Analysis of limit equilibrium zone for roadway side wall considering engineering disturbance and geological condition

To analyze the change law of the influences of parameters D and GSI on internal friction angle and cohe- sion,the formula of nonlinear rock strength parameters (internal friction angle and cohesion),related to the extent of engineering disturbance ( D) and rock geological strength index ( GSI), was proposed based on the Hoek-Brown strength criterion and Mohr-Coulomb strength criterion. Coal and rock under intact and crushed condition was taken as an example,the equations of both normal stress over slip plane and the width of the limit equilibrium zone for roadway sidewall,associated with parameters D and GSI,were established based on the proposed nonlinear M-C criterion. Influ- ences of both D and GSI on the limit equilibrium zone were studied. The results show that the smaller the parameter D,the greater the GSI,the greater the angle of internal friction and cohesion,which denotes that the better rock mass integrity,the greater the value of nonlinear rock strength parameters. The normal stress over slip plane of roadway side- wall decreases with the increase of parameter D,increases with the increase of parameter GSI. The width of limit equi- librium zone increases with the increase of parameter D,decreases with the increase of parameter GSI. Finally,through the analysis of a project case,the research results are verified to be reasonable.