Himal Hydro is accustomed to difficult site conditions. We have adapted equipment and process to solve difficult logistics problems thereby enabling the timely completion of projects in remote and high altitude sites..
Himal Hydro undertook the construction of a lined channel with a gate structure for controlled discharge of water to lower the water level of Tsho Rolpa glacier lake to reduce the risk of GLOF (glacier lake out burst flood). Tsho Rolpa glacier lake is situated at an altitude of 4600 meters (15000 ft) from the mean see level. The site is reachable only after 7 days of trek.
Pipe Roofing with Boomers and Tubex 76 (Fore poling)
Due to extremely poor ground conditions(landslide mass) for excavation of penstock tunnel in the Middle Marsyangdi Hydroelectric Project, some form of additional ground treatment system also known as Pipe Canopy or Umbrella Method was required to allow NATM tunneling to progress. This method was used for the first time in Nepal and it was very successful. A total of 15 holes were drilled in the crown of the tunnel at 0.5 m centers. Length of installed threaded casing was 12.5 m. Diameter and wall thickness of the casing were 89 mm and 4.5mm respectively. The length of each casing were 315 mm,1285 mm and 1895 mm respectively as this would allow easier handling for Tubex inside the tunnel. A false portal was built at the tunnel entrance, and the spacing of the steel arches was continued at 1.5 m under the Tubex umbrella. Atlas Copco H282 Boomer along with Sandvik tubex 76 drilling accessories were used for drilling operation.
A 90 m long horse-shoe shaped tunnel having cross section area 40 m2 was constructed using this method, which was completed ahead of schedule.