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SUMMARY: The problem of designing and construction of water tunnels and pressure shafts of large diameters under high internal pressures is encountered more and more in contemporary water power engineering. The paper presents results of investigations concerning the following problems of coaction of steel sheet lining, concrete and rock mass, for cases of steel lining application: methodology of the rock mass investigations, general theoretical aspects of the rock mass - lining coaction, statical analyses of the "steel sheet - concrete - rock mass" system, trial testing of adopted solutions and observation of ready - made linings. Conclusions of interest to practice were drawn, with the basic attitude that under given conditions, solutions nay be implemented involving full Coaction of the rock mass in accepting internal water pressures. ZUSAMMENFASSUNG: Im zeitgemassen hydroenergetischen Bauwesen wird das Problem der Projektierung und des Ausbaus von Druckstollen und Druckschachten mit grossen Durchmessern und grossen Innendruecken immer deutlicher. 1m Bericht werden Ergebnisse der Zusammenwirkung der Felsnasse, des Betons und des Stahlpanzerung behandelt, und zwar fuer Falle, bei denen eine Anwendung des Stahlauskleidung in Frage komnt: Methodologie der Erforschung der Felsnasse, algemeiner theoretischer Aspekt der Zusammenwirkung zwischen der Auskleidung und der Felsnasse, statische Analyse des Systems "Stahe - Beton - Felsnasse", Pruefung der angenomenen Lösungen, sowie die Beobachtung der ausgefuehrten Auskleidungen. Es werden fuer die Praxis interessante Schlussfolgerungen gezogen, deren Grungstellungnahme darin besteht, das man, unter gewissen Bedingungen, Lösungen anwenden kann, bei denen auf volle Zusammenwirkung der Felsnasse bei der Aufnahme der Innendruecke gerechnet wird. RÉSUMÉ: Dans l''utilisation actuelle des forces hydrauliques se pose de plus, en plus le probleme du projet et de la construction des galeries et des puits de grands diametres et soumis a de grandes charges internes. Dans le travail on montre les resultats des recherches des questions suivantes se rapportant a l''interaction de la tole, du beton et de la roche dans les cas de consideration de l''application du revetement en acier et cela comme suit: methodologie des essais de la nasse rocheuse, aspect theorique general de l''interaction du revetement et de la roche, le calcul statique du systeme "tole - beton - masse rocheuse", essais des solutions adoptees et auscultation des revetements en exploitation. On tire des conclusions d''interet pour la pratique avec une attitude generale que, sous quelques conditions, on peut adopter les solutions dans les quelles on compte sur une pleine interaction de la nasse rocheusse dans l''action des charges internes. INTRODUCTION This paper presents results and conclusions drawn from and extensive study entitled "Load-sharing by Rock Mass, Concrete and Steel in Pressure Tunnels and Shafts of Pumped Storage Plants" carried out by the Structural and Geotechnical Engineering Department of the Jaroslav Cerni Institute of Water Resources Engineering, for the Corporate Electricity Company of Belgrade. The authors were B. Kujundzic (study director), Z. Radosavljevic, K. Ivanovic, O. Markovic, Z. Nikolic, M. Manojlovic and Lj. Petrovic. This condensed review presents the overall philosophy development, design concepts, the rock mass investigations necessary and modes of presentation of the results, a general discussion of the coaction of lining and rock mass, stress analysis of the steel-concrete-rock mass system, pilot tests of the lining during design and construction, testing and observation of the finished lining, and a final summing up. GENERAL Constantly accelerating economic growth demands ever more electricity and hence ever greater investment in power systems. Load peaks are a crucial problem whose solution may be sought either in trying to discourage peak consumption by making it more expensive than off-peak electricity, or by rendering the system capable of handling load peaks. This latter solution usually means building hydroelectric plants, and lately especially pumped storage plants, as standby or backup sources. However, as the ratings of thermal and nuclear plants go higher and higher to meet the ever increasing power demands, so the chances of a large-scale dropout become greater.
