ABSTRACT:

The ZEDEX project was set up jointly by ANDRA, France, SKB, Sweden, and UK Nirex, UK to improve understanding of the properties and extent the Excavation Disturbed Zone (EDZ). The project was performed at the Äspö Hard Rock Laboratory (HRL) in Sweden. The in situ measurements had to be performed in short time slots dictated by the schedule set for the excavation of the laboratory. This necessitated detailed planning and coordination of all activities with the excavation contractor. The management structure set up worked very well. The positive spirit within the project group and the good collaboration with the excavation contractor made it possible to successfully perform all measurements planned and to complete the project within the allocated budget.

RESUME:

Le projet ZEDEX a ete creè par ANDRA, France, SKB, Suede, et UK Nirex, Grande Bretagne en commun et a ete execute à Äspö HRL pour ameliorer la comprehension des caractère et des extension de la Zone Derange d'Excavation (EDZ) II a ete necessaire de performer les mesures in situ dans des periodes de temps courts dictees par la table creee pour l'excavation de la laboratoire. Ceci a rendu necessaire un planning en detail et une coordination de toutes les activites avec I'entrepreneur de I'excavation. La structure de I'exploitation etablie a functione tres bien. L'esprit positif dans Ie groupe du projet et la bonne collaboration avec l'entrepreneur de l'excavation a permi d'executer toutes les mesures projetees et de mener à bout Ie projet en se tenant dans Ie cadre du budget.

ZUSAMMENFASSUNG:

Fuer das Projekt ZEDEX wurde eine Arbeitsgemeinschaft bestehend aus ANDRA (Frankreich), UK Nirex (England), und SKB (Schweden) gebildet und im Aspö "Hard Rock Labaratory" (HRL) durchgefuehrt. Das Ziel des Projektes war es, das Wissen ueber die Entstehung von Unregelmassigkeiten beim Ausbruch zu verbessern und Methoden zu dessen Abhilfe zu testen. Die "in situ" Messungen mussten in kurzen Zeitabstanden durchgefuehrt werden um den Zeitrahmen der Vortriebsarbeiten des HRL-Projektes einhalten zu können. Genaue Planung und Koordinierung der Vortriebsarbeiten waren daher notwendig. Die dafuehr gewahlte Arbeitsvorbereitung hat sehr gut funktioniert Die positieve Einstellung zum Projekt und die gute Zusammenarbeit mit dem Bauunternehmen haben ermöglicht alle geplanten Messungen zeitgemass durchfuehren zu können.

1 INTRODUCTION

The ZEDEX (Zone of Excavation Disturbance EXperiment) project was performed in order to improve understanding of the properties and extent the Excavation Disturbed Zone (EDZ). The properties and extent of the disturbed zone must be considered In the design of deep geological repositories for radioactive waste and in the assessment of their long-term safety. This is because the excavation of shafts and tunnels may compromise rock mass stability and alter hydraulic properties. The ZEDEX project was set up jointly by ANDRA, France, SKB, Sweden, and UK Nirex, United Kingdom and executed at the Äspö Hard Rock Laboratory (HRL) which is an underground laboratory operated by SKB. These organizations are responsible for the management of waste from nuclear power reactors in their respective countries.

2 PROJECT INITIATION

The construction of the underground tunnels of the Äspö HRL commenced in October 1990. During spring 1991 SKB conducted the Blasting Damage Experiment to study the extent of damage for three different blast designs. The experiment was carried out in conjunction with excavation of the main access tunnel for the length interval 525 to 565 m (Pusch and Stanfors, 1992). Based on the results from this experiment SKB and the contractor agreed on a blast design to be used thereafter that would cause a limited damage zone around the tunnel perimeter.

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