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Geomechanical explanation of the Enguri power tunnel leakage

Niederhuber, Thomas ORCID iD icon 1; Müller, Birgit I. R. 1; Röckel, Thomas; Kalabegishvili, Mirian; Schilling, Frank 1; Aberle, Bernd
1 Institut für Angewandte Geowissenschaften (AGW), Karlsruher Institut für Technologie (KIT)

Abstract (englisch):

The Enguri Dam (Georgia) is one of the highest arch dams in the world, located at Enguri river in the Greater Caucasus. A 15 km long pressure tunnel with a slope of 1.1 % connects the reservoir to the power station. The tunnel was initially flooded in 1978 and takes a flow rate of up to 450 m³/s. Annual water level changes in the reservoir reach 100 m and generate variable internal water pressure, which places a considerable and dynamic strain on the structure. Water losses of more than 10 m³/s required extensive rehabilitation work in 2021.

The pressure tunnel is lined by upper and lower concrete parts separated by longitudinal construction joints. During the rehabilitation in spring 2021, an approximately 40 m long section of a construction joint with a gaping fissure and several smaller cracks were located.

To explain why only one of the construction joints was leaking, we combined field observations with numerical modelling of the stress state around the pressure tunnel. To infer the regional tectonic stress field various stress indicators have been used like borehole observations (borehole televiewer data) in the field, hydraulic fracturing and earthquake focal mechanisms. ... mehr

DOI: 10.5194/egusphere-egu22-11830
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Vortrag
Publikationsdatum 26.05.2022
Sprache Englisch
Identifikator KITopen-ID: 1000148146
Veranstaltung European Geosciences Union General Assembly (EGU 2022), Wien, Österreich, 23.05.2022 – 27.05.2022
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