Bouira tunnel is a 1.3 km twin road tunnel and it is a part of the East-West Algerian motorway. Each tube has a diameter of 17 m with a separation of 40 m between axes.

PRO GEO experience has helped to solve the following aspects:

• Verification of the new excavation sequence.
• Analyses of the front face geotechnical stability.
• Design and verification of the primary lining.

A set of three dimensional geomechanical analyses have been developed in order to reproduce the excavation process. Shotcrete behavior features, such as ageing and creep have been reproduced. These studies have allowed a construction process optimization.

Geomechanical model during the tunnel excavation. The secondary lining is shown in black, yellow, green, red or blue depending on the shotcrete age.

Front stability. Total deviatoric strain.

Vertical displacements at final phase of the constructive process.