Determination of the soil water characteristic curve of highly compressible materials: Case study of pulp and paper by-product

Abstract

Abstract: A technique was developed for the determination of various points of the soil-water characteristic curve (SWCC)—including the air entry value (AEV)—of compressible materials from one single test. The testing setup, which employs the axis-translation technique, is presented and the testing methodology, explained.With the proposed methodology, it is possible to determine the volume of the sample at various stages of the desaturation process, thus making it possible to determine the degree of saturation and volumetric water content for each level of suction applied. The results of some tests performed on deinking residues (DR), a fibrous and highly compressible industrial by-product used in geoenvironmental works, are presented and discussed. It is shown that if volume changes that samples undergo during desaturation are not considered, the volumetric water content and degree of saturation of the sample is underestimated at all suction values. One important consequence is that lower hydraulic conductivities are obtained from mathematical models based on the SWCC.