Experimental Study of Marble Elastoplastic Parameters and Its Application

A method of determining elastoplastic parameters in laboratory is given in the paper. For marble samples from Fangshan area in Beijing, systematic measurement has been done by tri-axial test, and the whole stress-strain curves can be simplified as a four-linear model corresponding to initial and peak and residual yield surface. Using the isotropic Mohr-Coulomb model, elastoplastic parameters was calculated, such as cohesion strength and friction angle vary with the internal plastic variable. The stress-strain curves of whole process of marble samples can be simplified described by a four-linear model, for there is strong plastic hardening before the peak strength and softening after the peak strength. Using these parameters a slop stability was analyzed by finite element model (FEM) strength reduction method. The results indicated that the degree of plastic deformation will be underestimated if the hardening properties of marble rock not be considered, and the slope safety factor calculated would be greatly increased about 23.6% at the same time. These are useful for engineering design.