Abstract
The purpose of the paper is to investigate experimentally the effect of skew angle of a roller cutter positioned in the center part of a tunnel boring machine on the amount of excavation and wear against granite and two-pyroxene gabbro. The radial cross section of the tip of roller cutter was designed to be trianglular shape for increasing the amount of excavated debris. The experiment was executed for a skew angle from 0 to ±π/9rad and a normal load of 0.98 to 11.8kN. As the results, it was observed that, the amount of excavation of two-pyroxene gabbro increases with skew angle and the amount of excavation per unit work has peak values at skew angle of ±π/36rad, after that it increases with skew angle, the amount of wear can be expressed as the exponential function of skew angle, normal load and rolling distance, and that the optimum skew angle to maximize the amount of excavation per unit work and minimize the amount of wear is ±π/36rad.
