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Single-function approach to calibrating whatman no. 42 filter paper based on suction versus water content relationships

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Resumo:Several suction–water-content (s-w) calibrations for the filter paper method (FPM) used for soil-suction measurement have been published. Most of the calibrations involve a bilinear function (i.e., two different equations) with an inflection point occurring at 60 kPa<s<100 kPa (i.e., 40 %<w<50 %). An approach for defining a continuous calibration function with a smooth transition between the high and low suctions based on a regression analysis of various previously published calibrations obtained for filter paper Whatman No. 42 (W42) is presented and discussed. The approach is applied herein to data obtained from three establish bilinear calibrations (six equations) for W42 filter paper to determine the two fitting parameters of the continuous function. An experimental evaluation of the new calibration show that the suctions estimated by the contact FPM test using the proposed function compare well with suctions measured by other laboratory techniques for two different soils for the suction range of 50 kPa<s<400 kPa, which corresponds to a water content range of 30 %<w<55 %.
Autores principais:Bicalho, Katia
Outros Autores:Bertolde, Adelmo; Cupertino, Kamila; Fleureau, Jean-Marie; Correia, A. Gomes
Assunto:Unsaturated soil Soil suction Filter paper Calibration Engenharia e Tecnologia::Engenharia Civil
Ano:2015
País:Portugal
Tipo de documento:artigo
Tipo de acesso:acesso restrito
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho
Descrição
Resumo:Several suction–water-content (s-w) calibrations for the filter paper method (FPM) used for soil-suction measurement have been published. Most of the calibrations involve a bilinear function (i.e., two different equations) with an inflection point occurring at 60 kPa<s<100 kPa (i.e., 40 %<w<50 %). An approach for defining a continuous calibration function with a smooth transition between the high and low suctions based on a regression analysis of various previously published calibrations obtained for filter paper Whatman No. 42 (W42) is presented and discussed. The approach is applied herein to data obtained from three establish bilinear calibrations (six equations) for W42 filter paper to determine the two fitting parameters of the continuous function. An experimental evaluation of the new calibration show that the suctions estimated by the contact FPM test using the proposed function compare well with suctions measured by other laboratory techniques for two different soils for the suction range of 50 kPa<s<400 kPa, which corresponds to a water content range of 30 %<w<55 %.