Abstract:Firstly,the computation method of the strength of rock micro-unit based on Mohr-Coulomb strength criterion is introduced. A damage constitutive model is established according to the rock triaxial stress-strain test curve and the assumption that the strength of rock micro-unit is of Weibull distribution. The model can reflect the full process of rock failure under specific confining pressure. Then,the model parameters are rectified based on the relation between damage model parameters and confining pressure. A three-dimensional damage constitutive model,which answers to the fact,is established accordingly. Finally,the approach for erecting rock strength criterion is discussed by acquiring extrema using multivariate functions according to the conception of yielding or failure;and the Mohr-Coulomb strength criterion is rationally rectified accordingly. The comparison of the rectified Mohr-Coulomb strength criterion with practical result and the Mohr-Coulomb strength criterion shows that the former has obvious advantages over the latter.