The intensive works on excavation of headrace tunnel for the future HPP Dabar (l=12.25 km) in the hydro-technical system Gornji Horizinti are performed during the whole 2018. During this period, the access tunnel Vodostan (l = 227 m) was excavated at the end of the headrace tunnel and the access inlet at the intake structure on the starting side of the intake tunnel, while, during 2017, the access tunnel Straževica (l = 652 m) was excavated in the middle part of the headrace tunnel.
In this way, it is possible to execute works simultaneously at four points. Total of 5.8 kilometers of tunnels were excavated until now. The works will be continued during the winter period. In this period, the work schedule will be conditioned by the expected occasional high ground and surface waters as well as low temperatures.
The limestone rocks of different composition and characteristics prevail in the direction of the excavation of the headrace tunnel. In addition, during the work execution, we find numerous caverns filled with clay and stone. Caverns require the additional work execution and the execution of more complex shapes of support. (Caverns are underground karst forms that occur from the expansion of cracks in limestone by the chemical action of water.)
The basic characteristics of headrace tunnel for the future HPP Dabar:
- length l= 12,125.00 m
- altitude of the start point of tunnel H=813,00 m
- altitude of the end point of tunnel H=787,06 m
- longitudinal inclination i=2,139‰;
- circular cross-section of tunnel clearance profile D=4.6 m on the length of l=7,853.00 m
- horseshoe cross-section of the excavation height H=5.20 m on the length of l= 4,272.00 m
- it is constructed with New Austrian tunneling method.
HPP Dabar Headrace Tunnel – Situation
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