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The influence of soil deformations on the permeability to air
Author(s) -
KIRBY J. M.
Publication year - 1991
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1991.tb00404.x
Subject(s) - macropore , permeability (electromagnetism) , air permeability specific surface , soil water , materials science , geotechnical engineering , soil science , cracking , characterisation of pore space in soil , soil structure , mineralogy , geology , composite material , porosity , chemistry , biochemistry , layer (electronics) , membrane , mesoporous material , catalysis
SUMMARY Samples were reconstituted in the laboratory from a cracking grey clay soil. Some samples were created with a granular structure in which there was no preferred macropore orientation, others were created with a strongly preferred macropore orientation. The samples were compressed and their air permeability measured. They were then sheared and their air permeability measured again. In the samples with a granular structure the change in permeability was dominated by the change in the volume of the pore space. Volume increase led to permeability increase and volume decrease led to permeability decrease. At low shear strains and low volume increases there was some loss of pore continuity leading to small permeability decreases. In contrast, permeability change in the samples with a preferred macropore orientation was dominated by macropore continuity. Permeability decreased both when volume decreased and also over a wide range of volume increases. These results are interpreted in terms of critical‐state soil mechanics and used to construct ‘critical state for permeability’ lines analogous to the usual critical‐state lines. It is suggested that these forms of behaviour encompass the likely bounds of behaviour of soils in many circumstances.