Abstract：The general composite element concept is proposed firstly，then the principle of the model is used to establish a fully-grouted rock bolt element model which comprises rock material，grout material，bolt material，rock-grout interface and bolt-grout interface. The composite element can be incorporated into the conventional finite element analysis easily with hierarchical technique. On one hand，when one element contains no bolt segments，the composite element will be degenerated into the conventional finite element. On the other hand，if the number and direction of bolts are changed in the optimal reinforcement design，the FE grid will keep unchanged. In this way the mesh generation of the large scale reinforced rock structures becomes relatively convenient and feasible. The model has been implemented in the FEM software CORE3，and some numerical examples are presented.
