Abstarct: Despite the development of the excavation methods for tunneling and support systems, Now a days, Finding an appropriate method for stabilization of the underground excavations is still a challenge. Utilization of pre-support systems are effective methods for ground improvement before the excavation process starts. Understanding the mechanism of the mentioned systems requires modeling and analysis. The function of the Umbrella Arch system, Utilized in Tehran-Shomal highway tunnel, Had been numerically modeled and analysed in this study. Geological studies in this area showed that some extents of the profile have high potentials of collapse and therefore the common support systems can not satisfy the safety goals. As a result, the umbrella arch pre-support system which is proper for this sort of conditions, had been numerically modeled in FLAC3D. In addition, the effect of geometrical parameters such as installation angle of the pipes, spacing of the pipes and injection radius had been analysed beside the analysis of the umbrella arch system function. Analyses are baxsed on crown displacement. Results indicates that increase in pipe installation angle and decrease in pipe spacing have positive effects on tunnel stability and utilization of the umbrella arch system, reduces the crown displacement by 60 percent. As another result, the proposed spilling method of the consultant engineers, which is a sub-category of the umbrella arch system, performed well in the analysis and the utilization of this system has less difficulties.