On the basis of observations and experience on tunnels constructed in heavily faulted rock, a research project was initiated. It was found, that when using the orientation of displacement vectors in space, not only changes in rock mass stiffness several diameters in advance can be detected, but also deviations in primary stress orientation. New tools for efficient data processing and visualisation have been development. The tools allow a better evaluation of the stress situation around tunnel and improved short-term prediction of ground mass ahead of the face. Warning mechanisms used to identify critical situations. By automatically comparing the vector orientation to allowable limits of deviation from a "normal" value can be used. "Normal" vector orientation are defined during the design and adjusted during construction. Practical examples with field data are shown.


Les experiences avec des progressions du tunnel dans les zones remaniements et les travaux du recherche se base ont mont, que les orientation dans l'espace pêut indiquer des modifications des proportion des rigidite quelques diamètres du tunnel d'avance. En même temps il est possible à tirer des conlusions de I' orientation de la contrainte primaire. En ce qui concern ces resultat on a developpe des nouveaux procedes exploitations et representations. Avec ces ressource on pêut realiser un pronostic exact à temps bref des comportements des strates. On present les nouveaux ressources au moyen des exemples pratiques.


Die Erfahrungen bei Tunnelvortrieben in Störungszonen und darauf basierende Forschungsarbeiten haben gezeigt, daß die Raumstellung der Verschiebungsvektoren einige Tunneldurchmesser im voraus auf Anderungen der Steifigkeitsverhaltnisse im Gebirge hinweisen kann. Weiters erscheinen Rueckschluesse auf die Orientierung der Primarspannung möglich. Auf Grundlage dieser Ergebnisse wurden neue Auswertungs- und Darstellungsverfahren von geodatischen Verschiebungsmeßdaten entwickelt. Mit diesen Hilfsmitteln sollte eine zutreffende Kurzeitprognose des Gebirgsverhaltens ermöglicht Werden. Es wird an einem teilautomatischen Kontrollmechanismus gearbeitet, der die Vektororientierung auf Abweichungen gegenuber einem vordefiniertem "Normalzustand" ueberprueft. Die neuen Hilfsmittel werden anhand von einigen praktischen Beispielen vorgestellt.


The problems experienced when tunnelling in poor rock and fault zones are well known over the world. Low strength, high deformability and heterogeneity of the rock mass lead to difficulties in prediction of the tunnel performance: Although the general geological situation may be known from the investigation programme, singularities will strongly influence stresses, deformations and thus the stability of the tunnel during excavation. For safe and economical tunnelling under such conditions a continuous adaptation of excavation and support is required. In addition the amount of necessary over excavation to account for the displacements has to be estimated in advance. It is obvious, that a good short term prediction of the rock mass structure and quality ahead of the face and outside the excavation area is essential for successful tunnelling. Besides a proper modelling during the design, continuous and adequate monitoring of the behaviour of the rock mass - support structure is the basis for decisions on site. Systematic monitoring for the purpose of determination of support type and quantity, as well as control of the tunnel stability is an important feature of the NATM. Over the decades monitoring techniques have been considerably improved [1]. Determination of absolute displacements during tunnel excavation by geodetic methods have to a large extent replaced relative displacement measurements at least in Austria. The increase in information has led to additional possibilities in data visualisation. The plotting of lines of influence, trend lines, or displacement vectors in a plane perpendicular to the tunnel axis have become common practice in many places [2,3,6,7,10].

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