Abstract: Generalized Hoek-Brown criterion is indicated as a dimensionless quantity; on this basis, elasto-plastic analytical method of circular underground chamber in uniform stress field has been established. According to the following three kinds of circumstances: 1) without considering rock dilatancy and elastic deformation in plastic zone, 2) considering rock dilatancy and constant elastic deformation in plastic zone, 3) considering rock dilatancy and varied elastic deformation in plastic zone, surrounding rock plastic zone displacement of deep buried underground chamber has been comparatively analyzed for different quality rock mass. The results have shown that surrounding rock plastic zone displacement is the maximum under the circumstance of considering rock dilatancy and varied elastic deformation in plastic zone. For soft rock chamber in poor and average quality rock mass, rock dilatancy and varied elastic deformation in plastic zone must be considered in the process of analysis on surrounding rock plastic zone displacement. For chamber in good quality rock mass or hard rock chamber, rock dilatancy and elastic deformation in plastic zone may not have to be considered.

Key words: Hoek-Brown criterion, deep buried underground chamber, plastic zone displacement, dilatancy, elastic deformation