The effect of stress state factor on fracture of sandstones under true triaxial loading

Autor: A. D. Alexeev, I. Y. Prokhorov, V. N. Revva, Leonid Bachurin
Rok vydání: 2008
Předmět:
Zdroj: International Journal of Fracture. 149:1-10
ISSN: 1573-2673
0376-9429
Popis: Experimental results on rock deformation and fracture under true triaxial compression have revealed a misfit between strain state and stress state, strain state varying from generalized compression to generalized shear at σ3 ≠ 0. This misfit can lead to data misinterpretation during the stress field reconstruction after unloading. Fracture of rock specimens under true triaxial compression occurs by a combined longitudinal/transverse shear and produces the highest dilatancy. An increase in the hydrostatic pressure level diminishes limiting values of shear strains and suppresses the dilatancy effect. A maximum of dilatancy coincides with a maximum of fresh surface area formed during the fracture of the rock. The generalized cleavage of rocks becomes energetically disadvantageous in a true triaxial compressive stress field. Some sandstone becomes more brittle under true triaxial compression (σ2 ≠ 0) at low values of the minimal stress component (σ3) due to high initial porosity and dilatancy.
Databáze: OpenAIRE