14 research outputs found

    Stochastic analysis of seepage under water-retaining structures

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    This paper investigated the problem of confined flow under dams and water retaining structures using stochastic modelling. The approach advocated in the study combined a finite elements method based on the equation governing the dynamics of incompressible fluid flow through a porous medium with a random field generated hydraulic conductivity using a lognormal probability distribution. The resulting model was then used to analyse confined flow under a hydraulic structure. Cases for a structure provided with cutoff wall and when the wall did not exist were both tested. Various statistical parameters that reflected different degrees of heterogeneity were examined and the changes in the mean seepage flow, the mean uplift force and the mean exit gradient observed under the structure were analysed. Results reveal that under heterogeneous conditions, the reduction made by the sheetpile in the uplift force and exit hydraulic gradient may be underestimated when deterministic solutions are used

    Determination of aquifer units using vertical electrical sounding technique: a case study of federal low cost housing estate, Okeho, SW Nigeria

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    The groundwater development of Federal Low Cost Housing Estate Okeho involved the use of schlumberger vertical electrical sounding technique. The result of the survey showed that qualitatively three major curve types H, QH and KH were observed. The geoelectric layers range from 3 to 4 while the quantitative interpretation resulted in deducing layer parameters of 190-1103Ώm and 0.70-1.10m for the topsoil. The intermediate layer has layer resistivity of 93 -1590Ώm and thickness of 0.9-4.70m while the weathered basement has resistivity and thickness of 18-50Ώm and 6.0-10.4m. The bedrock resistivity range from 426-6284Ώm with an infinite thickness; the bedrock resistivity of less than 1000Ώm in this area and the weathered layer constitute the aquifer. Keywords: aquifer occurrences, geoelectric parameters, sounding curves Nigeria Journal of Pure and Applied Physics Vol. 4(1) 2005: 60-6
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