GEOTECHINCAL EVALUATION OF THE POSSIBLE CAUSES OF ROAD FAILURE ALONG 20TH STREET,BENIN DEVELPOMENT HOUSING ESTATE,OVIA NORTH EAST,SOUTHERN NIGERIA

ABTRACT

This work investigated the cause of road failure using geotechnical analysis along the 20^th Street,BDPA.Ugbowo in Benin city. Soil samples from the failed section of the road were analysed to ascertain their particle size distribution, liquid limit,maximum dry density,plastic limit,moisture content and California bearing ratio. The analyses were carried out in accordance to the British standard Institution(BS 1377 1990). The result from the particle size distribution analysis showed that soils were well graded(GW) with percentage fines ranging from 26 to 49.7%,specific gravity from 2.4 to 2.6,liquid limit from 21.52 to 29.79%,plastic limit ranged from 11.73 to 18.80%,plasticity index 8.29 to12.49% and California bearing ratio (unsoaked) from 9 to 29%. The compaction text results showed that the Maximum Dry Density ranged from 1.7mg/m to 1.8mg/m and Optimum Maximum Content from 11- 14%. It was found that there is a significant difference between the geotechnical characteristics set by the Federal Ministry of Works. This led to the conclusion that the soil geotechnical characteristics is a causative factor of road failure.