Kherrata tunnels are located on the RN09 road along the Sétif – Bejaia route in Bejaia Province, Algeria. Tunnels were opened to service in 1988. 

Contract scope is the refurbishment design of inner linings, drainage systems and road surfaces of:

Tunnel 1: Length L = 1,500.86 m
Tunnel 2 South: Length L = 1,194.96 m
Approach tunnel: Length L = 410.60 m

Many cracks and defects of different sizes and excessive water ingress can be observed on the existing lining of the tunnels.

Main refurbishment measures include:

• Designing a drainage system that would relieve pressure build-up behind the tunnel lining.
• Constructing an additional lining layer with drainage nets, drainage drillings, drainage channels and sprayed waterproofing membrane to facilitate flow of water into drainage system and prevent water ingress through the lining.
• Reconstruction of longitudinal drainage system with the introduction of road surface drainage elements for flammable and toxic liquids.
• Construction of a bottom trench and additional drainage drillings where necessary.
• Contact injections to reduce water ingress where necessary.

In addition, compliance with EU directives regarding safety of the tunnels will be evaluated and recommendations will be made where necessary.