Tehri Hydro Development Corporation Ltd.
Tehri spillway structures are unique & complex which have been adopted for the first time in its design and construction on reservoir project in India & Asian region as a whole. The maximum velocity at the heel of the spillway structures is about 45 m/sec. Adequate measures were implemented in the design of structures to ensure safeguard against the two most common and potential problems encountered for the safe operation of spillway structures from cavitation and abrasion erosion. The high performance concrete with micro silica of M-40 and M-60 grades were designed and provided in various components of Tehri Dam spillways to provide adequate abrasion resistance during the operation of the spillways. Further, protection against abrasion was also ensured through the 100% Elastomeric Polyurethane Spray Coating popularly known as ‘Polyurea’. This paper deals with the innovative techniques adopted during finalization of spillway layout, hydraulic model studies in evolving the efficient hydraulic design of spillway structures, energy dissipation measures adopted and the innovation done for guarding the structures against the cavitation and abrasion erosion. The experience during the design and construction of the shaft spillways at Tehri project has been technologically unique in respect of the protection measures for cavitation and abrasion.
