الفهرس | Only 14 pages are availabe for public view |
Abstract The cliffs of the upper Mokattam plateau are jointed sedimentary rock slopes composed of intercalated layers of limestone and shale.· The fundamental problem of such slopes is shale slake and the associated degradation of its durability and dclorruubi Iity (softening) upon welling and, hence. the tendency of the affected sections of the cliff to move or even 1:111. The assessment of the overall stability of such slopes and their behavior has become one of the urgent topics in geotechnical engineering of these areas because of the presence of residential buildings in the immediate vicinity. The numerical modeling. based on the finite clement method, has proved to be the most powerful ami dependable technique in stability analysis of such slopes. In this research. a finite clement program (PLAXIS) has been utilized, through an clasto-plasiic model based on the Mohr-Coulomb failure criterion. The softening process of the shale is simulated through different stages of reduction in its shear strength and deformations characteristics. The numerical model was adopted, firstly, to investigate the constitutive behavior of a special case of intercalated jointed rock cut in the upper Mokauam plateau. Deformations of shale layer and the tendency of jointed limestone to topple or slide arc also examined. The analytical results arc compared with in-situ mcusurcrucnts. Secondly, an extensive parametric study has been carried out to investigate the relative effect of different factors on the behavior of jointed sedimentary rock slopes. These factors arc: thickness of the lower limestone layer between the shale layer and the slope toe level, thickness of the shale layer, thickness and width of the upper limestone blocks, total number of the potentially unstable limestone blocks, slope angle. inclination of the shale layer, and the presence of two shale layers in the rock slope. Finally. the numerical model has been uti Iized to assess the suggested stabilization methods that can he used for jointed rock slopes in the hazard areas of EI-Mokattam upper plateau. The assessment and optimization or benches of compacted fill for stabilization in different cases of’jointcd sedimentary rock slopes arc investigated. |