Combined Seismic Refraction and Ground Penetrating Radar Geophysical Investigation Techniques for Evaluating Road Pavement Failure in Part of Ibadan Metropolis, Southwestern Nigeria

Authors

  • Olawale Olakunle Osinowo

Keywords:

Road pavement; Subgrade; Reflector morphology; Radargram; Quartz Schist.

Abstract

Combined subsurface imaging strength of both Seismic Refraction (SR) and Ground Penetrating Radar (GPR) geophysical investigation techniques have been employed to study the road pavement and the underlying near surface rock units in order to evaluate the integrity of both the riding surface as well as the supporting earth material and thus establish the causes of road pavement failure along some sections of Apete-Akufo road in Ibadan metropolis southwestern Nigeria. The SR data acquired from eight 120 m long profiles using roll along technique of data acquisition and processed based on the General Reciprocal Method (GRM) generated P- and S-wave velocities, subsurface velocity models and refractors morphology which gave insight into the near surface geologic materials that bears the burden of the road. The filtered GPR data on the other hand generated 2D radargrams across the established seismic profile stations and provided detailed information employed to characterize the road pavement, base – course down to the subgrade. Three (3) distinct geoelastic layers having characteristic P wave velocities of 354-661m/s, 592-1948 m/s and 1890-5192 m/s, with thicknesses of 0–17 m, 16.4–35 m > 35 m corresponding to topsoil, weathered/lateritic layer and partially weathered/unweatherd basement rocks were delineated. The GPR reflection signatures identified asphalt thickness of only around 150 mm and presented chaotic reflection patterns with truncations in reflection continuity at points of road pavement failure. A combination of poor road design and improper construction resulting from lack of subsurface geological/geophysical information is responsible for the failure of the road.

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Published

2022-04-14

How to Cite

Osinowo, O. O. (2022). Combined Seismic Refraction and Ground Penetrating Radar Geophysical Investigation Techniques for Evaluating Road Pavement Failure in Part of Ibadan Metropolis, Southwestern Nigeria. JOURNAL OF SCIENCE RESEARCH, 18(1), 11. Retrieved from http://jsribadan.ng/index.php/ojs/article/view/127