Geological and geotechnical data are essential for the design of tunnels. To determine the rock mass behavior and the support of a planned tunnel excavation a consistent method for rock mass characterization and excavation and support determination has been developed. Probabilistic data processing with analytical methods is used for the quantification of the procedure and allows an evaluation of the applicability and the technical risk of different excavation and support methods. The sensitivity of the procedure on selected input parameters is highlighted in a parametric study. Finally an application of the procedure illustrates the use of the described method of probabilistic excavation and support determination for tunnels.
Des donnees geologiques et geotechniques sont decisives pour la planification d'un tunnel. Pour la determination du comportement des strates, le choix du soutènement et de la methode de progression une description comprehensible de la montagne a ete developpee. À l'aide d'un traitement de donnees probabiliste, la procedure proposee est transposee quantitative sur une base de methodes analytiques. De cette manière l'evaluation des methodes de construction et la determination du risque technique deviennent possibles. La sensitivite de la procedure de differents paramètres d'entree est representee dans une etude de paramètre. Pour finir, l'application de la procedure decrite est montree à l'aide d'un cas pratique.
Geologische und geotechnische Daten sind entscheidend fuer die Planung von Tunnels. Fuer die Ermittlung des Gebirgsverhaltens und der Festlegung von Ausbruch und Stuetzung wurde ein nachvollziehbarer Ablauf der Gebirgsbeschreibung entwickelt. Mit Hilfe von probabilistischer Datenverarbeitung auf Grundlage analytischer Methoden wird die vorgeschlagene Prozedur quantiativ umgesetzt. Dadurch werden die Bewertung von Baumethoden und die Ermittlung des technischen Risikos ermöglicht. Die Sensitivitat des Verfahrens von einzelnen Eingangsparametern wird in einer Parameterstudie dargestellt. Abschließend wird anhand eines Beispiels die Anwendung des beschriebenen Verfahrens gezeigt.
A sound and economical tunnel design heavily relies on a quality rock mass characterization. In the past, tunnel design was primarily based on experience, basic empirical calculations, and standardized rock mass classification systems. Due to uncertainties in the rock mass behavior, the final excavation and support design should continue through the project development (Riedmueller & Schubert 1999). For this reason a consistent method for tunnel design, from the pre-construction phase through the tunnel construction, applicable to all rock mass conditions was developed and published as a Guideline in Austria (OGG 2001). The classification of the rock mass is based on its behavior during tunnel construction. Throughout the development of a tunnel project the quantity and quality of the available geotechnical data change. Due to this variation the parameters should be processed probabilistically by using distributed values. This process includes geological modeling as well as rock mass characterization and tunnel design.
The goal of the Guideline was the development of a consistent procedure for the determination of excavation and support. The step by step procedure promotes an engineering approach to the design and construction of tunnels. In the pre-construction phase support concepts are based on Rock Mass Behavior Types developed from Rock Mass Types and Influencing Factors.
