article · International Journal of Engineering Processing and Safety Research
This study assesses the geotechnical properties and bearing capacity of subgrade soils in Calabar, Nigeria, to guide flexible pavement design. Field investigations used Dynamic Cone Penetrometer (DCP) testing across two boreholes, combined with standard laboratory tests including grain-size distribution, Atterberg limits, compaction, and California Bearing Ratio (CBR) measurements. The soils were identified mainly as clayey sand with low to moderate plasticity and fines content below 35 percent. Laboratory soaked CBR values averaged 14.4 percent, aligning closely with in situ DCP-derived CBR averages of approximately 15 percent. Subsurface profiling identified three layers, establishing the second layer at 0.5 metres depth as the main foundation. Under the evaluated conditions, flexible pavement thicknesses of roughly 270 millimetres for express roads and 375 millimetres for airport taxiways were determined to be adequate, confirming DCP testing as a reliable, rapid field method.
Roads and runways rely heavily on the strength of underlying soils to prevent structural failure. Demonstrating that field-based Dynamic Cone Penetrometer tests match detailed laboratory results allows civil engineers to evaluate ground conditions more quickly and at lower cost, aiding the design of durable transport infrastructure in tropical environments.
The findings are applied and field-tested, offering civil engineering contractors, transport agencies, and geotechnical testing firms a validated basis for using Dynamic Cone Penetrometer tools instead of slower laboratory testing. The direct correlation enables faster site assessments and informed pavement thickness specifications for local highway and airport taxiway construction projects, although adoption depends on adherence to regional transport design standards.
AI-generated from the published abstract. Always read the original work before citing.
The properties and bearing capacity of subgrade soils in selected parts of Calabar, Cross River State, Nigeria, to determine their suitability for flexible pavement design. Field investigations comprised drilling and Dynamic Cone Penetrometer (DCP) testing for two borehole locations, while representative soil samples were subjected to laboratory analyses including particle-size distribution, Atterberg limits, Standard Proctor compaction, and California Bearing Ratio (CBR) tests following ASTM and AASHTO standards. The soils were predominantly classified as clayey sand (SC) with low to moderate plasticity, exhibiting Plasticity Index values below 15% and Liquid Limit values below 40%, indicative of good subgrade characteristics. Particle-size analysis revealed fines content of less than 35%, while the Standard Proctor compaction test produced an Optimum Moisture Content of approximately 14% and a Maximum Dry Density of 1.93 gm/cm³. Laboratory soaked CBR values averaged 14.4%, whereas DCP-derived CBR values averaged approximately 15%, demonstrating good agreement between field and laboratory assessments. The DCP profiles identified three distinct subsurface layers, with the second layer, located approximately 0.5 m below the ground surface, constituting the principal pavement foundation. Based on the evaluated subgrade conditions, flexible pavement thicknesses of approximately 270 mm for express roads and 375 mm for airport taxiways were found to be adequate under the specified traffic loading conditions. The close correlation between DCP and laboratory CBR results demonstrates that DCP testing provides a rapid, reliable, and cost-effective method for subgrade evaluation and pavement design in tropical environments. engineering performance of flexible pavements is strongly influenced by the strength and deformation characteristics of the underlying subgrade soils. This study evaluates the geotechnical.
This page summarises published work. The authoritative version sits with the publisher.
DOI: 10.70382/caijepsr.v12i5.030
Is something wrong with this record? Report it or request removal.
Discussion
Have you built on this work, tried to replicate it, or seen it applied in practice? Share what you know. Verified researchers and MARATTO™ domain experts can open a discussion, and any member can reply. Contributions are reviewed before they appear.
No discussion yet. Open the first thread.
New to MARATTO™? Create a free account.
