Abstarct: Design and execution of the support system is one of the most important issues, with regard to the nature and sensitivity of the tunnel construction. Supporting is one of the main stages in the underground spaces construction. The simplicity of application, with the environmental conditions, can enhance the system performance. Mechanized tunneling such as using of Tunnel Boring Machine (TBM) is one of the common methods for tunnel excavation. One of the advantages of this method is concurrent execution of the tunnel permanent support system in conjunction with the excavation using the precast concrete segments. Since the use of precast concrete is important in the support system, so it requires an optimal analysis of the segmental lining and the interfaces between them. The studies in Numerical Analysis of the tunnel lining behavior in the Closed-face shielded TBM driven tunnels show that the most researchers have used simplified models. The appropriate compatibility of support systems with the environmental condition can enhance it’s the applicability. Obviously, these assumptions will cause a lot of errors in the results. In this study, the behavior of the segmental lining of the Chamshir water transfer tunnel was modeled as continuous ring, using 3DEC and compared with discontinuous rings. This software is capable of modeling the three dimensional environment, considering the properties of the rock mass which is more realistic than the studies that use the beam-spring model that models the earth by means of springs. In this software, the joints of segmental lining are defined by conventional formulas via properties of the joints. Analysis of the obtained results from modeling showed an increase in displacements in segmented state in comparison with the continuous rings, that represents optimistic modeling in continuous state. Also, generally, stresses in the segmental lining are less than that of continuous state, except in the joints that causes stress concentration. This stress concentration and rotation at the joints causes damage in concrete. So, in order to achieve more realistic results, considering segmental lining joints are necessary in the design phase of construction.