Partic. vol. 23 pp. 82-89 (December 2015)
doi: 10.1016/j.partic.2014.11.013

Using a modified direct shear apparatus to explore gap and size effects on shear resistance of coarse-grained soil

Wenxi Fu^a, Xing Zheng^b, Xiaozhang Lei^a,*, Jianhui Deng^a

xiaozhang_lee@sina.com

Abstract

This work used a modified direct shear apparatus, created newly by the authors, to explore effects of the gap between shear box halves and specimen size on the shear resistance of coarse-grained soil. The shear boxes of this apparatus were assembled from a series of steel structures capable of superimposition and nesting. Such characteristics facilitated variation of specimen size in both diameter and height. The new device can also maintain a constant gap during shearing. We performed a series of gap-effect and size-effect tests for two uniformly graded, coarse-grained soil samples. The test results showed that both the gap space and specimen size had significant influences on shear resistance of the coarse-grained soil. Further, analysis of variations in shear strength indices led to a reasonable gap dimension and specimen size of the two soil samples.

Graphical abstract

Keywords

Direct shear apparatus; Gap effect; Size effect; Shear resistance; Coarse-grained soil