How do you calculate the RQD of a rock?

Therefore, RQD = (640/1200)x100 = 53\% which is fair quality rocks, i.e. rocks are moderately weathered.

What means RQD?

Rock quality designation
Rock quality designation Rock-quality designation (RQD) is a rough measure of the degree of jointing or fracture in a rock mass, measured as a percentage of the drill core in lengths of 10 cm or more. High-quality rock has an RQD of more than 75\%, low quality of less than 50\%.

What is RQD rock mechanics?

Rock quality designation (RQD) is a standard technique in the mining industry for the qualitative and quantitative assessment of rock quality and degree of jointing, fracturing, and shearing in a rock mass.

What is rock quality designation What is it used for?

RQD was devised in 1964 as an index for classifying the relative quality of rock core obtained from small diameter core drilling (about 50 mm) (Deere and Deere 1989). Since such a humble beginning, RQD has been adopted as a fundamental tool in characterizing rock masses.

Is Rqd a code?

on a modified core recovery procedure, which in turn, is based indirectly on the number of fractures and the amount of softening or alteration in the rock mass as observed in the rock cores from a drill hole. RQD shall be based on IS : 11315 ( Part 11) – 1985*.

Which is considered while calculating Rqd?

3.1 The RQD denotes the percentage of intact rock retrieved from a borehole. All pieces of intact rock core equal to or greater than 100 mm (4 in.) long are summed and divided by the total length of the core run, as shown in Fig. 1.

What is RMR value?

RMR combines the most significant geologic parameters of influence and represents them with one overall comprehensive index of rock mass quality, which is used for the design and construction of excavations in rock, such as tunnels, mines, slopes, and foundations. …