Abstract: When mining in deep rock mass under high stress and complicated geological conditions， the stability of rock pillar system is quite important for safe-mining. A series of numerical simulations were conducted to evaluate the effect of uniaxial compressive strength on the failure processes of serial and parallel pillar systems by using the RFPA^3D-Parallel code. Results show that the stability of the serial pillar system depends on pillar of lower uniaxial compressive strength， which means that monitoring and reinforcement of the relatively weak pillar in the serial pillar system is quite essential to the stability control of the serial pillar system. For the parallel pillar systems， the pressure-transfer is closely related to the compressive strength of the pillars， that is， stress will be transferred from the weak pillar to the strong pillar till the failure of the whole pillar system. It is also found that the multi-peak phenomenon of the acoustic emission(AE) counts or the step-curve of the accumulative AE counts can be deemed as the hint of stress transfer from the fractured weak pillar to the nearby strong pillars.

Key words: rock pillar system, mechanical property, failure mechanism, numerical analysis, acoustic emission(AE)