Aerosol injection in soft soils: permeability enhancement by fractures

Abstract

In our recent paper, we reported the development and application of the aerosol injection technique to accelerate the consolidation in soft soils. Aerosol injection technique is a process that involves injecting air under high pressure into soft soil to create a network of fractures, which gives rise to enhanced permeability. In this paper, we present an experimental study on the permeability of soft soil specimens with pre-made fractures in a triaxial device. Some emphasis is given to the variation of permeability with time. Some major influence factors are considered, e.g. the fracture roughness, confining pressure, pre-consolidation pressure, soil structure and mineral composition. The decrease in permeability with time is mainly due to the self-healing mechanism in soft soils, which is dictated by the soil deformation and migration of fines driven by the confining pressure and hydraulic gradient.