The problem of siting the underground powerhouses in the environment which is most favourable ''for Construction and operation of the powerhouse necessitates maintaining stability of large-size caverns. Excavation of such caverns in the mountain regions which are still tectonically active and are characterized by high seismisity sets some special requirements for the minuteness of investigations in elements of engineering geology and their Consideration in locating of the underground works, configuration and orientation of the caverns. In the USSR, like detailed investigations are carried out for all proposed hydrodevelopments with underground powerhouses and deep-set water-conveying tunnel systems. The paper deals with some results of investigations of the above factors and their accounting in design of the Rogun project on the Vakhsh River whose power house cavern is proposed to be 28 m wide, 68 m high and 200 m long.
Das Problem der bau-und betriebsguenstigen Lage von Maschinenkavernen fuer Wasserkraftwerke steht im Zusammenhang mit der dauerhaften Standsicherheit von Hohlraumen grosser Abmessungen. Der Bau derartiger Hohlraume in Gebirgsgebieten, die durch rezente tektonische Aktivitaten und starke Erdbebenwirkung gekennzeichnet sind, erfordert die umfassende Erfor- Schung von mehreren ingenieur-geologischen Einfluessen und deren Beruecksichtigung bei der Auswahl des Standortes, der Querschnittsform und Raumstellung dieser unterirdischen Hohlraume. In der USSR werden derartige Untersuchungen fuer all zu projektierenden Wasserkraftanlagen mit Maschinenkavernen und tiefliegenden Umleitungsstollen durchgefuehrt. 1m Bericht werden einige Untersuchungsergebnisse und deren Ausnutzung fuer die Projektierung der Wasserkraftanlage Rogun am Wachsch mit der Maschinenkaverne von 28 × 68 × 200 m beschrieben.
L''implantation des centrales hydroelectriques souterraines dans les conditions les plus favorables pour leur construction et exploitation exige la stabilite de longue duree des cavernes de grandes dimensions. La creation de telles cavernes dans les regions montagneuses, qui se caracterisent par une activite tectonique recente et par une sismicite elevee, impose des exigences particulieres a l''etude detaillee de divers facteurs geologiques et à leur consideration pendant le choix des emplacements des ouvrages souterrains, de la forme de leur section et de leur orientation dans l''espace. En URSS, les etudes de ce genre s''etfectuent pour tous les amenagements hydrauliques projetes avec les centrales en caverne ou les derivations en souterrain de grande profondeur. Dans le rapport sont examines certains resultats d''etude des facteurs indiques et leur consideration pendant l''elaboration du prQjet de l''amenagement hydraulique de Rogoune sur le Vakch dont la caverne puur la salle des machines a une largeur de 28m, une hauteur de 68 met, une longueur de 200m.
Construction of underground structures having large sections and which are to be constructed in mountainous regions characterized with great seismicity, modern tectonic movements at fructures and with availability of great natural stresses, has on the one hand to meet the particular engineering and geological requirements when substantiating the design, and on the other hand to take into account all peculiarities and abilities of the rock mass when designing. In this sense the Rogoun hydroelectric station is extremely demonstrative; the construction of this station has been started some years ago on the Vakhsh river in Tajikistan, USSR.
The project consists of the following structures: a rock and earth dam 320 m high, a water intake structure, inlet tunnels, an underground power house which is located in upstream at a depth of 420m from the surface of the ground, and the outlet tunnels. The power house has a two-room layout: the machine room of the power house and the premises for transformers are located in parallels and have the following size: they are 28 m wide, 68 m hd.gh, and 200 m long.
From geological point of view the Rogoun project area is located within the zone of a joint of the two largest structural-facial regions of Middle Asia - south-west Tien Shan and east Pamirs - and it is characterized with highly active modern tectonic movements.
