ABSTRACT:

A formal method for independently assessing the validity of the design of complex modern rock engineering projects is presented. The interface of the design with other disciplines can be included. Three levels of audit are proposed: 1st level - the relevant variables and mechanisms are considered; 2nd level - modelling of the system to establish the most significant processes and hazards; and, 3rd level - back analysis to generate additional information unobtainable prior to excavation. First and second level audits can be implemented immediately. The third level audit requires further development.

RESUME:

Une methode formelle d'evaluation independente du dessin de projets complexes d'ingenierie des roches. L'interaction du dessin avec d'autres disciplines peut être inclus. Trois niveaux de verification se proposent. 1" niveau - on considère les variables et mecanismes pertinents; 2' niveau - on modèle le système pour etablier les procès et les hasards les plus importants; et, 3' niveau - retro-analyse pour generer des informations additionelles que l'on ne peut pas obtenir avant d'excaver. On peut executer immediatement les deux premiers niveaux de verification, mais Ie troisième niveau demande plus d' amplification.

ZUSAMMENFASSUNG:

Eine formelle Methode fuer das unabhangige Abwagen der Gueltigkeit des Entwurfs eines komplexen modernen Felsingenieurwesenprojekts wird hier prasentiert. Beruehrungspunkte des Entwurfs mit anderen Gebieten können eingeschlossen werden. Drei Pruefungniveaus werden vorgeschlagen. 1. Niveau - die relevanten Variablen und Mechanismus werden in Ruecksicht genommen; 2. Niveau - Modellkonstruktion des Systems um die wichtigsten Prozessen und Gefahren zu finden; und, 3 Niveau _ Ruck-analyse um zusatzliche Daten hervorzurufen, die sonst vor dcm Ausgrabung unerhaltlich sind. Das erstc und zweite Niveau können sofort durchgezogen werden. Das dritte braucht weitere Entwicklung.

1 INTRODUCTION

The history of applying the discipline of rock mechanics to rock engineering has been rapid and has occurred relatively recently over the last three decades. In a nutshell, this development has included the study of intact rock, discontinuities, rock masses, in situ stress, water flow, excavation, support, and the application of this knowledge for improving the design and performance of rock engineering structures. There have been major developments in all these subjects, with the revolution in computing capability enhancing all aspects. It is an appropriate time now to take stock and consider whether the design of rock structures does indeed take into account currently available knowledge and how we would audit this for a specific project. The way in which the individual rock mechanics subjects contribute to the design of a specific project can only be established completely by considering the ‘rock mass’-‘engineering project’ as a system. The components of this system and the links between the components have to be considered first. The operation of the system, how it behaves internally and how it responds to external perturbations, has to be considered next. The specific values for the site are input so that the system model becomes site-specific. The extreme performance behaviour, i.e. hazardous behaviour, is identified and the site conditions and/or the design modified as appropriate Finally, back analysis information becomes available and is used to confirm the design. Establishing that all this has been done is the motivation for the development of the information audits. All the components potentially contribute to the operation of the ‘rock mass’ -‘engineering project’ system. However, further analysis is required to establish which are the dominant system components and what are the characteristics of these components that will affect the performance of the system in terms of its internal operation and its vulnerability to external disturbances. At this stage, the design may be initial or have been proposed in some detail.

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