December 10, 2011 : HCC's Pare Hydroelectric Project team achieved a major breakthrough when they successfully completed the daylighting of their diversion tunnel on December 10, 2011.
Our engineers had commenced work on the project from August 31, 2009 in accordance with the Letter of Intent (LOI) received from the North Eastern Electric Power Corporation (NEEPCO). The project scope included construction of a diversion tunnel of length 281.7 m, having a finished diameter of 8 m.
As part of the civil works, underground excavation of the diversion tunnel was carried out initially from the outlet end, and subsequently from the inlet end. The rock strata belonged to the sandstone type and the rock was in Class-IV/Class-V. The tunnel excavation was carried out using a by Drill & Blast method, and the underground excavation of the heading portion was completed with a rib support system.
During the construction phase, the Pare HEP team had to overcome many a challenge. These included factors such as late issuance of excavation and slope protection drawings and also frequent revision in construction drawings from the client. The construction activity was also impacted by the monsoon season. In fact, the tunnel excavation had to be halted between July 13 - October 20, 2011, as the tunnel was filled with slush and rainwater after very heavy rainfall. In addition, there were stoppages due to bandhs and other local issues.
Despite all these challenging scenarios and the constant race against time, the project team remained steadfast in their focus and committed efforts. On December 10, 2011, the Pare HEP team successfully completed the 'final breakthrough' of the diversion tunnel heading at a co-ordinate of 273 m length. This success required significant logistical planning, a huge fleet of equipment and the efficient establishment of work cycle timings.
Congratulations to the Pare HEP team for this truly admirable engineering accomplishment.
The jubilant Pare HEP team joins in the celebration after completion of the tunnel daylighting.