Geoelectrical Investigation of Road Failure Along Minna-Bida Road, Niger State, Nigeria

Abstract

The study is meant to reveal the horizontal and vertical geological discontinuities on the said road that has suffered repairs in the past. Probable zones of untimely failure along the road are then investigated by variation in resistivity. The resistivity values for profiles A, B, C, D and F range between 0.10 and 30.4 Ωm; indicating failed segments which are typical of fractured or fissured zone, as a result of clayey nature of the topsoil/sub-grade soil on which the road pavement is founded. The stable segment which is characterized by high ranging resistivity (16.4 – 4628 Ωm) shows no evidence of any major geologic feature such as fault and fractured zone that could have precipitated failure. The range of values characteristically places the regions in a basement complex area with the presence of clay-sandstone intercalation. The causes of road pavement failure on the studied road was found to be majorly as a result of a combination of clayey topsoil/sub grade soils, water-logged sands with characteristically low resistivity values and thin pavement unable to withstand pressure exerted on the road.