The use of geotextiles as filters in unsteady flow conditions

摘要

The paper deals with the design of geotextile filters in unsteady flow conditions, typical of geotechnical applications in coastal and hydraulic structures such as canals, inland waterways, reservoirs. In these applications, boundary conditions (i.e. vertical stresses and interface continuity) and flow conditions can be very different and not always easy to predict. In particular, while in the applications of geotextiles as filters under flexible revetments the vertical effective stresses are low and the contact between the filter and the base soil may be not continuous, in submerged or submersible foundations of coastal structures vertical effective stresses are high and the geotextile filter is in close contact with the base soil. In the paper the influence of design parameters on the soil - filter interaction in unsteady flow condition is analyzed and some indications on the choice of the appropriate design criteria for such specific applications are provided.