Geotechnical Index Properties of Soils in Abua and Environs: A Case Study of Obedum-Anyu-Emelago Road

Abstract

The frequent collapse of engineering structure and in incessant cracks witnessed on walls of buildings within the Obedum-Anyu-Emelego axis of Abua/Odual Local Government Area of Rivers State prompted the need for geotechnical investigation to assess the suitability of soils and characterize their engineering properties as a guide to foundation designs. Soil samples were obtained between 0 and 30 metres depth and used in the study. The field boring and laboratory results shows that the stratigraphy is predominantly of medium with soft to firm brown mottle grey salty peaty clay and soft to firm grey mottle brown salty peaty clay in shallow borings of 2 m. The organic peaty clay layers are very poorly suited to support foundations due to very high compressibility compared to other materials. Laboratory analyses showed that the clays are characterized by moderately high moisture content and compressibility and fairly low undermined strength. CBR values between 5.7 percent to 8.5 percent, liquid limit between 38.8 percent and 50.6 percent, plasticity limit 18.8 percent and 25.5 percent. Comparison of these ranges of geotechnical properties with Bench Mark for sub grade indicated that they are of low standard. Recommendation includes the need for stabilization with lime and cement to avoid the collapse of structure or buildings within the study area.