It has been 20 years since the research scheme of intelligence of rock mechanics was proposed in 1993, based on the encouraging achievements on investigation of artificial intelligence and expert system and its application to rock mechanics and engineering problems started from 1986. The past 20 years have seen enormous progress in the development of the new direction-intelligent rock mechanics (IRM) as proposed thereafter in 1997 (Feng et al., 1997), both in basic theories, fundamental techniques, algorithms and tools and applications. Even at present, the methodology of IRM has been added as a complementary standard for rock engineering design (Feng & Hudson, 2011). The aim of this work is to quickly review the past 20 years of research and work in the field. It covers some of the most important methods that have been developed, with a focus on the applications to some of the most complicated rock engineering problems constructed in China during the last decade.
The second author started the research of artificial intelligence and expert system and its application to rock mechanics and rock engineering problems since 1986, based on the acknowledgement that the deterministic method inherited from the conventional sciences like Material Strength and Elasto-plastic Viscosity are not always satisfactory, especially under the conditions that many new and more complicated problems will be met in rock mechanics with the construction of large and new engineering projects. During the following several years, different methods from the fields of artificial intelligence, nonlinear sciences and system sciences, etc. are investigated and a variety of theories, techniques, algorithms and tools are developed, verified and applied in different rock engineering with encouraging results. This indicated us a new research scheme of intelligence of rock mechanics in a more interdisciplinary manner as proposed in 1993, and "A new direction-intelligent rock mechanics" was proposed thereafter (Feng et al., 1997). Besides the development of new analysis methods in rock mechanics, some new design concepts are systematically programmed for rock slopes, underground openings and underground mines. A more definite explanation was publish in 2000 (Feng, 2000) after extensive validation of the research scheme.