NUMERICAL EXPERIMENT FOR VIRTUAL PLASTER MODEL TESTS SIMULATING BLOCK SHEAR TESTS

Abstract

The strength of in-situ rock masses has been estimated by in-situ rock shear tests for a long time.
However, the mechanisms for the appearance of strength in such tests have not been clarified sufficiently. This
paper presents the results of a numerical analysis of virtual plaster model tests used to simulate block shear
tests, which are of a kind of in-situ test. In the authors’ former study, results were obtained for rock shear tests,
another kind of in-situ test, along with real plaster model tests and finite element analyses. In the present study,
some cases simulating block shear tests were analyzed. The appearance and propagation of cracks in the testing
process were simulated with enhanced elements, which represented the displacement discontinuity in each
element, as in the former analysis. The results were compared with the former results to investigate the
differences between the two conditions. The shear strength in the two sets of results was found to be generally
similar; however, there were some small differences. The patterns for the appearance and propagation of cracks
differed from each other, while some common features also appeared. The concentration of stress in the two
testing processes occurred in different parts of the materials under the two conditions, and this led to differences
in both the failure mechanism and the shear strength.