The slide rock mass on the right bank of Chichkhan river (Armenia) of about 6·106 m3 in volume is described in this paper in connection with the Getik reservoir design. The results of geological explorations in the area near the rock mass are given; various factors influencing its stability are analysed, and efficiency of some antislide measures is valued. The December 1988 earthquake in Armenia influence on the slide is estimated.
Dans cet article, on fait l"examen d"un massif d"eboulement rocheux situe à la rive droite de la rivière Tchitchkhan (en Armenie) d"un volume de 6 millions de m3 environ en rapport avec l"etude du projetde la retenue Guetiksky. On y trouvera les resultats des reconnaissances du sol dans la region du massif, l"analyse de l"influence des differents facteurs sur sa stabilite, l"evaluation de l"efficacite de certaines mesures d"antiglissement. L"article contient la description de l"effet du tremblement de terre qui a eu lieu en Armenie au mois de decembre 1988, sur le glissement.
ZUSAMMENFASSUNG: Im Beitrag wird das Rutschungs-Felsmassiv am rechten Ufer des Tschitschchan (Armenien) mit einem Volumen von ca. 6 Mio m3 anlaBlich der Projektierung des Getik-Stausees analysiert. Angefuhrt werden die Ergebnisse der ingenieur-geologischen Untersuchungen im Raum des Massivs, analysiert wird der EinfluB verschiedener Faktoren auf des sen Stabilitat, eingeschatzt wird die Effektivitat einiger rutschverhindernder MaBnahmen. Beschrieben wird der EinfluB des Erdbebens auf die Rutschung, das im Dezember 1988 in Armenien stattfand.
In the late 1970 and early 1980-th specialists of the Armhydroprojekt (design institute) in Armenia worked over a design of the Getik reservoir on the Chichkhan river. In accordance with the design a 60 m high earth dam with reservoir capacity of about 30°106 m3 was planned. One of the serious problems to be taken into account during designing was stability evaluation of the large slide mass located on the right bank of the river, 400 m upper dam location.
The designers feared possible negative influence. of the reservoir on sliding processes (as a result of additional moistening of the slip surface), as well as could-be seismic phenomena in this area. A seismic level for bedrock was estimated to be 7 points and 8 points intensity for loose alluvial sedimentations.
Quick move of the mass into reservoir could provoke an overflow wave over the dam and its damage, and this would stipulate serious consequences in the downstream.
This paper deals with the results of geological explorations of the slide, analysis of various factor infuence on its stability and evaluation of the efficiency of some anti-slide measures.
The area concerned relates to a tectonically active territory with a comparatively contrasting regime of modern vertical movements.
A river valley on the slide sector has a latitude direction, slope steepness is small.
The rock mass where the slide formed consists of tuffits, ash tufs and tuff stones. Rocks monoclinally lay, with north-west descending under 18–22°. At their output to the surface the rocks easily, stratificate and come apart.
