Preliminary Analysis of Stress Nonuniformities in Triaxial Tests of Bedded Rocks.

摘要

When a bedded rock such as oil shale is tested with its bedding planes oriented at an arbitrary angle to the specimen axis, the stress distribution in a sample can become highly nonuniform. This nonuniformity is caused by the anisotropy of the rock coupling with the end constraints imposed on the sample by the testing machine. Neglect of this effect, as apparently has been done by previous investigators, can lead to serious errors in interpreting test results. In particular, the stress state at which fracture occurs may be underestimated. In this paper, we present the results of a two-dimensional (plane strain) finite element computer code study assessing the magnitude of the stress nonuniformity. (ERA citation 02:025936)