Fuzziness in the evaluation of the stability of underground excavations is generally found unavoidable. In this paper, a fuzzy evaluation approach to the stability of underground excavations is developed in the light of fuzzy mathematics theory and Rock Engineering Systems theory. In the approach developed, the stability of an underground excavation is divided into 5 classes which are considered as a fuzzy evaluation set. Each of the parameters selected to characterize the stability is fuzzily evaluated through the fuzzy membership functions and the evaluation result of each parameter is considered as a fuzzy subset in the woe fuzzy set. After defining the weighted numbers of the parameters, a fuzzy evaluation of the stability will be obtained through the fuzzy operation. Finally, a case study IS illustrated as an example of a practical application of the evaluation approach.


L'imprecision dans l'evaluation de la stabilite des excavations souteraines est generalement inevitable. Dans cet article est developpe I'aspect imprecis de l'evaluation de la stabilite des excavations souteraines grace à la theorie des mathematiques approchees et celle des Systèmes de Techniques des Roches. En ce qui concerne l'approche developpee, la stabilite des excavations souteraines est divisee en cinq classes qui sont considerees comme un groupe devaluation approchee. Chacun des paramètres selectionnes pour characteriser la stabilite est approximativement calcule grace à certaines fonctions approachees et le resultat de l'evaluation de chaque paramètre est considere comme un sous groupe approche du groupe approche entier. Après avoir defini le nombre de paramètres coefficientes, une evaluation approchee de la stabilite sera obtenue grace aux operations approchees. Pour finir, un cas d'etude est presente en tant qu'exemple de l'application pratique de cet aspect evaluatoire.


Die Verworrenheit bezueglich der Bewertung der Stabilitaet von Grubenbau Aktivitaeten unter Tage wird generell aIs unausweichlich betrachtet. In diesem Aufsatz wird ein Bewertungsversuch fuer diese Stabilitaet im Hinblick auf mathematische sowie gebirgsmechanische Theorien entwickelt. Hierbei wird die Stabilitaet in fuenf Kategorien aufgeteilt die zusammen als komplexe Einheit zur Bewertung betrachtet werden. Jede dieser fuenf Kategorien wird durch ihr eigene, komplizierte Funktionen berechnet. Anschliessend erhaelt man mit Hilfe einer Methode eine Bewertung der Stabilitaet. Diesem Aufsatz ist eine Fallstudie aIs Beispiel fuer eine praktische Anwendung angeschlossen.


The stability of underground excavations critically influences their safety and functional serviceability so the stability of underground excavations has been on of issues which we are deeply concerned about in mining and other rock engineering. Because there are many factors affecting the stability of the excavations, such as in situ stress, rock mass structure, excavating method, depth, rock and rock mass quality, it is usually difficult to evaluate the stability of underground excavations synthetically and quantitatively. With the advent of the systems of rock mass classifications (e.g. Bieniawski 1973; Barton et al., 1974) and their applications in rock engineering, significant progress has been made in the assessment of stability of underground excavations (Mathews, 1981; Bieniawski, 1983, 1984, 1989; Laubscher, 1984; Afrouz, 1992). There is therefore a technique for evaluating the stability of excavations taking into account the diversification of factors affecting the stability, the variation of engineering circumstances encountered in excavating, and the limitation of measurement methods and investigation used for characterizing rock and rock mass. However, the ratings for parameter values in the evaluation of the stability of excavations in most evaluation approaches is generally a fixed numerical score. Thus, subjectivity, inexactness and indefiniteness will often exist in the evaluation.

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