Geomechanical stratigraphy defines foundation suitability of Turonian carbonates in New Giza Egypt
Year: 2026
Type: article
Abstract: Geotechnical parameters—including uniaxial compressive strength (UCS), Young’s modulus (E), Poisson’s ratio (ν), and derived competence indices (Material Index γ, Concentration Index Ci, and Stress Ratio Si)—were evaluated to assess foundation quality in Turonian carbonate rocks at Pyramids Heights (New Giza), Egypt. Direct uniaxial compression tests (ASTM D7012) were conducted on core and block samples from 228 boreholes to ensure spatial fidelity. Results show UCS values ranging from 4.93 to 19.69 MPa. Young’s modulus varies between 2.86 and 14.30 GPa. Allowable bearing capacities (Qₐ) range from 1.25 to 4.99 MPa. These values indicate low to moderate rock strength with moderate stiffness, consistent with diagenetically altered, marly, or vuggy carbonate facies. Unlike previous Egyptian carbonate studies that relied on empirical correlations, this study provides the first site-specific geomechanical stratigraphy model for the Abu Roash Formation based on direct UCS measurements. Competence indices classify the rock as fairly to moderately competent. The Acteonella Series shows the strongest response (Qₐ = 4.8–5.0 MPa), while the Flint Series exhibits the weakest (Qₐ = 1.2–2.1 MPa). Weak zones, particularly in marly or cavernous intervals (e.g., BH-4, B12), require ground improvement such as grouting or micropiles prior to construction. This integrated geomechanical–geological assessment establishes quantitative links between Turonian lithofacies and foundation performance. The model provides actionable, code-compliant (EGP 202–2005) guidance for urban development in New Giza and similar carbonate provinces.
Source: Discover Geoscience
Authors: El-Hussein M. Ali, Ali Mahdy, Abdel Moktader A. El Sayed, Salah El-Din A. Mousa, Mohie El-Din M. El-Mashad
Institutions: Ain Shams University, National Water Research Center
Language: English
Topic: Rock Mechanics and Modeling
Subfield: Mechanics of Materials
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7213770503