ABSTRACT
Analytical design method based on principal statement of contact interaction between rock mass and underground opening support is applied for design of tunnel linings in very soft grounds like sands or soft clays as well as in unstable brittle rocks failured in ahead of the tunnel face. According to the theory of tunnel lining design it needs to determine the initial inward radial displacements of the tunnel surface before the tunnel lining is erected. The relations for initial radial displacements of ground mass have been obtained taking into account physically non-linear (plastic and failure) behaviour of the rock mass surrounding tunnel. Excluding of the initial displacements is considered in the tunnel lining design scheme by introducing the α * decreasing coefficient to the components of the intact ground mass stress state. That coefficient depends from the depth of the tunnel, characteristics of the strength properties of the ground.
