Study on the deformation and strength characteristics of hard rock under true triaxial stress state using bonded-particle model

K. Duan, S. Wu, S. Zhang
Computers and Geotechnics
Dilatancy, Discrete element method, Hard rocks, Intermediate Principal Stress, Magnitude distribution, peak strength

Deformation and strength characteristics of granite under true triaxial stress states (σ1⩾σ2⩾σ3) are studied using 3D discrete element method (DEM). Lode angle θσ and the minimum principal stress σ3 are kept constant during each test by using distortional periodic boundary, eliminating the end effect and isolating the effect of intermediate principal stress σ2. Results reveal significant effect of σ2 on the common mechanical behavior and magnitude distribution of acoustic emission events. Based on a three-invariant strength criterion, variations of the instantaneous internal friction angle upon failure give an explanation for the σ2 effect on peak strength, which can be explained additionally by the energy release quantified as b-value.

Keywords: Discrete element method, Hard rocks, Intermediate principal stress, Peak strength, Dilatancy, Magnitude distribution,

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