Development of geotechnical properties geo-database for soil in Kano metropolis to enhance building construction

Abstract

Building collapse is a prevalent and concerning issue that resulted in significant loss of lives and properties in many places in Nigeria including Kano state and determination of Geotechnical properties of soil could play a crucial role in preventing building collapse. This study uses Geographic Information System (GIS) methodologies to create a geospatial database of soil properties in Kano Metropolis. The database, created using Inverse Distance Weighting (IDW) and spatial interpolation techniques, provides 212 sets of soil properties being meticulously mapped across the study area. These meticulously generated maps illustrate various soil characteristics prevalent in the metropolis, offering invaluable insights for preliminary designs and construction planning for buildings within Kano Metropolis. The soils in this area are predominantly classified as CL (Clay of low plasticity), SC (Sandy Clay), and SM (Silty Sand) using Unified Soil Classification System (USCS). The moisture content spans from 2.01 to 46%, specific gravity within the range of 2.32 to 2.75, liquid limits varying between 17.2 and 45%, plastic limits within the range of 10.1 to 40.5%, and linear shrinkage values spanning from 1 to 13%. Furthermore, the shear strength parameters of the soil across the study area varies. The unit weight varies between 15.61 and 22.16 kN/ m3 , the cohesion (c) values ranging from 1.28 to 29.1 kN/m2 , and the angle of internal friction (ϕ) spanning from 5.5° to 32.2°. Despite variations in ultimate and allowable bearing capacity with depth, the ultimate bearing capacity (qult) generally ranges between 108 and 1150 kN/m2 , with the corresponding allowable bearing capacity (qall) falling between 40 and 343 kN/m2 . This research provides valuable geospatial knowledge to engineers, architects, and construction professionals in Kano Metropolis, enhancing decision-making and project planning precision, ultimately contributing to sustainable development and growth of Kano metropolis.