Evaluation of coarse-grained mechanical properties using small direct shear test

ABSTRACT

Coarse-grained soils are known for their high shear strength and are widely used in geotechnical projects. Shear strength of granular soils can be examined by friction angle which is obtained from direct shear or triaxial test. According to the proposed standards, there are limitations on sample size depending on the diameter of the largest grain. . Furthermore, there is a tendency to use small direct shear instead of large-scale direct shear apparatus, due to some difficulties and lack of large-scale apparatus in most of the laboratories. In this study, a new method is presented for modifying particle size distribution of a well-graded gravel for testing in small direct shear samples. The results showed that the proposed modification reduces the maximum shear strength, peak dilation, and friction angles of the samples. Hence, based on this method, one can determine the friction angle of a coarse-grained soil using small direct shear apparatus.

KEYWORDS:

• Coarse-grained
• shear strength
• direct shear test
• size effect
• dilation
• friction angle

Disclosure statement

No potential conflict of interest was reported by the authors.