Analysis of slope stability hazards along hilly highways: Ain Sukhna- Zafarana highway, North Galala Plateau, Eastern Desert, Egypt

Abstract

A part of the eastern side of the North Galala plateau is subjected to intense slope stability hazards. The present study aims at assessing and analyzing the different slope failures along the North Galala plateau and predicting the failure types through their kinematic/deterministic and rockfall analyses, followed by the suggestion of mitigation and supporting measures for the unstable zones. The slope rock masses consist of the Paleozoic interbedded rock units of sandstone and claystone at the base and the Cretaceous-Eocene carbonate rock units at the top. Assessment and analysis of rock masses revealed that the studied area shows, planar, wedge, and toppling failures which are controlled mainly by the unfavorable discontinuities. Kinematic analysis of the studied discontinuities with the slope angles and orientations identifies the occurrence of these slope failures through the steeper segments of each slope profile. Deterministic analysis and calculated factor of safety (FS) show that the most studied rock slope discontinuities are stable under both dry static and dynamic condition, and their stability condition is significantly reduced in saturated conditions where the calculated FS is frequently less than unity. Rockfall simulation is constructed at ravelling zones to assess the block trajectories, runout distance, kinetic energy, and bounce profiles of the falling blocks. Supporting and mitigation measures are recommended based on the slope stability analysis, site inspection, and encountered engineering geological conditions of different rock masses.