2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 161-10
Presentation Time: 3:45 PM


POLK, Jason1, FEDERICO, Ric2, HAM, Brian C.2, NEDVIDEK, Daniel2, MCCLANAHAN, Kegan3, NORTH, Leslie4, KAMBESIS, Patricia N.5 and MARASA, Michael6, (1)Center for Human-GeoEnvironmental Studies, 1906 College Heights Blvd. #31066, Bowling Green, KY 42101, (2)EnSafe, Inc., 1148 College Street, Bowling Green, KY 42101, (3)WKU Dept. Geog & Geol, 1906 College Heights Blvd. #31066, Bowling Green, KY 42101, (4)Center for Human-GeoEnvironmental Studies, Department of Geography and Geology, Western Kentucky University, 1906 College Heights Blvd. #31066, Bowling Green, KY 42101, (5)Dept. of Geography & Geology, Western Kentucky University, Bowling Green, KY 42101-1066, (6)Hayward Baker, Inc., 53 Century Blvd., Suite 200, Nashville, TN 37214, jason.polk@wku.edu

On February 12th, 2014, a sinkhole occurred at the National Corvette Museum in Bowling Green, Kentucky. The collapse occurred inside the Skydome portion of the building, where eight rare Corvettes fell into the hole that opened in the concrete floor. Investigation of the sinkhole collapse began immediately while the Corvettes were extracted from the void. Due to the complex nature of the sinkhole’s location inside the building and threat of further damage and safety concerns, a multi-disciplinary approach was used to collaboratively bring cave and karst geoscience, geology, engineering, hydrology, construction, and geophysical methods together to investigate and explore the sinkhole and underlying cave passage. Techniques used for investigation included water jet drilling, downhole cameras and drone footage, a microgravity surface survey, 3D laser mapping, various analytical techniques for monitoring and mineralogical investigation, and high-resolution survey of the void and accompanying cave. These data, which provided one of the most robust sets of information on a sinkhole of this type, allowed for a detailed interpretation of its formation and best path for remediation. The cause of the sinkhole was determined to be a cave roof collapse in a breakout dome. The cave passage underlying the collapse is about 65 meters long and averages 12 meters wide, with a maximum depth of 20-25 meters. Structural integrity of the thinly interbedded limestone and chert located at a contact between two major bedrock units is lacking in the area. Talus and breakdown are abundant in the cave in which the sinkhole formed and the progression of the roof failure likely occurred over a long span of time, eventually giving way due to a variety of conditions, including speleogenetic and climatic factors. The sinkhole has been remediated based on the investigation’s findings using a micropile supported concrete floor and subsequent investigation of a portion of the passage since construction indicated that the cave is currently stable and no additional changes occurred during the work. The project highlights the importance of collaborative karst geotechnical investigations to better understand and remediate karst hazards, such as sinkholes, and the usefulness of combining existing and new methods during the process.