When mountain tunnels traverse complex geological structures, mud inrushes and water gushing disasters seriously threaten construction safety and progress. Taking a tunnel surmount project as an example, this paper systematically analyzes the causes of surge disasters and proposes an integrated treatment scheme of "left tunnel reinforcement, right tunnel drainage, combination of plugging and drainage". Key optimizations were made to advanced curtain grouting technology: (1) Adopting segmented forward grouting combined with ultra-fine cement material to enhance slurry diffusion capability in sand layers; (2) Optimizing grouting section length to 25 m to improve construction efficiency; (3) Implementing drainage holes and grout walls to control groundwater dynamic equilibrium. During field construction, the grouting range covered 6 m beyond the arch excavation line. Multiple materials including cement mortar, single-fluid slurry, cement-sodium silicate dual-fluid slurry, and ultra-fine cement were selectively used with PVC pipe bottom grouting technology, achieving over 80% grout filling rate. Water pressure tests in inspection holes revealed permeability rates below 2 L/min, verifying reinforcement reliability. Additionally, ?108 mm advanced pipe roof support was installed in the arch section complemented by real-time dynamic monitoring for early warning of abnormal conditions. Results demonstrate that the optimized solution effectively addressed water-rich fractured surrounding rock reinforcement challenges, showing uniform grout vein distribution and significantly improved stability after excavation. These findings provide technical references for advanced treatment of tunnel surge disasters under similar geological conditions.