Performance of the PVR Rock Slope at Valdez Marine Terminal

Five areas within Alyeska Pipeline Service Company's (Alyeska's) Valdez Marine Terminal (VMT) have steeply cut rock slopes that have been reinforced with rock bolts and monitored since the VMT was constructed. Monitoring has included regular reading of pneumatic piezometers that were installed in the slopes during construction. Flag levels were established for each piezometer on these slopes based on stability calculations or historical water levels. Annual reports are prepared to compare groundwater levels at each piezometer during that year to the established flag levels. If flag levels are exceeded, engineering reviews are made to assess the potential impacts of these excursions. Some piezometers have required maintenance and repair, and some rockbolts have required maintenance to maintain them to the standards assumed by the slope designers. Scaling and localized shotcreting have be required in some areas to control the potential for rockfall. This paper addresses the history of one of the VMT slopes, presents some of the long-term monitoring data, discusses the meaning of the data, and describes the maintenance activities that have taken place on the slope.