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An experimental investigation of the scale effects observed in mine waste rock
Thesis (MEng)--Stellenbosch University, 2021.
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| Format: | Thesis |
| Language: | en_ZA |
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2021
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| _version_ | 1867614037973401600 |
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| access_status_str | Open Access |
| author | Teek, Shane |
| author2 | Fouche, Nanine |
| author_browse | Fouche, Nanine Teek, Shane |
| author_facet | Fouche, Nanine Teek, Shane |
| author_sort | Teek, Shane |
| collection | Thesis |
| description | Thesis (MEng)--Stellenbosch University, 2021. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/110023 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:45:40.774Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/110023 An experimental investigation of the scale effects observed in mine waste rock Teek, Shane Fouche, Nanine Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Scale effects Shear testing of soils Mine waste rock Grain -- Morphology Geotechnical engineering Thesis (MEng)--Stellenbosch University, 2021. ENGLISH ABSTRACT: The Direct Shear test remains a cornerstone of the geotechnical industry, despite the well-known inherent drawbacks presented by this test method. The primary objective of this dissertation was to systematically investigate the effects of Shear Mould size,particle shape and specimen gradation on the resultant Direct Shear strength parameters, shedding light on the scale effects present in the Direct ShearTest. Experimentally it has been found that the peak shear strength measured in Direct Shear tests ona given material decreases with the length and increases with the height scales of the test specimen. The aspect ratio provided a unique lens through which to study the opposing effects oftheShear Mould length and height scaleson the macromechanical shear behaviourof granular materials. By assessing the combined effects of the specimen length and height scales, by means of the aspect ratio, an inflexion point was identified where the macromechanical (i.e. shear strength and related) behaviour became less uniform and more difficult to predict. Grain shape and particle regularity are important factors that may determine the repeatability of direct sheartests conducted near the maximum box scale ratios suggested by ASTM D3080-11, e.g. increased uniformity in the particle shapes of test specimens seemingly reduced the errors associated with test results. Other key findings of the present study include observations made on the effects of grain size distributions and the Shear Mould aspect ratio and their effects. Well-graded grain size distributions yielded greater strength parameters, but only at smaller box length scales; when the box length scale was increased, the poorly-graded grain size distribution yielded greater peak strength parameters.The peak stress ratio is typically inversely proportional to the aspect ratio of the Shear Mould size and has been shown to fit an exponential function. AFRIKAANSE OPSOMMING: DieDirekteSkuifboks Toets bly die hoeksteen van die geotegniese industrie, ten spyte van die bekende erkendenadele van hierdie toetsmetode. Die primêre doel van hierdie skripsie is om stelselmatig ‘n ondersoek te voltooi wat die effek van die ‘Shear Mould’ grootte, partikel vorm en gradering van ‘n monster op die gevolglike Skuifboks sterkteparameters te kan verduidelik en lig te werp op skaal-effekte wat voorkom in dieDirekteSkuifboks Toets. Dit is eksperimenteel bewys dat die piekspanningsparameters wat gemeet is gedurende Direkte Skuifboks Toetse verminder metdie lengte envermeerder met diehoogte-skale van dietoetsmonster. Die beeldverhouding voorsien ‘n unike lens waardeur die opponerende gevolge van die ‘Shear Mould’ lengte-en hoogte-skale op die makromeganiese skuifgedrag van korrelmateriale kan bestudeer word.Deur die gekombineerde effekte vanmonster lengte-en hoogte-skalete beoordeelmet die gebruik van die beeldverhouding, was ‘n infleksiepunt geidentifiseer waardie mikromeganiese(d.w.s. skuifsterkte en verwante) gedrag minder eenvormig word, en moeliker om te voorspel.Die korrelvorm en partikel-reëlmaat is belangrike faktore wat die herhaalbaarheid van die Skuifboks Toetse naby die maksimum voorgestelde ASTM D3080-11 boksskaalverhoudings bepaal. So, byvoorbeeld, verminder die verhoogde eenvormigheid in korrelvorms van proefmonsters die foute wat geassosieer word met eksperimentele toetsresultate Ander kernbevindings van die huidige studie sluit in waarnemings van die effekte wat die verspreiding van verskillende korrelgroottes en ‘Shear Mould’ beeldverhoudings het. Goed gegradeerde korrelgrootte-verspreiding het groter sterkte parameters opgelewer, maar net op kleiner skaallengtes. Wanneer die bokslengte-skaal verhoog is, het die swak gegradeerde korrelgrootteverspreiding groter piekspanningsparameters opgelewer. In hierdie studie is die beeldverhouding tipies omgekeerd proporsioneel tot die piekspanningsverhouding, en dit pas by 'n eksponensiële funksie. Masters 2021-03-02T11:33:56Z 2021-04-21T14:36:53Z 2021-03-02T11:33:56Z 2021-04-21T14:36:53Z 2021-03 Thesis http://hdl.handle.net/10019.1/110023 en_ZA application/pdf |
| spellingShingle | Scale effects Shear testing of soils Mine waste rock Grain -- Morphology Geotechnical engineering Teek, Shane An experimental investigation of the scale effects observed in mine waste rock |
| title | An experimental investigation of the scale effects observed in mine waste rock |
| title_full | An experimental investigation of the scale effects observed in mine waste rock |
| title_fullStr | An experimental investigation of the scale effects observed in mine waste rock |
| title_full_unstemmed | An experimental investigation of the scale effects observed in mine waste rock |
| title_short | An experimental investigation of the scale effects observed in mine waste rock |
| title_sort | experimental investigation of the scale effects observed in mine waste rock |
| topic | Scale effects Shear testing of soils Mine waste rock Grain -- Morphology Geotechnical engineering |
| url | http://hdl.handle.net/10019.1/110023 |
| work_keys_str_mv | AT teekshane anexperimentalinvestigationofthescaleeffectsobservedinminewasterock AT teekshane experimentalinvestigationofthescaleeffectsobservedinminewasterock |