A statistical reconsideration on the parameters for geomechanics classification of rock mass has been carried out to apply in the Japanese geological conditions.

Procedures to produce the parameters and a form of data base are discribed herein on the investigation of geomechanical rock conditions and tunnelling techniques.

A comparison of produced parameters and the results with the presented methods by WI CHAM G.E., BIENIAWSKI Z.P. and BARTON N. are being analized at present.

An analized example of parameter is shown in conjunction with the magnitude of tunnel deformation.


Eine statistische Neubetrachtung der Parameter fuer die geomechanische Klassifizierung von Gebirgskörpern wurde durchgefuehrt, um eine Anwendung fuer die geologischen Gegebenheiten in Japan zu ermöglichen.

Die Verfahren zur Erstellung der Parameter und zur Bildung einer oatenbank werden hierin im Zusammenhang mit der Untersuchung von geomechanischen Gesteinsverhaltnissen und Tunnelbautechniken beschrieben.

Ein Vergleich der ermittelten Parameter mit den Ergebnissen der Methoden von WICHAM G.E., BIENIAWSKI Z.P. und BARTON N. wird zur Zeit analysiert.

Ein analysiertes Beispiel fuer Parameter wird im Zusammenhang mit dem Ausmaß der Tunnelverformung gezeigt.


Un examen statistique des paramètres pour la classification geomecanique de la masse rocheuse a ete execute a nouveau pour application aux conditions geologiques japonaises.

Les procedes d'obtention des parametres ainsi que la forme de la base des donnees, sont decrits ici concernant les recherches des conditions de roche geomecanique et les techniques de percement de tunnels.

Une comparaison entre les parametres obtenus et les resultats suivant les methodes de WI CHAM G.E., BIENIAWSKI Z.P. et BARTON N., est actuellement en cours d''examen.

Un exemple de parametre est donne concurremment avec l''importance de la deformation du tunnel.


In recent years, much importance has been attached to new engineering classification of rock masses related to rock excavation such as tunnelling, stabilization of rock slopes, rock foundations, cavern excavation etc. as a method of assessment related to the works. As old examples of rock mass classification related to tunnelling works, there are some ideas proposed by Terzaghi (1946), Lauffer (1958) and Deer (1964). In Japan also, rock classifications made by respective authorities from their standpoint are being used. These are mainly utilized in the planning stage of the works and used as criteria to determine the method of excavation, support system, and thickness of lining suitable for the rock. Though quantitative arrangement such as seismic wave velocity, interval of cracks, core recovery rate etc. is made partially, the most part is assessed qualitatively and the data relating to the behaviour of rock masses after excavation are not provided. From about 1972, methods of assessment that analyse parameters controlling behaviour of rocks after tunnel excavation from past construction data and quantify it after weighting the factors have been developed in relation with the modern tunnelling techniques. As examples, there are t.hose developed by wickham and others (1972), Bieniawski (1973) and Barton and others (1974). These assessment techniques were applied to actual tunnel excavation by Houghton (1976) and Rutledge and others (1978) for verification and comparative studies were made by them. From the results of the above, some problems in application of above-mentioned classification were pointed out. These are summarized in this paper.

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