The partial reception of the Djebel El-Ouahch tunnel T1 in the wilaya of Constantine is scheduled for the end of June 2024.
Cosider and TREVI appear to be keeping their commitment. Especially since the asphalting work has been launched.
Djebel El Ouhch tunnel T1 is part of the East-West Hi- ghway, with a length of 1216 km the project was divided into 3 lots West, center and East.
The Eastern lot with a length of 399 km was initially per- formed by a Japanese group consortium including TREVI participation. The long tunnel of almost 2 km is composed
of 2 tubes, one left was always in phase of construction, and the other right one was operational and subject to a collapse on January 1st 2014, obliging the traffic to stop.
The project owner decided to award the Rehabilitation works to the National enterprise COSIDER with TREVI as a subcontractor and SWS as the engineering design office.
The project consisted principally of consolidation works for the damaged galleries after the top of tunnel has collapsed, causing the obstruction of the left tube and so many serious damages to the right tube, over a linear of 150 m to the right tube and 470 m to the left tube; the grouting for consolidation was carried out between the two tubes.
Constantine (Djebel Ouahch) is one of the Algerian regions that is mostly reached by the phenomenon of Landslide, because it is situated inside a complex geomorphological
environment. The instability of the soil in this region dangerously affected many sites and several highway roads.
The main cause of this instability is the nature the conglomerates formation based on heterometric elements cemented by a clayey-sandy matrix, sands and gravels, gypsiferous clay and limestones.
Those materials are permeable and fragile, but certain sands and gravels have a great importance, because they help charge water into the rock massif.
Some studies have confirmed that the fundamental role is played by the superficial water, the drainage and the slope effect that accelerate the soil instability process.
The Italian company TREVI was responsible for this operation by carrying out the establishment of an expertise, an investigation and an in-depth study by a private Italian company, specializing in geotechnics, in order to allow a better management of this site presenting a danger for workers.
For better and reinforcement of the areas most exposed to risk on this site, TREVI has delivered certain technologies that helped increase the resistance against landslides.
This fundamental solution has erased the cause itself by improving the natural conditions.
S.B.
