Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Design of Underground Caverns For Tehri Hydropower Project, India By Numerical Modelling
Dasgupta, B. (Advanced Technology and Engineering Services) | Sharma, M.K.V. (AGM (D), Tehri Hydro Power Corporation) | Verma, M. (Advanced Technology and Engineering Services) | Sharma, V.M. (Advanced Technology and Engineering Services)
ABSTRACT: This paper describes the methodology of the design of large underground caverns in the Himalayan region of India. The design process involved continuous evaluation of rock parameters, detailed 2D and 3D numerical modeling and monitoring program. Hoek and Brown (1997).failure criterion was used to estimate the rock mass strength parameters for the model analysis and the model results validated with the field measurements. RÉSUMÉ: Cette communication-decrit la methodologie de la conception des grandes cavernes souterraines dans la region himalayenne de l'Inde. Le processus de conception implique l'evaluation continue des parametres de rochers, Ie modelage numerique à deux et trois dimensions et le programme de contrôle, Le critere d'echec de Hoek et Brown (1997) a ete utilise pour estimer les parametres de force de la masse de rochers pour l'analyse du modeleet les resultats du modele qui sont valides avec les mesures sur le terrain. ZUSAMMENFASSUNG: Diese Papier beschreibt die Methodenlehre des Musters von große Untergrundhöhlen in der Region des Himalayas, Indien. Die Zeichnungsprozeß verwickelte fortdauernde Abschatzung der Felsenparametern., ausfuehrliche 2D und 3D Zahlenmodelierung und Warnzeichenprogramm. Hoek und Brown (1997) Fehlenkennzeichen waren benutzt urn die Felsenkraftparameter fuer die analyse zu bewerten, und die Modelergebnisse bestatigen mit die Feldmessen. INTRODUCTION The Tehri Hydro Power Project is under construction at Tehri, U.P, India by J'ehri Hydro Power Corporation (THDC). The first stage of the project, planned to generate 1000 MW, includes a 260m high earth and rockfill dam across the river Bhagirathi downstream of Tehri town and underground powerhouse complex on the left abutment hill of the dam. Numerical modeling coupled with instrumentation was the basis for design of the excavations. Combination of two- and three-dimensional modeling was ‘used’ for effective and optimized support design, FLAC, (Itasca, 1995a) was used for 2D analysis for design of pattern support system. Shear zones and major shear planes were modeled in 3D discontinuum analysis with 3DEC (Itasca, 1995b). Instrumentation scheme was planned and implemented to calibrate the model. This paper demonstrates the role of advanced numerical modeling technique in the analysis and design of the caverns. POWER HOUSE COMPLEX The powerhouse complex consists of two main parallel caverns namely the Machine Hall (MH) and the Transformer Hall (TH) located about 370m below the surface. The MH cavern is 188m long, 22m wide and 47m high. There are four turbine pits 16m deep on the floor of the machine hall. The TH cavern is 161m long, 18.5m wide and 36m high located upstream of the MH with a 41.75m rock pillar between them. In addition there are other excavation such as pressure tunnels, draft tubes, bus duct tunnels and adits joining the main caverns and drainage galleries. The Tehri hydropower project is located in the Lesser Himalayas. The rock formation 10 the power house area is mainly massive to thinly bedded Phyllitic Quartzite with caverns oriented perpendicular to foliation strike direction. There are four major joint sets and several shear planes with varying thickness (Navani, 1996).
- Asia > India > NCT (0.16)
- North America > United States > Minnesota (0.15)
ABSTRACT: The stability analysis of the multiple chambers for desilting of river water in 1500 MW Nathpa Jhakri Hydroelectric project is described in this paper. Two-dimensional numerical modeling was used for analyzing the chambers during the construction stage and during the operating stage when the rock mass gets saturated and the-chambers are regularly emptied and filled. The modeling involved stress analysis, seepage analysis and support interaction analysis for support and liner design with the rock mass strength estimated from Hoek and Brown (1997) failure criterion. RÉSUMÉ: L'analyse de la stabilite des multiples bassins pour Ie desenvasement de l'eau fluviale dans Ie cadre du Projet hydroelectrique de 1500 MW Nathpa Jhakri est decrite dans cette communication. Le modelage numerique à deux dimensions a ete utilise pour analyser les bassins à l'etape de construction et d'exploitation quand la masse de rochers se sature et les bassins sont vides et remplis regulierement: Le modelage implique l'analyse de resestance, l'analyse de suintement et l'analyse d'interaction de support pour la conception du support et du revêtement avec la masse de rochers etant estimee par Ie critere d'echec de Hoek et Brown (1997). ZUSAMMENFASSUNG: Die Festigkeitsanalyse des vielfach Kammers, fuer die Vertreibsandung der Fluessewasser im 1500MW Nathpa Jhakri Hydroelektrik projekt wurde in diese Papier beschrieben. Zwei dimensional Zahlenmodelieren waren benutzt fuer die Analysierung des Kammers wahrend die Autbaustelle, und wahrend die Betiebsstufe wann die Felsenmasse durchgenaßt ist und die Kammern regemaßig ausgeleert und eingefuellt. sind. Die Modelierung verwickelte Belastungsanalyse, Sickerwasseranalyse und Stuetzewechselwirkunganalyse fuer Stuetze und Futtermuster mit die Felsenmassekraft von Hoek und Brown (1997) Fehlenkennzeichen bewertet. INTRODUCTION An underground complex for desilting of water is under construction for the Nathpa Jhakri Power Corporation in Himachal Pradesh, India. A discharge of 405 cumecs will be diverted from the river Sutlej by a 60.5m high concrete dam to the headrace tunnel through the desilting chambers. The water will flow through four parallel desilting chambers at a low velocity to remove a large percentage of fine sediments coming with the river water. The analysis and design of support and liner for desilting chambers required special consideration during construction and during operating condition when the rock mass will be saturated after impounding of the reservoir. This paper demonstrates the role the numerical modeling played in ensuring the stability of the chambers, and design of the support system and the liner. DESILTING COMPLEX The desilting complex. consists. of four parallel caverns. Each chamber is 525m long, 16.31m wide and 27.5m high. The chambers are egged shaped with semi-circular roofs, curved walls and hopper shaped bottoms, At the bottom of the hopper there is 3m wide settling trench. The minimum width of rock pi1larsbetween the chambers is 29m. The rock cover varies from 300 to 500m along the length of the cavern. The rock in the area is predominantly massive Augen Gneiss and Gneiss with minor bands of Biotite Schist In this rock mass there are five major joint sets and shear seams of varying thickness.
- Geology > Geological Subdiscipline > Geomechanics (0.72)
- Geology > Rock Type > Metamorphic Rock > Gneiss (0.45)
- Energy > Renewable > Hydroelectric (0.61)
- Energy > Power Industry > Utilities (0.61)