Abstract: Advance grouting reinforcement reduces groundwater inflow and stabilizes surrounding rock, facilitating TBM recovery and bypass tunnel excavation in large-section, high-pressure, water-rich granite alteration zones. The authors systematically investigate the feasibility and key technologies of advance grouting reinforcement under extremely complex and adverse geological conditions. Based on engineering practice at the Gaoligongshan tunnel exit section along the Dali-Ruili railway, a comprehensive technical framework is established—incorporating geological identification, grouting simulation, process innovation, material development, and equipment upgrading. A multi-physical field coupling grouting simulation is conducted to model grout migration within fracture networks under hydrodynamic conditions, leading to the proposal of key technologies for dynamic advance grouting. Field tests yield three major breakthroughs: (1) a high-torque, high-frequency hydraulic rotary drilling system is developed to resolve the low drilling efficiency problem; (2) a high-permeability, dynamic water-resistant composite grout is formulated using ultrafine cement modified with high-performance admixtures; and (3) an ultra-high-pressure drilling and grouting system capable of pressures up to 15 MPa is designed. Engineering results demonstrate that: the system achieves 85% grout retention under hydrodynamic erosion, 92%－95% water-sealing efficiency, deformation control within 18 mm, and an overall grouting efficiency improvement of approximately 72%. This approach proves essential for comprehensive treatment in complex alteration zones.

Key words: ultra-high-pressure water-rich granite alteration zone, grouting simulation, grouting test, high-performance admixture, advance grouting reinforcement technology