<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>The undrained shear strength (Su) and cohesion (Cu) of cohesive soils are frequently determined using an unconfined compression test. However, the test results are heavily dependent on specimen size. This causes uncertainty in geotechnical analyses, constitutive models, and designs by overestimating or underestimating the shear strength of cohesive soils. Therefore, the study aims to assess the effect of the height-to-diameter ratio on the unconfined compressive strength (UCS) of cohesive soil. The soil specimen was tested on a compacted cylindrical specimen at the maximum dry density and optimum moisture content with a height to diameter (H/D) ratio of 1–3 for 38, 50, and 100 mm specimen diameters. Disturbed sample specimens were considered for the laboratory program. Accordingly, the standard Proctor compaction test determines soil classification and compaction characteristics. The unconfined compression test was performed for undisturbed and compacted remolded states of various diameters of cohesive soil specimens to investigate the strength variation with the specimen variation in H/D ratio. The laboratory test results revealed that cohesive soil's unconfined compression strength value drops rapidly with height-to-diameter ratios and the soil specimens’ diameter increases. However, the UCS value was stable at H/D ratio from 1.75 to 2.25. As the specimens’ diameter and H/D ratio increased, the peak UCS value axial strain decreased. Similarly, the gap between the axial strains of peak UCS value for the smallest and the most significant H/D ratio decreased with increase in the specimens’ diameter.</p>
</abstract>

The undrained shear strength (Su) and cohesion (Cu) of cohesive soils are frequently determined using an unconfined compression test. However, the test results are heavily dependent on specimen size. This causes uncertainty in geotechnical analyses, constitutive models, and designs by overestimating or underestimating the shear strength of cohesive soils. Therefore, the study aims to assess the effect of the height-to-diameter ratio on the unconfined compressive strength (UCS) of cohesive soil. The soil specimen was tested on a compacted cylindrical specimen at the maximum dry density and optimum moisture content with a height to diameter (H/D) ratio of 1–3 for 38, 50, and 100 mm specimen diameters. Disturbed sample specimens were considered for the laboratory program. Accordingly, the standard Proctor compaction test determines soil classification and compaction characteristics. The unconfined compression test was performed for undisturbed and compacted remolded states of various diameters of cohesive soil specimens to investigate the strength variation with the specimen variation in H/D ratio. The laboratory test results revealed that cohesive soil's unconfined compression strength value drops rapidly with height-to-diameter ratios and the soil specimens’ diameter increases. However, the UCS value was stable at H/D ratio from 1.75 to 2.25. As the specimens’ diameter and H/D ratio increased, the peak UCS value axial strain decreased. Similarly, the gap between the axial strains of peak UCS value for the smallest and the most significant H/D ratio decreased with increase in the specimens’ diameter.

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Faculty of Civil and Environmental Engineering

Wroclaw University of Science and Technology

Studia Geotechnica et Mechanica

This work is licensed under the Creative Commons Attribution 4.0 International License.

The undrained shear strength (Su) and cohesion (Cu) of cohesive soils are frequently determined using an unconfined compression test. However, the test results...

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Article Category: Original Study

Published Online: Mar 09, 2023

Page range: 112 - 132

Received: Jun 05, 2022

Accepted: Nov 29, 2022

DOI: https://doi.org/10.2478/sgem-2023-0001

Keywords
Height to diameter ratio, Unconfined compression strength, UCS scale effect

© 2023 Haile Tsegay Gebresamuel et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Effect of Specimens’ Height to Diameter Ratio on Unconfined Compressive Strength of Cohesive Soil

Article Category: Original Study

Published Online: Mar 09, 2023

Page range: 112 - 132

Received: Jun 05, 2022

Accepted: Nov 29, 2022

DOI: https://doi.org/10.2478/sgem-2023-0001

KeywordsHeight to diameter ratio, Unconfined compression strength, UCS scale effect

© 2023 Haile Tsegay Gebresamuel et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Keywords
Height to diameter ratio, Unconfined compression strength, UCS scale effect