Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects
This paper investigates the effects of initial porosity index and load range on the shear strength of a sand sample using direct shear tests performed with a standard direct shear apparatus under varying densities, from loose to compacted. This study focuses on the distinction between the peak <i...
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2025-05-01
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| author | Krzysztof Żarkiewicz Roman Bednarek |
| author_facet | Krzysztof Żarkiewicz Roman Bednarek |
| author_sort | Krzysztof Żarkiewicz |
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| description | This paper investigates the effects of initial porosity index and load range on the shear strength of a sand sample using direct shear tests performed with a standard direct shear apparatus under varying densities, from loose to compacted. This study focuses on the distinction between the peak <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><msub><mi>ϕ</mi><mi>p</mi></msub><mo>)</mo></mrow></semantics></math></inline-formula> and critical <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><msub><mi>ϕ</mi><mrow><mi>c</mi><mi>v</mi></mrow></msub><mo>)</mo></mrow></semantics></math></inline-formula> internal friction angles and their variation with stress level and initial porosity. Results show that the internal friction angle of sand depends on the stress state and initial porosity, reaching a peak value at maximum shear stresses and a critical value at constant sample volume. Higher initial compaction increases the peak friction angle, while higher effective stresses reduce the critical porosity index. The critical state line (CSL) defines the contraction and dilation behaviour of soils, with the critical porosity index varying with average soil stress. The analysis confirmed Bolton’s empirical relationship, linking the peak friction angle with the critical state angle and the dilation angle. This study emphasizes the importance of accurately defining the internal friction angle and considering the nonlinear relationship between shear strength and normal stresses. These findings are significant for geotechnical engineering, particularly in foundation bearing capacity, earth pressure, and slope stability analysis. |
| format | Article |
| id | doaj-art-0b8893aad91e4907948b585da28e0f49 |
| institution | OA Journals |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-05-01 |
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| series | Applied Sciences |
| spelling | doaj-art-0b8893aad91e4907948b585da28e0f492025-08-20T02:23:08ZengMDPI AGApplied Sciences2076-34172025-05-011511590210.3390/app15115902Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress EffectsKrzysztof Żarkiewicz0Roman Bednarek1Department of Geotechnical Engineering, Faculty of Civil and Environmental Engineering, West Pomeranian University of Technology, 70-310 Szczecin, PolandDepartment of Geotechnical Engineering, Faculty of Civil and Environmental Engineering, West Pomeranian University of Technology, 70-310 Szczecin, PolandThis paper investigates the effects of initial porosity index and load range on the shear strength of a sand sample using direct shear tests performed with a standard direct shear apparatus under varying densities, from loose to compacted. This study focuses on the distinction between the peak <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><msub><mi>ϕ</mi><mi>p</mi></msub><mo>)</mo></mrow></semantics></math></inline-formula> and critical <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>(</mo><msub><mi>ϕ</mi><mrow><mi>c</mi><mi>v</mi></mrow></msub><mo>)</mo></mrow></semantics></math></inline-formula> internal friction angles and their variation with stress level and initial porosity. Results show that the internal friction angle of sand depends on the stress state and initial porosity, reaching a peak value at maximum shear stresses and a critical value at constant sample volume. Higher initial compaction increases the peak friction angle, while higher effective stresses reduce the critical porosity index. The critical state line (CSL) defines the contraction and dilation behaviour of soils, with the critical porosity index varying with average soil stress. The analysis confirmed Bolton’s empirical relationship, linking the peak friction angle with the critical state angle and the dilation angle. This study emphasizes the importance of accurately defining the internal friction angle and considering the nonlinear relationship between shear strength and normal stresses. These findings are significant for geotechnical engineering, particularly in foundation bearing capacity, earth pressure, and slope stability analysis.https://www.mdpi.com/2076-3417/15/11/5902shear strength of sandnonlinear strength envelopecritical and peak friction anglessand |
| spellingShingle | Krzysztof Żarkiewicz Roman Bednarek Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects Applied Sciences shear strength of sand nonlinear strength envelope critical and peak friction angles sand |
| title | Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects |
| title_full | Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects |
| title_fullStr | Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects |
| title_full_unstemmed | Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects |
| title_short | Shear Strength of Sand: Integrated Analysis of Initial Porosity and Stress Effects |
| title_sort | shear strength of sand integrated analysis of initial porosity and stress effects |
| topic | shear strength of sand nonlinear strength envelope critical and peak friction angles sand |
| url | https://www.mdpi.com/2076-3417/15/11/5902 |
| work_keys_str_mv | AT krzysztofzarkiewicz shearstrengthofsandintegratedanalysisofinitialporosityandstresseffects AT romanbednarek shearstrengthofsandintegratedanalysisofinitialporosityandstresseffects |