Client
Landsvirkjun /National Power Company/
Superior contractor
ÍSTAK hf, Iceland
Construction period
August 2008 – October 2008
Objects description:
- tunnel Grjóta is an aqueduct of the water tank and dam Grjóta
- tunnel was excavated at the same time from two sides
- tunnel has two portals – P6 and P7
Construction technology:
Excavation works were carried out by drilling and blasting works (NMT – Norwegian Tunnelling Method). Drilling works were executed by using of 2-arms drilling jumbo Tamrock Axera Data T08 with power of drill hammers 22kW. Blasting works were executed by using of emulsion explosive – slurry type and Mini-SSE charging device. Loading and mucking was carried out by wheel loader Volvo L180 with side tipping and lorries MB Actros 4131.
Executed works:
- driving of tunnel tube, profile 20 m2, length 301 m
- rock support by sprayed steel fibre reinforced shotcrete and rockbolts