Abstract: A numerical code RFPA2D is used to simulate the failure process of a rock sample with fault material during compression.We select six points to monitor the spatio-temporal distribution of stress, displacement and acoustic emission during fracture nucleation and failure under constant displacement load.The results show that the stress and displacement of the same point at different time or different points at the same time are not the same, and stress, displacement and AE show a series of complicated spatio-temporal images.The observed phenomena do not occur randomly but follow some principle and physical process.From the results it is also found that the variation of displacement depended on fault structure closely.Stress is built up both in the strong asperities, but stress is very lower in and adjacent to the fault.Stress and displacement change greatly as well as acoustic emission change greatly when the sudden collapse occurs.The simulation provides a physical model based on RFPA forecasting.Because the variations of displacement and stress are more important than the value of themselves, anomaly of one physical parameter does not lead to a certain fracture.

Key words: Stress, Displacement, Acoustic emission, Fracture precursor