The accident in the Awali tunnel (Litani hydroelectric scheme, Lebanon, 1950s): analyses and interpretations of more than 3 kilometres of tunnel flooded by sand and water
Year: 2026
Type: article
Abstract: This case study details a spectacular accident that occurred in a construction tunnel in the 1950s, fortunately without any fatalities. Located in Lebanon, the Awali tunnel was the main tunnel of a hydroelectric scheme along the Litani River, which also included a water intake, several tunnels, falls, and a powerhouse. The Litani hydroelectric development was characterised by its significant depth, reaching 1000 meters below the Lebanon mountain range, as well as its varied geological terrains, including sandstone. Even if the investigation carried out before the tunnel design and excavation had been rather limited, it has revealed the existence of poorly cemented layers within a major sandstone formation. As a result of this accident, over three kilometres of tunnel section were flooded and backfilled with sand. To our knowledge, it is the most devastating water impact in a tunnel, in terms of flow, pressure, and associated erosion. Applying principles of rock mechanics in structural and seismic tectonic environments enables us to understand the physical mechanisms underlying the accident’s origin and progression, in particular the interaction between natural stress and successive rock burst events.
Source: Soils and Rocks
Authors: Philippe Vaskou, Eda Quadros
Institution: CY Cergy Paris Université
Language: English
Topic: Rock Mechanics and Modeling
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
Funder: Electricité de France
OpenAlex ID: W7204897702