Rock slope stability and design in Arafat–Muzdalifa area, Saudi Arabia

• Published in: Arabian journal of geosciences 2014-10, Vol.7 (10), p.4029-4042
• Main Authors: Abd-Allah, Ali M. A., El-Sawy, E. K., Seif, El-Sayed Sedek Abu, El-Fakharani, Abdelhamid, Sharaf, Mohammed Amin M.
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Earth Sciences; Original Paper
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-013-1030-2

The present contribution is a complete study extending before, during, and after the excavation of the mountain side that lying north of road 7. It includes slope stability analysis, rock cut design, and rockfall modeling for natural slope and rock cut face. Neoproterozoic granodiorite and biotite granite forming the slope body have medium to very high strengths. Mineral compositions and textures of these intact rocks control the strength values. These rocks are intensively dissected by fractures that are filled with montmorillonite and chlorite. The high plasticity and slippery nature of these filling materials represent the main problem that may face a rock cut designer because they damage the mechanical properties of these fractures. The problem begins with the selection of the rock mass classification that deals with the fracture fillings and extends during the stability analysis and the suggestion of mitigation and supporting measures. The rock masses building the natural slope are suffered by plane, wedge, and toppling failures. Therefore, two rock cut designs are suggested to avoid the hazards related to these failures and considering the construction cost as well. Rockfall modeling for the natural slope and rock cut designs was done to assess the hazards related to these falling of the blocks. The kinetic energy of falling blocks is represented on the roadway by the coverage distance and block rebound amplitude. Slope height has a positive effect on the values of these distance and amplitude, whereas the steepness of berm height has a negative effect on them. Coverage distance is a function to the location of rockfall barrier and to the width of road ditch, while the amplitude controls the barrier height.