Reasonable vertical position of the advanced center drift in super deep buried soft rock tunnel

Abstract

In super deep-buried soft-rock tunnels, significant deformation disasters often accompany high-ground stress. Advanced center drift stress release technology to release some in-situ stress in advance can effectively solve many problems caused by large deformation. Therefore, based on the Haba Snow Mountain Tunnel in the Lijiang Section of the Yunnan-Tibet Railway, the research on the vertical reasonable position of the advanced center drift is carried out. Using literature research, numerical simulation, and on-site experiments, the deformation of surrounding rock, the stress distribution of support, and the distribution of the plastic zone of surrounding rock at different vertical positions of the advanced center drift are studied. The application effect of the advanced center drift is analyzed through on-site monitoring data. The results show that different advanced center drift vertical positions have a stress-release particular impact. When the arch top of the advanced center drift is 2 m away from the main tunnel arch top, the stress release effect and support stress are relatively ideal, and the on-site measured tunnel deformation can reduce by an average of 44.52%. The research results can provide a reference for the design of advanced center drift in similar projects.