A micromechanical-based failure criterion for rocks after high-temperature treatment

Abstract

The strength properties of rocks after high-temperature treatment are substantially impacted by thermally-induced cracks. In this work, a new parameter of temperature-dependent initial damage or crack density is proposed and a micromechanical-based failure criterion incorporating it is developed to characterize the strength properties of rocks after high-temperature treatment under compressive loading. The mathematical expression of the suggested nonlinear failure criterion coincides with the Hoek-Brown failure criterion for intact rocks. The micromechanical-based failure criterion is then verified using the experimental results of five sets of rocks (Macheng granite, Tournemire shale, red sandstone, coarse marble and veined marble) after high-temperature treatment. The results shown that the strength properties of rocks after high-temperature treatment can be well captured using the failure criterion incorporating temperature-dependent initial damage. Three evaluation indicators (root mean square error, correlation coefficient and mean absolute error) are indicated that the failure criterion incorporating temperature-dependent initial damage has a strong predictive capability. The parameter of temperature-dependent initial damage provides a great description of the effect of thermally-induced damage on the strength evolution of rocks after high-temperature treatment. The proposed failure criterion in this work will become an effective alternative for predicting the nonlinear strength evolution of pre-heated rocks under compressive loading due to its high reliability and easy-to-use.