Engineering Rock Mechanics

180 Testing techniques

I

I I , 1 I

10 20 30 40 i 50

(^10) L (^20) I (^30) I 40 ‘50 I 60
20 30 40 50 Bo .a
20 30 40 50 80 v
Schmidt hammer (type L) rebound number
0 Broch &Franklin (1972)
x D’Andrea el al. (1965)
+Bieniawski (1974)
X
a
Strong
norite
C
0
0 50 I00 150 200 250 300 350
Uniaxial compressive strength ucf MN/m2
Figure 11.6 Schmidt hammer and point load test calibration curves.