Quantitative determination of PFC3D microscopic parameters

It is important to calibrate micro-parameters for applying partied flow code (PFC) to study mechanical characteristics and failure mechanism of rock materials. Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code (PFC3D). Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters (elastic modulus E, Poisson ratio v, uniaxial compressive strength sigma(c), and ratio of crack initial stress to uniaxial compressive strength sigma(ci)/sigma(c)) in order to obtain the actual uniform design talbe. The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined. The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions (including the macroscopic mechanical parameters, stress-strain curves and failure process) are in good agreement with experimental results, which can prove the validity of the calculation equations of microscopic and macroscopic parameters.