Abstract: Considering the influence of existence of joints in rockmasses, an equivalent model has been erected based on the general Cosserat continuum theory and the analysis of a representative element. The equivalent model aims at rockmasses with two sets of nonorthogonal joints. Moreover, it also could be used to simulate rockmasses with two sets of orthogonal joints or one set of joint under certain condition. The equivalent model has been coded into a FEM program and the numerical analysis has been carried out to predict settlement of rock foundation ； at the same time, the Goodman ' s joint element method has been applied to solving the same problem. It can be found that the deformation results obtained from above mentioned two methods have a good agreement with each other. Moreover ， two sets of joints with different included angles are discussed with equivalent model, the results show that the proposed equivalent model is reasonable and effective for numerical analysis in jointed rockmasses.

Key words: jointed rockmass  , Cosserat theory  , equivalent model  , FEM analysis  ,  couple  stress