The Place of Soil Geotechnical Characteristics in Road Failure, a Study of the Onitsha-Enugu Expressway, Southeastern Nigeria.

Abstract

This work investigated the place of soil geotechnical characteristics along the road in the road failure. Soil samples from both failed and un-failed sections of the road were analyzed to ascertain their particles size distribution, liquid limit, plastic limit, maximum dry density, optimum moisture content and California bearing ratio. The data so generated from the eight sample stations established across the road were tested using Students T-test. It was found that there is significant difference between the geotechnical characteristics of the soil and the standard for geotechnical characteristics set by the Federal Ministry of Works at the failed sections but there is no significant difference at the un-failed sections. This led to the conclusion that the soil geotechnical characteristics is a causative factor of the road failure. Hence, it was recommended that the geotechnical and geological characteristics of sub-grades and fill materials be taken into consideration during road construction while relevant geologists, meteorologists/climatologists should be enlisted during the pre-construction design and planning of highway pavements. Also recommended are the following: proper compaction during construction, adequate maintenance programme for the road after construction, installation of good drainage channels for flooded sections, axle load control, careful choice of consulting engineers, prosecution of corrupt consulting engineers and ministry officials, prompt payment of contractors by the government and motivational packages for distinguished contractors so as to mitigate the problem of the failure of the road.

Keywords: road failure, causes, environmental implications and remedies.