Abstract：This paper narrates the typical modes of rock mass failures in engineering activities，the conditions under which such failures occur，and the approaches to predict these failures. A brief description is presented of the evolution，the current state，and the feature of numerical modelling methods for jointed rock mass. Attention is paid to the technique of generating 3-dimensional joint net in rock mass and randomly simulating the properties of each individual joint on the basis of accessible functions in a 3DEC numerical model. Such technique enables 3DEC to build up a model that contains various joints corresponding to the realistic distributions of joints in rock mass and，furthermore，achieve a determinative description of joint distributions by transplanting joint mapping data into a 3DEC model. This，in some degree，fulfills the numerical modelling of geomechanical behaviours of jointed rock mass combined with the computerized simulations of its geometry. The essential principles are discussed of applying numerical modelling techniques for discontinuum into engineering projects.
