Abstract:

In light of the heterogeneity of rock, by introducing the constitutive model based on damage mechanics and statistical theory and using the RFPA2D, the influene of the horizontal in-situ stresses on the distributions of plastic zones is discussed. The deformation and nonlinear gradual failure characteristics of circular roadway in deep rock mass as well as the displacement and the stress variation of the key positions in the periphery of the roadway are analyzed, When ≤1, the plastic area is large-scale, but deflection more little; when , the plastic area is little-scale, but deflection more big. The study indicates that the stress concentration occurs in the periphery of the roadway after evacuation and plastic deformation zone engenders under the persisting stress of the surrounding rock; then the cracks appear and expand continuously; the broken rock zone appears at last and the intensity of the stress concentration decreases as well as the stress field shifts beyond. This study is very useful and significant both on the theoretical and practical aspects.

Key words: circular aperture, in-situ stresses, broken rock zone, coefficient of lateral pressure, numerical simulation