- Energy > Power Industry (0.74)
- Energy > Oil & Gas > Upstream (0.46)
SUMMARY: The type of lining chosen for this plant (now under construction) was non-reinforced concrete with pressure grouting. The tunnel is driven by a Robbin''s mole, Pressure grouting has the following aims: to prestress the lining and the rock mass, to reduce heterogeneity and anisotropy effects of the rock mass, and to decrease its permeability. The paper presents the following: data on the tunnel, stress analysis of the lining-rock mass system, the design concept with prestressing by pressure grouting, the methods used for rock mass investigation and testing the lining on pilot stretches, an overview of the results. The conclusions arrived at are generally applicable to pressure tunnels; in particular, an analytical-experimentaldesign methodology for tunnels with pressure grouting is formulated. ZUSAMMENFASSUNG: Als Lösung zur Sicherung der Undurchlassigkeit und Stabilitat der Druckstollen eines Purnpspeicherwerkes (in Ausbau) wurde eine vorgespannte Auskleidung angenorrrnen. Der Ashub erfolgt mit einer Maschine Typ "Robbins". Der Zweck der Spannungsinjektierung besteht lin folgenden: Vorspannung der Tunnelauskleidung und der Felsmasse, Verminderung des Einflusses der Nichthomogenitat und der Anisotropie der Felsmasse, sowie Verminderung deren Wasserdurchchlassigkeit. In der Arbeit sind die Daten ueber dem Tunnel gegeben, Spannungsfeld im System "Belag - Felsmasse" analisiert, Konzeption der technischen Lösung mit Vorspannung mittels Spannungsinjektierung dargestellt, die angenwandten Methoden der Erforschung der Felsmasse und der Untersuchung der Betonauskleidung auf speziellen Versuchsstrecken beschrieben, sowie eine zusammenfassende Übersicht der erhaltenen Ergebnisse gegeben. Die erhaltenen Schlussfolgerungen haben fuer Druckstollen eine allgemeine Gueltigkeit. Insbesondere wurde eine analytisch - experimentelle Methode der Projektierung solcher Tunnele formuliert, wenn die Spannungsinjektierung angenwandt wird. RESUME: Comme solution d''impenreabilitie et de la stabilite d''une galerie en charge d''une centrale hydraulique de pompage (en construction) on a adopte un revetement en beton non anme avec des injections de precontrainte, L'' exavation est faiite avec une machine du type Robbins. Le but des injections de precontraintes en est: la precontrintes du revêtement et de la roche, diminuer l''influence d''heterogeneite et d''anisotropie de la masse rocheusse ainsi que diminuer la permeabilite On presante des donnees sur la galerie, on analyse I''etat des contraintes dans le systeme "revêtement- masse rocheusse", on fait voir la conseption de la solution technique avec la precontraintes par injection, on decrit les methods appliquees dans les essais de la masse rocheusse et du revêtement en beton sur des secteurs d''essais et on donne une revue sommaire des resultats obtenus. Les conclusions ont un caractere generale pour les galeries en charges; avec un apercu particulier sur la formule de la methode analytico - experimentale de projet des galeries avec l''application des injections de precontrainte. INTRODUCTION The basic tasks of design and design investigation for the pressure tunnel were:to determine the nature and scope of geotechnical investigations which must be carried out before and during construction to determine lining dimensions and pressure grouting parameters to determine the nature and scope of tests to verify the effects of pressure grouting. The analyses which enabled the final design choice and laid the groundwork for solving the problems encountered, as presented in this paper, and which in particular enabled the formulation and application of an analytical-experimental methodology for solving the problems associated with this kind of lining, are the result of team work involving staff of the Department of Structural and Geotechnical Engineering of the Jaroslav Cerni Institute and of Energoprojekt. DATA ON THE TUNNEL Both from the constructional and the operational aspect the two-way tunnel is the most important feature of a pumped storage plant. The length of the tunnel is 8 km, 5.6 km through Triassic limestone, and 2.4 km through marl and marly limestone. It is of circular cross-section, with an excavated diameter of 7.0 m, an insided diameter of 6.3 m and a lining thickness of 35 cm. The maximum internal hydrostatic pressure ranges from 8.0 bar at the intake to 11.0 m at the surge tank. The hydrodynamic maximum at the surge tank is 2.5 bar, so that the maximum total pressure ranges from 8.0 to 13.5 bar. The "coefficiant of boldness", 2a.pu'' is 6.3 × 135 = 850. The tunnel is excavated by a Robbins mole. Immediately behind the advancing mole prefabricated reinforced concrete footwall elements are laid, to provide a bed for the central track for transporting excavated material and the outer tracks for cranes and lining concreting and grouting gear. In the center of the footwall is a drainage duct. The length of the prefabricated elements is about 1/4 of the tunnel circumference and their thickness 35 cm like the rest of the lining which is subsequently cast in situ (Fig.. 3).
- Geology > Structural Geology > Fault (0.54)
- Geology > Rock Type > Sedimentary Rock > Carbonate Rock > Limestone (0.45)