Taking up Shirahama sandstone, Shirakawa welded tuff, and Tage tuff as specimens for the experiment, the permeability coeffieient was obtained in accordance with the transient pulse test and falling head test. The ratio of the permeability ranged between 0.7 and 1.4, which implies that the values obtained by both the experimental tests are, judging from a viewpoint of practicality, almost in coincidence with each other. To examine the difference between both the experimental tests, an exact solution was introduced from the general one-dimensional diffusion equation with respect to the individual tests. After that, numerical simulation was made with the transient variations of hydraulic head and transient distributions of hydraulic gradient in the process of the permeability experiment. As a result, it is explained that the hydraulic head distribution or dynamic hydraulic gradient assumes a considerably complicated aspect: In evaluating the permeability of rock, special attention should be paid to the hydraulic head: hydraulic gradient, and the three dimensional storage coefficient of the specimen.
Sur des specimens de gres Shirahama, de tufs soudes Shirakawa et de tufs Tage pour l'experience, le coefficient de permeabilite a ete obtenu conformernent à la methode d'impulsion transitoire et la methode à charge variable. Le taux de ladite permeabilite varie entre 0.7 et -1.4, ce qui implique que les valeurs obtenues par les deux methodes experirnentales coincident quasiment, à en juger du point de vue de la faisabilite. Pour examiner la difference entre les deux methodes experimentales, une solution stricte a ete introduite à partir de l'equation de diffusion à une dimensionnelle ordinaire par rapport à ces methodes individuelles. Ensuite, une simulation numerique a ete faite pour les variations transitoires de charge hydraulique et les repartitions transitoires de pente de ligne piezometrique dans le processus de l'experience de permeabilite. Comme resultat, iI est explique que la distribution de la charge hydraulique ou la pente de ligne piezometrique a un aspect tres complexe. Pour l'evaluation du coefficient de permeabilite des roches, une attention perticuliere doit être donnee à la charge hydraulique, à la pente de ligne piezometrique et au volume d'accumulation specifique etc. du specimen.
Mit Shirahama-Sandstein, Shirakawa-Schmelztuff und Tage-Tuff als Proben wurde nach dem Impulsverfahren und dem Falldruckverfahren der Durchlassigkeitskoefflzient erhalten. Das Verhaltnis der Durchlasigkeit innerhalb von 0.7 bis -1.4 zeigt, daß die aus den beiden Verfahren erhaltenen Werte praktisch gleich sind.Zur Untersuchung der Unterschiede der beiden Versuchsverfahren wurde eine strikte Lösung aus der allgemeinen Gleichung fuer eindimensionale Diffusion unter Beruecksichtigung der individuellen Verfuehren eingefuehrt, Anschließend erfolgte eine numerische Simulation mit Schwingvariationen der Druckhöhe und Schwingverteilungen des Druckgefalles wahrend des Durchlassigkeitsversuchs.Als Folge ergibt sich, daß die Druckhöhenvertei-lung oder das dynamische Druckgefalle einen stark komplizierten Aspekt ausmacht. Bei der Bewertung des Durchlassigkeitskoef-fizienten von Felsgestein sollte deshalb besonderes Augenmerk der Druckhöhe, dem Druckgefalle, der spezifischen Lagerung usw. der Proben gelten.
The permeability measurement of core size specimen is very important in understanding and estimating on underground hydraulic environments of various fields, for example, oil recovery, geothermal energy, radioactive waste repository, dam foundation, tunnel, and so on. In general, the falling head test and constant head test are used to obtain the permeability of the specimen for the reason that- both measurements are convenient. However these methods have accurate restriction on measure- ment range between 10−2cm/sec to about 10−7cm/sec. The measurement of rather smaller permeability below 10−7 cm/sec is necessary to adopt the transient pulse test or the flow pump test, in which the permeability is calculated from the measured hydraulic gradient and flow rate through the specimen. Brace et al. (1968) introduced the transient pulse test to measure the very low permeability of granitic rock specimen. Their analysis assumes that there is no compressive storage in the rock specimen, and the permeability is simply calculated from the observed pressure decay in the upstream reservoir. In most cases, the falling head and transient pulse tests are, practically used to measure only the rock permeability. To examine the difference between the falling head test and the transient pulse test.
