A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Engineering properties and slope stability of road cuttings along the enugu-onitsha express road, Southeastern Nigeria
Abstract The new express highway linking Enugu (in Enugu State) and Onitsha (in Anambra State) both in Southeastern Nigeria, is plagued with landslides, a few years after completion. The active landslides are concentrated on the road cuttings between Otuocha junction and Awka, specifically between km 29 and km 40 from the Onitsha end of the road. Three of these slides have been studied. The investigation involved detailed field and laboratory studies of the physical conditions and geotechnical properties of the sites and soils therein. The laboratory tests performed included grainsize distribution analysis, Atterberg limits, specific gravity, natural water content, bulk density, permeability and shear strength. Each site was analysed for stability using the strength parameters obtained from laboratory tests and Bishop's 1955 simplified method of analysis. There is evidence from the analyses results that although the cut slopes are vulnerable to toe undermining and over-steepening by runoff, the generally “loose” nature of the soils as evidenced by the low bulk density (1580–1960 kg/$ cm^{3} $), fairly high void ratio (0.53–0.66) but low permeability (2.15–3.25×$ 10^{−3} $ cm/s) and consequent high saturation and strength reduction during the rains, are the major contributors to instability of the cut slopes.
Engineering properties and slope stability of road cuttings along the enugu-onitsha express road, Southeastern Nigeria
Abstract The new express highway linking Enugu (in Enugu State) and Onitsha (in Anambra State) both in Southeastern Nigeria, is plagued with landslides, a few years after completion. The active landslides are concentrated on the road cuttings between Otuocha junction and Awka, specifically between km 29 and km 40 from the Onitsha end of the road. Three of these slides have been studied. The investigation involved detailed field and laboratory studies of the physical conditions and geotechnical properties of the sites and soils therein. The laboratory tests performed included grainsize distribution analysis, Atterberg limits, specific gravity, natural water content, bulk density, permeability and shear strength. Each site was analysed for stability using the strength parameters obtained from laboratory tests and Bishop's 1955 simplified method of analysis. There is evidence from the analyses results that although the cut slopes are vulnerable to toe undermining and over-steepening by runoff, the generally “loose” nature of the soils as evidenced by the low bulk density (1580–1960 kg/$ cm^{3} $), fairly high void ratio (0.53–0.66) but low permeability (2.15–3.25×$ 10^{−3} $ cm/s) and consequent high saturation and strength reduction during the rains, are the major contributors to instability of the cut slopes.
Engineering properties and slope stability of road cuttings along the enugu-onitsha express road, Southeastern Nigeria
Okagbue, C. O. (author) / Ifedigbo, O. T. (author)
1995
Article (Journal)
English
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