Development of a new laboratory apparatus for the examination of the rotary-percussive penetration in tunnel boring machines

This paper describes the design and implementation of a new laboratory apparatus to model the recently proposed rotary-percussive penetration (RPP) technology to be applied in tunnel boring machines (TBMs). It also deals with the tests carried out to explore the pure effect of appending a percussive load to the other applied loads during excavation in the prepared specimens. Results of this study confirmed that the combined mode of cutting-impact is very effective in the cutting of the moulded specimens. A good agreement was also achieved between the results of the experiments and the previously developed analytical model. Therefore, this research generally shows that the percussive load can ultimately improve the rate of penetration (ROP) of disc cutters of a modelled tunnel boring machine.

► Design and implementation of a new laboratory apparatus to model the RPP technology. ► Determination of the pure effect of appending a percussive load to the other applied loads in TBMs. ► Showing the capability of the percussive load to improve the ROP of disc cutters of a modelled TBM. ► Good agreement between results of the experiments and the previously developed analytical model.