DETERMINATION OF ENGINEERING PROPERTIES OF TWO SOILS AT FOHREC (KADE) AND SIREC (KPONG)

ABSTRACT

Agriculture, its operations, and soils properties are inter-related. Cultivation of crops; tillage, irrigation and farm operations, commuting to and from farm plot and building of structures are greatly influenced by the soil specifically its properties. Shear stress, cohesion and angle of friction are parameters that play major roles in influencing how soils are used or worked on. It is, therefore, important to determine the shear stress, cohesion and angle of friction of the soils in Kade and Kpong. As a result, a study was conducted on two soils from Forest and Horticulture Research Centre (FOHREC), Kade, and Soil and Irrigation Research Centre (SIREC), Kpong, at depth ranges of 0-15cm and 15-30cm under saturated and unsaturated conditions to determine the shear stress, cohesion and angle of friction to ascertain how they will affect tillage, traction and trafficability, irrigation and structures such as dams and foundations. Normal stress ranging from 1kg/cm2 to 5kg/cm2 was used as an independent variable to determine the stated properties. The results showed that the Kpong soil had a higher shear stress under all conditions than that of Kade soil. An interesting observation was made concerning the soil under unsaturated condition where at 3kg/cm2 it behaved as if it is is under saturation. The normal stress had a significant effect (p < 0.05) on shear stress, cohesion and angle of friction, where increase in normal stress reflected an increase in shear stress and cohesion but a decrease in angle of friction. The research provided ample data on shear stress required for failure to occur normal to the shear plane, cohesion and coefficient of internal friction. These measurements are relevant and important for the design of farm equipment, farm structures such as dam wall, storage buildings, etc. Kpong soil (Akuse series) had a higher shear stress under all conditions than that of the Kade soil (Kokofu series). Keywords: Shear Strength, Cohesion, Angle of friction, Trafficability, Tillage, Moisture content