Effects of height-to-diameter ratio (H/D) for specimens with various water contents on unconfined compressive strength of a clayey soil

YILMAZ Y., Eun J., Panahi S. S., Mousavi M. S.

ENGINEERING GEOLOGY, vol.257, 2019 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 257
  • Publication Date: 2019
  • Doi Number: 10.1016/j.enggeo.2019.05.013
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Gazi University Affiliated: Yes


This study investigated the effect of height -diameter (H/D) for test specimens on the unconfined compressive strength (UCS) of a plastic clayey soil. The specimens of a clayey soil were prepared with various water contents and dry unit weights by static compaction method. Extensive numbers of unconfined compression tests were carried out on a total of 232 specimens with water contents, dry unit weights, and H/D ratios ranged from 6% to 38%, 13 kN/m(3) to 21 kN/m(3), and 1.3 to 2.9, respectively. The experimental results indicated that the effect of H/D ratio on the UCS of clayey soils can be statistically negligible, in particular, when the water content is less than the optimum water content of the specimen. However, it was found that the water content of the specimen is highly related to the UCS, which results in the strong correlation between the UCS and the Liquidity Index (LI). The UCS dramatically reduced at LI between -0.6 and -0.4. The clay with negative LI showed that the soil has a water content less than the optimum water content, and induced to be very sensitive to change the strength with the water content. Based on the results with statistical analysis, it was concluded that the H/D ratio can be adaptable from 2.0 +/- 0.5 for an unconfined compressive test.