Abstract: The study on compaction characteristics of fractured rock mass is considered as one of the basic work of underground engineering in coal mines. Since fractured rock mass exists in the hidden and dangerous environment, laboratory experiments and numerical simulations are normally applied to determine the compaction characteristics indirectly. To construct three-dimensional (3D) model of fractured rock mass, this paper presented a novel method which was based on the 3D Voronoi numerical model of intact rock mass. In this model, the porosity was pre-determined and the structure of fractured rock mass was retrieved by randomly removing the blocks in the intact rock mass. Moreover, the Weibull distribution was introduced to describe mechanical parameters of joints. In addition, uniaxial compression experiments were conducted to investigate the compaction characteristics. Compared with existing theoretical and experimental results, this method demonstrated good agreements with them. It is proved that this parametric method can reflect the fragmentation, bulking and compaction characteristics of fractured rock mass more accurately. Therefore, this study provides a new and effective method for the safety control of underground engineering in coal mines, which can be widely used in the gravel experiments.

Key words: broken rock, discrete element method, modelling method, lithologic distribution model, compaction characteristics