Inspection, Repair and Maintenance of Tunnels at Pong Dam Project-A Case Study Sharma Devendra Kr., Sharma S.K., Singh Tarlochan Bhakra Beas Management Board, Chandigarh Online published on 20 April, 2019. Abstract Bhakra Beas Management under Ministry of Power, Govt. of India is looking after three major projects of North India namely-Bhakra Nangal Dam Project, Pong Dam Project and Beas Sutlej Link Project having total installed capacity of 2918.73 MW. These projects are now 40 to 55 years old. Ageing of any project requires extensive maintenance. Bhakra Beas Management Board has ensured effi cient and trouble free running of these projects by maintaining high standards of operation and maintenance. Safety of these structures is of utmost importance for safeguarding large scale national economic interests. Unsafe structure defi nitely poses a grave danger to the human life as well as property in the downstream areas. Strict compliance of the provisions contained in Operation & Maintenance Manuals of Bhakra Beas Management Board Projects is being ensured. This paper focus on repair and maintenance of tunnels of Pong Dam (Beas Dam) located at village Pong in District Kangra of Himachal Pradesh across Beas River. Pong Dam an earth core-gravel shell dam, 132.60 m high from deepest foundation level, with a crest length of 1950 m is located about 40 km from Mukerian, a railway station on Delhi-Pathankot railway line. Width of the dam at the crest is 13.72 m and at the base is 610 m. For passing the fl oods, radial-gate-controlled chute spillway has been provided on the left abutment. The spillway caters for design fl ood of 33, 555 cubic meter per second peak discharge and has a maximum outfl ow of 12375 cubic meter per second. Five diversion tunnels each of 9.14 m diameter having aggregate length of 5017 m were constructed during construction stage. Two of these tunnels were converted into irrigation tunnels while the remaining three are being utilized as penstock tunnels. The pong power plant located at the downstream end of these penstock tunnels has generation capacity of 396 MW. Tunnels constitute a vital component of any hydroelectric or multipurpose project. To ensure continued smooth running of underground structures, their regular inspection, repair and maintenance is of prime importance. In the recent past, Bhakra Beas Management Board has undertaken inspection, repair and maintenance of three penstock tunnels from 18.04.2016 to 07.06.2016 and one of the irrigation tunnels out of two tunnels from 26.05.2017 to 15.06.2017, during low reservoir level. The repainting/repair in steel liner portion of three penstock tunnels in an area of about 3370 square meter was also carried out meticulously. Entry to these penstock tunnels was through a single manhole of about 1 meter diameter. Carrying out repairs in the overt portion of the penstock tunnels was challenging and risky as well. Concrete lined tunnel repair of an area of about 3120 square meter with epoxy mortar has been carried out. It was a challenging task and lot of diffi culties were encountered. These were handled effi ciently by the experienced project engineers and technical staff. This case study summarizes the experiences gained in maintenance task and completion of the work before schedule. Top |