Influence of polyurethane foam on chemical clogging of nonwoven geotextile and tailings caused by ferrous iron

Abstract

The chemical clogging of geotextiles filters is a common issue, which threatens the safety of engineering projects. To reduce the chemical clogging of nonwoven geotextiles and enhance their drainage capability, a polyurethane foam was innovatively placed under the nonwoven geotextiles in this paper. A series of column tests were conducted to study the mechanism of the polyurethane foam to reduce the chemical clogging of the nonwoven geotextile filters in tailings caused by ferrous iron. In addition, the influence of the concentration of Fe2+, hydraulic gradient and thickness of the tailings specimen on the chemical clogging of the polyurethane foam and nonwoven geotextiles was examined. Less chemical clogging of geotextiles caused by polyurethane foam was observed and the related mechanism was firstly explained. The polyurethane foam under the geotextile reduced the contact between the geotextile and air. As a result, the chemical clogging of the geotextile was alleviated, which increased the drainage capability of the geotextiles. A high water saturation of the polyurethane foam would help to a reduce the extent of the chemical clogging of the geotextile. The chemical clogging characteristics of geotextiles and polyurethane foam under different concentrations of Fe2+ and hydraulic gradients were observed.