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| Enlargement of the Tierfehd II reservoir |
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Linthal, Glarus, Switzerland
Mid April 2010 until (probably) end August 2010 |
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General
The Linthal 2015 project provides for an expansion of the existing Tierfehd pumped storage hydro power station. One element of the project involves enlarging the capacity of the equalising reservoir in the valley. To achieve this, a second equalising reservoir is being provided to the north of the current one. A channel linking the two will allow water to move between the two so their levels correspond.
Forming the east side of the new reservoir is the existing terrain, while the dam is to be raised on the west side. The crest of the dam will be at alt. 813.5m above sea level; the base of the reservoir, which represents the lowest point of the construction, will be at alt. 802.0m. Asphalting should be completed by the end of August.
Substrate
The new equalising reservoir is located above a groundwater zone and thus comes within the Au groundwater protection zone. Because of this, the work has to meet a number of special requirements.
Building methods
Before work could begin on the new reservoir, the two concrete structures previously erected in the existing reservoir were embedded in the asphalt lining.
Together with the slope paver, the profile of the new reservoir, previously prepared by the excavation contractor, is receiving a 20cm layer of filter ballast. An 8cm binding layer will then be applied to the slope and the base, followed by an 8cm sealing layer. The physical connections to the construction are being created using sealing liners and joint grouting material. Some of the connections are to be reinforced by means of sheet copper. Following the above activities the slope area will receive a coating of mastic. This serves to protect the sealing lining against the elements and UV radiation. An asphalted road on the crest of the dam will allow access for operators and maintenance staff during the service life of the facility.
Points to note
In Switzerland it is rare for new equalising reservoirs to be built using an asphaltic approach. The site's proximity to the operations centre in Schlieren is facilitating a number of logistical and organisational aspects. |
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| Existing and new reservoir under construction |
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Owner
Kraftwerke Linth-Limmern AG |
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Project planning
Axpo AG |
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Engineering
M. Schlegel, Axpo AG
Construction management
R. Hug, Axpo AG |
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Consortium
ARGE Becken |
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Technical details
18'000m2 slope area
36'000m2 base area
1:1.75 slope gradient
24m slope length
approx. 800m reservoir circumference |
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| Refilling of the existing reservoir incorporating the two new concrete structures |
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| Applying dense asphalt to the new reservoir |
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Walo Bertschinger AG
Dam and landfill construction
Postfach 1155
8021 Zürich
Tel. +41 44 745 23 11
Fax +41 44 740 31 40
 asphalt.lining@walo.ch
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Print sheet