Abstract
In-situ rock shear tests and laboratory shear tests are common for evaluating shear strengths of rock masses and rock cores. However, these methods are rather time consuming and costly, so that they are not appropriate for preliminary stage of geotechnical investigation. In this study, a novel technique of instrumented drilling under cyclically controlled thrust (ID-CCT) is developed as a simple and inexpensive sounding method for evaluation of strength characteristics of rock ground. A series of prototype drilling tests are conducted in two kinds of rocks, siltstone and tuff breccia, to investigate the influence of drilling conditions on the results of ID-CCT sounding. The tests demonstrate that the obtained results are insensitive to various drilling conditions except the type of drilling bit.
