抄録
It has been pointed out in the calculation of pressure acting on a tunnel lining that the medium around a tunnel cannot be assumed to be an elastic body even for the first degree of approximation. Since the pressure usually increases with time, time must be considered in its theoretical analysis. In the designing purpose of the lining, however, the maximum pressure rather than the transient pressure change is of importance.
The authors have previously proposed a method of calculation of the maximum pressure acting on the lining installed in a viscoelastic isotropic underground medium. The proposed method does not require a time-dependent analysis, but follows exactly the same technique based on the theory of elasticity.
The real state of the medium, however, exhibits more or less anisotropic mechanical characteristics, so that the anisotropy must be considered in the calculation. In this paper, the proposed method is extended to the case of an orthotropic viscoelastic medium of Kelvin type, and some numerical results are shown for a circular lining.
