Time-dependent analysis of stress components around lined tunnels with circular configuration considering tunnel advancing rate effects

An analytical solution is recommended in this paper for time-dependent stress analysis of lined tunnels with a circular shape, regarding tunnel advancing rate. In previous works, it was assumed that the tunnel is excavated under an infinite advancing rate such that the progressing rate effect was neglected, the assumption which is not always true. However, this barrier is removed in this paper. The non-hydrostatic stress field is assumed as initial stress within rock mass. The concrete lining, and surrounding mass are supposed as isotropic homogenous materials, following elastic and viscoelastic constitutive models, respectively. The Burgers model is assumed to dominate viscoelastic behavior. The solution benefits from time discretization for both tunnel advancing rate, and rock support interaction, along with employing complex variable method. The solution presents a good agreement with COMSOL finite element software simulation for different advancing rates. It is found that there exist the progressing rate and time limits, which for higher values, the problem could be solved assuming instantaneous excavation of the hole.