Discussion of "development of an internal camera-based volume determination system for triaxial testing" by s. e. salazar, a. barnes, and r. a. coffman. the technical note was published in Geotechnical Testing Journal, Vol. 38, No. 4, 2015. [DOI: 10.1520/GTJ20140249]

Abstract

Salazar et al. (2015) presented a new method to measure the volume and volumetric strains of soil specimen during the triaxial test. To eliminate the optical distortions due to refraction at the fluid-cell wall and cell wall-atmosphere interfaces, they installed a camera-based system inside the triaxial cell. The discussers wished to highlight some points about taking into account the refraction of light and other related issues in image processing for evaluating the volumetric strains and show that there is another simple way to overcome this problem.