Your partner for civil construction works for Hydro, Tunnel, Undergrounds and Infrastructure projects

info@3hc.com.np

Tunnelling

Tunnelling is a complicated task requiring accurate adoption of technological solutions to prevailing geological conditions. The rock mass properties in the Himalayan region are very complex. There is a great need of a professional approach in excavation and rock support methods in such geologically complex rocks. It may seem simple to dig a hole through  a mountain. However difficulty arises when rockfalls, squeezing, water seepage, flowing mass or total collapse occurs which is not unlikely in tunnelling. It is the preparedness in terms of technological skills and equipment to address these problems that makes the tunnelling project a success.

High Himalaya Hydro possess a fleet of tunnelling equipment including shotcrete machines, ventilation fans etc. In addition, we have sufficient support equipment like concrete mixers, compressors and generators. We have qualified and trained crew to undertake any underground works.

Below, you will get a glimpse of the underground works that our company, employees/promoters have undertaken including horizontal tunnels, caverns, inclined tunnels and shafts.

Horizontal Tunnels

We have completed construction of:

  • Headrace Tunnel 3926.23m (3.2m x 3.2m), Branch Tunnel to Surge Shaft 17.20m, Adit Tunnel 184m of Hewa Khola A Hydroelectric Project (15 MW)
  • Headrace Tunnel 2070.5m (2m x 2.5m), Rate Khola Diverson Tunnel 148m (2m x 2m) of Upper Mai Hydroelectric Project (10 MW)
  • Headrace Tunnel 975.6m (2m x 2m) of Upper Mai ‘C’ Hydroelectric Project (5.1 MW)
  • Headrace Tunnel 1121.2m (3m x 3m) of Midim Khola (Karapu) Hydropower Project (3 MW)
  • Headrace Tunnel 1471.96m (2.4m x 2.5m), Adit Tunnel 41.28m of Siprin Khola Hydroelectric Project (10 MW)
  • Test Adit Tunnel 746m (2m x 2m), Test Chamber 8m x 4m x 5m of Budhi Gandaki Hydropower Project (1200 MW)
  • 3 nos Test Adit Tunnel 485m (2.5m x 2m) of Tanahu Hydropower Project (140 MW)

Our employee/promoters were involved in the construction of :

  • Power Tunnel (34 m2), Bypass Tunnel (34 m2), Ventilation Tunnel (12 m2) and Penstock Tunnel (44m2) of Middle Marsyangdi Hydroelectric Project totaling 750m.
  • Headrace Tunnel (14 m2), Tailrace (22m2), Access Tunnel (24m2) and Adit Tunnels (14 m2) of Khimti I Hydropower Project totaling 12,000 m
  • Headrace tunnel (17 m2), Penstock Tunnel (28 m2) and Adits (17 m2) of Modi (14MW hydropower plant of NEA) totaling 2,299m
  • Test adit (7.5 m2) for Melamchi (planned drinking water supply scheme for Kathmandu) totaling 524m
  • A 1100 m Headrace tunnel (8.5 m2) of Jhimruk Hydro and Rural Electrification Project
  • A total of 2,500 m tunnel that comprised the 7.5 m2headrace and 8.5 m2 Tailrace of Andhikhola Hydroelectric and Rural Electrification Project
  • A total of 1,400 m of test adit (4 m2)  for Arun III (planned  402 MW hydropower project of Nepal)
  • Access Tunnel to Powerhouse (7m x7m, 760 m long inverted D) for Upper Tamakoshi Hydroelectric Project (456 MW)

In the course of these projects, our technical experts had applied the full range of construction methods from hand operated to advanced mechanised technologies; dealt with very complex geology encountered during tunnelling through the MCT (Main Central Thrust); and achieved the highest tunnelling productivity of 64m/week (at Khimti Access Tunnel).

Our employees/promoters have also completed the construction of Penstock tunnel in soft ground using Pipe Canopy Method at Middle Marsyangdi Hydroelectric Project for DDC-JV. Such method has been used in Nepal for the first time.

Inclined and Vertical Shafts

We have completed construction of:

  • Surge Shaft 3.2m dia and 6m dia 10m and 37m high of Hewa Khola A Hydroelectric Project (15 MW)
  • Surge Shaft 32m high 6m dia of Upper Mai Hydroelectric Project (10 MW)

Our employees/promoters have gained experience during construction of :

  • Surge Shaft of Middle Marsyangdi Hydroelectric Project: 22 m ø, 53.5 m high (biggest underground tank in Nepal)
  • Khimti Penstock Tunnel: 6 m ø, 45• inclination, 909m long
  • Jhimruk Penstock tunnel 2.1 m ø, 45inclination, 280 m long
  • Andhikhola Vertical shaft 4.5 m ø, 245m long
  • Modi Surge Shaft 10 m ø, 40 m long
  • Modi Penstock Vertical Shaft 4.6 m ø, 51 m long
  • Surge Shafts of Jhimruk, Tatopani, Khimti and Tinau

Caverns

We have completed construction of:

  • 2 nos Desilting Basin Cavern (100m x 8.5m x 13m) of Mistri Khola Hydroelectric Project (42 MW)

Our employees/promoters were involved in construction of:

  • Khimti underground Powerhouse (70 m long, 11 m wide, 17 m high)
  • Andhikhola underground Powerhouse
  • Tinau underground Powerhouse
  • Tatopani Underground Desilting Basin