Abstract: Based on the three-dimensional discrete element numerical simulation (3DEC), the model of flow and heat transfer in single fracture rock mass has been established. Furthermore，combined with global sensitivity analysis method of Morris, the“elementary effect”of each parameter has been calculated by the value variation of one parameter in turn. In addition, the mean value μ and variance σ have also been obtained. Moreover, according to the value of μ and σ，the effect of each parameter on model temperature output and the law of the spatial and temporal distribution of μ and σ have been analyzed. Research results have shown that：slit aperture (b), fluid-rock heat transfer coefficient (h)，rock Thermal conductivity (KT ), rock mass specific heat (Cs), and fluid specific heat (Cf) have an important impact on the temperature output of the model, what is more, rock thermal conductivity (KT ), rock mass specific heat (Cs), and slit aperture (b) have a great interaction with other parameters. With the increasing of time step, μ and σ could be basically divided into 3 stages: rapidly increasing stage, slowly increasing stage and stable stage. Furthermore, along with the direction of fracture fluid flow and crack normal, the value of μ and σ has presented a decreasing tendency. More interestingly, compared with the negative influence of b and Cf on the temperature value, Cs has presented a positive effect. However, for the different positions of h, u and KT , those parameters have both positive and negative effects.

Key words: single fracture rock, temperature field, Morris, parameter sensitivity analysis