ABSTRACT
Many rock cutting theories have been developed in the past decennia. In most cases, these theories apply to tunnelling (and not to dredging or trenching). A data-bank search specifically in ground excavation carried out at the US Army Waterways Experiment Station, Vicksburg, Mississippi, produced over 25,000 references, over a thousand pertaining to rock excavation. During many rock cutting experiments, the formation of chips of rock material in front of chisels, picks, bits or wedges has been observed. Dalziel and Davies and Bisschop measured cutting forces during rock cutting experiments. The formation mechanism and the shape of rock chips might be determined by factors like rock material (and rock mass) properties, shape of the cutting tool and depth of cut. A possible explanation for the difference in cutting action and wear could be that the limestone behaved in a ductile fashion whereas the sandstone behaved in a brittle fashion during cutting.
