| Popis: |
Rock Quality Designation, RQD, was introduced by Deere as a form of modified core recovery index which could be used to describe the quality of a rock mass. RQD has since been used to predict cavability of rock mass, determine support requirements for tunnels and drifts, and generate functional relationships with other physical properties of rock masses. The difficulty in generalizing the use of RQD (often without exercising due caution) is that RQD as an index may not be robust, that is, not all variables of which RQD is a function may be impacting on the core-drilling phenomenon. Specific examples of the problems involving RQD include the use of RQD for characterizing rock masses for cavability and the influence of core breakage on RQD. |
