Evaluation of Subsoil Engineering Properties for Road Construction at Oboto, Ondo East, S

Abstract

Oboto community is located in Ondo East, Southwestern Nigeria in the tropical region. The engineering properties of the twelve soil samples obtained at the depth of between 0.6m and 1m were determined for potential road construction material. The natural moisture content (NMC), liquid limit, plastic limit, plasticity index and linear shrinkage values with their mean and standard deviation values of the twelve soil samples range from 10.2% to 14.4% (12.4% ± 1.42), 39.0% to 48.4% (43.5% ± 3.23), 22.1% to 29.4% (24.9% ± 2.37), 13.9% to 22.7% (18.6% ± 2.64) and 7.9% to 9.3% (8.4% ± 0.46) respectively. The NMC values fall under marginal engineering material; the atterberg limits of the soil samples met the requirement of subgrade material; while the linear shrinkage values show that the soil samples are good as subgrade, subbase and base materials. For grain size analysis, only three soil samples from locations OTP2, OTP10 & OTP11 met the specification of less than 35% of weight finer than NO 200BS test sieve. Ten soil samples fall within the clay medium compressibility except for OTP4 and OTP5 that have silt medium compressibility. The specific gravity shows that the soil samples are within sandy and silty sand. Three soil samples from locations OTP2, OTP11 & OTP12 have good ratings of A-2-6 or A-2-7; soil sample from location OTP3 has fair rating while the remaining soil samples have A-7-6 rating. The California bearing ratio values of 18% to 34% (mean & standard deviation values of 28.4% ± 4.6) show that the soil samples are good as subgrade material. The Maximum dry density and Optimum moisture content values show that the soil samples have fair to poor ratings. Soil samples from locations OTP1, OTP2, OTP3 OTP7, OTP11 & OTP12 have medium degree of compressibility and settlement values of less than 1 mm/year.

Publication Info:

Author: Ale, T.O. , Ogunribido, T.H.T. , Faseki, O.E. , Ale, T.A. ,

Volume: 58

Issue: September

Published By: Journal of Mining and Geology Vol. 58(2) 2022. pp. 1 - 9, 2022-09-01