New Applications for Smart Geosynthetics

Abstract

Most geosynthetics play a passive role, e.g. barriers stop the passage of liquids: reinforcement provides tensile resistance, but only after an initial strain has occurred; and drains provide a passage for water but do not cause the water to flow. New applications for geosynthetics can be identified if the geosynthetic can provide an active role, initiating chemical or physical change to the matrix in which it is installed as well as providing the established functions. Smart geosynthetics are ideal candidates to initiate electro-kinetic processes. It has already been established that conductive geosynthetics, acting as electrodes can be used to effect the movement of contaminants through soil to the electrodes and then adsorb them. Using electrophoresis it is possible to dewater industrial wastes, which are currently untreatable and can only be disposed of in vast tailings lagoons. Conductive geosynthetics can be used to reduce the volume of industrial wastes by electro-osmosis thus significantly lowering the cost of disposal; the use of conductive reinforcement can permit the use of fine wet materials as fill for reinforced structures. Initial studies have shown that the use of electrically conductive band drains could prevent liquefaction of susceptible soils during earthquakes. Other applications can be seen in different fields such as sport and horticulture. The use of conductive geosynthetics can resolve some of the problems inherent in many large stadia, such as the detrimental effect of shade on growing surfaces. An electrically conductive geosynthetic laid as a continuous porous membrane at root level provides oxygen directly to the root system as well as offering a method to control drainage, aeration, and ball bounce. A working model of this technology was exhibited in the Science Museum in London during the 2002 football world cup. Designing with smart geosynthetics involves consideration of soil properties not usually considered in design. The paper identifies these and illustrates their relevance. A number of new applications for smart geosynthetics are identified.