Research status and prospect of rock breaking form in mechanized excavation of mining hard rock roadway

Rapid excavation of hard rock tunnels was a crucial aspect in achieving intelligent and efficient coal mining. Cantilever roadheaders, TBMs, and bottom cutting equipment are all attempting to address this challenge. The development of excavation technologies and equipment directly impacts the safety and economic benefits of mining operations. Firstly, the applicable range and current status of cutting tool consumption of cantilever roadheaders in hard rock cutting conditions were summarized, followed by an analysis of on-site rock cutting experiments. The results indicated that under high rock strength conditions, cutting tool consumption doubles compared to normal wear, resulting in a mismatch between excavation speed and mining speed, severely constraining mine production. Secondly, the application of roller cutting rock breaking methods and equipment in the mining sector and the current status of new products was analyzed. The results showed that mobile mining excavation equipment using roller cutting for rock breaking results in less chunky debris, more powder, and low cutterhead thrust, leading to insufficient rock breaking capacity. Lastly, the principles and equipment development status of linear bottom cutting rock breaking technology and nonlinear bottom cutting technology were analyzed. The results demonstrated that with an increase in oscillation frequency, cutting forces significantly decreased, and nonlinear bottom cutting rock breaking consumes less energy per unit volume, showing clear advantages. However, key issues such as excavation efficiency and equipment stability in hard rock conditions remain to be verified. Nonlinear bottom cutting technology is expected to break through the technical difficulties of future hard rock excavation in mines.