Use of randomly reinforced soils in barrier systems

This paper investigates the use of fibre reinforcement as a means of increasing the shear strength in a low permeability soil barrier system, whilst maintaining the required hydraulic properties. Bentonite enhanced soil (BES) has been used as a host material since fibres can be added during the existing mixing process, thus requires minimal additional mixing plant. Results have shown that fibre reinforcement can provide both peak and post peak shear strength improvements. Behaviour of the soil fibre composite is improved by increasing fibre content to at least 0.5% (by weight) and fibres of 20mm in length are shown to give greater strength increases than fibres of 10mm. Preliminary permeability tests have shown that the fibre reinforcement has little effect on the hydraulic performance and a typical target permeability for use in landfill applications of 1 × 10⁻¹⁰ms⁻¹ can still be achieved.