Research on rock damage characteristics of gravity tunneling machine based on different rotational speeds.

To address the challenges of difficult rock excavation and low mechanical breaking efficiency in vertical shafts, a gravity-driven shaft tunneling machine with improved adaptability for medium-hardness rock tunneling has been developed. By integrating numerical simulation and field testing, this study clarifies the dynamic rock-breaking mechanism of the cutter under the combined action of gravitational force and the tunneling machine's rotational force. The approach aims to investigate the dynamic destruction process of rock under varying drum rotation speeds, analyzing rock crack development, crushing characteristics, and the variation laws of the cutter's rolling and normal forces. Research results indicate that once the cutter of the new shaft tunneling machine penetrates the rock, driven by its self-gravity and the machine body's rotational force, the tensile and shear stresses exerted on the rock exceed its inherent tensile strength, compressive strength, and shear strength thresholds. This leads to rock disintegration and separation from the main rock structure. The findings provide an effective reference for actual shaft construction projects.