Abstract: In order to accurately simulate the rock mass, considering the effects of the unconformity to simulation, the method was purposed to simulate the different contact situation using PFC3D based on the Particle flow theory, include: integration, parallel unconformity, angular unconformity. Simulation step include: define the rock coordinate system; determine the key points of contact trend; use MATLAB to fit the trend curve and get the parameters; use PFM to construct the model; shaping contact surface using FISH according the parameters. The structured model satisfies the above requirements, which proved the model is close to the actual rock mass mechanics performance.

Key words: simulation of rock mass, contact surface, Particles Fall Method, PFC3D, parallel unconformity, angular unconformity