Study Assesses Best Ways to Stop Road Damage from Rocks

Brief 

Roadway hazards posed by rockfalls can be mitigated with a framework developed by researchers at West Virginia University. Using prioritization and sensitivity analysis to assess the degree of hazard, the study concludes that soldier piles and precast concrete panels are the most preferred option.

Insight

Drivers on winding West Virginia roads often encounter road damage caused by rockfalls, even if they aren’t present when the rocks tumble down the hillside.

West Virginia University researchers hope to cut down on these events, as a pair of engineers have examined countermeasures considered useful in mitigating rockfalls, which can result in vehicle damage, traffic disruptions and injury or death to motorists.

Yoojung Yoon and Hota GangaRao, professors in the Wadsworth Department of Civil and Environmental Engineering, offer a framework to evaluate the cost-effectiveness of design options for rockfall countermeasures that focus on rural local road rockfall. The framework is composed of three main steps: rockfall hazard assessment, prioritization and sensitivity analysis.

The duo’s research has been published by the American Society of Civil Engineers.The two researchers’ prioritization framework was demonstrated with a case study in West Virginia, which confirmed that it was able to provide decisionmakers with a sense of certainty about the top-ranked alternative, which was soldier piles and precast concrete lagging.

Soldier piles are steel piles that are vertically drilled into the earth prior to excavation. Precast concrete lagging are concrete panels that are inserted behind the front pile flanges. The lagging efficiently resists the load of soil and transfers it to the piles.

“Rockfalls are caused by the freezing and thawing of rocks resulting in expansion and contraction over a period of time (thermal fatigue),” GangaRao said. “Also, falls may happen due to increased overburden near steep cliffs due to building construction, change in direction of run-off water or other man-made disturbances at sites. Other potential reasons could be attributed to blasting of sites resulting in fissures in geological formation near the blast site.”