Unreinforced geosynthetic clay liner case history

This paper describes a slope failure involving an unreinforced geosynthetic clay liner (GCL) in a municipal solid waste (MSW) landfill liner system. The precise mechanism for the shear movement of the interim slope is not known. However, the significant damage observed in the upper components of the composite liner system suggests that the failure was translatory primarily along the interface between the recompacted soil liner and the overlying hydrated bentonite of the geomembrane-backed GCL. It also appears evident that the slope inclination, slope height, physical characteristics, e.g. high unit weight, of the waste, and possibly the overlying smooth geomembrane/geonet interface played a significant role in the movement. Design recommendations for interface strengths and stability analyses are also presented.