Design aspects of the Dam

Under the Stage-I of Tehri Hydro Electric Project, a 260.5 m high Earth and Rock-fill dam has been constructed on river Bhagirathi in district Tehri Garhwal of Uttarakhand. The project area is in high seismic zone and falls in Zone-IV of the seismic zoning map of India. In such complex environment, a rockfill dam with slightly inclined clay core has been designed by utilizing locally available fill materials, with little or no processing. Design of the dam has been finalized by involving internationally renowned expert Institutes in the field viz. HPI, Moscow and DEQ, IIT, Roorkee. Geometry of the dam core has been optimized by carrying out detailed stress-strain analysis. Extensive surface as well as sub-surface treatment of the core seat foundation i.e. grouting has been done for improving its properties. For monitoring the health of the dam during construction and operation period, a large number of instruments have been installed within the body of dam and its foundation. One of the unique features of this dam is the provision of inspection galleries within the core of the dam through which physical inspection and monitoring of the dam behaviour is possible during the operation period of the project.