Strain-softening characterization of granitic rocks and numerical simulation of servo-controlled strength tests

摘要

The main objective of this study regards the analysis of results of a series of compressive strengthrntests on granite rocks carried out on a press with servo-controlled loading in order to characterize their strainsofteningrnbehavior.We pay particular attention to the evolution of failure criteria from peak to residual strengthrnthat obviously presents plastic strain dependence. A graphical methodology was used to link strength withrnplastic strain all along the process of plastic yield and for different levels of confining pressure. It was possiblernto fit a mathematical expression, which is able to reflect this relation and which also allows obtaining evolvingrnstrength criteria (cohesion and friction values). We have also accounted for the post-failure dilation behaviorrnof these rocks, studied elsewhere. The derived model has been implemented in a numerical code, and somernsimple simulations are carried out. These models have been able to reproduce the initial experimental resultsrnreasonably well.