Slope Stabilization with Recycled Plastic Pins

A scheme to stabilize minor slope instabilities is currently being developed. The scheme uses a distributed network of “pins” fabricated from recycled plastics and other waste materials to provide positive reinforcement of a soil mass. Although the application is similar to stabilization of slopes with soil nails or micropiles, significant modifications to conventional design and construction are necessary to account for the reduced strength and increased ductility and creep exhibited by plastic materials compared with concrete and steel. Using recycled plastics has the advantage of providing reinforcing members with low susceptibility to degradation and provides a market for materials that otherwise might be buried in a landfill. An extensive investigation is under way to evaluate the potential for using recycled plastic pins (RPPs) to stabilize minor slope failures. This evaluation includes quantification of appropriate material and engineering properties of RPPs, evaluation of RPP resistance to degradation in various environments, development and evaluation of suitable mechanisms for installing RPPs, evaluation of RPP resistance to driving stresses, development of a design procedure that accounts for the reduced structural capacity of RPPs compared with steel or concrete members, and installation and monitoring of several full-scale field demonstration sites. The ongoing evaluation program that is described focuses on laboratory tests to determine fundamental engineering and material properties, field driving trials to evaluate potential driving mechanisms, and preliminary development of a suitable procedure for designing RPP stabilization schemes.