Comparative analysis of sandstone experiment strength and different strength criteria prediction results

Tested Meiyukou mine roadway sandstone Brazil splitting, uniaxial and conventional triaxial strength. Analyzed sandstone the characteristics of deformation and strength, according to the overall minimum fitting error of square root identified the parameters of 5 strength criteria, compared the difference of the overall fitting precision of various strength criteria and the difference between experiment strengths and prediction values of tensile strengths and compressive strengths of various strength criteria. Obtained the following main research conclusions:Sandstone brittle characteristics is significant under uniaxial compression and lower confining pressure, the yield stage increases obviously with the increasing of confining pressure, Sandstone failure characteristics gradually change from brittle into ductile. For the overall fitting precision of experiment data, Mohr-Coulomb criterion is not the most ideal, exponential strength criterion is the best, Hoek-Brown criterion and Bieniawski criterion have the little difference. For the tensile strength prediction value, Mohr-Coulomb criterion significantly overestimates the tensile strength, thus it is not suitable for predicting the tensile strength, exponential strength criterion is the most ideal, Bieniawski strength criterion cannot reflect the tensile strength properties of rock. For uniaxial strength and compressive strength of different confining pressure, linear Mohr-Coulomb criterion deviates from the most experimental data, the prediction results deviate significantly from the true value especially under higher confining pressure, Hoek-Brown criterion and Bieniawski criterion almost have the consistent prediction results, Sheory cri-terion prediction results are slightly higher under higher confining pressure, exponential strength criterion is close to most of the test data, the prediction precision is the best.