**2. Case study. Djebel El Kantour tunnel**

T4 tunnel is located in the north-east of the department of Constantine. It crosses Djebel El Kantour from south to north with a total length of 2500 m. Its cover is higher than 15 m, and reaches 224 m in maximum points (**Figure 1**).

The section of the tunnel was chosen according to the geometric characteristics, the geological and geotechnical data tests performed on the ground in question as well as the height of the cover. To take into account the natural conditions of the surrounding terrain, an arched profile has been adopted to ensure the stability of the structure and the service conditions during the constructions process.

**Figure 1.** *Position of the tunnel T4.*
