New customized testing equipment specifically developed to address the dynamic fracture of material excavated by a roadheader at a laboratory scale is shown. Furthermore, limestone and cement-based material samples are tested to analyze the response of both the material and the cutting head when the number of acting picks is increased as a consequence of the translation of the whole roadheader during the excavation process. Results prove that the new equipment allows to identify the initial and end points of the contact between the sample and each of the picks, as well as the relation between the material strength and the mechanical specifications of the excavating machine. Thus, the new equipment can be used to tailor cutting head designs and to optimize the cutting parameters for a particular mechanical removal operation.
Mining and civil engineering projects usually require to remove huge quantities of rock material in order to build galleries or tunnels. Main methods used to achieve such challenge are blasting and mechanical excavation. Using explosives is a complex and expensive technique, as its transport, storage and use have to be carefully executed under different law requirements (Deshmukh et al. 2020). Consequently, mechanical excavation is consistently becoming commonplace nowadays, as it involves less risk to the surrounding buildings, slopes and structures such as damns or mines themselves. The vast majority of these mechanical removal methods are based on the action of several picks, arranged on a cutter head, that crash against the rock material producing its breakage in form of chips. Literature on the physical phenomenon involved in this mentioned interaction between the pick and the material is mainly based on the theory proposed by Evans (I. Evans 1962; Ivor Evans 1984a, 1984b). His contribution lead to many improvements on the cutting techniques over the years, allowing the development of the state of the art in related fields as: weathering and damaging of picks (Fan et al. 2023), efficient design and safety requirements (Li et al. 2012), or even models to estimate the performance of roadheaders depending on the geological characteristics of the rock mass (Wang et al. 2021).
