Shear strength properties of naturally occurring bituminous sands

Abstract

Shear strength properties of three oil sand materials were determined in the laboratory by simulating field loading conditions of large capacity mining trucks and shovels. Both monotonic triaxial compression and direct shear tests were performed on the oil sand materials with bitumen contents of 8.5%, 13.3% and 14.5% at 20C and 30C test temperatures. Results from the two tests could not be effectively compared since the triaxial tests produced zero fric-tion angles for all the oil sand materials because of the cohesive nature of bitumen contents. However, results from the direct shear tests were comparable to properties of oil sands reported earlier from various other laboratory tests. Based on the direct shear test results, Mohr-Coulomb failure envelopes were determined to establish shear strength properties of the three oil sand samples. The results presented in this paper may be used to estimate friction angles and cohesion intercepts of oil sand materials with similar characteristics in the field