This case study reviews the observation of recurring tension cracks near the crest of a closed landfill with a composite cover system. It delves into the subsequent stop-gap repairs, monitoring, and eventual design and implementation of a long-term solution.

After attempts to repair the obvious damage, monitoring and observation demonstrated that something larger was occurring. The landfill owner surveyed hubs set in and around the section of slope in question, demonstrating that the slope was creeping. The tension cracks reappeared. Eventually, it was decided to implement a more aggressive repair, including the removal of cover soils, replacement of damaged geosynthetic components, and incorporation of a geogrid reinforcement layer to provide the tensile strength required to stabilize the slope before replacing the cover soils.

Once uncovered, the configuration of the geosynthetic components told their own compelling story about the relationship between design and proper construction principals. Like most disasters, this ongoing failure was not likely the result of one isolated issue, but the compounding of multiple issues related to the cell construction, landfilling, and geosynthetic placement. The field team battled adverse weather conditions to complete the repair, and the cover has remained stable through eight spring seasons so far.

About the Speaker

Gordon Parish
Senior Engineering Geologist | T&M Associates Inc.

Gordon Parish graduated from Michigan Technological University with a BS in Geological Engineering and a MS in Environmental Engineering. Out of college, he began his career with Malcolm Pirnie Inc., working on Solid and Hazardous Waste Projects. Over the years, he has worked on landfill designs including composite cover and liner systems, slope stability and settlement, and landfill gas collection systems. He has been with T&M Associates since October 2012, working with landfill clients in Ohio, Michigan, and New Jersey.