Abstract

In this paper, an analytical modeling has been carried out to realize the effect of appending a supplementary percussive load to the rotary energy of tunnel boring machine's disc cutters, as a novel technology. In this path, two models have been built by using the theory of plasticity for prediction of the amount of penetration of a disc cutter assumed in form of a V-shaped indenter in rock medium. Since the types of applied loads at two phases (rotary versus percussive) differ, it was obligatory to consider different analytical models for each phase. At first stage of the modeling process, a part of previously constructed model for determination of tool penetration into rock has been used. Then, at the next stage, the depth of penetration resulted from the impacts of a striker on the disc cutter has been modeled by using the kinematic method. The aggregative penetration of the disc by application of rotary-percussive load has been considered as non-algebraic summation of penetrations in two stages. Finally, an illustrative example has been presented to show the application of the models in a real situation. In both models, the friction between penetrating tool and the rock has been taken into account.

Key words: Novel rotary-percussive technology, hard rock TBM, analytical modeling, disc penetration.