Rock Quality Designation (RQD) is a measure of quality of rock core taken from a borehole. RQD signifies the degree of jointing or fracture in a rock mass measured in percentage, where RQD of 75% or more shows good quality hard rock and less than 50% show low quality weathered rocks.

KEY WORDS: rock mechanics, Rock Quality Designation index, modulus of deformation, jointed rock, tunnel supports, rock mass classification, core logging The Rock Quality Designation (RQD) index has been used for over 20 years as an index of rock quality. It measures the percentage of "good" rock within a borehole.

The RQD Analysis option allows you to calculate the Rock Quality Designation (%) calculated from distance measurements recorded along a linear or borehole Traverse.

RQD is defined as the percentage of intact core pieces longer than 100 mm (4 inches) in the total length of core. The core should be at least NW size (54.7 mm or 2.15 inches in diameter) and should be drilled with a double-tube core barrel.

Jun 26, 2024 · Rock Quality Designation (RQD) measures the quality of rock cores from boreholes by calculating the percentage of core pieces longer than 10 cm. It helps assess rock mass integrity, with higher RQD values indicating better quality rock with fewer fractures, and lower values indicating more fractured, poorer quality rock.

The RQD Analysis option allows you to calculate the Rock Quality Designation (%) calculated from distance measurements recorded along a linear or borehole Traverse.

Download scientific diagram | Procedure for measurement and calculation of Rock Quality Designation (RQD) (Deere and Deere, 1988) from publication: Most used rock mass classifications for ...

Sep 4, 2024 · Rock Quality Designation (RQD) is an important measure in geotechnical engineering used to assess the quality and fracturing of rock masses. It is calculated as the percentage of rock core pieces longer than 10 cm (4 inches) relative to the total drilled length.

It is a quantitative classification system for estimates of tunnel support, based on a numerical assessment of the rock mass quality using the following six parameters: Rock quality designation (RQD). Number of joint sets (Jn). Roughness of the most unfavourable joint or discontinuity (Jr).

Jun 26, 2011 · Rock Quality Designation (RQD) is the ratio of sum of drill core lengths longer than 10 cm to total drill length which gives the degree of the fractures in rock mass (Fig.1). It is developed by Deere in 1963 [4]. It is a widely used parameter in rock quality determination because of its simplicity.