Stability Analysis of Rock Slope Along National Road 43 (Northeast Algeria)

The national road 43 connecting Jijel to Bejaia (Northeast Algeria) runs along the Mediterranean Sea and crosses a volcano-sedimentary rock massif of more than 50 km. The road development of this ledge is constantly being considered for the needs of road traffic. However, several topographic and geotechnical constraints permanently threaten the rock cliffs overhanging the sea. Various land movements (landslides, rockfalls) occur during the multiple realizations of road works on the sections treated in this study. Before deciding on the state of stability or behavior of the Liassic rock mass in the study section (RN 43), we were interested in several sites divided into stations and in particular the station Aftis, part of the study region of national road 43 linking Jijel to Ziama (Northeast Algeria). We also want to recall that the fragile state of this massif has been detected by the records of discontinuities observed on site. All this disparity of discontinuity orientations has been recorded throughout the tectonic phases within the Brek unit and the Babors in general, whose tectonic compartmentalization was initiated in the Lias and remobilized during the Meso-Cenozoic. Slope mass rating and Continuous Slope Mass Rating are used for the evaluation of the assessment of slope stability. The stability analysis is also used in this study to determine a factor of safety value (Fs). The result indicates that Continuous Slope Mass better asses the slope stability from the stability calculation and field observations. Our works demonstrate that the rock slopes of station Aftis are classified as unstable rock slopes with a probability of falling from the wedges block (95.80%).