Abstract
While the long facebolting method has become widely used in mountain tunneling as a stabilization measure of tunnel faces, its reinforcing effects have yet to be quantitatively estimated. In this paper, the in-situ measurements are conducted at a tunnel site to investigate the behavior of facebolts installed at a tunnel face. Three-dimensional numerical analyses are successfully performed to simulate the measured behavior. Furthermore, the parametrics study on the cohesive properties of the bolts with ground has shown that the restraining effets of the face extrusion are significantly affected by the cohesive properties that exhibit different magnitudes and distribution patterns on the induced axial forces.
