STABILIZATION OF WEDGE FAILURE IN ROCK SLOPE

A wedge failure in a rock slope 21 m (70 ft) high was stabilized by unloading the top third of the failure, constructing a concrete wall to reinforce the toe, and installing tensioned rock anchors. Because the potential failure was located above a major railroad line, it was necessary to carry out this work with minimal interruption of traffic. This required careful blasting to ensure that the track below the slope was not damaged by falling rock and the use of equipment that would not block the track. The use of decision analysis to review the alternative stabilization methods and select the optimum method is discussed. The probabilities of slope failure, which were used as input in decision analysis, were obtained from a Monte Carlo analysis. The purpose of the Monte Carlo analysis was to quantify the uncertainties in the rock strength and structural geology parameters that were used in the design. (Author)