Determination of failure zone of vane shear test using artificial transparent soil

Abstract

In this study, a special cylinder testing chamber equipped with vane shear device mounted at the center of the chamber base was developed to study the failure mechanism during the vane shear test. The soil was simulated using a mixture of amorphous silica and mineral oil, which becomes transparent when the refractive indices between the oil and the silica are well matched. One-dimensional consolidation method was carried out to prepare and determine the consolidation properties of the transparent soil. The vertical section aligned with the vane blade centerline was illuminated with laser light and sequence of digital images was recorded using a digital camera. Close range photogrammery and Particle Image Velocimetry (PIV) were used to determine the failure mechanism during vane shear test. Based on the contours, it can be revealed that, the failure zone is developed under a approximately a block pattern (uniform shear stress distribution) in the range 5-30% from the diameter of the blade which is closed to the conventional assumption of a uniform shear stress distribution of the failure surface.