The Missouri Rock Fall Hazard Rating System (MORFH RS), a risk/consequence based classification system has recently been completed. The system was specially developed for Missouri, which tends to have low but highly weathered cuts, with special problems from highly weathered karst features such as filled sinkholes.
MORFH RS utilizes mobile video imaging for primary screening of rock cuts. Rock cuts identified as potentially problematic are assigned for further evaluation. Images of the rock cut, taken from the video, are used to make measurements of rock cut parameters such as slope height, slope angle, ditch width, ditch depth, potential rock fall quantity, and shoulder width, and other parameters required for the rating. Other properties such as face looseness, instability, weathering, strength, block size need to be assessed by field inspection, for the problematic cuts only. Location information is obtained from a GPS receiver. Rock cut locations, attributes, hazard ratings, digital photographs, GPS coordinates, and other data are presented in a single page report.
MORPH RS then calculates a risk and a consequence rating, based on the measured and assessed parameters. Separating risk and consequence of failure is important because sometimes high risk and low consequence can be tolerated more than low risk and high consequence. In addition, some parameters such as block size are used in both the risk and consequence ratings: Larger block size decreases the risk of failure, but increases the consequence.
MORPH RS, during development, has been used to analyze over 500 Missouri rock cuts. Over 300 cuts were analyzed in detail and are ranked according to risk and consequence. These results can be used by the Department of Transport to prioritize remediation. A simulation has been conducted that shows the relative merits of various forms of remediation treatments.
Missouri. Department of Transportation
University of Missouri Research Board
- Missouri Rock Fall Hazard Rating System (MORFH RS),
- Mobile Video Imaging,
- Rock Cuts
Available at: http://works.bepress.com/norbert-maerz/17/