Variation of rock quality designation (RQD) with scanline orientation and length: a case study in Korea

摘要: Abstract Rock quality designation (RQD) has been widely used to evaluate the degree of fracturing rock masses. Although it frequently pointed out that RQD is dependent on orientation measurement and scanline length, these effects have not considered in site investigation for tunneling Korea. Therefore, a series practical examinations using situ data collected from recent sites Korea conducted. Variation with was observed be as high 24% sub-horizontal where design based results vertical drill core logging. In addition, range possible variation length analyzed four different models, including two new models introduced this case study first time. It shown at least 4 m required maintain reliable value three models. The simulation so-called A–A–S model showed same reliability situation only much smaller extent (i.e. 0.4 m) exposure available field. hoped will provide tunnel engineer an enhanced understanding method.