Abstract:Determination of mechanical parameters of rock mass is very important for the design and optimization in rock engineering. It is difficult to get the mechanical parameters of rock mass by filed or lab tests, hence the method to determine macro mechanical parameters of jointed rock mass using numerical experiment is presented in this paper. Firstly, jointed rock mass are discretized into rock and joints; then determine their mechanical parameters by lab test; after that, assemble the rock and joints to form rock mass; finally get the mechanical parameters of rock mass using numerical experiments. This method is applied in expressway project in Guizhou province. The optimization analysis of rock mass parameters for rock slope is conducted. The effects of specimen size, anisotropy, mechanical parameters of rock and joints on the macro parameters of rock mass are studied. The numerical test method provides a new idea for determination and optimization of mechanical parameters for jointed rock mass in engineering.