Anchorage-Seepage Coupling Mechanisms and Multi-Objective Optimization for Progressive Failure Control in Water level fluctuation Zones

Reservoir water-level fluctuation (WLF) zones are critically destabilized by cyclic seepage heterogeneity and soil erosion. This poses major threats to infrastructure resilience and slope stability. This study aims to elucidate the failure mechanisms and design adaptive reinforcement strategies. We combine transparent soil physical modeling with a machine learning-driven optimization framework. High-resolution visualization of nine orthogonal test scenarios was conducted. Results show that rapid reservoir drawdown induces upward migration of preferential flow paths. These paths are located within the 3rd to 6th permeability bands. This process triggers a six-stage retrogressive failure sequence. It begins with initial toe erosion, progresses to mid-slope tensile cracking, and finally forms terraced microtopography through collapse-slide interactions. A prestressed umbrella anchor systems was tested as a reinforcement measure. This system counteracts failure dynamics by densifying the soil structure. It also redirects failure surfaces to intersect anchor positions. Consequently, it effectively suppresses liquefaction-driven sliding. Furthermore, it converts catastrophic fluid-like collapse into localized, stress-controlled instability. A novel multi-objective optimization model was developed. It synthesizes asymmetric Nash bargaining and proximal policy optimization (PPO). This model resolves the key trade-off between slope angle, anchor spacing, drawdown rate. It generated 12 Pareto-optimal solutions that balance hydraulic and mechanical constraints. These designs achieve a 62–93% improvement in stability and yield 18–47% cost savings. Their performance was validated against displacement variance thresholds. This study establishes a dual intervention paradigm for WLF zones. It harmonizes seepage field management with strategic mechanical reinforcement. This integrated approach mitigates progressive failure under extreme hydrological cycles.