Multi-parameter geotechnical mapping of lateritic soils in the urban perimeter of Ngaoundal (Cameroon) for pavement and foundation design

• Direct relevance to local infrastructures (Ngaoundal) and applicability to similar geological contexts. • Multi-parameter analysis provides a robust and detailed characterization of the soils. • Soils exhibit low moisture sensitivity and high mechanical strength. • Soil classification (good, medium, poor) offers a practical decision-making tool for engineers and planners. • Establishes a reference database for future infrastructure projects in a previously under-documented area. • Confirms the suitability of local lateritic soils for supporting infrastructures, ensuring stability and durability of urban developments. Lateritic soils are widely used in tropical regions for road construction and urban infrastructure, yet their geotechnical variability poses challenges for stability and durability. This study presents a multi-parameter geotechnical mapping of soils from the urban perimeter of Ngaoundal, Adamawa, Cameroon, aiming to evaluate their suitability for supporting pavements and shallow foundations. Laboratory tests were conducted on water content, particle size distribution, plasticity index (PI), swelling potential, specific gravity, maximum dry density, California Bearing Ratio (CBR), and allowable stresses. Results indicate that water content ranges from 10.0 to 15.0%, with fines fractions (silt and clay) between 14.6 and 24.7%. Plasticity indices vary from 23.6 to 26.3%, while swelling values range from 0.05 to 0.41, reflecting low moisture sensitivity. Specific gravity and maximum dry density values range from 2.580-2.648 g/cm³ and 2.040-2.188 g/cm³, respectively. High CBR values (78-95.1%) and allowable stresses (0.237-3.671 MPa) demonstrate good load-bearing capacity. Based on a multi-parameter analysis, soils were classified into three categories: good, medium, and poor. Dense, low-plasticity soils are suitable for pavement layers and foundations, whereas high-plasticity, water-rich soils require stabilization measures such as compaction enhancement or chemical treatment. The generated geotechnical maps provide a spatial visualization of soil variability , offering practical guidance for engineers and urban planners to optimize design and construction in heterogeneous tropical soils. The study also establishes reference data for future infrastructure projects in Ngaoundal and similar tropical urban environments.