Page 29 - Handbook GEOTEKNIK_Final_Neat

Rock Quality Designation (RQD) Field Testing

Field Works Description/ Limitation Photos
 The RQD is a modified Purpose
core recovery

 Measure of the degree of 3.  to obtain  not reliable
fractures, joints, and Mackintosh the bearing for deep
discontinuities of rock Probe (MP) capacity foundation
mass or indication and critical
JKR Probe by no. of areas.
blows per
 RQD = sum of pieces > 300mm  does not
100 mm divided by total give soil
core run description

Table 4 : Rock Quality Description
 unable to
penetrate
RQD (%) Description of rock hard stratum
quality or gravel

bed
0 - 25 Very Poor
 max depth
25 – 50 Poor
15.0m
50 – 75 Fair

75 – 90 Good

90 - 100 Excellent

Figure 7: Mackintosh Probe (MP) and MP Logs
Figure 6: Rock Quality Designation

12 PUBLIC WORKS DEPARTMENT MALAYSIA GEOTECHNICAL ENGINEERING HANDBOOK 13