Fitting And Evaluation Of The Conventional Triaxial Strength Criteria With Test Data

Strength criteria for rocks have various forms. Test data of12rocks cited frompublic literatures and red sandstone carried in our lab are used to study the applicationconditions of five conventional triaxial strength criteria. The parameters in the criteriaare determined for the least absolute deviation. The criteria are compared on the misfitsand the difference between the real magnitudes and calculations of uniaxial compressivestrength, and tensile strength as well.The linear Mohr-Coulomb criterion is feasible to describe the strength property ofrock under low confining pressure, about up to20%of the uniaxial compressivestrength. The generalized Hoek-Brown criterion, exponential strength criterion andROCKER criterion with three parameters present uniaxial compressive strength just thesame with the experimental value; and the generalized Hoek-Brown criterion is the bestone. The tensile strength from ROCKER criterion closes to the real magnitude. Thegeneralized Hoek-Brown criterion whose fitting curve through or closes to the datapoints has the least fitting misfit, and the whole fitting effect is good. The least absolutedeviation of ROCKER criterion is close to the generalized Hoek-Brown criterion butslightly high. One datum of the tensile strength does not significantly influence on thefitting solutions.