engleski

The Influence of the Primary Support in Tunnel Design

Intensity of the support loading acting on rock depends on shifts of the statically undefined rock-support system. Rock deformations increase until the stress conditions in rock harmonise with reactive pressure of the support and with equalising of the deformations on the contact. It is difficult to determine the influence of the rock on the primary support, as well as the relation between the support deformation (e.g. from shotcrete) and its bearing capacity, which results in these deformations because support concrete is green and relaxed. The New Austrian Tunnel Method is an excavation method adaptable to frequent changes of geological and geotechnical conditions at the working face. In massive rock the full tunnel cross-section can be opened at the same time. The multi-stage excavation is applied when the conditions of rock mass along the tunnel route frequently change. In case of road tunnel driving, the method of boundary elements with the Hoek-Brown’ s failure criteria was used in computations. There is an obvious need in engineering practice for researching the complex problem of interaction between rock and primary support in making an underground opening driving safe.

Shotcrete; New Austrian Tunnel Method; Boundary Element Method

nije evidentirano