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IGS-ICE Webinar Shares Insight On Landslide

Lessons learned from the catastrophic Yeager Airport landslide were explored during a recent ICE-IGS webinar.

The virtual event, organized by the North West region of the Institution of Civil Engineers (ICE) with the UK Chapter of the IGS, discussed the failure of the reinforced soil slope (RSS), which caused a landslide damaging part of a runway, buildings and a valley road.

The public airport near Charleston, West Virginia, in the United States, sits on a hilltop about 100m above the Elk and Kanawha river valleys. In March 2015 a section of slope, composed of a 67-metre-high engineered fill of 1.5 million cubic yards of dirt created in 2006, caused part of the hill to slip into the valley below.

Speakers Dr. Jim Collin and Ryan R. Berg explained how in 2013 a tension crack was observed at the top of the slope, and two years later the RSS collapsed. The webinar shared findings from the forensic investigation determining the causes and lessons for future prevention.

 Yuli Doulala-Rigby, senior vice-chair of ICE NW, said: “We don’t often get to hear post-failure examinations so the webinar was a great reminder of how important a good preliminary desk study and site investigation is for every geotechnical project.

“The talk also reinforced, once again, the importance of proper assessment of foundations and proved why design specifications must not change during construction prior to checking that the changes won’t harm the stability of the end structure. In this case the design length of the base geogrid layers was arbitrarily shortened during construction, which was one of the many reasons that led to this catastrophic failure

“One of my favourite quotes from one of the attendees was, ‘Interesting lecture about Yeager. An example on how to design a failure.’”

Patricia Guerra, IGS UK’s vice-chair, said: “It was really interesting to learn the different approaches used to analyse the failure, how they studied all the elements of the structure, and the different scenarios to understand the causes.

“The failure occurred just over eight years after the reinforced slope was in service, which also demonstrates the importance of the analysis for short, medium and long term, especially when the structures are so big with complicated ground conditions.”

She added: “Having a joint event with ICE was a great opportunity for the IGS Chapter to reach a bigger audience and have a higher impact within the engineering community.”

The live online event drew more than 126 attendees, with many more expected to view the recording, which is available here.

The speakers have authored a journal article on the subject, available here, which is published in the latest issue of Geotextiles and Geomembranes. Explore more articles for free through the IGS website here.