Presented by AGS Newcastle with the CGSE.
Experimental studies of the behaviour of mixtures of sand with short flexible polypropylene fibres have been carried out using triaxial compression, triaxial extension, and shear box tests. Provided the fibres have appropriate orientations the attempt to stretch them generates an axial force which boosts the stress in the soil and generates a shear force which augments the measured shear resistance.
Successful modelling of these observations has been achieved using an established sand constitutive model as a basis. It is found necessary to assign a significant amount of void space to the fibres in order that the sand left behind should be sufficiently dilatant.
Analogies can be drawn between these fibres and the mass of roots of some species of plants. In combination with a model for the more substantial roots nearer the ‘surface’ of the soil, a complete model of rooted soil can be generated. This model can be used to estimate the beneficial influences of plants on slope deformation and stability.
About Professor David Muir Wood
David Muir Wood obtained his PhD at Cambridge University in 1974. He has held lectureship/professorship posts in Cambridge, Glasgow, Bristol and Dundee universities. His research interests have focussed on development of constitutive models for soils and on laboratory testing of soils in unusual apparatus. Prof Muir Wood is widely regarded as a world authority on fundamental soil behaviour and constitutive modelling of geomaterials.
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