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An Analytical Solution for Axisymmetric Tunnel Problems in ElastoViscoplastic MediaAbstract:An analytical solution is presented for the timedependent stresses and displacements around a circular hole when it is loaded by an axisymmetric internal and farfield pressure. The material is assumed to be elastoviscoplastic with dilatant plastic deformations according to a nonassociated flow rule. Strain softening is considered by a modified St. Venant slider which is characterized by MohrCoulomb yield conditions for both the peak and the residual strengths. Authors:Fritz, PitIndex Terms:tunnel; rotational symmetry; analytical; rock; TunnelingGroup; rheology; analysisRemarks:It may be shown that for the elastoviscoplastic material model presented, an optimum time of installation for the lining does not exist. This is because for an infinitely small, but positive internal pressure, numerically a stable equilibrium will be reached, even without a lining. The introduction of such a small, fictitious internal pressure for numerical reasons only seems always to be justified. Disregarding big deformations, stability will therefore, theoretically, always be guaranteed. Further Information:Date published: 1984 
