Modelling the Behaviour of Marl and Chikoko Soil of the Niger Delta Under Multiple Wetting and Drying Cycles

This study critically analyzed the behaviour, encompassing volumetric changes, deformation characteristics, and tensile strength properties, of two predominant problematic soils from the Niger Delta region: Marl and Chikoko soils, under the influence of multiple wetting and drying cycles. The experimental methodology employed the modified oedometer tests, systematically integrated within a three-level four-factor full factorial design framework. This robust experimental design allowed for a comprehensive investigation into the intricate effects of key environmental and geotechnical parameters. Specifically, the study meticulously examined the independent and interactive effects of varying moisture content (ranging from 14% to 16.5% for Chikoko soil and 47% to 51.5% for Marl soil), dry density (ranging from 1.70 to 1.96 g/cm3 for Chikoko soil and 1.00 to 1.28 g/cm3 for Marl soil), surcharge pressure (between 1 and 10 kN/m2), and the number of wetting and drying cycles (up to a specified maximum, usually 3-5 cycles in typical studies) on the chosen soil properties. The cyclic nature of wetting and drying amplifies these effects, highlighting the critical need to account for such environmental factors in the design of foundations, pavements, and other geotechnical structures in the Niger Delta. The research provides valuable insights into the mechanistic behaviour of these soils, offering a scientific basis for developing more resilient and sustainable infrastructure in the region.