ABSTRACT
Rock bolts in-situ traditionally are testedby means of diamond drilling or hydraulic jacks. Both methods are destructive and must not be used on production bolts. In addition pull out testing is limited to a maximum grout length of 25 cm. A new technique for non-destructive testing has opened away of “looking into” the rock or the bolt in-situ. Results from tests in Sweden and other countries have indicated faults on grout and bolt stem which otherwise would have been invisible.
