Publications

The evaluation of the stability of the openings for the Exploratory Studies Facility and a potential repository for high-level nuclear waste at Yucca Mountain, Nevada will require computer codes capable of predicting slip on rock joints resulting from changes in thermal stresses. The geometrical method of analysis of moire fringe analysis was used to evaluate the magnitude and extent of frictional sliding in a layered polycarbonate rock mass model containing a circular hole. Slips were observed in confined zones around the hole and micron resolutions were obtained. Unpredicted and uncontrolled uniform slip of several interfaces in the model were observed giving considerable uncertainty in the boundary conditions of the model, perhaps making detailed comparison with numerical models impossible.

Prediction of the deformation behavior of large engineering structures in jointed rock under a specified loading history requires the extensive use of numerical simulation. For example, the evaluation of the stability of the openings for the Exploratory Studies Facility and a potential repository for high-level nuclear waste at Yucca Mountain, Nevada will require computer codes capable of predicting slip on rock joints resulting from changes in thermal stresses. The testing and ultimate validation of these complex finite element computer codes is an important step in their development before their use as a design tool for an engineering structure or for the study of some other practical problem. While field tests may be ultimately necessary, the authors propose a different and more thorough approach where early tests are done on a bench scale with easily characterized materials and geometries. For these bench-scale tests, the basic approach is to construct a laboratory specimen with a known geometry from an easily characterized material. Digital video imaging combined with the geometric moire fringe method of strain analysis is used to measure and derive the displacements on the sample under load. Here the authors present the method of acquiring and analyzing the moire data and give an analysis of its problems and benefits.