The pumped storage plant Estangento Sallente, which at present is under construction, is located in the Pyrenees in the province of Cataluna in Spain. The main structure is the 20 m wide, 38 m high and 90 m long powerhouse cavern, which is located in schist. The overburden amounts to 100 m. An extensive exploration and a rock mechanical testing program as well as stability analyses using the Finite Element Method have been carried out. The selected support of the vault consists of reinforced shotcrete and bolting and additional prestressed anchors in places. Parallel to the excavation of the vault an extensive monitoring program was performed. A result of the geological mapping of the vault is the unexpected local occurrence of discontinuities running parallel to the cavern axis and revealing additional stability analyses of the cavern walls.
La centrale de pompage Estangento Sallente, actuellement en construction, est situee dans les Pyrenees, dans la province de Catalogne, en Espagne. La caverne de l'usine souterraine est la structure principale et a une largeur de 20 m, une hauteur d'environ 38 met une longueur d'environ 90 m. Elle se trouve dans des schistes cristallins et a un-terrain de recouvrement d'une epaisseur d'environ 100 m. Un important programme d'investigations a ete execute pour la reconnaissance des lieux des points de vue de la geologie et de la mecanique des roches. La stabilite de la cavite a ete realisee au moyen de la methode des elements finis et a conduit au blindage de la calotte à l'aide de beton arme projete et de boulons d'ancrage. De plus, des tirants precontraints ont ete prevus localement. Pour le contrôle de stabilite, des mesures des deformations, des contraintes et des forces d'ancrage ont ete prises parallèlement au creusement de la calotte. La cartographie geologique de la surface excavee montre l'apparition locale inattendue de surfaces de discontinuite se: developpant parallèlement à l'axe de la caverne. Pour cette raison des analyses de stabilite complementaires des murs de la caverne se sont averees necessaries.
Das im Bau befindliche Pumpspeicherwerk Estangento Sallente liegt in der spanischen Provinz Catalunien in den pyrenaen. Das Hauptbauwerk is. die 20 m breite, 38 m hohe und 90 m lange Maschinenkaverne, die in kristallinen Schiefern liegt und eine Überdeckung von 100 m besitzt. Zur Erkundung der geologischen und felsmechanischen Verhaltnisse wurde ein umfangreiches Untersuchungsprogranm durchgefuehrt. Die Standsicherheit des Hohlraums wurde nach der Methode der Finiten Elemente untersucht und fuehrte zu einer Sicherung der Kalotte mittels armiertem Spritzbeton und Felsnageln. Örtlich wurden zusatzlich Vorspannanker vorgesehen. Parallel zum Ausbruch der Kalotte wurden Verformungs-, Spannungs- und Ankerkraftmessungen zur Überwachung der Standsicherheit durchgefuehrt. Die geologische Kartierung der Ausbruchlaibung ergab, daß örtlich Trennflachen auftreten, die parallel zur Kavernenachse streichen und vorher nicht erwartet worden waren. Aus diesem. Grunde wurden erganzende Standsicherheitsuntersuchungen der Kavernenwande notwendig.
The underground powerhouse of the Pumped Storage Plant Estangento Sallente in the Pyrenees in Spain is still under construction. In the following paper after a brief description of the project the results of the geological and rock mechanical exploration are presented. Also the measurements of the displacements, the stresses in the shotcrete and the prestressing loads of the anchors, which were performed during excavation of the vault are outlined in the paper. The detailed geological mapping performed during the excavation of the vault have led to the necessity of a modification of the assumptions adopted during the design phase and consequently revealed additional stability analyses of the cavern walls, which are also briefly described. The authors like to acknowledge the support of the Managing Direction of Fuerzas Electrica de Cataluna given towards the publication of this paper. In particular we would like to thank Dr. Riverola and Dr. Veiga for their particular interest in this publication. We also wish to thank all the engineers on the site for their cooperation.
The pumped storage plant Estangento Sallente, which is located in the Pyrenees in the Province of Cataluna in Spain, is equipped with four units with a total capacity of 415 MW (Fig. 1). The upper reservoir is the natural lake Estangento with a capacity of 3 hm3 (Fig.2–5). This lake is connected with a series of other natural lakes, by transmission tunnels. The lower reservoir of 5.4 hm3 capacity is created by a rock fill dam with an asphalt concrete membrane on the upstream face. The height of this dam which was designed by INYSA, Consulting Engineers, Madrid, is 50 m and the length of the crest is 350 m. The head between the upper and lower reservoirs is approximately 400 m. The two pressure shafts with an internal diameter of 3.50 m are steel lined and inclined at 51g. The discharge capacity amounts to 125 m3/s. The excavation is performed by a tunnel boring machine (Fig. 3- 5).
