Experimental study on progressive yielding of marble

Abstract

Cyclic loading experiments were widely used to study the progressive yielding of rock‐like materials. For brittle rocks, around the peak stress or in the post‐peak region, brittle failure occurred as soon as the axial stress was unloaded. In order to conduct the cyclic loading around and after peak stress, a new loading method was proposed based on the elastic–plastic theory. Comparison between the results of conventional triaxial compression tests and cyclic loading tests showed that the new loading method had little influence on the yielding process of marble. Based on the results of cyclic loading tests, a plastic internal variable was defined which took the influence of confining stress on the yielding process into consideration. Then, the variation of elastic parameters was obtained according to the plastic internal variable. The result showed that when the rock underwent plastic deformation, shear modulus progressively decreased while the bulk modulus changed slightly. The efforts of this paper can provide basic data for future study of the mechanical model of brittle rock.

Keywords:

• Cyclic loading experiment
• Plastic internal variable
• Elastoplastic coupling

This work was supported by the National Natural Science Foundation of China (grant nos. 50979104 and 10772190) and the National Basic Research Program of China (grant no. 2010CB732006).