It has been stated that there is no reliable method of predicting the overall strength and deforma-tion behavior of a rock mass from the results of laboratory tests, such as the unconfined compression
test on small rock specimens. This is because the settlement behavior of rock is strongly influenced
by large-scale in situ properties, such as joints, fractures, faults, inhomogeneities, weakness planes,
and other factors. Hence using small core specimens to predict settlement behavior will often pro-duce highly inaccurate results, with the inaccuracy increasing as the RQD decreases (see Sec. 4.2.8
for definition of RQD). Because of this limitation, field tests are preferable, with some options for
determining the settlement of heavily loaded foundations on rock as follows: