NUMERICAL SIMULATION OF MECHANISM OF CIRCULAR ROADWAY LOOSE ROCK ZONE IN DEEP ROCK MASS

To study the failure laws of surrounding rocks forthe roadway in deep rock mass, in view of the heterogeneity of rock, weuse a constitutive model based on damage mechanics and statisticaltheory and the RFPA^\rm 2D, to analyze the deformation and nonlinear gradualfailure characteristics of circular roadway in deep rock mass as well as thedisplacement and the stress variations in the key positions in the peripheryof the roadway, and also the mechanism of loose rock zone inthe surrounding rock of the circular roadway. The studyindicates that the stress concentration occurs in the periphery of theroadway after evacuation and plastic deformation zone is engendered under thepersisting stress of the surrounding rock, then the cracks appears andextends continuously, the loose fraction zone (loose rock zone) appears atlast and the intensity of the stress concentration decreases as well as thestress field shifts beyond.