Study of pressure distribution within the crushed zone in the contact area between rock and disc cutters

Abstract

Estimation of the cutting forces acting on a disc cutter while cutting rock has been used for cutterhead design and performance prediction of tunnel boring machines (TBMs) and various other mechanical excavators. The cutting forces are the result of the pressure in the contact area between the disc cutter and rock surface. This paper presents the result of direct measurement of pressure in this contact area and observed pressure distribution patterns when cutting various rock types. The results show that the pressure within the contact zone is more concentrated, and the actual pressurized area is smaller, than the size of the contact zone that has been assumed by previous models. The measurements also show that there are areas of no pressure within the theoretical contact zone both in front of the highly concentrated pressure zone and behind it. This indicates that the peak stresses within the cutter ring are higher than normally expected, and explains the reason for some observed behavior of various disc cutters in the field.