Scale dependence of shear strength for a coarse granular soil using a superimposition-nest type of direct shear apparatus

• Published in: Arabian journal of geosciences Vol. 8; no. 12; pp. 10301 - 10312
• Main Authors: Fu, Wen-Xi, Dai, Feng
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.12.2015
• Subjects: Earth and Environmental Science; Earth Sciences; Original Paper; Shear strength; Coarse granular soil; Scale dependence; Direct shear apparatus
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-015-1978-1

This study applies a modified superimposition-nest type of direct shear apparatus (DSA) to exploring the scale dependence of shear strength from the direct shear test (DST) of soil. The modified apparatus enables the variation of the diameter D and height H of specimens and can adjust the gap T between the upper and lower shear box halves. The DSTs in different combinations of T , D , and H were conducted under a constant vertical normal stress σ for a coarse granular soil. In each combination situation, five sets of tests were performed in parallel under the same σ value to validate the reproducibility and reliability of testing. The gap effect results show the influence of T on the failure shear stress τ f . The diameter and height effect results reveal the dependence of τ f on the D and H of specimen. The reasonable values of T , D , and H relative to the maximum particle diameter d max of the soil are evaluated for the coarse granular soil as well as the reasonable shear strength envelopes.