Evaluation of allowable bearing capacity of Ayila Soil, south-west Nigeria

Abstract

Accurate determination of allowable bearing capacity of soil is key to geotechnical foundations design so as to prevent collapse of structures built on them. Allowable bearing capacity of the study location has been determined by shear wave velocity approach. The seismic data used in this study are the in-situ shear and compressional wave velocities values measured by a 12-channel signal enhancement seismograph. Three layers were detected by the method. Empirical formulations and mathematical relationship between seismic velocities and elastic parameters were used to evaluate the allowable bearing capacity and other parameters presented in Table 1. Results show that allowable bearing capacity for layer 1 ranges from 123.56 to 173.54kN/m². Layer 2 ranges from 233.24 to 377.62kN/m², while layer 3 ranges from 437.62 – 616kN/m². It was observed that allowable bearing capacity increases with depth – a 13% difference between layers 1 and 2 while between layer 2 and 3 there is a 22% difference. By comparison, the allowable bearing capacities evaluated in this study are in agreement with empirical values of allowable bearing capacity of soils proposed by other scholars. Findings show the study location is suitable for geotechnical foundation designs.

Keywords: Ayila, Shear wave velocity, Allowable bearing capacity, Coefficient of subgrade reaction