Abstarct: Depend on the conditions of surrounding ground of tunnel, different methods of maintenance and stability of tunnel could be utilized. In this regard, in the excavated tunnels in near ground surface or grounds with weak geomechanical behavior, use of pre-support methods is inevitable. In this research work which is accomplished in Chaloos water conveyance tunnel, considering the weak geomechanical behavior of surrounding ground, it is essential the use of pre- supporting methods instead of ensure the stability of tunnel, which baxsed on status of the tunnel, pipe umbrella support and tunnel face reinforcement bolts have been designed. Instead of improvement of understanding the maintenance and surrounding ground of tunnel behavior as well as determining various parameter of pipe umbrella support, it is necessary to be carried out the numerical modeling. For this purpose FLAC3D software has been used. In the following, baxsed on numerical modeling results, the requisiteness of using the pre- supporting as well as calculation of various parameter of pipe umbrella and bolt reinforcement have been implemented. Investigated parameters are consist of length, lateral spacing, dip and overlapping for pipe umbrella method and the number of bolts per square meter of tunnel face in the bolt reinforcement method. Current study is baxsed on displacement in the ground surface and tunnel crown. Also, evaluation of safety and stability maintenance has been performed using Sakurai risk assessment method. baxsed on obtained results of aforementioned studies, use of pipe umbrella and reinforcement bolt is reasonable planning. According to this study, spacing of reinforcement bolt should be adjust to 0.5 meter. Furthermore using of pipe umbrella with length of 6 meters, 0.5 meter spacing, dip of 5 degrees and 1 meter of overlapping in the tunnel crown has been offered. Use of pipe umbrella and reinforcement bolt prevent the displacements in the tunnel crown and ground surface up to 70% and 50% respectively. Also displacement could be improved up to 50% in the tunnel face.