The Application Research of Cantilever Roadheader in Soft Rock Tunnels of the Qinling Mountains

To address the challenges of high support deformation risk in soft rock tunnels of the Qinling Mountains and slow construction speeds in small-section tunnels due to spatial constraints, this study leverages the engineering geological characteristics of the region. These include predominantly mudstone and sandstone, well-developed joints and fissures, and moderately strong surrounding rock. Based on the Lianhua Mountain Tunnel project, the use of a cantilever roadheader in small-section tunnels with soft rock geology was introduced. Through in-depth research on adaptability and design parameters, it was demonstrated that the cantilever roadheader exhibits good adaptability in the soft rock regions of the Qinling Mountains and has significant potential for broader application. The application research results show that the cantilever roadheader causes minimal disturbance to the surrounding rock, resulting in smaller deformation. It also demonstrates a notable progress advantage in sandstone and conglomerate tunnels, particularly in Class IV and V surrounding rock, where construction speed increased by nearly 90% compared to the drilling and blasting method.