Elastoplastic analysis of cracked surrounding rock in deep roadway based on Drucker-Prager criterion

Based on Drucker-Prager yield criterion and non-associated flow rule, the closed analytical solution of stress,displacement and plastic zone radius has been deduced by considering the influence of intermediate principal stress,the elastic strain of plastic zone and rock dilatancy. By comparing numerical examples and analyzing the influ- ences of different yield criteria and parameters on surrounding rock’s stress,displacement and plasticity,the research results show that with a significant interval effect,the intermediate principal stress has a significant influence on the plastic deformation of surrounding rock,the distribution of fracture zone and the surface displacement;the surrounding rock plasticity,the radius of fracture zone and surface displacement become larger as dilatancy angle and dilation coef- ficient increase;the surrounding rock plasticity and the radius of fracture zone become smaller with the increase of sup- porting resistance and surrounding rock parameters ( residual cohesion,residual internal friction angle,initial cohesion);comparing the research results with unified strength criterion,twin shear strength criterion and Mohr-Coulomb criterion,the surrounding rock plasticity,the radius of fracture zone and surface displacement are fairly large and they are closest to Mohr-Coulomb;under the same conditions of surrounding rock deformation,the supporting resistance re- quired by Drucker-Prager criterion is larger than that of other three criteria and it is more inclined to take the form of rigid support form. The results can provide an important theoretical basis for roadway surrounding rock’s stability eval- uation and quantitative support design.