Design considerations for slip interfaces on steepwall liner systems

Richard Thiel, Edward Kavazanjian Jr., and Xuan Wu present the design considerations for slip interfaces on steep-wall liner. In the design of steep slope lining systems, the authors believe it is necessary to be able to accommodate down-drag without incurring any damage to the primary liner system. Furthermore, tension in liner system elements, and in particular in the geomembrane component of a liner system, should be minimized. Protection of a steep-slope liner against down-drag damage can be accomplished in two ways. One method is to provide one or more preferential slip surfaces above the primary liner. The design approach suggested by the authors to safely mitigate the potential for undesirable shearing and tension of the primary geomembrane is to introduce a slip element underlain by a high strength geotextile that would be anchored on the intermediate benches of the side slope and extend partway down the slope. The design concept of using a slip interface in conjunction with a high-strength geotextile to accommodate down-drag is a feasible design methodology.