Error quantification in oriented-core data and its influence on rock slope design / Количественная оценка погрешности в данных ориентированного керна и ее влияние на проектирование скального откоса

Rock slope design requires detailed knowledge of the rock joint fabric, which is the most important parameter in bench-scale analysis. Rock-fabric data for open pit slope design may be difficult to obtain because mine planning often requires design slope angles years in advance of excavation and outcrop exposure. When rockfabric data cannot be obtained from surface mapping, one of the most cost-effective alternatives to obtain these data is oriented-core drilling. Because of various uncertainties in the core orienting process and the scale effect of measuring orientations over the length of a core diameter, oriented-core joint sets typically display greater dispersion than do the same sets from surface mapping. This paper presents a method to quantify some of the errors induced during the core orientation process with a simple measurement taken by the technician at the time of core logging, called the difference angle. The error distribution is quantified from the distribution of the difference angles and removed from the measured data population. The result is an improved representation of the in situ variation on the joint set. This reduction in data scatter is particularly important when conducting probabilistic bench-scale analysis with a joint set whose dip is near the joint friction angle. An example is given where the design slope interramp angle is increased by two degrees as a result of the reduction in the variance of the oriented-core data utilizing this method.  <...>