Abstract:Conventional triaxial test and pre- and post-peak unloading confining pressure tests of marble have been performed. Mohr stress circles under different confining pressures and envelopes are achieved. The results indicate that linear Mohr envelope can not match stress circle very well;and the Mohr-Coulomb criterion describing marble strength will bring large error. In order to solve the problem,a nonlinear Mohr strength criterion is proposed,i.e. power function Mohr strength criterion,to fit the test data and compare the theoretical values and test values. The failure curve of power function Mohr strength criterion in p plane is presented;and the failure curve of Mohr-Coulomb strength criterion is then compared. It is shown that the power function of Mohr strength criterion can describe marble strength much better.