Design Methods

Different methods are used for calculating underground structures.

Convergence-Confinement

Action-Reaction

Finite elements

Finite elements methods are based on the principle of discretization of a body into a number of finite elements. The behaviour of these elements can be controlled by imposing certain laws of mechanics which prescribe the behaviour of these elements in a predefined manner under the action of external influences. Finite elements methods can be used the behaviour of tunnel structures for a variety of assumed ground conditions; these include linear or non-linear elastic responses and non-linear material behaviour (plasticity).

ITA Endorsed publications

ITA Guidelines for the Design of Tunnels- ITA WG n°7
( Tunnelling and Underground Space Technology, Vol. 3, Nr. 3, pp. 237 - 249, 1988)

Views on structural design models for tunnelling- ITA WGn°7
( Advances in Tunnelling Technology and Subsurface Use, Vol. 2, Nr. 3, pp. 153 - 228, 1982)