Abstract
Element Free Galerkin Method (EFGM) was applied to rock tests for engineering purposes. EFGM is free from connectivity between nodes and elements, and it assures high accuracy with a small number of elements. In the numerical simulation, rock specimens were considered as a statistical heterogeneous material having local strength distributions, such as a Weibull-type distribution. Uniaxial tensile tests and Brazilian tests which examine tensile strength of the rock specimen were numerically simulated. In both simulations, microscopic failures were observed prior to the generation of macroscopic failure plane. In uniaxial tensile test, microscopic failures were observed all over the specimen when stresses were enough lower than the failure strengths of the specimens. On the other hand, in Brazilian tests, microscopic failures were observed only around the center of the specimen and formed an elongated ellipse with its major axis parallel to the loading direction. In both simulations, these microscopic failure plane localize inside the specimen with an increase in the loading stress. Finally macroscopic failure planes were formed perpendicular and parallel to the loading direction for the uniaxial tensile tests and Brazilian tests, respectively. The microscopic and macroscopic failure developing processes in both simulations correspond to that of laboratory tests.
In order to verify whether numerical simulation method used in this study reflects statistical distribution of local strength, the correlativity between output shape parameters and input shape parameters was examined using evaluation technique based on the relationship between AE counts and loading stress during uniaxial tensile test. There was consistent correlation between output shape parameters and input shape parameters in our simulation results.
