engleski

Computation of Primary Tunnel Support

The computation of stress and strain conditions for tunnel profile excavation is performed by the Boundary Element Method (BEM). It is a numerical method performed in geotechnics for resolving of the stress and strain distribution in a rock massif where the change of stress condition occurs during some operations. The method is timesaving procedure for the problem definition in design process, it offers flexibility in assumptions on input parameters characterising the massif, and in observing the influence of changes on the stress and strain conditions. A computer programme has been developed for the purpose. This programme facilitates computation to the influence of different primary support systems on the stress and strain condition. In this paper, the stress and strain conditions for a tunnel profile excavation are compared with the stress and strain conditions for shotcrete lining supported excavation profile. Analogously to the treatment of reinforced concrete, the ultimate bearing capacity of the concrete and steel are considered. The flexibility of the primary support structure is important. The shotcrete lining shall be slender in order to avoid bending moments.

Tunnel; Primary support; Bearing capacity; Rock mass; Boundary element method

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