Abstract：Classification of rock drillability in real time using the curves of drilling process parameters is a bottleneck of the development and application of the instrumented drilling system. According to analysis of statistical mode recognition and characteristics of drilling parameter data，a discriminant classification method and validity test method have been established respectively for known categories and categorical numbers as well as for unknown categories and categorical numbers by minimum-distance clustering criterion. The methods have been used to classify the weathered granite formation by diamond penetrating specific energy curve. The results show that the clustering approach possesses excellent performance in classification，high precision and low misjudgment ratio and well agrees with the geological logs of rock core in general weathered granite formations，which can provide a quantitative discriminant approach for automatic classification of geotechnical engineering.
