Elasto-plastic analysis of a circular opening in rock mass with confining stress-dependent strain-softening behaviour

摘要: Abstract In strain-softening rock mass, it is widely accepted that the confining stress in plastic zone around a circular opening varies with radial distance. The variable gives rise to critical softening parameter (η∗). This paper aims take η∗ into account development of elasto-plastic solutions for and strain states opening. First, model (VCSM) recommended effect η∗; criterion presented judging whether or not mass transfers from state residual state. Then, new numerical procedure implementation VCSM proposed on basis Hoek–Brown failure non-associated flow rule. procedure, zones are divided set concentric rings by an assigned increment. increments each ring can be calculated successive manner finite difference method. Finally, using series parametric studies conducted compare existing constant models (CCSM), also investigate variation components, parameter, strength parameters zone. results indicate CCSM tends underestimate deformation surrounding poor quality. stability includes two different aspects: one govern zone, other control radii zones.