Abstract:The comparative study of the composite element method(CEM) and the conventional finite element method(FEM) is carried out for the rock bolt crane girder of an underground powerhouse. The attention is paid to the portion of the contact face between girder and surrounding rock masses,the contact faces between bolts and surrounding rock masses,as well as to the portion where rock bolt penetrates the contact face. The excavation procedure of the underground cavern,the installation procedure and operation procedure of the rock bolt crane girder are simulated;and the characteristics and efficiency of the CEM and FEM are presented. It is shown that the results by the CEM are close to those of conventional FEM in the explicit simulation of reinforced jointed rock masses;the CEM is able to provide more detailed messages concerning the stress and deformation;and the CEM has the advantages in the simplification of pre-process. The study also shows that since the complicated pre-process works in the FEM are replaced by the complicated computation works in the CEM,more computation time is required in the application of the CEM.