The rock mass properties such as deformability and permeability are highly dependent on the existence of cracks. The Ratio of Crack Opening Dependency (RCOD) was proposed as a new index to evaluate the deformability of infinite jointed rock mass. The RCOD is defined as the ratio of total amount of crack opening and the total deformation of jointed rock mass. The theoretical relation between the RCOD and the effective compliance of jointed rock mass is discussed and confirmed through two-dimensional numerical analysis by the SC-DDM, together with the applicability to the rock engineering.
Les proprietes de masse rocheuse telles que la deformabilite et la permeabilite sont très dependantes de l'existence de fissures. Le rapport de dependance d'ouverture des fissures a ete propose comme un nouvel index d'evaluation de la deformabilite de masse rocheuse à assemblage infini. Le rapport de dependance d'ouverture des fissures est defini comme etant le pourcentage de quantite totale d'ouverture des fissures et de deformation totale de la masse rocheuse assemblee. Le rapport theorique entre le rapport de dependance d'ouverture des fissures et la compliance efficace de masse rocheuse assemblee sont traites et confirmes au travers d'une analyse numerique à deux dimensions par SC-DDM en même temps que l'applicabilite à l'ingenierie des roches.
Die Felsmasseneigenschaften wie Verformbarkeit und Durchlassigkeit sind hochgradig abhangig von dem Vorhandensein von Rissen. Das Verhaltnis der Riss-Öffnungsabhangigkeit (RCOD) wurde als neuer Index der Verformbargkeit von infinit zerkluefteter Felsmasse vorgeschlagen. Der RCOD wird als Verhaltnis der Gesamtmenge der Rissöffnungen und der Gesamtverformung der zerkluefteten Felsmasse definiert. Die theoretische Beziehung zwischen RCOD und der effektiven Verformbarkeit von zerkluefteter Felsmasse wird diskutiert und durch zweidimensionale numerische Analyse mit SC-DDM bestatigt, zusammen mit der Anwendbarkeit auf Bergbautechnik.
The rock mass properties such as deformability and permeability are highly dependent on the existence of cracks. Especially, open cracks give crucial effects to these factors and the evaluation of open cracks is inevitable for the assessment of whole rock mass stability. Various kinds of rock mass evaluation methods, such as RMR method (Bieniawski, 1979), Q-system method (Barton et al., 1974) and Acoustic Emission (AE) method (Ishida et al., 1992), have been introduced and widely used. These methods are mainly based on the experiences and more theoretical consideration is required for the precise quantification of rock mass. On the other hand, theoretical analyses of the deformability and the elastic modulus of the cracked materials have been also conducted (Eshelby, 1920, Walsh, 1974, Oda et al., 1990, Hirakawa et al. 2001). It is, difficult to expand those methods to the in-situ rock mass evaluation, since the determination of parameters used for the analysis is almost impossible.
In this study, the Ratio of Crack Opening Dependency (RCOD) is proposed as a new index to evaluate the mechanical property of cracked structure. The RCOD is an index which is defined as the ratio of total amount of crack opening and the total deformation of cracked structure, and it is theoretically derived that the RCOD directly indicates the deformability of the cracked structure.
