncertain. Recommendations are given for future studies.http://dx.doi.org/10.1155/2020/8890237 |
| spellingShingle | Akram Deiminiat Li Li Feitao Zeng Thomas Pabst Paul Chiasson Robert Chapuis Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review Advances in Civil Engineering |
| title | Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review |
| title_full | Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review |
| title_fullStr | Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review |
| title_full_unstemmed | Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review |
| title_short | Determination of the Shear Strength of Rockfill from Small-Scale Laboratory Shear Tests: A Critical Review |
| title_sort | determination of the shear strength of rockfill from small scale laboratory shear tests a critical review |
| url | http://dx.doi.org/10.1155/2020/8890237 |
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