Headrace tunnel and tailrace tunnel of the Beles MPP in Ethiopia / Druckstollen und Unterwasserstollen des Wasserkraftwerks Beles in Äthiopien
| Author(s): |
Alois Vigl
Reinhold Gerstner Francesco Bartimoccia Marco Cruciani |
|---|---|
| Medium: | journal article |
| Language(s): | English, German |
| Published in: | Geomechanics and Tunnelling, 2013, n. 5, v. 6 |
| Page(s): | 422-433 |
| DOI: | 10.1002/geot.201300038 |
| Abstract: |
The Beles Multipurpose Project, with a total installed capacity of 460 MW, is located in the Lake Tana region in the northwest of Ethiopia. The headrace system consists of the low pressure headrace tunnel and a 270 m deep vertical shaft with a power cavern at its lower end. A tailrace tunnel transports the turbine water to the Beles river where it is used again for agricultural purposes. The entire tunnel length of the tailrace tunnel and most of the length of the headrace tunnel encountered various types of volcanic rock at an overburden between 50 and 370 m. This volcanic section of 17.5 km length was excavated by a hard rock double shield TBM and lined with an "open" segmental lining. Control of water loss and water ingress had to be achieved through the permeability characteristics of the surrounding rock, the hydrogeological conditions and by means of grouting where required. The intake area is characterised by Quaternary lacustrine deposits over a length of about 1,600 m at an overburden up to a maximum of 120 m. For this lacustrine section, the DS-TBM was modified to run in a semi-EPB mode and the requirements to withstand pressurized backfilling were to be achieved by a gasket-sealed segmental lining. |
| Keywords: |
lining concept lining design filling depletion test operation
|
| Available from: | Refer to publisher |
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data sheet - Reference-ID
10069419 - Published on:
15/12/2013 - Last updated on:
13/08/2014
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