Correction and application of the Bandis empirical formula

A reasonable method was discussed for choosing and applying stiffness parameters in a 3D distinct element code. The formulas of pre-peak shear stiffness and normal stiffness of the fracture were derived through theoretical analysis. In combination with data from indoor shearing experiment,a corrected Bandis empirical formula of shear stiffness and a normal stiffness empirical formula were developed,which were proved to be logical by numerical analytical study. At last,a reality engineering of slope slide was discussed as a further evidence to describe the applicability of stiffness parameters chosen by the method mentioned above. It is obvious that the stiffness parameters of the fracture are a function of stress whether shear stiffness or normal stiffness. The corrected Bandis empirical formula can reflect the behavior of shear stiffness in the pre-peak range well. It is practicable to make the stiffness of the fracture changed with stress by developing a FISH program(in 3DEC),and therefore,the simulation can more in line with the practical engineering. In conclusion,the method mentioned above is proved to be reasonable.