Abstract: Rockburst disasters present serious threats to the structural integrity of deep tunnels, construction progress, and personnel safety. To address the limitations of existing support technologies in dissipating rockburst energy and maintaining the stability of surrounding rock, targeted research is conducted on the Qinling water conveyance tunnel of the South-to-North Water Diversion Project. Given the frequent rockbursts in the deep-buried section of the project, a three-dimensional negative Poisson′s ratio (NPR) active support system is implemented to replace traditional passive support methods for rockburst prevention and control. This approach includes experimental and monitoring efforts. During construction, pressure sensors, reserved deformation measurements, and a high-resolution microseismic monitoring system are deployed on-site to evaluate and compare the effectiveness of the three-dimensional NPR active support system against conventional passive support approaches. The findings are as follows: (1) The proposed system combines the synergistic effects of high prestress active confinement and energy absorption, effectively reducing the depth of rockburst craters, the stress on the steel arch frame, and the cumulative deformation of the surrounding rock, thus demonstrating superior prevention and control capabilities compared to traditional passive support approaches. (2) The system effectively minimizes displacement in critical areas, such as the tunnel crown and arch waist, and markedly reduces the distribution area of the surrounding rock′s plastic zone, thus enhancing the overall stability of the surrounding rock. (3) Comparative experiments under different support timings show that earlier support leads to slower deformation rates and lower final damage levels in the surrounding rock.

Key words: deep tunnel, rockburst prevention and control, negative Poisson′s ratio bolt, active support system, microseismic monitoring, numerical simulation