An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment
The CERCHAR abrasivity test is a widely used index test in earth and subsurface works, delivering numerical values for abrasion that are critical to the selection of excavation tools, TBM performance or cost and project schedule estimates. The test evaluates the wear of the tip of a standardized met...
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MDPI AG
2024-12-01
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| author | Markus Kaspar Christine Latal |
| author_facet | Markus Kaspar Christine Latal |
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| description | The CERCHAR abrasivity test is a widely used index test in earth and subsurface works, delivering numerical values for abrasion that are critical to the selection of excavation tools, TBM performance or cost and project schedule estimates. The test evaluates the wear of the tip of a standardized metal pin after a scratch test on a rock surface. However, excavatability is not considered in this test. The present study presents an approach to assessing the material removal of a rock specimen due to the scratching action of a steel pin. The concept is tested for a broad range of sedimentary, metamorphic and igneous rocks. The volume of removed rock material is determined by measuring the width of the scratch groove and assuming an idealized trapezoid geometry. The <i>CAI</i> and volumetric removal are used to calculate the CERCHAR abrasivity ratio (<i>CAR</i>), and the results are in good agreement with those from the literature where specialized equipment was used. A classification scheme to estimate the excavatability of rock based on the <i>CAI</i> in combination with the material removal of a rock specimen is introduced. Based on the amount of material removed and the wear on the pin, an estimate can be made as to whether the excavation is likely to be economical in terms of time and material costs. The approach does not require additional testing, but rather makes use of the inherent geometry of the steel pin and the scratch groove on the rock specimen. The approach can be implemented as a complementary analysis to the existing CERCHAR test with little additional effort. |
| format | Article |
| id | doaj-art-9a51a26bfbf848dd8b7116ee040959de |
| institution | Kabale University |
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| language | English |
| publishDate | 2024-12-01 |
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| series | Geotechnics |
| spelling | doaj-art-9a51a26bfbf848dd8b7116ee040959de2024-12-27T14:28:25ZengMDPI AGGeotechnics2673-70942024-12-01441246125810.3390/geotechnics4040063An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability AssessmentMarkus Kaspar0Christine Latal1Institute of Applied Geosciences, Graz University of Technology, 8010 Graz, AustriaInstitute of Applied Geosciences, Graz University of Technology, 8010 Graz, AustriaThe CERCHAR abrasivity test is a widely used index test in earth and subsurface works, delivering numerical values for abrasion that are critical to the selection of excavation tools, TBM performance or cost and project schedule estimates. The test evaluates the wear of the tip of a standardized metal pin after a scratch test on a rock surface. However, excavatability is not considered in this test. The present study presents an approach to assessing the material removal of a rock specimen due to the scratching action of a steel pin. The concept is tested for a broad range of sedimentary, metamorphic and igneous rocks. The volume of removed rock material is determined by measuring the width of the scratch groove and assuming an idealized trapezoid geometry. The <i>CAI</i> and volumetric removal are used to calculate the CERCHAR abrasivity ratio (<i>CAR</i>), and the results are in good agreement with those from the literature where specialized equipment was used. A classification scheme to estimate the excavatability of rock based on the <i>CAI</i> in combination with the material removal of a rock specimen is introduced. Based on the amount of material removed and the wear on the pin, an estimate can be made as to whether the excavation is likely to be economical in terms of time and material costs. The approach does not require additional testing, but rather makes use of the inherent geometry of the steel pin and the scratch groove on the rock specimen. The approach can be implemented as a complementary analysis to the existing CERCHAR test with little additional effort.https://www.mdpi.com/2673-7094/4/4/63CERCHAR abrasivity indexrock excavationrock testing |
| spellingShingle | Markus Kaspar Christine Latal An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment Geotechnics CERCHAR abrasivity index rock excavation rock testing |
| title | An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment |
| title_full | An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment |
| title_fullStr | An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment |
| title_full_unstemmed | An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment |
| title_short | An Extended Evaluation of the CERCHAR Abrasivity Test for a Practical Excavatability Assessment |
| title_sort | extended evaluation of the cerchar abrasivity test for a practical excavatability assessment |
| topic | CERCHAR abrasivity index rock excavation rock testing |
| url | https://www.mdpi.com/2673-7094/4/4/63 |
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