Dynamic mechanical properties and constitutive model for jointed mudstone samples subjected to cyclic loading

Abstract

The dynamic properties of rocks are of great significance to the stability and safety of rock slopes and geological engineering under dynamic loads (e.g. seismic load). In this paper, triaxial cyclic tests were carried out on jointed mudstone samples with the prefabricated half-through joint, and their corresponding dynamic properties and deformation features are explored and analyzed in accordance with the hysteresis characteristics and the residual deformation forms. Moreover, based on the obtained fatigue properties under test conditions of diverse dip angles, confining pressures and dynamic stress, a dynamic stress ratio $R_s$ is proposed, which gives a logarithmic correlation with the fatigue life of mudstone samples. Finally, on the basis of the breakage mechanics and homogenization theory, a dynamic binary-medium constitutive model is proposed, and the validations accompanied with the comparisons to test results are also given. It shows that this model can not only preferably duplicate the typical features of hysteresis loops and the gradually accumulation of the residual strain, but also gives a good consistence with the deformation features and fatigue life obtained from cyclic tests.

Keywords:

• Jointed mudstone
• cyclic loading
• dynamic binary-medium constitutive model
• homogenization theory

Disclosure statement

No potential conflict of interest was reported by the authors.

Figure A1. Comparisons of laboratory and computed results under confining pressure conditions for $\theta$=15°: (a) Test No. D15-0, (b) Test No. D15-1, (c) Test No. D15-2.

Figure A2. Comparisons of laboratory and computed results under confining pressure conditions for $\theta$=30°: (a) Test No. D30-0, (b) Test No. D30-1, (c) Test No. D30-2.

Data availability statement

All data, models generated or used during the study appear in the submitted article.

Additional information

Funding

The authors appreciate the funding of National Natural Science Foundation of China (Grant No. 41472296), the China Geological Survey (Grant No. DD20190717), and Open Fund Research at the State Key Laboratory of Hydraulics and Mountain River Engineering.