Pretensioning in the Rockbolts and Its Effect on the Plastic Zone Around of Tunnels

Abstract

Rock bolts that hold the tools in the area sustainability underground spaces and roofing stone is used and its role connecting to discontinuous rock mass and tunnel stability. Rock bolts can be used in various positions for the stability of the tunnel. In this research the effect of pre stressing rock bolts on displacements around Roush dam tunnel in Turkey in weathered tuff rock is being evaluated. So different tunnel models due to shape and dimension were designed and different size rock bolts were analyzed and the effect of predestining on them, were evaluated and the results were compared. The samples made in this research were analyzed by Phase2 software. In this study the strain in the tunnel section is assumed two dimensional. The results show that by increasing the pre stressed strength in rock bolts, the displacements around the tunnel decrease until a specific point and then increase again.