New analytical approach to simulate the longitudinal fiberglass dowels performance installed at the face of a tunnel embedded in weak and weathered rock masses

A new theoretical method is proposed to simulate the fiberglass dowels performance in the confinement of the tunnel face in weak rock masses. In this method, to find the stress distribution ahead of the tunnel face, the spherical symmetry hypothesis is used. Thus, the tunnel's cylindrical shape is approximated by a hemispherical void with the same radius. Considering the relative shear displacements between the reinforcing elements and rock mass, the distribution of the axial forces and shear stresses along the reinforcements are obtained. Some examples are solved, and the results are compared with those derived from FLAC3D simulations. A good agreement is observed between the results obtained with both methods.