The convergence confinement method as an aid in the design of deep tunnels

Abstract

The convergence confinement method is used in its original form for the analytic or graphical description of the ground and system behaviour of underground excavations. The purpose of the method is to derive the support measures required from the combination of the ground characteristic curve, a model of the development of the radial deformations of the excavation surface in the axial direction of the tunnel, the support characteristic curve and the installation time and location of the support measures. The convergence confinement method is mostly used in the preliminary design of underground structures.Typical applications of the convergence confinement method are deep tunnels and tunnels with ground behaviour types where displacements play a major role. If sudden ruptures occur, in shallow tunnelling and in loose ground, this method is not to be recommended. An absolute precondition for the correct use is an understanding of the theory of the convergence confinement method and the course of failure mechanisms in the rock mass and their effects on the system behaviour.

Ground reaction and lining curves /

“…It therefore quite understandable that the ground reaction curve should be used for this [4]. The final design is actually undertaken on site by the head tunnelling engineer or in a team.…”

Beitrag zur Anwendung des Kennlinienverfahrens

“…Ebenso wurden Lösungen für unterschiedliche Materialgesetze und unterschiedliche Verhalten im Post-failure-Bereich (Abb. 2) abgeleitet.Abbildung 3 zeigt, dass die Lösungen der Verschiebungsverteilungen der unterschiedlichen Ansätze variieren14 . Dies liegt einerseits in den unterschiedlichen Randbedingungen, andererseits in der Berücksichtigung verschiedener Dehnungsanteile im plastischen Bereich.…”