In March, a rock slope failure along State Route 7 in Mingo Junction prompted the Ohio Department of Transportation (ODOT) to initiate a rock slope repair project. As the planning and design for a major excavation got underway, ODOT combined the use of televiewers — an advanced geotechnical methods in exploration (A-GaME) technology — with conventional boring data to reduce uncertainties and boost confidence in the design.
According to Christopher (Cody) Notz, P.E., district geotechnical engineer for ODOT-District 11, ODOT crews took five soil borings on the slope above the rock slide. The soil borings showed that the rock was very poor quality, with high angle fractures and significant water. “We knew that the information we got from the soil borings and from the rock cores wasn’t enough for us to confidently design this slope,” Notz points out. “Once you pull the rock cores from the borehole, you can view the joints and the discontinuities, but there is core loss so you don’t have a full picture of what’s actually in the hole.
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