Geotextile filter design and simulated bridge formation at the soil--geotextile interface

摘要

A set of geotextile filter design criteria has been developed by simulating soil particle bridges on the surface of idealised geotextiles. The soil particles were represcnted by discs in two- dimensional models and by spheres in three-dimensional models. The models examined the relationship between uniformity coefficient, particle size and pore size, and resulted in two overlapping phenomena being observed. At uniformity coefficients less than 2.0, bridge formation is dependant upon particle interlock and packing, whilst at uniformity coefficients greater than 2.0, large particles act as catalysts for bridge formation. These phenomena resulted in the specification of an upper O_90/d_90 ratio. Further analysis revealed that certain particles did not usefully contribute to bridge formation, which resulted in the specification of a lower O_90/d_90 ratio. Both these concepts have been incorporated on a final design chart, which is then compared to other published filter design criteria.